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19-1692; rev 2; 10/12 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maximintegrated.com. max8869 1a, microcap, low-dropout, linear regulator general description the max8869 low-dropout linear regulator operatesfrom a +2.7v to +5.5v input and delivers a guaranteed 1a load current with a low 200mv dropout. the high- accuracy (?%) output voltage is preset at +5v, +3.3v, +2.5v, +1.8v, or +1.0v or is adjustable from +0.8v to +5v with an external resistor-divider. the max8869 uses microcap technology and requires only a small 1? output capacitor for guaran-teed stability. an internal pmos pass transistor allows low 500? supply current, making this regulator useful for networking and telecom hardware as well as bat- tery-operated equipment. other features include soft- start, low-power shutdown, short-circuit protection, and thermal shutdown protection. the max8869 is available in a 1.5w, 16-pin tssop package, which is 30% smaller than a sot223 and only 1.1mm high. ________________________applications telecom hardwarenetwork equipment mobile phone base stations personal computers notebook computers features ? guaranteed 1a output current ? stable with c out = 1 f ? low 200mv dropout at 1a ? ?% output voltage accuracy preset at +5v, +3.3v, +2.5v, +1.8v, or +1.0vand adjustable from +0.8v to +5.0v ? 54db psrr at 100khz ? adjustable soft-start ? 3ms reset output ? foldback output current limit ? thermal overload protection ? high-power 16-pin tssop package (1.5w) 30% smaller than sot223 (only 1.1mm high) 1615 14 13 12 11 10 9 12 34 5 6 7 8 n.c. n.c. outout out out set gnd n.c. top view max8869 tssop-ep inin rst inin shdn ss + pin configuration inin in in shdn ss outout out out rst set gnd on off 1 f 1 f v in +2.7v to +5.5v v out up to 1a reset output max8869 typical operating circuit ordering information microcap is a registered trademark of american technical ceramics corp. part pin-package v out (v)* max8869eue50+ 16 tssop-ep** +5.0 max8869eue33+ 16 tssop-ep** +3.3 max8869eue25+ 16 tssop-ep** +2.5 max8869eue25/v+ 16 tssop-ep** +2.5 max8869eue18+ 16 tssop-ep** +1.8 max8869eue10+ 16 tssop-ep** +1.0 note: all devices are specified over the -40? to +85? temperature range. + denotes a lead(pb)-free/rohs-compliant package. * or adjustable from +0.8v to +5.0v. contact factory for other preset output voltages. ** ep = exposed pad. /v denotes an automotive qualified part. downloaded from: http:///
max8869 1a, microcap, low-dropout, linear regulator 2 maxim integrated absolute maximum ratings electrical characteristics (v in = +2.7v or v out(nom) + 0.5v (whichever is greater), shdn = in, ss = open, set = gnd, c out = 1?, t a = 0? to +85? , unless otherwise noted. typical values are at t a = +25?.) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. in, shdn , rst , ss to gnd ......................................-0.3v to +6v out, set to gnd ........................................-0.3v to (v in + 0.3v) output short-circuit duration ........................................indefinite continuous power dissipation (t a = +70?) 16-pin tssop-ep (derate 26.1mw/? above +70?)......2.0w operating temperature range ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range ...............................-65? to 150? lead temperature (soldering, 10s) .................................+300? soldering temperature (reflow) .......................................+260? parameter symbol conditions min typ max units input voltage range v in 2.7 5.5 v input undervoltage lockout typical hysteresis = 50mv 2.35 2.45 2.55 v output voltage accuracy i out = 1ma, t a = +85 c- 1 1 % set regulation voltage(adjustable mode) i out = 150ma, t a = +85 c 792 800 808 mv line regulation ? v lnr v in = v out + 0.5v to +5.5v, i out = 10ma 0.1 %/v load regulation ? v ldr i out = 1ma to 1a 0.8 1.5 %/a ad j ustab l e o utp ut v ol tag e range 0.8 5 v maximum output current i out continuous 1 a rms short-circuit current limit i lim v out = 0v 1.0 1.9 a in-regulation current limit i lim v set = 0.76v 2.0 4.0 a set dual mode threshold 40 80 120 mv set input bias current i set v set = +0.9v 50 300 na i out = 100? 