general description the max8887/max8888 low-dropout linear regulatorsoperate from a 2.5v to 5.5v input and deliver up to 300ma continuous (500ma pulsed) current. the max8887 is optimized for low-noise operation, while the max8888 includes an open-drain power-ok (pok) ouput flag. both regulators feature exceptionally low 100mv dropout at 200ma. these devices are available in a vari- ety of preset output voltages in the 1.5v to 3.3v range. an internal pmos pass transistor allows the low 55? supply current to remain independent of load, making these devices ideal for portable battery-powered equip- ment such as personal digital assistants (pdas), cellu- lar phones, cordless phones, and notebook computers. other features include a micropower shutdown mode, short-circuit protection, thermal shutdown protection, and an active-low open-drain pok output that indicates when the output is out of regulation. the max8887/max8888 are available in a thin 5-pin sot23 package that is only 1mm high. ________________________applications notebook computerswireless handsets pdas and palmtop computers digital cameras pcmcia cards hand-held instruments features ? guaranteed 300ma output current (500ma forpulsed loads) ? low 100mv dropout at 200ma load ? pok output (max8888) ? 42 v rms output noise (max8887) ? preset output voltages (1.5v, 1.8v, 2.85v, and3.3v) ? 55 a no-load supply current ? thermal-overload and short-circuit protection ? foldback output current-limit protection ? 60db psrr at 1khz ? 0.1 a shutdown current ? thin 5-pin sot23 package, 1mm high max8887/max8888 low-dropout, 300ma linear regulators in sot23 ________________________________________________________________ maxim integrated products 1 gnd bp shdn 15 out in max8887 top view 234 gnd pok shdn 15 out in max8888 234 pin configurations max8887max8888 on off input 2.5v to 5.5v in shdn gnd (bp) pok out v out 300ma c in 2.2 f c out 2.2 f c bp 0.01 f ( ) are for max8887 only. typical operating circuit 19-1859; rev 4; 7/09 ordering information part temp range pin- package t o p mark m a x8 8 8 7 e z k15+ t -40 c to +85 c 5 sot23 adqd max8887ezk18+ t -40 c to +85 c 5 sot23 adpx max8887ezk29+ t -40 c to +85 c 5 sot23 adpy max8887ezk33+ t -40 c to +85 c 5 sot23 adpz max8887ezkxy+ t* -40 c to +85 c 5 sot23 m a x8 8 8 8 e z k15+ t -40 c to +85 c 5 sot23 adqe max8888ezk18+ t -40 c to +85 c 5 sot23 adqa max8888ezk18/v+ t -40 c to +85 c 5 sot23 max8888ezk29+ t -40 c to +85 c 5 sot23 adqb max8888ezk33+ t -40 c to +85 c 5 sot23 adqc max8888ezkxy+ t* -40 c to +85 c 5 sot23 * other versions (xy) between +1.5 and +3.3v are available in 100mv increments. contact factory for other versions. minimum order quantity is 25,000 units. + denotes a lead(pb)-free rohs-compliant package. /v denotes an automotive qualified part . for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. downloaded from: http:///
max8887/max8888 low-dropout, 300ma linear regulators in sot23 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v in = v out + 1v, shdn = in, t a = -40? to +85?, unless otherwise noted.) (note 1) 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 , pok, to gnd...........................................-0.3v to +7v out, bp to gnd ............................................-0.3 to (v in + 0.3v) output short-circuit duration.....................................continuous continuous power dissipation (t a = +70 c) 5-pin sot23 (derate 9.1mw/ c above +70 c)............727mw operating temperature range ...........................-40 c to +85 c junction temperature ......................................................+150 c storage temperature range .............................-65 c to +150 c lead temperature (soldering, 10s) .................................+500 c parameter symbol conditions min typ max units input voltage v in 2.5 5.5 v input undervoltage lockout v in rising (2% typical hysteresis) 2.15 2.4 v t a = +25?, i out = 100ma -1.2 +1.2 i out = 100? to 300ma, t a = 0 c to +85 c -2 +2 output voltage accuracy i out = 100? to 300ma -3 +3 % continuous 300 maximum output current 10ms pulse 500 ma v out = 0 300 current limit v out > 93% of nominal value 420 ma no load 55 100 ground-pin current i out = 300ma 65 ? i out = 1ma 0.5 i out = 200ma 100 200 dropout voltage (note 2) v out = +3.3v i out = 300ma 150 mv line regulation v in = 2.5v or (v out + 0.4v) to 5.5v, i out = 5ma -0.15 0 0.15 %/v max8887 10hz to 100khz, c bp = 0.01?, c out = 2.2?, esr cout < 0.1 42 output noise max8888 10hz to 100khz, c out = 2.2?, esr cout < 0.1 360 ? rms max8887 f < 1khz, c bp = 0.01?, c out = 4.7?, esr cout < 0.1 60 psrr max8888 f < 1khz, c out = 2.2?, esr cout < 0.1 40 db downloaded from: http:///
