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1/48 pc755b/745b september 2000 powerpc755b/745b risc micropro- cessor features 18.1specint95, estimates 12.3 specfp95 @400mhz (pc755b) 15.7specint95, 9specfp95 @350mhz (pc745b) 733 mips @ 400mhz (pc755b) et 641 mips@350mhz (pc745b) selectable bus clock (12 cpu bus dividers up to 10x) p d typical 6,4w @ 400mhz, full operating conditions. nap, doze and sleep modes for power savings superscalar (3 instructions per clock cycle) (two instruction + branch) 4 petabyte virtual memory, 4 gigabytes of physical memory. 64-bit data and 32-bit address bus interface. 32kb instruction and data cache. six independent execution units. write-back and write-through operations. f int max = 400mhz (tbc) f bus max = 100mhz voltage i/o 1,8v/3,3v ; voltage int 2.0 v description pc755b and pc745b powerpc microprocessors are high-performance, low-power, 32-bit implementations of the powerpc reduced instruction set computer (risc) architecture, spe- cially enhanced for embedded applications. pc755b and pc745b microprocessors differ only in that the pc755b features an enhanced, dedicated l2 cache interface with on-chip l2 tags. the pc755b is a drop-in replacement fo r the award winning powerpc 750 tm microprocessor and is footprint and user software code compat- ible with the mpc7400 microprocessor withaltivec tm technology. the pc745b is a drop-in replacement for the powerpc 740 tm microprocessor and is also footprint and user soltware code compatible with the powerpc 603e tm microprocessor. pc755b/745b microprocessors provide on-chip debug support and are fully jtag-compliant. the pc745b microprocessor is pin compatible with the tspc603e family. screening this product is manufactured in full compliance with : cbga upscreenings based upon atmel-grenoble standards full military temperature range (tj=-55 o c,+125 o c) industrial temperature range (tj=-40 o c,+110 o c) pbga255 flip-chip plastic ball grid array zf suffix preliminary specification a -site pbga360 flip-chip plastic ball grid array zf suffix
2/48 pc755b/745b summary 1. simplified block diagram 3 . . . . . . . . . . . . . . . . . . . 1.1. general parameters 4 . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2. features 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. pin assignements 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1. pinout listings 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.1. pinout listing for the pc745b, 255 pbga 9 . . . . . . . 2.1.2. pinout listing for the pc755b, 360p pbga package. 11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2. signal description 15 . . . . . . . . . . . . . . . . . . . . . . . . . .
1. scope 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. applicable documents 16 . . . . . . . . . . . . . . . . . . . . . 3. requirements 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. general 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. design and construction 16 . . . . . . . . . . . . . . . . . . . . 3.2.1. terminal connections 16 . . . . . . . . . . . . . . . . . . . . . . 3.2.2. absolute maximum rating 16 . . . . . . . . . . . . . . . . . . . 3.3. recommendated operating conditions 18 . . . . . . . 3.4. thermal characteristics 18 . . . . . . . . . . . . . . . . . . . . . 3.4.1. package characteristics 18 . . . . . . . . . . . . . . . . . . . . . 3.4.2. thermal management assistance 19 . . . . . . . . . . . . 3.4.3. thermal management information 20 . . . . . . . . . . . . 3.5. power consideration 22 . . . . . . . . . . . . . . . . . . . . . . . . 3.5.1. power management 22 . . . . . . . . . . . . . . . . . . . . . . . . 3.5.2. power dissipation 23 . . . . . . . . . . . . . . . . . . . . . . . . . . 4. electrical characteristics 24 . . . . . . . . . . . . . . . 4.1. static characteristics 24 . . . . . . . . . . . . . . . . . . . . . . . 4.2. dynamic characteristics 25 . . . . . . . . . . . . . . . . . . . . . 4.2.1. clock ac specifications 25 . . . . . . . . . . . . . . . . . . . . . 4.2.2. processor bus ac specifications 26 . . . . . . . . . . . . . 4.2.3. l2 clock ac specifications 28 . . . . . . . . . . . . . . . . . . 4.2.4. l2 bus input ac specifications 31 . . . . . . . . . . . . . . 4.2.5. ieee 1149.1 ac timing specifications 33 . . . . . . . . 5. preparation for delivery 37 . . . . . . . . . . . . . . . . . . 5.1. packaging 37 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2. certificate of compliance 37 . . . . . . . . . . . . . . . . . . . . 6. handling 37 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. package mechanical data 38 . . . . . . . . . . . . . . . . . . 7.1. parameters for the pc745b 38 . . . . . . . . . . . . . . . . . . 7.1.1. package parameters for the pc745b pbga 38 . . . 7.1.2. mechanical dimensions of the pc745b pbga package 39 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2. parameters for the pc755b pbga 40 . . . . . . . . . . . . 7.2.1. package parameter for the pc755b pbga 40 . . . . 7.2.2. mechanical dimensions of the pc755b pbga 40 . 8. clock relationships choice 41 . . . . . . . . . . . . . . . 9. system design information 43 . . . . . . . . . . . . . . . . . 9.1. pll power supply filtering 43 . . . . . . . . . . . . . . . . . . 9.2. power supply voltage sequencing 43 . . . . . . . . . . . 9.3. decoupling recommendations 43 . . . . . . . . . . . . . . 9.4. connection recommendations 44 . . . . . . . . . . . . . . 9.5. output buffer dc impedance 44 . . . . . . . . . . . . . . . . 9.6. pull-up resistor requirements 45 . . . . . . . . . . . . . . 10. definitions 46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11. differences with commercial part 46 . . . . . . . 12. ordering information 47 . . . . . . . . . . . . . . . . . . . . .
pc755b/745b 3/48 a. general description 1. simplified block diagram the pc755b is targeted for low power systems and supports the following power management features-doze, nap, sleep, and dynamic power management. the pc755b consists of a processor core and an internal l2 tag combined with a dedicated l2 cache interface and a 60x bus. completion instruction fetch control unit 32k icache bht/btic dispatch system unit branch unit fxu1 fxu2 gprs rename buffers lsu fpu 32k dcache l2 tags l2 cache biu fprs rename buffers 60x biu not in the pc745b figure 1 : pc755b block diagram
4/48 pc755b/745b 1.1. general parameters the following list provides a summary of the general parameters of the pc755b: technology 0.22 m cmos, six-layer metal die size 6.61 mm x 7.73 mm (51 mm 2 ) transistor count 6.75 million logic design fully-staticpackages pc745b: surface mount 255 plastic ball grid array (pbga) pc755b: surface mount 360 plastic ball grid array (pbga) core power supply: 2.0v 100 mv dc (nominal; see table 5 for recommended operating conditions) i/o power supply 1.8v 100 mv dc or 2.0v 100 mv dc or 3.3v 165mv dc (input thresholds are configuration pin selectable) 1.2. features this section summarizes features of the pc755b's implementation of the powerpc architecture. major features of the pc755b are a s follows: branch processing unit - four instructions fetched per clock - one branch processed per cycle (plus resolving 2 speculations) - up to 1 speculative stream in execution, 1 additional speculative stream in fetch - 512-entry branch history table (bht) for dynamic prediction - 64-entry, 4-way set associative branch target instruction cache (btic) for eliminating branch delay slots dispatch unit - full hardware detection of dependencies (resolved in the execution units) - dispatch two instructions to six independent units (system, branch, load/store, fixed-point unit 1, fixed-point unit 2, floati ng- point) - serialization control (predispatch, postdispatch, execution serialization) decode - register file access - forwarding control - partial instruction decode completion - 6 entry completion buffer - instruction tracking and peak completion of two instructions per cycle - completion of instructions in program order while supporting out-of- order instruction execution, completion serialization and all instruction flow changes fixed point units (fxus) that share 32 gprs for integer operands - fixed point unit 1 (fxu1)-multiply, divide, shift, rotate, arithmetic, logical - fixed point unit 2 (fxu2)-shift, rotate, arithmetic, logical - single-cycle arithmetic, shifts, rotates, logical - multiply and divide support (multi-cycle) - early out multiply
pc755b/745b 5/48 floating-point unit and a 32-entry fpr file - support for ieee-754 standard single and double precision floating point arithmetic - hardware support for divide - hardware support for denormalized numbers - single-entry reservation station - supports non-ieee mode for time-critical operations system unit - executes cr logical instructions and miscellaneous system instructions - special register transfer instructions load/store unit - one cycle load or store cache access (byte, half-word, word, double-word) - effective address generation - hits under misses (one outstanding miss) - single-cycle unaligned access within double word boundary - alignment, zero padding, sign extend for integer register file - floating point internal format conversion (alignment, normalization) - sequencing for load/store multiples and string operations - store gathering - cache and tlb instructions - big and little-endian byte addressing supported - misaligned little-endian supported level 1 cache structure - 32k, 32-byte line, 8-way set associative instruction cache (il1) - 32k, 32-byte line, 8-way set associative data cache (dl1) - cache locking for both instruction and data caches, selectable by group of ways - single-cycle cache access - pseudo least-recently used (plru) replacement - copy-back or write through data cache (on a page per page basis) - supports all powerpc memory coherency modes - non-blocking instruction and data cache (one outstanding miss under hits) - no snooping of instruction cache level 2 (l2) cache interface (not implemented on pc745b) - internal l2 cache controller and tags; external data srams - 256k, 512k, and 1mbyte 2-way set associative l2 cache support - copyback or write-through data cache (on a page basis, or for all l2) - instruction-only mode and data-only mode. - 64byte (256k/512k) or 128byte (1m) sectored line size - supports flow through (register-buffer) synchronous burst srams, pipelined (register-register) synchronous burst srams (3-1-1-1 or strobeless 4-1-1-1) and pipelined (register-register) late-write synchronous burst srams - l2 configurable to direct mapped sram interface or split cache/direct mapped or private memory - core-to-l2 frequency divisors of 1, 1.5, 2, 2.5, and 3 supported - 64 bit data bus - selectable interface voltages of 1.8v/2.0v and 3.3v - parity checking on both l2 address and data