0.5 2.0 ground current i gnd i out = 1a 2.5 ma i out = 1ma, +2.7v < v in < +5.5v 0.2 dropout voltage(note 1) i out = 1a, v out = +3.3v (note 2) 200 350 mv output voltage noise f = 10hz to 1m hz, c ou t = 1f, i ou t = 150ma 150 v rms power-supply rejection ratio psrr f = 100khz, c out = 1? 54 db shutdown supply current i off shdn = gnd, v in = +5.5v, v out = 0 0.1 10 ? v ih 1.6 shdn input threshold v il +2.7v < v in < +5.5v 0.6 v shdn input bias current shdn = gnd or in 0 0.1 ? soft-start charge current i ss v ss = 0v 6 a rst output low voltage i sink = 1ma 0.1 v in operating voltage range forrst valid i sink = 10 a 1.0 5.5 v rst leakage v rst = +5.5v 0.01 1 a rst trip level referred to nominal v out falling edge, typical hysteresis = 10mv 89 92 95 % out rst release delay rising edge 1 3 5.5 ms thermal shutdown threshold t shdn typical thermal hysteresis = +20 c +170 o c dual mode is a trademark of maxim integrated products. downloaded from: http:///
max8869 1a, microcap, low-dropout, linear regulator 3 maxim integrated electrical characteristics(v in = +2.7v or v out(nom) + 0.5v (whichever is greater), shdn = in, ss = open, set = gnd, c out = 1?, t a = -40? to +85? , unless otherwise noted.) (note 3) note 1: dropout voltage is (v in - v out ) when v out falls to 100mv below the value of v out measured when v in = v out(nom) +0.5v. since the minimum input voltage is 2.7v, this specification is only meaningful when v out 2.7v. note 2: the output voltage is externally set using a resistive voltage-divider from out to set. note 3: specifications to -40? are guaranteed by design, not production tested. parameter symbol conditions min max units input voltage range v in 2.7 5.5 v input undervoltage lockout typical hysteresis = 50mv 2.3 2.6 v output voltage accuracy i out = 1ma, t a = +85? -1 1 % set regulation voltage(adjustable mode) i out = 150ma, t a = +85? 792 808 mv load regulation ? v ldr i out = 1ma to 1a 2.0 %/a ad j ustab l e o utp ut v ol tag e rang e 0.8 5 v maximum output current i out continuous 1 a rms short-circuit current limit i lim v out = 0v 1.0 a in-regulation current limit i lim v set = +0.76v 2.0 a set dual mode threshold 40 120 mv set input bias current i set v set = +0.9v 300 na ground current i gnd i out = 100? 2.0 ma dropout voltage (note 1) i out = 1a, v out = +3.3v (note 2) 350 mv shutdown supply current i off shdn = gnd, v in = +5.5v, v out = 0v 10 ? v ih 1.7 shdn input threshold v il +2.7v < v in < +5.5v 0.6 v shdn input bias current shdn = gnd or in 0.1 ? rst output low voltage i sink = 1ma 0.1 v in operating voltage range forrst valid i sink = 10? 1.0 5.5 v rst leakage v rst = +5.5v 1 a rst trip level referred to nominal v out falling edge, typical hysteresis = 10mv 88 95 % out rst release delay rising edge 1 6 ms downloaded from: http:///
max8869 1a, microcap, low-dropout, linear regulator 4 maxim integrated typical operating characteristics (v in = +5v, v out = +2.5v, shdn = in, ss = open, c out = 1?, t a = +25?, unless otherwise noted.) 0 -1.0 -0.5-2.0 -1.5-2.5 -3.0 0 1.0 1.5 0.5 2.0 2.5 3.0 output voltage deviation vs. output current max8869-01 output current (a) output voltage deviation (%) v in = +5v v in = +3v i out = 250ma -1.5 -1.0 -0.5 0 0.5 1.0 1.5 -40 -15 10 35 60 85 output voltage deviation vs. temperature max8869-02 temperature ( c) output voltage deviation (%) 0 1.00.5 2.01.5 3.02.5 3.5 02 3 14 5 ground current vs. input voltage max8869-03 input voltage (v) ground current (ma) i out = 0.5a i out = 1a i out = 0a 0 1.00.5 2.01.5 3.02.5 3.5 0 400 200 600 800 1000 ground current vs. output current max8869-04 output current (ma) ground current (ma) v in = +3v v in = +5v 0 0.5 1.51.0 2.0 2.5 -40 10 -15 35 60 85 ground current vs. temperature max8869-05 temperature ( c) ground current (ma) i out = 250ma i out = 0v v in = +3v v in = +5v 0 100 50 250200 150 400350 300 450 0 500 250 750 1000 1250 1500 dropout voltage vs. output current max8869-06 output current (ma) dropout voltage (mv) v out = +3.3v 0 100 50 200150 250 300 2.5 3.5 3.0 4.0 4.5 5.0 dropout voltage vs. input voltage max8869-07 input voltage (v) dropout voltage (mv) i out = 500ma in dropout, v out ? v in 0 2010 4030 6050 0.01 1 0.1 10 100 1000 psrr vs. frequency max8869-08 frequency (khz) psrr (db) i out = 300ma 10 0.01 0.01 10 1000 output noise spectral density vs. frequency 0.1 1 max8869-09 frequency (khz) noise ( v/ hz) 0.1 1 100 i out = 250ma downloaded from: http:///