max8887/max8888 low-dropout, 300ma linear regulators in sot23 _______________________________________________________________________________________ 3 parameter symbol conditions min typ max units shutdown shutdown supply current shdn = gnd, v in = 5.5v 0.1 2 ? v ih 2.5v v in 5.5v 1.6 shdn input threshold v il 2.5v v in 5.5v 0.6 v shdn input bias current shdn = in or gnd 10 100 na out discharge resistance inshutdown shdn = gnd 650 1100 pok (max8888 only) pok trip level, referred to outset point v out falling (1% typical hysteresis) 90 92.5 95 % operating in voltage range forvalid pok 1.0 5.5 v pok output voltage low v ol i sink = 1ma 0.1 v pok output leakage current v pok = 5.5v, shdn = in 100 na thermal protection thermal shutdown temperature 170 c thermal shutdown hysteresis 20 c electrical characteristics (continued)(v in = v out + 1v, shdn = in, t a = -40? to +85?, unless otherwise noted.) (note 1) note 1: all parts are 100% tested at t a = +25?. limits over the operating temperature range are guaranteed by design. note 2: typical and maximum dropout voltage for different output voltages are shown in the typical operating characteristics curves. typical operating characteristics ( typical operating circuit , t a = +25?, unless otherwise noted.) 0 1.00.5 2.01.5 3.02.5 3.5 2.0 3.0 3.5 2.5 4.0 4.5 5.0 5.5 output voltage vs. input voltage max8887/8 toc01 input voltage (v) output voltage (v) i out = 0 i out = 300ma -1.0 -0.6-0.8 0.0 -0.2-0.4 0.2 0.4 0.80.6 1.0 100 50 150 200 250 300 output voltage accuracy vs. load current max8887/8 toc02 load current (ma) % deviation (%) 0 -0.05 -0.02-0.03 -0.04 -0.01 0.0 0.01 0.02 0.03 0.04 0.05 -40 10 -15 35 60 85 output voltage accuracy vs. temperature max8887/8 toc03 temperature ( c) % deviation i out = 0 v in = v out + 500mv downloaded from: http:///
max8887/max8888 low-dropout, 300ma linear regulators in sot23 4 _______________________________________________________________________________________ 0 20 40 60 80 100 120 140 160 0 100 50 150 200 250 300 dropout voltage vs. load current max8887/8 toc04 load current (ma) v dropout (mv) t a = +25 c t a = +85 c t a = -40 c 0 50 100 150 200 250 300 2.5 2.7 2.9 3.1 3.3 dropout voltage vs. output voltage max8887/8 toc05 v out (v) v dropout (mv) i out = 200ma maximum typical 0 1.0 2.0 3.0 4.0 5.0 input voltage (v) 0 5025 100 75 125 150 ground-pin current vs. input voltage max8887/8 toc06 ground-pin current ( a) i load = 300ma i load = 0 0 20 6040 80 100 0 100 50 150 200 250 300 ground-pin current vs. load current max8887/8 toc07 load current (ma) ground-pin current ( a) v in = 5.5v v in = 3.8v 50 5654 52 58 60 62 64 66 68 70 -40 10 -15 35 60 85 ground-pin current vs. temperature max8887/8 toc08 temperature ( c) ground-pin current ( a) i out = 0 v in = v out + 500mv 70 0.01 0.1 1 10 100 1000 6050 40 30 20 power-supply rejection ratio vs. frequency max8887/8 toc09 frequency (khz) psrr (db) 10 0 c out = 2.2 f c bp = 0.01 f v out = 3.30v i load = 30ma max8887 only max8887 output noise dc to 1mhz v out 50 v/div max8887/8 toc10 40ms/div v out = 1.8v, v in = 3.8v, i load = 15 m a load-transient response 50mv/divac-coupled max8887/8 toc11 300ma10ma v out i out v out = 3.3v v in = 3.8v 10 s/div typical operating characteristics (continued) ( typical operating circuit , t a = +25?, unless otherwise noted.) downloaded from: http:///
max8887/max8888 low-dropout, 300ma linear regulators in sot23 _______________________________________________________________________________________ 5 line-transient response max8887/8 toc13 20mv/divac-coupled 4v 4.5v v out v in v out = 3.3v i load = 100ma 100 s/div shutdown waveform max8887/8 toc14 v shdn 1v/divdc-coupled 2v/div v out v out = 3.3v, r load = 10 ? 20 s/div pok waveform max8887/8 toc15 2v/div 2v/div 2v/div v out v pok v in v out = 3.3v, r load = 100 ? 20ms/div pin description max8887 max8888 name function 11i n regulator input. supply voltage can range from 2.5v to 5.5v. bypass with 2.2? capacitor to gnd (see the capacitor selection and regulator stability section). 