6/48 pc755b/745b memory management unit - 128 entry, 2-way set associative instruction tlb - 128 entry, 2-way set associative data tlb - hardware reload for tlbs - hardware or optional software tablewalk support - 8 instruction bats and 8 data bats - 8 sprgs, for assistance with software tablewalks - virtual memory support for up to 4 exabytes (2 52 ) of virtual memory - real memory support for up to 4 gigabytes (2 32 ) of physical memory bus interface - compatible with 60x processor interface - 32-bit address bus - 64-bit data bus, 32-bit mode selectable - bus-to-core frequency multipliers of 2x, 3x, 3.5x, 4x, 4.5x, 5x, 5.5x, 6x, 6.5x, 7x, 7.5x, 8x, 10x supported - selectable interface voltages of 3.3v and 1.8v/2.0v. low voltage selection allows compatibility with either the 2.0v vdd suppl y or with 1.8v supplies needed for peripheral devices. - parity checking on both address and data busses power management - low-power design with thermal requirements very similar to pc740/750. - selectable interface voltage of 1.8v/2.0v can reduce power in output buffers (compared to 3.3v) - three static power saving modes: doze, nap, and sleep - dynamic power management testability - lssd scan design - ieee 1149.1 jtag interface integrated thermal management assit unit - one -ship thermal sensor and control logic - thermal management interrrup for software regulation of junction temperature
pc755b/745b 7/48 2. pin assignements figure 2 (in part a) shows the pinout of the pc745b, 255pbga package as viewed from the top surface. part b shows the side prof ile of the pbga package to indicate the direction of the top surface view. part a pinout of the pc745b, 255 pbga package as viewed from the top surface a b c d e f g h j k l m n p r t 12 3 4 5 678 910111213141516 not to scale ?????????????? view die substrate assembly encapsulant part b figure 2 : pinout of the pc745b, 255 pbga package as viewed from the top surface
8/48 pc755b/745b figure 3 (in part a) shows the pinout of the pc755b, 360 pbga packages as viewed from the top surface. part b shows the side profile of the pbga package to indicate the direction of the top surface view. part a a b c d e f g h j k l m n p r t 12 3 4 5 678 910111213141516 not to scale 17 18 19 u v w ?????????????? view die substrate assembly encapsulant part b figure 3 : pinout of the pc755b, 360 pbga packages as viewed from the top surface
pc755b/745b 9/48 2.1. pinout listings 2.1.1. pinout listing for the pc745b, 255 pbga table 1 provides the pinout listing for the pc745b, 255 pbga package. table 1. pinout listing for the pc745b, 255 pbga package i/f voltages supported1 signal name pin number active i/o 1.8v/2.0v 3.3v notes a[031] c16, e4, d13, f2, d14, g1, d15, e2, d16, d4, e13, g2, e15, h1, e16, h2, f13, j1, f14, j2, f15, h3, f16, f4, g13, k1, g15, k2, h16, m1, j15, p1 high i/o e e aack l2 low input e e abb k4 low i/o e e ap[03] c1, b4, b3, b2 high i/o e e artry j4 low i/o e e avdd a10 e e 2.0v 2.0v bg l1 low input e e br b6 low output e e bvsel b1 high input gnd 3.3v 3, 4, 5 ci e1 low output e e ckstp_in d8 low input e e ckstp_out a6 low output e e clk_out d7 e output e e dbb j14 low i/o e e dbg n1 low input e e dbdis h15 low input e e dbwo g4 low input e e dh[031] p14, t16, r15, t15, r13, r12, p11, n11, r11, t12, t11, r10, p9, n9, t10, r9, t9, p8, n8, r8, t8, n7, r7, t7, p6, n6, r6, t6, r5, n5, t5, t4 high i/o e e dl[031] k13, k15, k16, l16, l15, l13, l14, m16, m15, m13, n16, n15, n13, n14, p16, p15, r16, r14, t14, n10, p13, n12, t13, p3, n3, n4, r3, t1, t2, p4, t3, r4 high i/o e e dp[07] m2, l3, n2, l4, r1, p2, m4, r2 high i/o e e drtry g16 low input e e gbl f1 low i/o e e
10/48 pc755b/745b table 1. pinout listing for the pc745b, 255 pbga package signal name notes 3.3v 1.8v/2.0v i/o active pin number gnd c5, c12, e3, e6, e8, e9, e11, e14, f5, f7, f10, f12, g6, g8, g9, g11, h5, h7, h10, h12, j5, j7, j10, j12, k6, k8, k9, k11, l5, l7, l10, l12, m3, m6, m8, m9, m11, m14, p5, p12 e e gnd gnd hreset a7 low input e e int b15 low input e e l1_tstclk d11 high input e e 2 l2_tstclk d12 high input e e 2 lssd_mode b10 low input e e 2 mcp c13 low input e e nc (noconnect) b7, b8, c3, c6, c8, d5, d6, h4, j16, a4, a5, a2, a3, b5 e e e e ovdd c7, e5, e7, e10, e12, g3, g5, g12, g14, k3, k5, k12, k14, m5, m7, m10, m12, p7, p10 e e 1.8v/2.0v 3.3v pll_cfg[03] a8, b9, a9, d9 high input e e qack d3 low input e e qreq j3 low output e e rsrv d1 low output e e smi a16 low input e e sreset b14 low input e e sysclk c9 e input e e ta h14 low input e e tben c2 high input e e tbst a14 low i/o e e tck c11 high input e e tdi a11 high input e e 5 tdo a12 high output e e tea h13 low input e e tlbisync c4 low input e e tms b11 high input e e 5 trst c10 low input e e 5 ts j13 low i/o e e tsiz[02] a13, d10, b12 high output e e
pc755b/745b 11/48 table 1. pinout listing for the pc745b, 255 pbga package signal name notes 3.3v 1.8v/2.0v i/o active pin number tt[04] b13, a15, b16, c14, c15 high i/o e e wt d2 low output e e vdd 2 f6, f8, f9, f11, g7, g10, h6, h8, h9, h11, j6, j8, j9, j11, k7, k10, l6, l8, l9, l11 e e 2.0v 2.0v voltdet f3 high output e e 6 notes: 1. ovdd supplies power to the processor bus, jtag, and all control signals and vdd supplies power to the processor core and the pll (after filtering to become avdd). these columns serve as a reference for the nominal voltage supported on a given signal as selected by the bvsel pin configuration of table 4 and the voltage supplied. for actual recom- mended value of vin or supply voltages see table 3. 2. these are test signals for factory use only and must be pulled up to ovdd for normal machine operation. 3. to allow for future i/o voltage changes, provide the option to connect bvsel independently to either ovdd (selects 3.3v) or to ognd (selects 1.8v/2.0v). 4. uses one of 15 existing no-connects in pc745's 255-bga package. 5. internal pull up on die. 6. internally tied to gnd in the pc745b 255-bga package to indicate to the power supply that a low-voltage processor is present. this signal is not a power supply input. 2.1.2. pinout listing for the pc755b, 360p pbga package. table 2 provides the pinout listing for the pc755b, 360 pbga. table 2. pinout listing for the pc755b, 360 pbga package i/f voltages supported1 signal name pin number active i/o 1.8v/2.0v 3.3v notes a[031] a13, d2, h11, c1, b13, f2, c13, e5, d13, g7, f12, g3, g6, h2, e2, l3, g5, l4, g4, j4, h7, e1, g2, f3, j7, m3, h3, j2, j6, k3, k2, l2 high i/o e e aack n3 low input e e abb l7 low i/o e e ap[03] c4, c5, c6, c7 high i/o e e artry l6 low i/o e e avdd a8 e e 2.0v 2.0v bg h1 low input e e br e7 low output e e bvsel w1 high input gnd 3.3v 3, 5, 6 ci c2 low output e e ckstp_in b8 low input e e
12/48 pc755b/745b table 2. pinout listing for the pc755b, 360 pbga package signal name notes 3.3v 1.8v/2.0v i/o active pin number ckstp_out d7 low output e e clk_out e3 e output e e dbb k5 low i/o e e dbdis g1 low input e e dbg k1 low input e e dbwo d1 low input e e dh[031] w12, w11, v11, t9, w10, u9, u10, m11, m9, p8, w7, p9, w9, r10, w6, v7, v6, u8, v9, t7, u7, r7, u6, w5, u5, w4, p7, v5, v4, w3, u4, r5 high i/o e e dl[0-31] m6, p3, n4, n5, r3, m7, t2, n6, u2, n7, p11, v13, u12, p12, t13, w13, u13, v10, w8, t11, u11, v12, v8, t1, p1, v1, u1, n1, r2, v3, u3, w2 high i/o e e dp[07] l1, p2, m2, v2, m1, n2, t3, r1 high i/o e e drtry h6 low input e e gbl b1 low i/o e e gnd d10, d14, d16, d4, d6, e12, e8, f4, f6, f10, f14, f16, g9, g11, h5, h8, h10, h12, h15, j9, j11, k4, k6, k8, k10, k12, k14, k16, l9, l11, m5, m8, m10, m12, m15, n9, n11, p4, p6, p10, p14, p16, r8, r12, t4, t6, t10, t14, t16 e e gnd gnd hreset b6 low input e e int c11 low input e e l1_tstclk f8 high input e e 2 l2addr[016] l17, l18, l19, m19, k18, k17, k15, j19, j18, j17, j16, h18, h17, j14, j13, h19, g18 high output e e l2avdd l13 e e 2.0v 2.0v l2ce p17 low output e e l2clkouta n15 e output e e l2clkoutb l16 e output e e
pc755b/745b 13/48 table 2. pinout listing for the pc755b, 360 pbga package signal name notes 3.3v 1.8v/2.0v i/o active pin number l2data[063] u14, r13, w14, w15, v15, u15, w16, v16, w17, v17, u17, w18, v18, u18, v19, u19, t18, t17, r19, r18, r17, r15, p19, p18, p13, n14, n13, n19, n17, m17, m13, m18, h13, g19, g16, g15, g14, g13, f19, f18, f13, e19, e18, e17, e15, d19, d18, d17, c18, c17, b19, b18, b17, a18, a17, a16, b16, c16, a14, a15, c15, b14, c14, e13 high i/o e e l2dp[07] v14, u16, t19, n18, h14, f17, c19, b15 high i/o e e l2ovdd d15, e14, e16, h16, j15, l15, m16, p15, r14, r16, t15, f15 e e 1.8v/2.0v 3.3v l2sync_in l14 e input e e l2sync_out m14 e output e e l2_tstclk f7 high input e e 2 l2vsel a19 high input gnd 3.3v 1, 3, 5, 6 l2we n16 low output e e l2zz g17 high output e e lssd_mode f9 low input e e 2 mcp b11 low input e e nc (no-connect) b3, b4, b5, w19, k9, k11 4 , k19 4 e e e e ovdd d5, d8, d12, e4, e6, e9, e11, f5, h4, j5, l5, m4, p5, r4, r6, r9, r11, t5, t8, t12 e e 1.8v/2.0v 3.3v pll_cfg[03] a4, a5, a6, a7 high input e e qack b2 low input e e qreq j3 low output e e rsrv d3 low output e e smi a12 low input e e sreset e10 low input e e sysclk h9 e input e e ta f1 low input e e tben a2 high input e e tbst a11 low i/o e e tck b10 high input e e
14/48 pc755b/745b table 2. pinout listing for the pc755b, 360 pbga package signal name notes 3.3v 1.8v/2.0v i/o active pin number tdi b7 high input e e 6 tdo d9 high output e e tea j1 low input e e tlbisync a3 low input e e tms c8 high input e e 6 trst a10 low input e e 6 ts k7 low i/o e e tsiz[02] a9, b9, c9 high output e e tt[04] c10, d11, b12, c12, f11 high i/o e e wt c3 low output e e vdd g8, g10, g12, j8, j10, j12, l8, l10, l12, n8, n10, n12 e e 2.0v 2.0v voltdet k13 high output e e 7 notes: 1. ovdd supplies power to the processor bus, jtag, and all control signals except the l2 cache controls (l2ce , l2we , and l2zz ); l2ovdd supplies power to the l2 cache interface (l2addr[0-16], l2data[0-63], l2dp[0-7] and l2sync-out) and the l2 control signals; and vdd supplies power to the processor core and the pll and dll (after filtering to become avdd and l2avdd respectively). these columns serve as a reference for the nominal voltage sup- ported on a given signal as selected by the bvsel/l2vsel pin configurations of table 4 and the voltage supplied. for actual recommended value of vin or supply voltages see table 5. 2. these are test signals for factory use only and must be pulled up to ovdd for normal machine operation. 3. to allow for future i/o voltage changes, provide the option to connect bvsel and l2vsel independently to either ovdd (selects 3.3v) or to ognd (selects 1.8v/2.0v). 4. these pins are reserved for potential future use as additional l2 address pins. 5. uses one of 9 existing no-connects in pc750's 360-bga package. 6. internal pull up on die. 7. internally tied to l2ovdd in the pc755b 360-bga package to indicate the power present at the l2 cache interface. this signal is not a power supply input. caution: this is different from the pc745b 255-bga package.