max8869 1a, microcap, low-dropout, linear regulator 5 maxim integrated 0 0.001 1 0.1 0.01 output noise vs. output current 60 20 140 100 180 80 40 160 120 max8869-10 output current (a) output noise (v rms ) 200 s/div line-transient response max8869-11 v in v out 5v3.6v 10mv/divac-coupled i out = 250ma 20 s/div load-transient response max8869-12 i out v out 1a 100ma 50mv/divac-coupled 20 s/div load-transient response max8869-13 i out v out 3a 10ma 200mv/divac-coupled 4ms/div 1mhz bandwidth output noise max8869-14 100 v/div i out = 100a 40s/div shutdown response max8869-15 5v/div v out v shdn 2v/div 10ms/div soft-start response max8869-16 5v/div c ss = 100nf i in 2v/div v out 1a/div v shdn 1ms/div reset output response max8869-17 5v/div v in v out 2v/div rst 2v/div rst output delay typical operating characteristics (continued) (v in = +5v, v out = +2.5v, shdn = in, ss = open, c out = 1?, t a = +25?, unless otherwise noted.) downloaded from: http:///
max8869 1a, microcap, low-dropout, linear regulator 6 maxim integrated detailed description the max8869 features dual mode operation, allowing afixed output of +5v, +3.3v, +2.5v, +1.8v, or +1.0v, or adjustable output from +0.8v to +5.0v. the regulators are guaranteed to supply 1a of continuous output cur- rent with only 1? of output capacitance. as shown in the functional diagram (figure 1), the device has a 0.8v reference, error amplifier, mosfet driver, p-channel pass transistor, internal feedback voltage-divider, soft-start function, reset timer, and dual mode and low v out comparators. the 0.8v reference is connected to the error amplifier?inverting input. the error amplifier compares this refer- ence with the selected feedback voltage and amplifies the difference. the mosfet driver reads the error sig- nal and applies the appropriate drive to the p-channel transistor. if the feedback voltage is high, the pass tran- sistor? gate is pulled up, allowing less current to pass to the output. the low v out comparator senses when the feedback voltage has dropped 8% below itsexpected level, causing rst to go low. the output voltage is fed back through either an inter-nal resistor-divider connected to out or an external resistor network connected to set. the dual mode comparator examines v set and selects the feedback path. if v set is below 80mv, the internal feedback path is used and the output voltage is regulated to the facto-ry-preset voltage. otherwise, the output voltage is set with the external resistor-divider. internal p-channel pass transistor the max8869 features a 1a p-channel mosfet passtransistor. unlike similar designs using pnp pass tran- sistors, p-channel mosfets require no base drive, which reduces quiescent current. pnp-based regula- tors also waste considerable current in dropout when the pass transistor saturates and use high base-drive currents under large loads. the max8869 does not suf- fer from these problems and consumes only 500? of quiescent current even in dropout. pin description pin name function 1, 9, 16 n.c. no connection. not internally connected. 2, 3, 4, 5 in regulator input. connect to power source (+2.7v to +5.5v). bypass with 1 f or greater capacitor to gnd (see capacitor selection and regulator stability ). connect all in inputs together for proper operation. 6 rst reset o utp ut. o p en- d r ai n outp ut i s l ow w hen v ou t i s 8% b el ow i ts nom i nal val ue. rst r em ai ns l ow w hi l e the outp ut vol tag e ( v out ) i s b el ow the r eset thr eshol d and for at l east 3m s after v out r i ses to w i thi n r eg ul ati on. c onnect a 100k ? p ul l up r esi stor to o u t to ob tai n an outp ut vol tag e. 7 shdn active-low shutdown input. a logic low reduces the supply current to 0.1 a. connect shdn to in for normal operation. in shutdown, rst is low and the soft-start capacitor discharges. 