2 2 gnd ground 33 shdn active-low shutdown input. a logic low reduces the supply current to below 0.1?. in shutdown, pok and out are driven low. connect to in for normal operation. ?p o k open-drain active-low pok output. pok remains low while the output voltage (v out ) is below the reset threshold. connect a 100k pullup resistor to out to obtain a logic level output. pok is driven low in shutdown. if not used, leave this pin unconnected. 4 bp reference bypass. bypass with a low-leakage 0.01? ceramic capacitor. 5 5 out regulator output. sources up to 300ma guaranteed. bypass with 2.2? (<0.2 typical esr) ceramic capacitor to gnd. load-transient response near dropout max8887/8 toc12 50mv/divac-coupled 300ma10ma v out i out v out = 3.3v v in = 3.4v 10 s/div typical operating characteristics (continued) ( typical operating circuit , t a = +25?, unless otherwise noted.) downloaded from: http:///
detailed description the max8887/max8888 are low-dropout, low-quies-cent-current linear regulators designed primarily for battery-powered applications. the devices supply loads up to 300ma and are available in several fixed output voltages in the 1.5v to 3.3v range. the max8887 is optimized for low-noise operation, while the max8888 includes an open-drain pok output flag. as illustrated in figure 1, the max8888 consists of a 1.25v reference, error amplifier, p-channel pass tran- sistor, and internal feedback voltage divider. internal p-channel pass transistor the max8887/max8888 feature a 0.5 ? p-channel mosfet pass transistor. unlike similar designs usingpnp pass transistors, p-channel mosfets require no base drive, which reduces quiescent current. pnp- based regulators also waste considerable current in dropout when the pass transistor saturates and uses high base drive currents under large loads. the max8887/max8888 do not suffer from these problems and consume only 55? of quiescent current under heavy loads as well as in dropout. output voltage selection the max8887/max8888 are supplied with various facto-ry-set output voltages ranging from 1.5v to 3.3v. the part number? two-digit suffix identifies the nominal out- put voltage. for example, the max8887ezk33 has a pre- set output voltage of 3.3v (see the ordering information ). shutdown drive shdn low to enter shutdown. during shutdown, the output is disconnected from the input and supplycurrent drops to 0.1?. when in shutdown, pok and out are driven low. shdn can be pulled as high as 6v, regardless of the input and output voltages. power-ok output the power-ok output (pok) pulls low when out is lessthan 93% of the nominal regulation voltage. once out exceeds 93% of the nominal voltage, pok goes high impedance. pok is an open-drain n-channel output. to obtain a logic level output, connect a pullup resistor from pok to out. a 100k ? resistor works well for most applications. pok can be used as a power-on-reset(por) signal to a microcontroller (?) or to drive other logic. adding a capacitor from pok to ground creates pok delay. when the max8887 is shut down, pok is held low independent of the output voltage. if unused, leave pok grounded or unconnected. current limit the max8887/max8888 monitor and control the passtransistor? gate voltage, limiting the output current to 0.8a (typ). this current limit is reduced to 500ma (typ) when the output voltage is below 93% of the nominalvalue to provide foldback current limiting. thermal overload protection thermal overload protection limits total power dissipa-tion in the max8887/max8888. when the junction tem- perature exceeds t j =+170?, a thermal sensor turns off the pass transistor, allowing the device to cool. thethermal sensor turns the pass transistor on again after the junction temperature cools by 20?, resulting in a pulsed output during continuous thermal overload con- ditions. thermal overload protection protects the max8887/max8888 in the event of fault conditions. for continuous operation, do not exceed the absolute maxi- mum junction-temperature rating of t j =+150?. operating region and power dissipation the max8887/max8888? maximum power dissipationdepends on the thermal resistance of the ic package and circuit board. the temperature difference between the die junction and ambient air, and the rate of air flow. the power dissipated in the device is p = i out ? (v in - v out ). the maximum allowed power dissipation is 727mw or: p max = (t j(max) - t a ) / ( jc + ca ) where t j(max) -t a is the temperature difference between the max8887/max8888 die junction and thesurrounding air; jc is the thermal resistance from the junction to the case; and ca is