pc755b/745b 15/48 2.2. signal description br bg abb ts tt[0-4] ap[0-3] tbst ts1z[0-2] gbl wt ci aack artry dbg dbwo dbb l2addr 16-0 l2data 0-63 l2dp 0-7 l2clk-out a-b l2we a[0-31] l2sync_out l2sync_in int smi mcp hreset ckstp_in ckstp_out sysclk, pll_cfg 0-3 4 17 64 8 factory test jtag:cop address arbitration address start address bus transfer attribute address termination data arbitration l2 cache address/ data l2 cache clock/control interrupts reset clock control test interface 1 1 2 1 1 1 1 1 1 5 3 1 1 1 1 1 1 32 4 5 3 1 1 1 1 1 1 1 d 0-63 64 data transfer dp 0-7 8 dbdis 1 ta data termination drtry tea 1 1 1 pc755b l2av dd l2v dd sreset 1 1 rsrv tben tlbisync qreq qack processor status control clk_out 1 1 1 1 1 1 1 1 v dd ov dd av dd l2ce l2zz not supported in the pc745b 1 bvsel l2vsel 1 voltdet gnd figure 4 : pc755b microprocessor signal groups
16/48 pc755b/745b b. detailed specification 1. scope this drawing describes the specific requirements for the microprocessor pc755b, in compliance with atmel grenoble standard screening. 2. applicable documents 1) mil-std-883 : test methods and procedures for electronics. 2) mil-prf-38535 appendix a : general specifications for microcircuits. 3. requirements 3.1. general the microcircuits are in accordance with the applicable documents and as specified herein. 3.2. design and construction 3.2.1. terminal connections depending on the package, the terminal connections is shown in table 1, table 2 and figure 4. 3.2.2. absolute maximum rating table 3. absolute maximum ratings characteristic symbol maximum value unit note core supply voltage vdd 0.3 to 2.5 v 4 pll supply voltage avdd 0.3 to 2.5 v 4 l2 dll supply voltage l2avdd 0.3 to 2.5 v 4 processor bus supply voltage ovdd 0.3 to 3.465 v 3 l2 bus supply voltage l2ovdd 0.3 to 3.465 v 3 input voltage processor bus v in 0.3 to ovdd + 0.3v v 2,5 l2 bus v in 0.3 to l2ovdd + 0.3v v 2,5 jtag signals v in 0.3 to 3.6 v storage temperature range t stg 55 to 150 o c notes: 1. functional and tested operating conditions are given in table 4. absolute maximum ratings are stress ratings only, and functional operation at the maximums is not guaranteed. stresses beyond those listed may affect device reliabil- ity or cause permanent damage to the device. 2. caution: vin must not exceed ovdd or l2ovdd by more than 0.3v at any time including during power-on reset. 3. caution: l2ovdd/ovdd must not exceed vdd/avdd/l2avdd by more than 1.2v at any time including during pow- er-on reset. 4. caution: vdd/avdd/l2avdd must not exceed l2ovdd/ovdd by more than 0.4v at any time including during pow- er-on reset. 5. v in may overshoot/undershoot to a voltage and for a maximum duration as shown in figure 2.
pc755b/745b 17/48 figure 5 shows the allowable undershoot and overshoot voltage on the pc755b and pc745b (l2) ovdd +20% (l2) ovdd +5% (l2) ovdd gnd - 1.0v gnd - 0.3v gnd v ih not to exceed 10% of t sysclk v il figure 5 : overshoot/undershoot voltage the pc755b provides several i/o voltages to support both compatibility with existing systems and migration to future systems. t he pc755b core voltage must always be provided at nominal 2.0v (see table 5 for actual recommended core voltage). voltage to the l2 i/os and processor interface i/os are provided through separate sets of supply pins and may be provided at the voltages shown i n table 4. the input voltage threshold for each bus is selected by sampling the state of the voltage select pins bvsel and l2vsel during operation. these signals must remain stable during part operation and cannot change. the output voltage will swing from gnd to the maximum voltage applied to the ovdd or l2ovdd power pins. table 4 describes the input threshold voltage setting . table 4. input threshold voltage setting bvsel signal l2vsel signal processor bus interface voltage l2 bus interface voltage 0 0 1.8v or 2.0v 1.8v or 2.0v 0 1 1.8v or 2.0v 3.3v 1 0 3.3v 1.8v or 2.0v 1 1 3.3v 3.3v note caution: the input threshold selection must agree with the ovdd/l2ovdd voltages supplied.
18/48 pc755b/745b 3.3. recommendated operating conditions table 5. recommended operating conditions characteristic symbol recommended value unit core supply voltage vdd 2.0v 100mv v pll supply voltage avdd 2.0v 100mv v l2 dll supply voltage l2avdd 2.0v 100mv v processor bus supply voltage bvsel = 0 ovdd 1.8v 100mv or 2.0 100mv v bvsel = 1 ovdd 3.3v 165mv v l2 bus supply voltage l2vsel = 0 l2ovdd 1.8v 100mv or 2.0 100mv v l2vsel = 1 l2ovdd 3.3v 165mv v input voltage processor bus v in gnd to ovdd v l2 bus v in gnd to l2ovdd v jtag signals v in gnd to ovdd v die-junction temperature t j -55 to 125 o c note : these are the recommended and tested operating conditions. proper device operation outside of these conditions is not guaranteed. 3.4. thermal characteristics 3.4.1. package characteristics table 6 provides the package thermal characteristics for the pc755b. table 6. package thermal characteristics characteristic symbol value rating pbga package thermal resistance, junction-to-case thermal resistance (typical) q jc 0.03 c/w pbga package thermal resistance, die junction-to-lead thermal resistance (typical) q jb 12 c/w pbga package typical thermal resistance, die junction-to-ambient resistance (convection only on 2s2p board) q ja 33 c/w pbga package thermal resistance, die junction-to-ambient resistance (100 ft/min airflow on 2s2p board) q ja 30 c/w note: r efer to section 3.4.3. , athermal management information,o for more details about thermal management. the board designer can choose between several types of heat sinks to place on the pc755b. there are several commercially-avail- able heat sinks for the pc755b provided by the following vendors: for the exposed-die packaging technology, shown in table 5, the intrinsic conduction thermal resistance paths are as follows : the die junction-to-case (or top-of-die for exposed silicon) thermal resistance the die junction-to-ball thermal resistance figure 6 depicts the primary heat transfer path for a package with an attached heat sink mounted to a printed-circuit board. heat generated on the active side of the chip is conducted through the silicon, then through the heat sink attach material (or thermal interface material), and finally to the heat sink where it is removed by forced-air convection.
pc755b/745b 19/48 since the silicon thermal resistance is quite small, for a first-order analysis, the temperature drop in the silicon may be neg lected. thus, the heat sink attach material and the heat sink conduction/convective thermal resistances are the dominant terms. external resistance external resistance internal resistance (note the internal versus external package resistance) radiation convection radiation convection heat sink printedcircuit board thermal interface material package/leads die junction die/package figure 6 : c4 package with heat sink mounted to a printed-circuit board 3.4.2. thermal management assistance the pc755b incorporates a thermal management assist unit (tau) composed of a thermal sensor, digital-to-analog converter, comparator, control logic, and dedicated special-purpose registers (sprs). specifications for the thermal sensor portion of th e tau are found in table 7. more information on the use of this feature is given in the motorola pc755b risc microprocessor user's m anual. table 7. thermal sensor specifications at recommended operating conditions (see table 5) characteristic min max unit notes temperature range 0 127 o c 1 comparator settling time 20 e s 2,3 resolution 4 e o c 3 accuracy -12 +12 o c 3 notes: 1. the temperature is the junction temperature of the die. the thermal assist unit's raw output does not indicate an absolute temperature, but must be interpreted by software to derive the absolute junction temperature. for infor- mation about the use and calibration of the tau, see motorola application note an1800/d, aprogramming the thermal assist unit in the pc750 microprocessoro. 2. the comparator settling time value must be converted into the number of cpu clocks that need to be written into the thrm3 spr. 3. guaranteed by design and characterization.