8s s soft-start control. connect a soft-start capacitor from ss to gnd (see soft-start capacitor selection ). leave ss open to disable soft-start. 10 gnd ground. solder both gnd and ep to a large pad or to the circuit-board ground plane tomaximize power dissipation. 11 set voltage-setting input. connect set to gnd for factory-preset output voltage. connect set toan external resistor-divider for adjustable output operation. 12, 13, 14, 15 out regulator output. bypass with a 1 f or greater low-esr capacitor to gnd (see capacitor selection and regulator stability ). connect all out outputs together for proper operation. ? p exposed pad. connect to a large ground plane to maximize thermal performance. notintended as an electrical connection point. downloaded from: http:///
max8869 1a, microcap, low-dropout, linear regulator 7 maxim integrated output voltage selection the max8869 features dual mode operation. connectset to gnd (figure 2) for preset voltage mode (see ordering information ). in adjustable mode, set the out- put between +0.8v to +5.0v through two external resis-tors connected as a voltage-divider to set (figure 3). the output voltage is set by the following equation: v out = v set (1 + r1 / r2) where v set = +0.8v. to simplify resistor selection: r1 = r2 (v out / v set - 1) since the input bias current at set is nominally 50na,large resistance values can be used for r1 and r2 to minimize power consumption without losing efficiency. up to 80k ? is acceptable for r2. in preset voltage mode, the impedance between setand ground should be less than 10k ? . otherwise, spu- rious conditions could cause the voltage at set toexceed the 80mv dual mode threshold. shutdown a logic low on shdn disables the max8869. in shut- down, the pass transistor, control circuitry, reference,and all biases are turned off, reducing supply current to typically 0.1?. connect shdn to in for normal opera- tion. in shutdown, rst is low and the soft-start capaci- tor is discharged. rst comparator the max8869 features a low v out indicator that asserts when the output voltage falls out of regulation.the open-drain rst goes low when out falls 8% figure 1. functional diagram figure 2. typical operating circuit with preset output voltage mosfet driver with foldback current limit shutdown logic 0.8v reference ss gnd shdn in outrst set v ss 6 a 736mv thermal sensor out delay timer in 3ms shutdown error amp dual mode comparator 80mv 92% v out detector v ss pmos nmos r1r2 max8869 inin in in shdn ss outout out out rst set gnd on off c out 1 f c in 1 f c ss v out v in resetoutput max8869 downloaded from: http:///
max8869 1a, microcap, low-dropout, linear regulator 8 maxim integrated below its nominal output voltage. rst remains low for 3ms after out has returned to its nominal value. a100k ? pullup resistor from rst to a suitable logic sup- ply voltage (typically out) provides a logic control sig-nal. rst can be used as a power-on-reset signal to a microcontroller (?) or can drive an external led forindicating a power failure. rst is low during shutdown. rst remains valid for an input voltage as low as 1v. soft-start as shown in figure 4, a capacitor on ss allows a grad-ual buildup of the max8869 output, reducing the initial in-rush current peaks at startup. when shdn is driven low, the soft-start capacitor is discharged. when shdn is driven high or power is applied to the device, a con-stant 6? current charges the soft-start capacitor. the resulting linear ramp voltage on ss increases the cur- rent-limit comparator threshold, limiting the p-channel gate drive (see soft-start capacitor selection ). leave ss unconnected to disable the soft-start feature. current limiting the max8869 features a 4a current limit when the out-put voltage is in regulation. when the output voltage drops by 8% below its nominal, the current limit folds back to 1.7a. the output can be shorted to ground for an indefinite period of time without damaging the device. avoid