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SM802108
ClockWorksTM 10GbE & GbE (156.25MHz, 125MHz) Ultra-Low Jitter, LVPECL Frequency Synthesizer
General Description
The SM802108 is a member of the ClockWorksTM family of devices from Micrel and provides an extremely low-noise timing solution for GbE and 10GbE Ethernet clock signals. It is based upon a unique patented RotaryWave(R) architecture that provides very low phase noise. The device operates from a 3.3V or 2.5V power supply and synthesizes two LVPECL output clocks at 156.25MHz and another two at 125MHz. The SM802108 accepts a 25 MHz crystal or LVCMOS reference clock. Data sheets and support documentation can be found on Micrel's web site at: www.micrel.com.
Features
* Generates two LVPECL clock outputs at 156.25MHz and two LVPECL clock outputs at 125MHz * 2.5V or 3.3V operating range * Typical phase jitter @ 156.25MHz (1.875MHz to 20MHz): 110fs (typical) at 3.3V * Industrial temperature range * Green, RoHS, and PFOS compliant * Available in 24-pin 4mm x 4mm QFN package
Applications
* 10Gigabit Ethernet * Gigabit Ethernet
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Block Diagram
ClockWorks is a trademark of Micrel, Inc RotaryWave is a registered trademark of Multigig, Inc. Micrel Inc. * 2180 Fortune Drive * San Jose, CA 95131 * USA * tel +1 (408) 944-0800 * fax + 1 (408) 474-1000 * http://www.micrel.com
January 2011
M9999-012111-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SM802108
Ordering Information
Part Number SM802108UMG SM802108UMGR
Note: 1. Devices are Green, RoHS, and PFOS compliant.
Marking 802108 802108
Shipping Tube Tape and Reel
Junction Temperature Range -40C to +85C -40C to +85C
Package 24-Pin QFN 24-Pin QFN
Pin Configuration
24-Pin QFN (Top View)
Pin Description
Pin Number 16, 17 20, 21 23, 24 3, 4 1 2 Pin Name /Q0, Q0 /Q1, Q1 /Q2, Q2 /Q3, Q3 VDDO2 VSSO2 Pin Type O, (DIF) O, (DIF) PWR PWR Pin Level LVPECL LVPECL Pin Function Differential Clock Outputs from Bank 1 156.25MHz Differential Clock Outputs from Bank 2 125MHz Power Supply for Output Bank 2 Power Supply Ground for Output Bank 2 PLL Bypass, Selects Output Source 5 PLL_BYPASS I, (SE) LVCMOS 0 = Normal PLL Operation 1 = Output from Input Reference Clock or Crystal 45K pull-down 6 XTAL_SEL I, (SE) LVCMOS Selects PLL Input Reference Source 0 = REF_IN, 1 = XTAL, 45K pull-up
January 2011
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SM802108
Pin Description (Continued)
Pin Number 7, 12, 15, 19 8 9 10 11 13, 14 18 22 Pin Name TEST VDD REF_IN XIN XOUT VSS VDDO1 VSSO1 PWR I, (SE) I, (SE) O, (SE) PWR PWR PWR LVCMOS 12pF crystal 12pF crystal Pin Type Pin Level Pin Function Factory Test Pins, Do not connect anything to these pins. Core Power Supply Reference Clock Input Crystal Reference Input, no load caps needed. See Fig. 5. Crystal Reference Output, no load caps needed. See Fig. 5. Core Power Supply Ground Power Supply for Output Bank 1 Power Supply Ground for Output Bank 1
Application Information
Input Reference When operating with a crystal input reference, do not apply a switching signal to REF_IN. Crystal Layout Keep the layers under the crystal as open as possible. Do not place switching signals or noisy supplies under the crystal.
Truth Table
PLL_BYPASS 0 1 - - XTAL_SEL - - 0 1 INPUT - - REF_IN XTAL OUTPUT PLL XTAL/REF_IN - -
January 2011
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Micrel, Inc.
SM802108
Absolute Maximum Ratings(1)
Supply Voltage (VDD, VDDOx) ........................................+4.6V Input Voltage (VIN). ............................. -0.50V to VDD + 0.5V Lead Temperature (soldering, 20sec.)....................... 260C Case Temperature ..................................................... 115C Storage Temperature (Ts) .........................-65C to +150C
Operating Ratings(2)
Supply Voltage (VDD, VDDOx) ................. +2.375V to +3.465V Ambient Temperature (TA) .......................... -40C to +85C Junction Thermal Resistance(3) QFN (JA) Still-Air.........................................................50C/W QFN (JB) Junction-to-Board .......................................30C/W
DC Electrical Characteristics(4)
VDD = VDDO1/2 = 3.3V 5% or 2.5V 5% VDD = 3.3V 5%, VDDO1/2 = 3.3V 5% or 2.5V 5% TA = -40C to +85C. Symbol VDD, VDDOx VDD, VDDOx IDD IDD Parameter 2.5V Operating Voltage 3.3V Operating Voltage Supply current VDD + VDDO Supply current VDD + VDDO Outputs open; REF_IN source, XTAL_SEL = 0 Outputs open; CRYSTAL source, XTAL_SEL = 1 Condition Min. 2.375 3.135 Typ. 2.5 3.3 130 145 Max. 2.625 3.465 165 185 Units V V mA mA
LVPECL DC Electrical Characteristics(4)
VDD = VDDO1/2 = 3.3V 5% or 2.5V 5% VDD = 3.3V 5%, VDDO1/2 = 3.3V 5% or 2.5V 5% TA = -40C to +85C. RL = 50 to VDDO - 2V Symbol VOH VOL VSWING
Note: 1. Permanent device damage may occur if absolute maximum ratings are exceeded. This is a stress rating only and functional operation is not implied at conditions other than those detailed in the operational sections of this data sheet. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. The data sheet limits are not guaranteed if the device is operated beyond the operating ratings. Package thermal resistance assumes exposed pad is soldered (or equivalent) to the devices most negative potential on the PCB. The circuit is designed to meet the AC and DC specifications shown in the above table(s) after thermal equilibrium has been established.