20/48 pc755b/745b 3.4.3. thermal management information this section provides thermal management information for the ceramic ball grid array (bga) package for air-cooled applications. proper thermal control design is primarily dependent upon the system-level design-the heat sink, airflow and thermal interface mate- rial. to reduce the die-junction temperature, heat sinks may be attached to the package by several methodsadhesive, spring cli p to holes in the printed-circuit board or package, and mounting clip and screw assembly; see figure 7. this spring force should not exceed 5.5 pounds of force. adhesive or thermal interface material heat sink heat sink clip printedcircuit board option bga package figure 7 : package exploded cross-sectional view with several heat sink options ultimately, the final selection of an appropriate heat sink depends on many factors, such as thermal performance at a given air veloc- ity, spatial volume, mass, attachment method, assembly, and cost. 3.4.3.1. adhesives and thermal interface materials 0 0.5 1 1.5 2 0 1020304050607080 silicone sheet (0.006 inch) bare joint floroether oil sheet (0.007 inch) graphite/oil sheet (0.005 inch) synthetic grease contact pressure (psi) specific thermal resistance (kin2/w) figure 8 : thermal performance of select thermal interface material
pc755b/745b 21/48 a thermal interface material is recommended at the package lid-to-heat sink interface to minimize the thermal contact resistanc e. for those applications where the heat sink is attached by spring clip mechanism, figure 8 shows the thermal performance of three t hin- sheet thermal-interface materials (silicone, graphite/oil, floroether oil), a bare joint, and a joint with thermal grease as a function of contact pressure. as shown, the performance of these thermal interface materials improves with increasing contact pressure. the use of thermal grease significantly reduces the interface thermal resistance. that is, the bare joint results in a thermal resi stance approximately 7 times greater than the thermal grease joint. heat sinks are attached to the package by means of a spring clip to holes in the printed-circuit board (see figure 7 ). this s pring force should not exceed 5.5 pounds of force. therefore, the synthetic grease offers the best thermal performance, considering the low interface pressure. the board designer can choose between several types of thermal interface. heat sink adhesive materials should be selected based upon high conductivity, yet adequate mechanical strength to meet equipment shock/vibration requirements. 3.4.3.2. heat sink selection example for preliminary heat sink sizing, the die-junction temperature can be expressed as follows: t j = t a + t r + ( q jc + q int + q sa ) * p d where : t j is the die-junction temperature t a is the inlet cabinet ambient temperature t r is the air temperature rise within the computer cabinet q jc is the junction-to-case thermal resistance q int is the adhesive or interface material thermal resistance q sa is the heat sink base-to-ambient thermal resistance p d is the power dissipated by the device during operation the die-junction temperatures (t j ) should be maintained less than the value specified in table 5. the temperature of the air cooling the component greatly depends upon the ambient inlet air temperature and the air temperature rise within the el ectronic cabinet. an electronic cabinet inlet-air temperature (t a ) may range from 30 to 40 o c. the air temperature rise within a cabinet (t r ) may be in the range of 5 to 10 o c. the thermal resistance of the thermal interface material ( q int ) is typically about 1 c/w. assuming a t a of 30 o c, a t r of 5 o c, a cbga package q jc = 0.03, and a power consumption (p d ) of 5.0 watts, the following expression for t j is obtained: die-junction temperature: t j = 30 o c + 5 o c + (0.03 o c/w + 1.0 o c/w + q sa ) * 5.0 w for a thermalloy heat sink #2328b, the heat sink-to-ambient thermal resistance ( q sa ) versus airflow velocity is shown in figure 9. 1 3 5 7 8 0 0.5 1 1.5 2 2.5 3 3.5 thermalloy #2328b pinfin heat sink approach air velocity (m/s) (25 x28 x 15 mm) 2 4 6 heat sink thermal resistance o c/w) figure 9 : thermalloy #2328b heat sink-to-ambient thermal resistance versus airflow velocity
22/48 pc755b/745b assuming an air velocity of 0.5 m/s, we have an effective r sa of 7 o c/w, thus t j = 30 o c+ 5 o c+ (0.03 o c/w +1.0 o c/w + 7 o c/w) * 5.0 w, resulting in a die-junction temperature of approximately 81 o c which is well within the maximum operating temperature of the compo- nent. other heat sinks offered by chip coolers, ierc, thermalloy, wakefield engineering, and aavid engineering offer different heat s ink- to-ambient thermal resistances, and may or may not need air flow. though the die junction-to-ambient and the heat sink-to-ambient thermal resistances are a common figure-of-merit used for compa r- ing the thermal performance of various microelectronic packaging technologies, one should exercise caution when only using this metric in determining thermal management because no single parameter can adequately describe three-dimensional heat flow. the final die-junction operating temperature, is not only a function of the component-level thermal resistance, but the system-leve l design and its operating conditions. in addition to the component's power consumption, a number of factors affect the final operating die-junc- tion temperatureeairflow, board population (local heat flux of adjacent components), heat sink efficiency, heat sink attach, he at sink placement, next-level interconnect technology, system air temperature rise, altitude, etc. due to the complexity and the many variations of system-level boundary conditions for today's microelectronic equipment, the co m- bined effects of the heat transfer mechanisms (radiation, convection and conduction) may vary widely. for these reasons, we rec om- mend using conjugate heat transfer models for the board, as well as, system-level designs. to expedite system-level thermal a naly- sis, several acompacto thermal-package models are available within flotherm ? . these are available upon request. 3.5. power consideration 3.5.1. power management the pc755b provides four power modes, selectable by setting the appropriate control bits in the msr and hido registers. the fou r power modes are as follows : full-power: this is the default power state of the pc755b. the pc755b is fully powered and the internal functional units are op erat- ing at the full processor clock speed. if the dynamic power management mode is enabled, functional units that are idle will aut omat- ically enter a low-power state without affecting performance, software execution, or external hardware. doze: all the functional units of the pc755b are disabled except for the time base/decrementer registers and the bus snooping logic. when the processor is in doze mode, an external asynchronous interrupt, a system management interrupt, a decrementer exception, a hard or soft reset, or machine check brings the pc755b into the full-power state. the pc755b in doze mode maintain s the pll in a fully powered state and locked to the system external clock input (sysclk) so a transition to the full-power state takes only a few processor clock cycles. nap: the nap mode further reduces power consumption by disabling bus snooping, leaving only the time base register and the pll in a powerred state. the pc755b returns to the full-power state upon receipt of an external asynchronous interrupt, a syste m management interrupt, a decrementer exception, a hard or soft reset, or a machine check input (mcp ). a return to full-power state from a nap state takes only a few processor clock cycles. when the processor is in nap mode, if qack is negated, the processor is put in doze mode to support snooping. sleep: sleep mode minimizes power consumption by disabling all internal functional units, after which external system logic may disable the ppl and susclk. returning the pc755b to the full-power state requires the enabling of the ppl and sysclk, fol- lowed by the assertion of an external asynchronous interrupt, a system management interrupt, a hard or soft reset, or a machine check input (mcp ) signal after the time required to relock the ppl.
pc755b/745b 23/48 3.5.2. power dissipation table 8. power consumption for pc755b processor (cpu) frequency unit notes 300mhz 350mhz 400mhz full-on mode typical 3.3 3.9 4.4 w 1, 3 maximum 4.9 5.7 6.4 w 1, 2 doze mode maximum 1.8 2.0 2.3 w 1, 2 nap mode maximum 500 510 530 mw 1, 2 sleep mode maximum 460 470 470 mw 1, 2 sleep modepll and dll disabled typical 340 340 340 mw 1, 3 maximum 430 430 430 mw 1, 2 notes: 1. these values apply for all valid processor bus and l2 bus ratios. the values do not include i/o supply power (ovdd and l2ovdd) or pll/dll supply power (avdd and l2avdd). ovdd and l2ovdd power is system dependent, but is typically <10% of vdd power. worst case power consumption for avdd = 15 mw and l2avdd = 15 mw. 2. maximum power is measured at vdd = 2.1v while running an entirely cache-resident, contrived sequence of instructions which keep the execution units maximally busy. 3. typical power is an average value measured at vdd = avdd = l2avdd = 2.0v, ovdd = l2ovdd = 3.3v in a system executing typical applications and benchmark sequences.
24/48 pc755b/745b 4. electrical characteristics 4.1. static characteristics table 9. dc electrical specifications at recommended operating conditions (see table 5) characteristic nominalb us voltage1 symbol min max unit notes input high voltage (all inputs except sysclk) 1.8/2.0 v ih 0.65 * (l2)ovdd (l2)ovdd + 0.15 v 2,3 3.3 v ih 2.0 (l2)ovdd + 0.3 v 2,3 input low voltage (all inputs except sysclk) 1.8/2.0 v il -0.3 0.35 * (l2)ovdd v 2 3.3 v il -0.3 0.8 v sysclk input high voltage 1.8/2.0 kv ih 1.5 ovdd + 0.3 v 3.3 kv ih 2.4 ovdd + 0.3 v sysclk input low voltage 1.8/2.0 kv il -0.3 0.2 v 3.3 kv il -0.3 0.4 v input leakage current, v in = l2ovdd/ovdd i in e 10 m a 2,3 hi-z (off-state) leakage current, v in = l2ovdd/ovdd i tsi e 10 m a 2,3,5 output high voltage, i oh = -6 ma 1.8/2.0 v oh (l2)ovdd - 0.45 e v 3.3 v oh 2.4 e v output low voltage, i ol = 6 ma 1.8/2.0 v ol e 0.45 v 3.3 v ol e 0.4 v capacitance, v in = 0 v, f = 1 mhz c in e 5.0 pf 3,4 notes: 1. nominal voltages; see table 5 for recommended operating conditions. 2. for processor bus signals, the reference is ovdd while l2ovdd is the reference for the l2 bus signals. 3. excludes test signals (lssd_mode, l1_tstclk, l2_tstclk) and ieee 1149.1 boundary scan (jtag) signals. 4. capacitance is periodically sampled rather than 100% tested. 5. the leakage is measured for nominal ovdd and vdd, or both ovdd and vdd must vary in the same direction (for example, both ovdd and vdd vary by either +5% or -5%).