continuous output current of more than 1a to prevent damage. both the in-regulation and short-circuit current limits can be reduced from their nominal values by reducing the voltage at the soft-start input (ss) below 1.25v. the cur- rent limits scale proportionately with the voltage by i lim = i lim_nom ? (v ss / 1.25). since the ss input sources a nominal 6? current, the current limit can be set by tying a resistor (r ss ) between ss and gnd, so that i lim = i lim_nom ? (i ss ? r ss / 1.25) where i ss = 6? . with r ss in place, soft-start can still be achieved by placing a capacitor (c ss ) in parallel with r ss . the output current now ramps up asymptotically to the reduced currentlimit rather than the nominal one, increasing the soft- start time. the time required for the current limit to reach 90% of its steady-state value is given by t ss = 2.3 r ss c ss . thermal overload protection thermal overload protection limits total power dissipa-tion in the max8869. when the junction temperature exceeds t j = +170?, the thermal sensor turns off the pass transistor, allowing the ic to cool. the thermal sen-sor turns the pass transistor on once the ic? junction temperature drops approximately 20?. continuous short-circuit conditions will consequently result in a pulsed output. thermal overload protection is designed to safeguard the max8869 in the event of fault conditions. for con- tinuous operation, do not exceed the absolute maxi- mum junction temperature rating of t j = +150?. operating region and power dissipation maximum power dissipation of the max8869 dependson the thermal resistance of the case and circuit board, the temperature difference between the die junction and ambient air, and the rate of air flow. the power dis- sipation across the device is p = i out (v in - v out ). the resulting maximum power dissipation is: p max = [(t j(max) - t a ) / ( jc + ca )] where (t j(max) - t a ) is the temperature difference between the maximum allowed die junction (150?)and the surrounding air; jc (junction to case) is the figure 3. typical operating circuit with adjustable output voltage inin in in shdn ss gnd outout out out rst set on off c out 1 f c in 1 f v out v in resetoutput max8869 r1r2 figure 4. typical operating circuit with soft-start and current- limit reduction inin in in shdn ss outout out out rst set gnd on off c out 1 f c in 1 f v out v in resetoutput max8869 c ss r ss downloaded from: http:///
max8869 1a, microcap, low-dropout, linear regulator 9 maxim integrated thermal resistance of the package chosen, and ca is the thermal resistance from the case through the pcboard, copper traces, and other materials to the sur- rounding air. figure 5 shows the allowable power dissi- pation for typical pc boards at +25?, +50?, and +70? ambient temperatures. the max8869 tssop-ep package features an exposed thermal pad on its underside. this pad lowers the package? thermal resistance by providing a direct thermal heat path from the die to the pc board. additionally, gnd also channels heat. connect the exposed thermal pad and gnd to circuit ground by using a large pad (1in 2 minimum recommended) or multiple vias to the ground plane. applications information capacitor selection and regulator stability capacitors are required at the max8869 input and out-put. connect 1? or greater capacitors between in and gnd (c in ) and out and gnd (c out ). due to the max8869? relatively high bandwidth, use only surface-mount ceramic capacitors that have low equivalent series resistance (esr) and high self-resonant frequen- cy (srf). make the input and output traces at least 2.5mm wide (the width of the four parallel inputs and outputs), and connect c in and c out within 6mm of the ic to minimize the impact of pc board trace induc-tance. the width of the ground trace should be maxi- mized underneath the ic to ensure a good connection between gnd and the ground side of the capacitors. the output capacitor? esr and srf can affect stability and output noise. use capacitors with greater than 5mhz srf and esr of 60m ? or less to ensure stability and optimum transient response. this is particularly true inapplications with very low output voltage (<2v) and high output current (>0.5a). since some capacitor dielectrics may vary over bias voltage and temperature, consult the capacitor manu- facturer specifications to ensure that the capacitors meet these requirements over all voltage and tempera- ture conditions used. soft-start capacitor selection a capacitor (c ss ) connected from ss to gnd causes the max8869 output current to slowly rise during start-up, reducing stress on the input supply. the rise time to full current limit (t ss ) is determined by: t ss = 2.08 ? 