the thermal resistance from the case through pc board, copper traces, andother materials to the surrounding air. refer to figure 2 for the max8887/max888 valid oper- ating region. noise reduction for the max8887 only, an external 0.01? bypasscapacitor at bp creates a lowpass filter for noise reduc- tion. the max8887 exhibits 42? rms of output voltage noise with c bp = 0.01? and c out = 2.2? (see the typical operating characteristics ) . applications information capacitor selection and regulator stability connect a 2.2? ceramic capacitor between in andground and a 2.2? ceramic capacitor between out and ground. the input capacitor (c in ) lowers the source impedance of the input supply. reduce noiseand improve load-transient response, stability, and power-supply rejection by using a larger ceramic out- put capacitor such as 4.7?. the output capacitor? (c out ) equivalent series resis- tance (esr) affects stability and output noise. use out-put capacitors with an esr of 0.1 ? or less to ensure max8887/max8888 low-dropout, 300ma linear regulators in sot23 6 _______________________________________________________________________________________ downloaded from: http:///
stability and optimum transient response. surface-mountceramic capacitors have very low esr and are com- monly available in values up to 10?. connect c in and c out as close to the max8887/max8888 as possible to minimize the impact of pc board trace inductance. noise, psrr, and transient response the max8887/max8888 are designed to operate withlow dropout voltages and low quiescent currents in bat- tery-powered systems while still maintaining excellent noise, transient response, and ac rejection. see the typical operating characteristics for a plot of power- supply rejection ratio (psrr) versus frequency. whenoperating from noisy sources, improved supply-noise rejection and transient response can be achieved by increasing the values of the input and output bypass capacitors and through passive filtering techniques. input-output (dropout) voltage a regulator? minimum input-to-output voltage differen-tial (dropout voltage) determines the lowest usable sup- ply voltage at which the output is regulated. in battery-powered systems, this determines the useful end-of-life battery voltage. the max8887/max8888 use a p-channel mosfet pass transistor. its dropout volt- age is a function of drain-to-source on-resistance (r ds(on) ) multiplied by the load current (see the typical operating characteristics ). v dropout = v in - v out = r ds(on) ? i out max8887/max8888 low-dropout, 300ma linear regulators in sot23 _______________________________________________________________________________________ 7 shutdown logic error amp 1.25v ref 95% ref p out pok gnd in shdn max8888 thermal sensor mos driver with i limit pok figure 1. functional diagram 0 100 200 300 400 0 1.0 2.0 3.0 0.5 1.5 2.5 3.5 4.0 maximum output current vs. input voltage (power dissipation limit) (v in - v out ) (v) maximum output current (ma) v out = +3.3v v out = +2.85v v out = +1.8v maximum recommended output current t a = +85 c t a = +70 c figure 2. power operating regions: maximum output current vs. input voltage downloaded from: http:///
max8887/max8888 low-dropout, 300ma linear regulators in sot23 8 _______________________________________________________________________________________ package information for the latest package outline information and land patterns, goto www.maxim-ic.com/packages . note that a "+", "#", or "-" in the package code indicates rohs status only. package draw-ings may show a different suffix character, but the drawing per- tains to the package regardless of rohs status. package type package code document no. 5 sot23 z5-1 21-0113 chip information transistor count: 620process: bicmos downloaded from: http:///
low-dropout, 300ma linear regulators in sot23 maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 9 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2009 maxim integrated products maxim is a registered trademark of maxim integrated products. max8887/max8888 revision history revision number revision date description pages changed 0 12/00 initial release 1 12/01 revised output voltage selection section. 6 2 6/04 revised absolute maximum ratings .2 3 11/06 updated ordering information and package outlines. 1, 8 4 7/09 revised ordering information .1 downloaded from: http:///
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