pc755b/745b 25/48 4.2. dynamic characteristics after fabrication, parts are sorted by maximum processor core frequency as shown in section 4.2.1.,aclock ac specificationso an d tested for conformance to the ac specifications for that frequency. these specifications are for 275, 300, 333 mhz processor co re frequencies. the processor core frequency is determined by the bus (sysclk) frequency and the settings of the pll_cfg[03] signals. parts are sold by maximum processor core frequency. 4.2.1. clock ac specifications table 10 provides the clock ac timing specifications as defined in table 3. table 10. clock ac timing specifications at recommended operating conditions (see table 5) characteristic symbol maximum processor core frequency unit notes 300 mhz 350 mhz 400 mhz min max min max min max processor frequency f core 200 300 200 350 200 400 mhz 1 vco frequency f vco 400 600 400 700 400 800 mhz 1 sysclk frequency f sysclk 25 100 25 100 25 100 mhz 1 sysclk cycle time t sysclk 10 40 10 40 10 40 ns sysclk rise and fall time t kr & t kf e 2.0 e 2.0 e 2.0 ns 2 t kr & t kf e 1.0 e 1.0 e 1.0 ns 2 sysclk duty cycle measured at ovdd/2 t khkl /t sysc lk 40 60 40 60 40 60 % 3 sysclk jitter e 150 e 150 e 150 ps 3,4 internal pll relock time e 100 e 100 e 100 m s 3,5 notes: 1. caution: the sysclk frequency and pll_cfg[03] settings must be chosen such that the resulting sysclk (bus) frequency, cpu (core) frequency, and pll (vco) frequency do not exceed their respective maximum or minimum operating frequencies. refer to the pll_cfg[03] signal description in table 17,o for valid pll_cfg[03] settings 2. rise and fall times measurements are now specified in terms of slew rates, rather than time to account for selectable i/o bus interface levels. the minimum slew rate of 1v/ns is equivalent to a 2ns maximum rise/fall time measured at 0.4v and 2.4v or a rise/fall time of 1ns measured at 0.4v to 1.4v. 3. timing is guaranteed by design and characterization. 4. this represents total input jitter - short term and long term combined and is guaranteed by design. 5. relock timing is guaranteed by design and characterization. pll-relock time is the maximum amount of time required for pll lock after a stable vdd and sysclk are reached during the power-on reset sequence. this specifi- cation also applies when the pll has been disabled and subsequently re-enabled during sleep mode. also note that hreset must be held asserted for a minimum of 255 bus clocks after the pll-relock time during the power-on reset sequence.
26/48 pc755b/745b figure 10 provides the sysclk input timing diagram. sysclk vm vm vm kvih kvil vm = midpoint voltage (ovdd/2) tsysclk tkr tkf tkhkl figure 10 : sysclk input timing diagram 4.2.2. processor bus ac specifications table 11 provides the processor bus ac timing specifications for the pc755b as defined in figure 11 and figure 13 . timing s pecifi- cations for the l2 bus are provided in section 4.2.1., a l2 clock ac specifications. table 11. processor bus mode selection ac timing specifications 1 at vdd=avdd=2.0v 100mv; -55 tj +125 o c, ovdd = 3.3v 165mv and ovdd = 1.8v 100mv and ovdd = 2.0v100mv parameter symbols 2 300, 350, 400 mhz unit notes min max mode select input setup to hreset t mvrh 8 e t sysclk 3,4,5,6,7 hreset to mode select input hold t mxrh e ns 3,4,6,7,8 notes: 1. all input specifications are measured from the midpoint of the signal in question to the midpoint of the rising edge of the input sysclk. all output specifications are measured from the midpoint of the rising edge of sysclk to the mid- point of the signal in question. all output timings assume a purely resistive 50 ohm load (see figure 11). input and output timings are measured at the pin; time-of-flight delays must be added for trace lengths, vias, and connectors in the system. 2. he symbology used for timing specifications herein follows the pattern of t (signal )(state)(reference)(state) for inputs and t (reference)(state)(s ignal )(state) for outputs. for example, t ivkh symbolizes the time input signals (i) reach the valid state (v) relative to the sysclk reference (k) going to the high(h) state or input setup time. and t khov symbolizes the time from sysclk(k) going high(h) until outputs (o) are valid (v) or output valid time. input hold time can be read as the time that the input signal (i) went invalid (x) with respect to the rising clock edge (kh) - note the position of the reference and its state for inputs -and output hold time can be read as the time from the rising edge (kh) until the output went invalid (ox). for additional explanation of ac timing specifications in motorola powerpc microprocessors, see the application note aunderstanding ac timing specifications for powerpc microprocessors.o 3. the setup and hold time is with respect to the rising edge of hreset (see figure 11). 4. this specification is for configuration mode select only. also note that the hreset must be held asserted for a mini- mum of 255 bus clocks after the pll re-lock time during the power-on reset sequence. 5. t sysclk is the period of the external clock (sysclk) in nanoseconds (ns). the numbers given in the table must be multi- plied by the period of sysclk to compute the actual time duration (in nanoseconds) of the parameter in question. 6. mode select signals are bvsel, l2vsel, pll_cfg[0-3] 7. guaranteed by design and characterization. 8. bus mode select pins must remain stable during operation. changing the logic states of bvsel or l2vsel during operation will cause the bus mode voltage selection to change. changing the logic states of the pll_cfg pins during operation will cause the pll division ratio selection to change. both of these conditions are considered outside the specification and are not supported. once hreset is negated the states of the bus mode selection pins must remain stable.
pc755b/745b 27/48 figure 11 provides the mode select input timing diagram for the pc755b. hreset mode signals tmvrh tmxrh vm = midpoint voltage (ovdd/2) vm figure 11 : mode input timing diagram figure 12 provides the ac test load for the pc755b. output ovdd/2 rl = 5 w z0 = 50 w figure 12 : ac test load table 12. processor bus ac timing specifications at vdd=avdd=2.0v 100mv; -55 tj +125 o c, ovdd = 3.3v 165mv and ovdd = 1.8v 100mv and ovdd = 2.0v 100mv parameter symbols 300, 350, 400 mhz unit notes min max setup times: all inputs t ivkh 2.5 e ns input hold times: all inputs t ixkh 0.6 e ns valid times: all outputs t khov e 4.5 ns output hold times: all outputs t khox 1.0 e ns sysclk to output enable t khoe 0.5 e ns 4 sysclk to output high impedance (all except abb , artry , dbb) t khoz e 6.0 ns 4 sysclk to abb , dbb high impedance after precharge t khabpz e 1.0 t sysclk 1,2,4 maximum delay to artry precharge t kharp e 1 t sysclk 1,3,4 sysclk to artry high impedance after precharge t kharpz e 2 t sysclk 1,3,4 notes : 1. t sysclk is the period of the external clock (sysclk) in nanoseconds (ns). the numbers given in the table must be multiplied by the period of sysclk to compute the actual time duration (in nanoseconds) of the parameter in question. 2. per the 60x bus protocol, ts , abb and dbb are driven only by the currently active bus master. they are asserted low then pre- charged high before returning to high-z as shown in figure 13. the nominal precharge width for ts , abb or dbb is 0.5* t sysclk , i.e. less than the minimum t sysclk period, to ensure that another master asserting ts , abb , or dbb on the following clock will not contend with the precharge. output valid and output hold timing is tested for the signal asserted. output valid time is tested for pre- charge.the high-z behavior is guaranteed by design. 3. per the 60x bus protocol, artry can be driven by multiple bus masters through the clock period immediately following aack . bus contention is not an issue since any master asserting artry will be driving it low. any master asserting it low in the first clock follow- ing aack will then go to high-z for one clock before precharging it high during the second cycle after the assertion of aack . the nominal precharge width for artry is 1.0 t sysclk ; i.e. it should be high-z as shown in figure 12 before the first opportunity for another master to assert artry . output valid and output hold timing is tested for the signal asserted. output valid time is tested for prechar- ge.the high-z and precharge behavior is guaranteed by design. 4. guaranteed by design and characterization.
28/48 pc755b/745b figure 13 provides the input/output timing diagram for the pc755b. sysclk all inputs vm vm = midpoint voltage (ovdd/2 or vin/2) all outputs tkhox vm (except ts, abb, artry, dbb) ts,abb,dbb artry vm tkhoz tkhabpz tkharpz tkharp tkhov tkhox tkhov tkhov tkhov tkhox tkhov tivkh tkhoe tixkh tkhoz figure 13 : input/output timing diagram 4.2.3. l2 clock ac specifications the l2clk frequency is programmed by the l2 configuration register (l2cr[4:6]) core-to-l2 divisor ratio. see table 13 for exam ple core and l2 frequencies at various divisors. table 13 provides the potential range of l2clk output ac timing specifications as defined in figure 14. the minimum l2clk frequency of table 13 is specified by the maximum delay of the internal dll. the variable-tap dll introduces up to a full clock period delay in the l2clkouta, l2clkoutb, and l2sync_out signals so that the returning l2sync_in signal is phase aligned with the next core clock (divided by the l2 divisor ratio). do not choose a core-to-l2 divisor which results in a n l2 frequency below this minimum, or the l2clkout signals provided for sram clocking will not be phase aligned with the pc755b core clock at the srams. the maximum l2clk frequency shown in table 13 is the core frequency divided by one. very few l2 sram designs will be able to operate in this mode. most designs will select a greater core-to-l2 divisor to provide a longer l2clk period for read and write access to the l2 srams. the maximum l2clk frequency for any application of the pc755b will be a function of the ac timings of the pc755b, the ac timings for the sram, bus loading, and printed circuit board trace length. motorola is similarly limited by system constraints and cannot perform tests of the l2 interface on a socketed part on a functi onal tester at the maximum frequencies of table 13. therefore functional operation and ac timing information are tested at core-to-l2 divis ors of 2 or greater. functionality of core-to-l2 divisors of 1 or 1.5 is verified at less than maximum rated frequencies. l2 input and output signals are latched or enabled respectively by the internal l2clk (which is sysclk multiplied up to the cor e frequency and divided down to the l2clk frequency). in other words, the ac timings of table 14 and table 15 are entirely indepe n- dent of l2sync_in. in a closed loop system, where l2sync_in is driven through the board trace by l2sync_out, l2sync_in only controls the output phase of l2clkouta and l2clkoutb which are used to latch or enable data at the srams. however, since in a closed loop system l2sync_in is held in phase alignment with the internal l2clk, the signals of table 14 and table 15 are referenced to this signal rather than the not-externally-visible internal l2clk. during manufacturing test, these times are act ually measured relative to sysclk. the l2sync_out signal is intended to be routed halfway out to the srams and then returned to the l2sync_in input of the pc755b to synchronize l2clkout at the sram with the processor's internal clock. l2clkout at the sram can be offset forward or backward in time by shortening or lengthening the routing of l2sync_out to l2sync_in. see motorola application note an179/d apowerpc ? backside l2 timing analysis for the pcb design engineer.o the l2clkouta and l2clkoutb signals should not have more than two loads.