10 -4 ? c ss where c ss is in nf. typical capacitor values between 10nf to 100nf, with a 5v rating, are sufficient. because this ramp is applied to the current-limit com- parator, the actual time for the output voltage to ramp up depends on the load current and output capacitor. leave ss open to disable soft-start. input-output (dropout) voltage a regulator? minimum input-to-output voltage differen-tial (dropout voltage) determines the lowest usable sup- ply voltage. in battery-powered systems, this determines the useful end-of-life battery voltage. since a 0.2 ? p-channel mosfet is used as the pass device, dropout voltage is the product of r ds(on ) and load current (see electrical characteristics and dropout voltage vs. output current in typical operating characteristics ). the max8869 operating current remains low in dropout. noise, psrr, and transient response the max8869 is designed to achieve low dropout volt-age and low quiescent current in battery-powered sys- tems while still maintaining good noise, transient response, and ac rejection (see psrr vs. frequency in the typical operating characteristics) . when operat- ing from very noisy sources, supply noise rejection andtransient response can be improved by increasing the values of the input and output capacitors and employ- ing passive postfiltering. max8869 output noise is typi- cally 150? rms. (see the output noise plot in the typical operating characteristics) . figure 5. power operating region: maximum output current vs. input-output differential voltage 0 0.60.4 0.2 0.8 1.0 1.2 1 03 24 5 input-output differential voltage maximum output current (a) maximum continuous current typical supply voltage limit t a = +70 c t a = +50 c t a = +25 c t j = +150 c typical dropout voltage limit downloaded from: http:///
max8869 1a, microcap, low-dropout, linear regulator 10 maxim integrated package information for the latest package outline information and land patterns (foot-prints), go to www.maximintegrated.com/packages . note that a ?? ?? or ??in the package code indicates rohs status only.package drawings may show a different suffix character, but the drawing pertains to the package regardless of rohs status. package type package code outline no. land pattern no. 16 tssop u16e+3 21-0108 90-0120 chip information process: bicmos downloaded from: http:///
maxim integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim integrated product. no circuit patent licenses are implied. maxim integrated reserves the right to change the circuitry and specifications without notice at any time. the parametric values (min and max limits) shown in the electrical characteristics table are guaranteed. other parametric values quoted in this data sheet are provided for guidance. maxim integrated 160 rio robles, san jose, ca 95134 usa 1-408-601-1000 ________________________________ 11 2012 maxim integrated products, inc. maxim integrated and the maxim integrated logo are trademarks of maxim integrated products, inc. max8869 1a, microcap, low-dropout, linear regulator revision history revision number revision date description pages changed 0 8/00 initial release 1 6/10 added lead-free versions to ordering information , updated continuous power dissipation and added soldering temperature to absolute maximum ratings , and added ep row to pin description 1, 2, 6 2 10/12 added automotive qualified part to ordering information 1 downloaded from: http:///

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