Parameter Output High Voltage Output Low Voltage Output Voltage Swing
Condition
Min. VDDO - 1.145 VDDO - 1.945 0.6
Typ. VDDO - 0.97 VDDO - 1.77 0.8
Max. VDDO - 0.845 VDDO - 1.645 1.0
Units V V V
2. 3. 4.
January 2011
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Micrel, Inc.
SM802108
LVCMOS (PLL_BYPASS, XTAL_SEL) DC Electrical Characteristics(4)
VDD = 3.3V 5%, or 2.5V 5%, TA = -40C to +85C. Symbol VIH VIN IIH IIL Parameter Input High Voltage Input Low Voltage Input High Current Input Low Current VDD = VIN = 3.465V VDD = 3.465V, VIN = 0V -5 Condition Min. 2 -0.3 Typ. Max. VDD + 0.3 0.8 150 Units V V A A
REF_IN DC Electrical Characteristics(4)
VDD = 3.3V 5%, or 2.5V 5%, TA = -40C to +85C. Symbol VIH VIL IIN IIN Parameter Input High Voltage Input Low Voltage Input Current Input Current XTAL_SEL = VIL, VIN = 0V to VDD XTAL_SEL = VIH, VIN = VDD Condition Min. 1.1 -0.3 -5 20 Typ. Max. VDD + 0.3 0.6 5 Units V V A A
Crystal Characteristics
NDK NX2520SA
Parameter Mode of Oscillation Frequency Equivalent Series Resistance (ESR) Shunt Capacitor, C0 Correlation Drive Level Condition 12pF Load Min. Typ. Max. Units MHz pF uW Fundamental, Parallel Resonant 25 50 3 7 100 300
January 2011
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Micrel, Inc.
SM802108
AC Electrical Characteristics(4, 5)
VDD = VDDO1/2 = 3.3V 5% or 2.5V 5% VDD = 3.3V 5%, VDDO1/2 = 3.3V 5% or 2.5V 5% TA = -40C to +85C. RL = 50 to VDDO - 2V Symbol FOUT1 FOUT2 Ppm FREF TR/TF ODC TSKEW TLOCK Parameter Output Frequency 1 Output Frequency 2 Output ppm Variation Reference Input Frequency LVPECL Output Rise/Fall Time Output Duty Cycle Output-to-Output Skew PLL Lock Time 156.25MHz Integration Range (1.875MHz - 20MHz) Integration Range (12kHz - 20MHz) Tjit() RMS Phase Jitter
(8)
Condition
Min.
Typ. 156.25 125
Max.
Units MHz
Crystal reference. Note 6 20% - 80% Within bank. Note 7
-50 25 80 48 175 50
50 350 52 45 20
ppm MHz ps % ps ms
110 250 fs 110 250 -73 -58 dBc
125MHz Integration Range (1.875MHz - 20MHz) Integration Range (12kHz - 20MHz) 6.25MHz 25MHz
Spurious Noise Components
Notes: 5. 6. 7. 8.
All phase noise measurements were taken with an Agilent 5052B phase noise system. Crystal tolerance at room less than +/- 15ppm, over temp less than +/- 20ppm. Defined as skew between outputs at the same supply voltage and with equal load conditions and same frequency; Measured at the output differential crossing points. Measured using 25MHz crystal as the input reference source.
January 2011
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SM802108
Phase Noise Plots
Phase Noise Plot: 156.25MHz, 1.875MHz - 20MHz 108fS
Phase Noise Plot: 156.25MHz, 12kHz - 20MHz 253fS
January 2011
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SM802108
Phase Noise Plots (Continued)
Phase Noise Plot: 125MHz, 1.875MHz - 20MHz 111fS
Phase Noise Plot: 125MHz, 12kHz - 20MHz 257fS
January 2011
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Micrel, Inc.
SM802108
Figure 1. Duty Cycle TIming
Figure 2. All Outputs Rise/Fall Time
Figure 3. RMS Phase/Noise/Jitter
January 2011
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M9999-012111-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SM802108
Figure 4. LVPECL Output Load and Test Circuit
Figure 5. Crystal Input Interface
January 2011
10
M9999-012111-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SM802108
Package Information
24-Pin QFN
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Micrel's terms and conditions of sale for such products, Micrel assumes no liability whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser's use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser's own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. (c) 2011 Micrel, Incorporated.
January 2011
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