pc755b/745b 29/48 table 13. l2clk output ac timing specification at vdd=avdd=2.0v 100mv; -55 tj +125 o c, ovdd = 3.3v 165mv and ovdd = 1.8v 100mv and ovdd = 2.0v 100mv parameter symbol 300,350,400 mhz unit notes min max l2clk frequency f l2clk 80 400 mhz 1,4 l2clk cycle time t l2clk 2,5 12.5 ns l2clk duty cycle tchcl/tl2clk 50 % 2,7 internal dll-relock time 640 e l2clk 3,7 dll capture window 0 10 ns 5,7 l2clkout output-to-output skew t l2cskw 50 ps 6,7 l2clkout output jitter 150 ps 6,7 notes: 1. l2clk outputs are l2clk_outa, l2clk_outb, l2clk_out and l2sync_out pins. the l2clk frequency to core fre- quency settings must be chosen such that the resulting l2clk frequency and core frequency do not exceed their respective maximum or minimum operating frequencies. the maximum l2lck frequency will be system dependent. l2clk_outa and l2clk_outb must have equal loading. 2. the nominal duty cycle of the l2clk is 50% measured at midpoint voltage. 3. the dll re-lock time is specified in terms of l2clks. the number in the table must be multiplied by the period of l2clk to co m- pute the actual time duration in nanoseconds. re-lock timing is guaranteed by design and characterization. 4. the l2cr[l2sl] bit should be set for l2clk frequencies less than 110 mhz. this adds more delay to each tap of the dll. 5. allowable skew between l2sync_out and l2sync_in. 6. this output jitter number represents the maximum delay of one tap forward or one tap back from the current dll tap as the pha se comparator seeks to minimize the phase difference between l2sync_in and the internal l2clk. this number must be compre- hended in the l2 timing analysis. the input jitter on sysclk affects l2clkout and the l2 address/data/control signals equally and therefore is already comprehended in the ac timing and does not have to be considered in the l2 timing analysis. 7. guaranteed by design and characterization. the l2clk_out timing diagram is shown in figure 14.
30/48 pc755b/745b vm = midpoint voltage (l2ovdd/2) l2clk_outa l2clk_outb l2 differential clock mode l2 singleended clock mode l2sync_out tl2clk tchcl l2clk_outa vm tl2cr tl2cf vm vm vm l2clk_outb vm vm vm vm vm tl2clk tchcl l2sync_out vm vm vm vm vm vm vm vm tl2cskw figure 14 : l2clk_out output timing diagram
pc755b/745b 31/48 4.2.4. l2 bus input ac specifications table 14 provides the l2 bus interface ac timing specifications for the pc755b as defined in figure 15 and figure 16 for the loading conditions described in figure 17. table 14. l2 bus interface ac timing specifications at vdd=avdd=2.0v 100mv; -55 tj +125 o c, ovdd = 3.3v 165mv and ovdd = 1.8v 100mv and ovdd = 2.0v 100mv parameter symbol 300 mhz 350 mhz 400 mhz unit notes min max min max min max l2sync_in rise and fall time tl2cr& tl2cf e 1.0 e 1.0 e 1.0 ns 1 setup times: data and parity tdvl2ch 1.5 e 1.5 e 1.4 e ns 2 input hold times: data and parity tdxl2ch 0.5 e 0.5 e 0.5 e ns 2 valid times: all outputs when l2cr[14-15] = 00 all outputs when l2cr[14-15] = 01 all outputs when l2cr[14-15] = 10 all outputs when l2cr[14-15] = 11 tl2chov 3.6 3.8 4.0 4.2 3.6 3.8 4.0 4.2 3.6 3.8 4.0 4.2 ns 3,4 output hold times all outputs when l2cr[14-15] = 00 all outputs when l2cr[14-15] = 01 all outputs when l2cr[14-15] = 10 all outputs when l2cr[14-15] = 11 tl2chox 0.5 0.7 0.9 1.1 0.5 0.7 0.9 1.1 0.5 0.7 0.9 1.1 ns 3 l2sync_in to high impedance: all outputs when l2cr[14-15] = 00 all outputs when l2cr[14-15] = 01 all outputs when l2cr[14-15] = 10 all outputs when l2cr[14-15] = 11 tl2choz 3.5 4.0 4.2 4.5 3.5 4.0 4.2 4.5 3.5 4.0 4.2 4.5 ns 3,5 notes: 1. rise and fall times for the l2sync_in input are measured from 20% to 80% of l2ovdd. 2. all input specifications are measured from the midpoint of the signal in question to the midpoint voltage of the rising edge of the input l2sync_in (see figure 15). input timings are measured at the pins. 3. all output specifications are measured from the midpoint voltage of the rising edge of l2sync_in to the midpoint of the signa l in question. the output timings are measured at the pins. all output timings assume a purely resistive 50 ohm load (see figure 16 ). 4. he outputs are valid for both single-ended and differential l2clk modes. for pipelined registered synchronous burst rams, l2cr[1415] = 01 or 10 is recommended. for pipelined late-write synchronous burst srams, l2cr[1415] = 11 is recom- mended. 5. guaranteed by design and characterization.
32/48 pc755b/745b figure 15 shows the l2 bus input timing diagrams for the pc755b. l2sync_in l2 data and data vm vm = midpoint voltage (l2ovdd/2) tl2cr tl2cf parity inputs tdvl2ch tdxl2ch figure 15 : l2 bus input timing diagrams figure 16 shows the l2 bus output timing diagrams for the pc755b. l2sync_in all outputs vm vm = midpoint voltage (l2ovdd/2) vm l2data bus tl2chov tl2chox tl2choz figure 16 : l2 bus output timing diagrams figure 17 provides the ac test load for l2 interface of the pc755b. output l2ovdd/2 rl = 50 w z0 = 50 w figure 17 : ac test load for the l2 interface
pc755b/745b 33/48 4.2.5. ieee 1149.1 ac timing specifications 4.2.5.1. timing specifications table 15 provides the ieee 1149.1 (jtag) ac timing specifications as defined in figure 18, figure 19, figure 20, and figure 21. table 15. jtag ac timing specifications (independent of sysclk)1 at recommended operating conditions (see table 5 ) parameter symbol min max unit notes tck frequency of operation ftclk 0 33.3 mhz tck cycle time ttclk 30 e ns tck clock pulse width measured at 1.4v tjhjl 15 e ns tck rise and fall times tjr & tjf 0 2 ns trst assert time ttrst 25 e ns 2 input setup times: boundary-scan data tms, tdi tdvjh t ivjh 4 0 e e ns 3 input hold times: boundary-scan data tms, tdi tdxjh tixjh 15 12 e e ns 3 valid times: boundary-scan data tdo tjldv t jlov e e 4 4 ns 4 output hold times: boundary-scan data tdo tjldh tjloh 20 12 e e ns 4 tck to output high impedance: boundary-scan data tdo t jldz tjloz 3 3 19 9 ns 4,5 notes: 1. all outputs are measured from the midpoint voltage of the falling/rising edge of tclk to the midpoint of the signal in question. the output timings are measured at the pins. all output timings assume a purely resistive 50 ohm load (see figure 18 ). time-of-flight delays must be added for trace lengths, vias, and connectors in the system. 2. trst is an asynchronous level sensitive signal. the setup time is for test purposes only. 3. non-jtag signal input timing with respect to tck. 4. non-jtag signal output timing with respect to tck. 5. guaranteed by design and characterization. figure 18 provides the ac test load for tdo and the boundary-scan outputs of the pc755b. output ovdd/2 rl = 50 w z0 = 50 w figure 18 : alternate ac test load for the jtag interface
34/48 pc755b/745b figure 19 provides the jtag clock input timing diagram. tclk vm vm vm ttclk tjr tjf tjhjl vm = midpoiont voltage (0v dd /2) figure 19 : jtag clock input timing diagram figure 20 provides the trst timing diagram. trst ttrst vm = midpoint voltage (ovdd/2) vm vm figure 20 : trst timing diagram figure 21 provides the boundary-scan timing diagram. vm vm tck boundary boundary boundary data outputs data inputs data outputs vm = midpoint voltage (ovdd/2) tdxjh tdvjh tjldv tjldz input data valid output output data valid tjldh data valid figure 21 : boundary-scan timing diagram
pc755b/745b 35/48 figure 22 provides the test access port timing diagram. tck tdi, tms tdo vm = midpoint voltage (ovdd/2) tdo vm vm tixjh tivjh tjlov tjloz input data valid output output data valid tjloh data valid figure 22 : test access port timing diagram 4.2.5.2. jtag configuration signals boundary scan testing is enabled through the jtag interface signals. the trst signal is optional in the ieee 1149.1 specification but is provided on all powerpc implementations. while it is possible to force the tap controller to the reset state using only the tck and tms signals, more reliable power-on reset performance will be obtained if the trst signal is asserted during power-on reset. since the jtag interface is also used for accessing the common on-chip processor (cop) function of powerpc processors, simply tying trst to hreset isn't practical. the common on-chip processor (cop) function of powerpc processors allows a remote computer system (typically a pc with dedi- cated hardware and debugging software) to access and control the internal operations of the processor. the cop interface connec ts primarily through the jtag port of the processor, with some additional status monitoring signals. the cop port requires the abi lity to independently assert hreset or trst in order to fully control the processor. if the target system has independent reset sources, such as voltage monitors, watchdog timers, power supply failures, or push-button switches, then the cop reset signals must be merged into these signals with logic. the arrangement shown in figure 23 allows the cop to independently assert hreset or trst , while insuring that the target can drive hreset as well. the pull-down resistor on trst ensures that the jtag scan chain is initialized during power-on if a jtag interface cable is not attached; if it is, it is responsible for driving trst when needed. figure 23 shows the suggested trst connection. hreset hreset trst from target board sources cop header 2kw qack qack 2kw pc755b figure 23 : suggested trst connection
36/48 pc755b/745b the cop header shown in figure 24 adds many benefitsebreakpoints, watchpoints, register and memory examination/modification and other standard debugger features are possible through this interface and can be as inexpensive as an unpopulated footprin t for a header to be added when needed. system design information the cop interface has a standard header for connection to the target system, based on the 0.025o square-post 0.100o centered header assembly (often called a abergo header). the connector typically has pin 14 removed as a connector key. figure 24 shows the cop connector diagram. 3 ckstp_out 13 9 5 1 6 10 2 top view 15 11 7 16 12 8 4 key no pin hreset sreset tms run/stop tck tdi tdo ground trst vdd_sense pins 10, 12 and 14 are noconnects. pin 14 is not physically present qack chkstp_in figure 24 : cop connector diagram there is no standardized way to number the cop header shown in figure 24; consequently, many different pin numbers have been observed from emulator vendors. some are numbered top-to-bottom then left-to-right, while others use left-to-right then top-to- bot- tom, while still others number the pins counter clockwise from pin one (as with an ic). regardless of the numbering, the signal place- ment recommended in figure 24 is common to all known emulators. the qack signal shown in table 15 is usually hooked up to the pci bridge chip in a system and is an input to the pc755b informing it that it can go into the quiescent state. under normal operation this occurs during a low power mode selection. in order for cop to work the pc755b must see this signal asserted (pulled down). while shown on the cop header, not all emulator products drive this sig nal. to preserve correct power down operation, qack should be merged so that it also can be driven by the pci bridge.
pc755b/745b 37/48 table 16 shows the pin definitions. table 16. cop pin definitions pins signal connection special notes 1 tdo tdo 2 qack qack add 2k pulldown to ground. must be merged with on-board qack , if any. 3 tdi tdi 4 trst trst add 2k pulldown to ground. must be merged with on-board trst , if any. see figure 23. 5 run/stop no connect used on 604e; leave no-connect for all other processors. 6 vdd_sense vdd add 2k pullup to ovdd (for short circuit limiting protection only). 7 tck tck 8 ckstp_in ckstp_in optional. add 10k pullup to ovdd. used on several emulator products. useful for checkstopping the processor from a logic analyzer of other external trigger. 9 tms tms 10 n/a 11 sreset sreset merge with on-board sreset , if any. 12 n/a 13 hreset hreset merge with on-board hreset . 14 n/a key location; pin should be removed. 15 ckstp_out ckstp_out add 10k pullup to ovdd. 16 ground digital ground 5. preparation for delivery 5.1. packaging microcircuits are prepared for delivery in accordance with mil-prf-38535 . 5.2. certificate of compliance tcs offers a certificate of compliances with each shipment of parts, affirming the products are in compliance either with mil-p rf-883 and guarantiyng the parameters not tested at temperature extremes for the entire temperature range. 6. handling mos devices must be handled with certain precautions to avoid damage due to accumulation of static charge. input protection devices have been designed in the chip to minimize the effect of static buildup. however, the following handling practices are recom- mended: a) devices should be handled on benches with conductive and grounded surfaces. b) ground test equipment, tools and operator. c) do not handle devices by the leads. d) store devices in conductive foam or carriers. e) avoid use of plastic, rubber, or silk in mos areas. f) maintain relative humidity above 50 percent if practical. g) for ci-cga packages, use specific tray to take care of the highest heigth of the package compared with the normal cbga.
38/48 pc755b/745b 7. package mechanical data the following sections provide the package parameters and mechanical dimensions for the pc745b, 255 pbga package as well as the pc755b, 360 cbga and pbga packages. while both the pc755b plastic and the ceramic packages are described here, both packages are not guaranteed to be available at the same time. all new designs should allow for either ceramic or plastic bga pa ck- ages for this device. for more information on designing a common footprint for both plastic and ceramic package types, please c on- tact your local motorola sales office. 7.1. parameters for the pc745b 7.1.1. package parameters for the pc745b pbga the package parameters are as provided in the following list. the package type is 21 x 21 mm, 255-lead plastic ball grid array (pbga) package outline 21 x 21 mm interconnects 255 (16 x 16 ball array - 1 pitch 1.27 mm (50 mil) minimum module height 2.25 mm maximum module height 2.80 mm ball diameter (typical) 0.75 mm (29.5 mil)
pc755b/745b 39/48 7.1.2. mechanical dimensions of the pc745b pbga package figure 25 provides the mechanical dimensions and bottom surface nomenclature of the pc745b, 255 pbga package. m notes: a. dimensioning and tolerancing per asme y14.5m, 1994. b. dimensions in millimeters. c. top side a1 corner index is a metalized feature with various shapes. bottom side a1 corner is designated with a ball missing from the array. d. capacitor pads may be unpopulated. 0.2 d 2x a1 corner e 0.2 b a a a1 a2 c 0.2 c b c 255x e 12345678910111213141516 a b c d e f g h j k l m n p r t a 0.3 c 0.15 b millimeters dim min max a 2.25 2.80 a1 0.50 0.70 a2 1.00 1.20 b 0.60 0.90 d 21.00 bsc e 21.00 bsc e 1.27 bsc figure 25 : mechanical dimensions and bottom surface nomenclature of the pc745b pbga
40/48 pc755b/745b 7.2. parameters for the pc755b pbga 7.2.1. package parameter for the pc755b pbga the package parameters are as provided in the following list. the package type is 25 x 25 mm, 360-lead plastic ball grid array (pbga). package outline 25 x 25 mm interconnects 360 (19 x 19 ball array - 1) pitch 1.27 mm (50 mil) minimum module height 2.22 mm maximum module height 2.77 mm ball diameter 0.75 mm (29.5 mil) 7.2.2. mechanical dimensions of the pc755b pbga figure 26 provides the mechanical dimensions and bottom surface nomenclature of the pc755b, 360 pbga package. c notes: a. dimensioning and tolerancing per asme y14.5m, 1994. b. dimensions in millimeters. c. top side a1 corner index is a metalized feature with various shapes. bottom side a1 corner is designated with a ball missing from the array. 0.2 b c 360x d 2x a1 corner e e 0.2 2x b a 1 2345678 910 11 12 13 14 15 16 a b c d e f g h j k l m n p r t a 0.3 c 0.15 b a a1 a2 0.2 c 17 18 19 u w v m millimeters dim min max a 2.22 2.77 a1 0.50 0.70 a2 1.00 1.20 b 0.60 0.90 d 25.00 bsc e 25.00 bsc e 1.27 bsc figure 26 : mechanical dimensions and bottom surface nomenclature of the pc755b pbga
pc755b/745b 41/48 8. clock relationships choice the pc755b's pll is configured by the pll_cfg[03] signals. for a given sysclk (bus) frequency, the pll configuration signals set the internal cpu and vco frequency of operation. the pll configuration for the pc755b is shown in figure 27 for example fre - quencies. table 17. pc755b microprocessor pll configuration pll_cfg [03] example bus-to-core frequency in mhz (vco frequency in mhz) bus-to-core multiplier core-to vco multiplier bus 33 mhz bus 50 mhz bus 66 mhz bus 75 mhz bus 80 mhz bus 100 mhz 0100 2x 2x e e e e e 200 (400) 1000 3x 2x e e 200 (400) 225 (450) 240 (480) 300 (600) 1110 3.5x 2x e e 233 (466) 263 (525) 280 (560) 350 (700) 1010 4x 2x e 200 (400) 266 (533) 300 (600) 320 (640) 400 (800) 0111 4.5x 2x e 225 (450) 300 (600) 338 (675) 360 (720) e 1011 5x 2x e 250 (500) 333 (666) 375 (750) 400 (800) e 1001 5.5x 2x e 275 (550) 366 (733) e e e 1101 6x 2x 200 (400) 300 (600) 400 (800) e e e 0101 6.5x 2x 216 (433) 325 (650) e e e e 0010 7x 2x 233 (466) 350 (700) e e e e 0001 7.5x 2x 250 (500) 375 (750) e e e e 1100 8x 2x 266 (533) 400 (800) e e e e 0110 10x 2x 333 (666) e e e e e 0011 pll off/bypass pll off, sysclk clocks core circuitry directly, 1x bus-to-core implied 1111 pll off pll off, no core clocking occurs notes: 1. pll_cfg[03] settings not listed are reserved. 2. the sample bus-to-core frequencies shown are for reference only. some pll configurations may select bus, core, or vco frequencies which are not useful, not supported, or not tested for by the pc755b; see section 4.2.1. , a clock ac specification s,o for valid sysclk, core, and vco frequencies. 3. in pll-bypass mode, the sysclk input signal clocks the internal processor directly, the pll is disabled, and the bus mode is set for 1:1 mode operation. this mode is intended for factory use only. note: the ac timing specifications given in this document do not apply in pll-bypass mode. 4. in pll-off mode, no clocking occurs inside the pc755b regardless of the sysclk input.
42/48 pc755b/745b the pc755b generates the clock for the external l2 synchronous data srams by dividing the core clock frequency of the pc755b. the divided-down clock is then phase-adjusted by an on-chip delay-lock-loop (dll) circuit and should be routed from the pc755b to the external rams. a separate clock output, l2sync_out is sent out half the distance to the srams and then returned as an input to the dll on pin l2sync_in so that the rising-edge of the clock as seen at the external rams can be aligned to the clocking of th e internal latches in the l2 bus interface. the core-to-l2 frequency divisor for the l2 pll is selected through the l2clk bits of the l2cr register. generally, the divisor must be chosen according to the frequency supported by the external rams, the frequency of the pc755b core, and the phase adjustment range that the l2 dll supports. figure 18 shows various example l2 clock frequencies that can be obtained for a given set of co re frequencies. the minimum l2 frequency target is 80mhz. table 18. sample core-to-l2 frequencies core frequency in mhz 1 1.5 2 2.5 3 250 250 166 125 100 83 266 266 177 133 106 89 275 275 183 138 110 92 300 300 200 150 120 100 325 325 217 163 130 108 333 333 222 167 133 111 350 350 233 175 140 117 366 366 244 183 146 122 375 375 250 188 150 125 400 400 266 200 160 133 note : the core and l2 frequencies are for reference only. some examples may represent core or l2 frequencies which are not useful, not supported, or not tested for by the pc755b; see section 4.2.1., a l2 clock ac specifications,o for valid l2clk frequencies. the l2cr[l2sl] bit should be set for l2clk frequencies less than 110 mhz.
pc755b/745b 43/48 9. system design information 9.1. pll power supply filtering the avdd and l2avdd power signals are provided on the pc755b to provide power to the clock generation phase-locked loop and l2 cache delay-locked loop respectively. to ensure stability of the internal clock, the power supplied to the avdd input signal sh ould be filtered of any noise in the 500khz to 10mhz resonant frequency range of the pll. a circuit similar to the one shown in figure 27 using surface mount capacitors with minimum effective series inductance (esl) is recommended. consistent with the recommendations of dr. howard johnson in high speed digital design: a handbook of black magic (prentice hall, 1993), multiple small capacitors of equal value are recommended over a single large value capacitor. the circuit should be placed as close as possible to the avdd pin to minimize noise coupled from nearby circuits. an identical but separate circuit should be placed as close as possible to the l2avdd pin. it is often possible to route directly from the capac itors to the avdd pin, which is on the periphery of the 360 bga footprint, without the inductance of vias. the l2avdd pin may be more diffic ult to route but is proportionately less critical. vdd avdd (or l2avdd) gnd low esl surface mount capacitors 2.2 m f 2.2 m f 10 w figure 27 : pll power supply filter circuit 9.2. power supply voltage sequencing the notes in figure 28 contain cautions about the sequencing of the external bus voltages and core voltage of the pc755b (when they are different). these cautions are necessary for the long term reliability of the part. if they are violated, the esd (ele ctrostatic discharge) protection diodes will be forward biased and excessive current can flow through these diodes. if the system power su pply design does not control the voltage sequencing, the circuit of figure 28 can be added to meet these requirements. the mur420 schottky diodes of figure 28 control the maximum potential difference between the external bus and core power supplies on pow- er-up and the 1n5820 diodes regulate the maximum potential difference on power-down. 3.3v 2.0v mur420 1n5820 mur420 mur420 1n5820 figure 28 : example voltage sequencing circuit 9.3. decoupling recommendations due to the pc755b's dynamic power management feature, large address and data buses, and high operating frequencies, the pc755b can generate transient power surges and high frequency noise in its power supply, especially while driving large capacit ive loads. this noise must be prevented from reaching other components in the pc755b system, and the pc755b itself requires a clean , tightly regulated source of power. therefore, it is recommended that the system designer place at least one decoupling capacito r at each vdd, ovdd, and l2ovdd pin of the pc755b. it is also recommended that these decoupling capacitors receive their power from separate vdd, (l2)ovdd and gnd power planes in the pcb, utilizing short traces to minimize inductance. these capacitors should have a value of 0.01 m f or 0.1 m f. only ceramic smt (surface mount technology) capacitors should be used to minimize lead inductance, preferably 0508 or 0603 orientations where connections are made along the length of the part. in addition, it is recommended that there be several bulk storage capacitors distributed around the pcb, feeding the vdd, l2ovd d, and ovdd planes, to enable quick recharging of the smaller chip capacitors. these bulk capacitors should have a low esr (equiva - lent series resistance) rating to ensure the quick response time necessary. they should also be connected to the power and grou nd planes through two vias to minimize inductance. suggested bulk capacitorse100-330 m f (avx tps tantalum or sanyo oscon).
44/48 pc755b/745b 9.4. connection recommendations to ensure reliable operation, it is highly recommended to connect unused inputs to an appropriate signal level through a resist or. unused active low inputs should be tied to ovdd. unused active high inputs should be connected to gnd. all nc (no-connect) sign als must remain unconnected. power and ground connections must be made to all external vdd, ovdd, l2ovdd, and gnd pins of the pc755b. 9.5. output buffer dc impedance the pc755b 60x and l2 i/o drivers are characterized over process, voltage, and temperature. to measure z 0 , an external resistor is connected from the chip pad to (l2)ovdd or gnd. then, the value of each resistor is varied until the pad voltage is (l2)ovdd/2 (see figure 29). the output impedance is the average of two components, the resistances of the pull-up and pull-down devices. when data is held low, sw2 is closed (sw1 is open), and r n is trimmed until the voltage at the pad equals (l2)ovdd/2. r n then becomes the resistance of the pull-down devices. when data is held high, sw1 is closed (sw2 is open), and r p is trimmed until the voltage at the pad equals (l2)ovdd/2. r p then becomes the resistance of the pull-up devices. aucun lien describes the driver impedance measurement curcuit described above. (l2)ovdd ognd rp rn pad data sw1 sw2 (l2)ovdd figure 29 : driver impedance measurement circuit alternately, the following is another method to determine the output impedence of the pc755b. a voltage source, v force , is connected to the output of the pc755b as in figure 30. data is held low, the voltage source is set to a value that is equal to (l2)ovdd /2 and the current sourced by v force is measured. the voltage drop across the pulldown device, which is equal to (l2)ovdd/2, is divided by the measured current to determine the output impedence of the pulldown device, r n . similarly, the impedence of the pullup device is determined by dividing the voltage drop of the pullup, (l2)ovdd/2, by the current sank by the pullup when the data is high and vforce is equal to (l2)ovdd/2. this method can be employed with either empirical data from a test set up or with data from simulation mod els, such as ibis. r p and r n are designed to be close to each other in value. then z 0 = (r p + r n )/2.
pc755b/745b 45/48 figure 30 describes the alternate driver impedance measurement circuit. (l2)ovdd bga data pin vforce ognd figure 30 : alternate driver impedance measurement curcuit table 19 summarizes the signal impedance results. the driver impedance values were characterized at 0 c, 65 c, and 105 c. the impedance increases with junction temperature and is relatively unaffected by bus voltage. table 19. impedance characteristics vdd = 2.0v, ovdd = 3.3v, tc = 0 - 105 c impedance processor bus l2 bus symbol unit r n 25-36 25-36 z 0 ohms r p 26-39 26-39 z 0 ohms 9.6. pull-up resistor requirements the pc755b requires high-resistive (weak: 10 k w ) pull-up resistors on several control pins of the bus interface to maintain the control signals in the negated state after they have been actively negated and released by the pc755b or other bus masters. these pins are ts , abb , artry . in addition, the pc755b has one open-drain style output that requires a pull-up resistor (weak or stronger: 4.7 k w 10 k w ) if it is used by the system. this pin is ckstp_out . during inactive periods on the bus, the address and transfer attributes may not be driven by any master and may therefore float in the high-impedance state for relatively long periods of time. since the pc755b must continually monitor these signals for snooping, this float condition may cause excessive power draw by the input receivers on the pc755b or by other receivers in the system. it is recom- mended that these signals be pulled up through weak (10 k w ) pull-up resistors by the system, or that they may be otherwise driven by the system during inactive periods of the bus. the snooped address and transfer attribute inputs are: a[0:31], ap[0:3], tt[0:4], tbst and gbl . the data bus input receivers are normally turned off when no read operation is in progress and therefore do not require pull-up resis- tors on the bus. other data bus receivers in the system, however, may require pullups, or that those signals be otherwise drive n by the system during inactive periods by the system. the data bus signals are: dh[0:31],dl[0:31] anddp[0:7] if 32-bit data bus mode is selected, the input receivers of the unused data and parity bits will be disabled, and their outputs will drive logic zeros when they would otherwise normally be driven. for this mode, these pins do not require pull-up resistors, and shoul d be left unconnected by the system to minimize possible output switching. if address or data parity is not used by the system, and the respective parity checking is disabled through hid0, the input rec eivers for those pins are disabled, and those pins do not require pull-up resistors and should be left unconnected by the system. if all p arity generation is disabled through hid0, then all parity checking should also be disabled through hid0, and all parity pins may be left unconnected by the system. the l2 interface does not normally require pull-up resistors.
46/48 pc755b/745b 10. definitions datasheet status validity objective specification this datasheet contains target and goal specification for discussion with customer and application validation. before design phase. target specification this datasheet contains target or goal specification for product development. valid during the design phase. preliminary specification site this datasheet contains preliminary data. additional data may be published later ; could include simulation result. valid before characterization phase. preliminary specification site this datasheet contains also characterization results. valid before the industrializa- tion phase. product specification this datasheet contains final product specification. valid for production purpose. limiting values limiting values given are in accordance with the absolute maximum rating system (iec 134). stress above one or more of the limiting values may cause permanent damage to the device. these are stress ratings only and operation of the device at these or at any other conditions above those given in the characteristics sections of the specification is not implied. exposur e to limiting values for extended periods may affect device reliability. application information where application information is given, it is advisory and does not form part of the specification. life support applications these products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be expected to result in personal injury. atmel-grenoble customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify atmel-grenoble for any damages resulting from such improper u se or sale. 11. differences with commercial part commercial part military part temperature range tj = 0 to 105 c tj = -55 to 125 c
pc755b/745b 47/48 12. ordering information temperature range : tj screening leve l (1) : package : pc755b m 300 m : -55, +125 c v : -40, +110 c u zf : fc-pbga (2) bus divider (to be confirmed) l:any valid pll configuration max internal processor speed (1) 300 : 300 mhz, 350 : 350 mhz, 400 : 400 mhz, tbc (1) for availability of the different versions, contact your atmel-grenoble sale office (2) fc-pbga = pbga with flip chip assembly process u : upscreening test type lx revision level (1) d : rev 2.7 e : rev 2.8 (pcx755b if prototype) zf information furnished is believed to be accurate and reliable. however atmel-grenoble assumes no responsibility for the conse- quences of use of such information nor for any infringement of patents or other rights of third parties which may result from i ts use. no license is granted by implication or otherwise under any patent or patent rights of atmel-grenoble. specifications mentioned in this publication are subject to change without notice. this publication supersedes and replaces all information previously supplied. atmel- grenoble products are not authorized for use as critical components in life support devices or systems without express written approval from atmel-grenoble. ? 2000 atmel-grenoble- printed in france - all rights reserved. this product is manufactured by atmel-grenoble- 38521 saint-egreve - france. for further information please contact : atmel-grenoble - route dpartementale 128 - b.p. 46 - 91401 orsay cedex - france - phone +33 (0)1 69 33 00 00 - fax +33 (0)1 69 33 03 21. internet:http://www.atmel-grenoble.com 6.

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