general description the max8516/MAX8517/max8518 low-dropout linear regulators operate from input voltages as low as 1.425v and are able to deliver up to 1a of continuous output current with a maximum dropout voltage of only 200mv. the output voltage can be set from 0.5v to (v in - 0.2v) and is 1.4% accurate over load and line variations, from 0? to +85?. these regulators use small, 1 f ceramic input capaci- tors and 4.7? ceramic output capacitors to deliver 1a output current. high bandwidth provides excellent tran- sient response and limits the output voltage deviation to 45mv for a 20ma to 1a load step, with only a 4.7? ceramic output capacitor, and the voltage deviations can be reduced further by increasing the output capacitor. designed with an internal p-channel mosfet pass transistor, the max8516/MAX8517/max8518 feature low 340? (typ) supply current during dropout condi- tions. soft-start reduces inrush current. other features include a logic-controlled shutdown mode, short-circuit protection, and thermal-overload protection. the MAX8517 features a power-ok (pok) output that transitions high when the regulator output is within ?0% of its nominal output voltage. the max8518 features a 150ms power-on reset output. the parts are packaged in a 10-pin ?ax package that includes an exposed pad for optimal power dispation. applications servers storage networking base stations optical modules features ? 1.425v to 3.6v input voltage range ? guaranteed 200mv dropout at 1a output current ? ?.4% output accuracy over load, line, and temperature (0? to +85?), ?.6% initial accuracy ? compatible with ceramic capacitors ? fast transient response ? 320? operating supply current ? <25? shutdown supply current ? short-circuit protection ? thermal-overload protection ? soft-start limits inrush current max8516/MAX8517/max8518 1.425v to 3.6v input, 1a, 0.2v dropout ldo regulators ________________________________________________________________ maxim integrated products 1 ordering information 19-3188; rev 1; 4/04 for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. evaluation kit available part temp range pin-package max8516 eub -40? to +85? 10 ?ax MAX8517 eub -40? to +85? 10 ?ax max8518 eub -40? to +85? 10 ?ax 1 2 3 4 5 10 9 8 7 6 n.c. out out fb n.c. in in en max8516 max top view gnd n.c. 1 2 3 4 5 10 9 8 7 6 n.c. out out fb pok in in en MAX8517 max gnd n.c. 1 2 3 4 5 10 9 8 7 6 n.c. out out fb n.c. in in en max8518 max gnd por pin configurations max8516 MAX8517 max8518 1 f 4.7 f input 1.425v to 3.6v output 0.5v to (v in - 0.2v), 1a power-on reset power-ok on off in_ por (max8518) pok (MAX8517) en gnd fb out_ typical operating circuit post regulators notebooks pdas ate 1 0 m a x 3 m m x 5 m m ?ax is a registered trademark of maxim integrated products, inc.
max8516/MAX8517/max8518 1.425v to 3.6v input, 1a, 0.2v dropout ldo regulators 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (circuit of figure 1. v in = +1.8v, v out = +1.5v, en = in, i out = 1ma, 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 rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. in, en, pok (MAX8517), por (max8518), fb to gnd .........................................................-0.3v to +4.0v out to gnd ..................................................-0.3v to (in + 0.3v) output short-circuit duration.....................................continuous continuous power dissipation (t a = +70?, ep soldered to pc board ground) 10-pin ?ax (derate 10.3mw/? above +70?) .........824mw operating temperature range ...........................-40 c to +85 c junction temperature ......................................................+150 c storage temperature range .............................-65 c to +150 c lead temperature (soldering, 10s) .................................+300 c parameter conditions min typ max units in input voltage range 1.425 3.600 v input undervoltage lockout v in rising, 70mv hysteresis 1.32 1.35 1.38 v out output voltage range 0.5 3.4 v load regulation i out = 1ma to 1a 0.1 %/a line regulation v in = 1.425v to 3.6v, v out = 1.225v, i out = 1ma -0.15 0 +0.15 % / v dropout voltage (v in - v out )v in = 1.425v, i out = 1a, v fb = 480mv 100 200 mv current limit v in = 3.6v, v out = 3v, v fb = 480mv 1.6 2 2.4 a output shutdown leakage v in = 3.6v, v out = 0, v en = 0 0.25 25 ? fb i out = 10ma, t a = +85 c 497 500 503 fb threshold accuracy v out = 1.225v to 3v, v in = v out + 0.2v to 3.6v, i out = 1ma to 1a 493 507 mv fb input bias current v fb = 0.5v, v in = 3.6v 0.001 1 a gnd v in = 3.6v, v out = 3v, i out = 100ma 320 gnd supply current dropout, v in = 3.6v, v fb = 480mv 340 600 ? gnd shutdown current v in = 3.6v, en = gnd 0.25 25 ? pok (MAX8517 only) fb high 540 550 560 pok threshold v fb moving out of regulation, v hys = 10mv, in = 1.425v to 3.6v fb low 440 450 460 mv pok output voltage low v fb = 0.4v or 0.6v, i pok = 1ma 25 200 mv pok output current high v pok = 3.6v 0.001 1 a pok fault delay time from fb to pok 25 50 100 ?
max8516/MAX8517/max8518 1.425v to 3.6v input, 1a, 0.2v dropout ldo regulators _______________________________________________________________________________________ 3 note 1: specifications to -40? are guaranteed by design, not production tested. note 2: measurements at high current are pulse tested, such that the junction temperature is ambient temperature. minimum supply voltage for output accuracy must be at least 1.425v. electrical characteristics (continued) (circuit of figure 1. v in = +1.8v, v out = +1.5v, en = in, i out = 1ma, t a = -40? to +85?, unless otherwise noted.) (note 1) parameter conditions min typ max units por (max8518 only) por reset threshold v fb falling, v hys = 10mv, v in = 1.425v to 3.6v 440 450 460 mv por output voltage low v fb = 0.4v or 0.6v, i por = 1ma 25 200 mv por output current high v por = 3.6v 0.001 1 a por rising delay time from fb to por 105 150 210 ms en en rising 1.2 enable input threshold v in = 1.425v to 3.6v en falling 0.4 v enable input bias current v en = 0 or 3.6v -1 +1 ? thermal shutdown t j rising +165 thermal-shutdown threshold output on or off t j falling +150 c output transient load transient i out = 20ma to 1a to 20ma, t rise = t fall = 1? 3 % line transient v in = 0.5v, t rise = t fall = 5? 3 % typical operating characteristics (circuit of figure 1, v in = +1.8v, v out = +1.5v, i out = 1a, c out = 4.7?, c in = 1?, t a = +25?.) output voltage vs. input voltage max8516/17/18 toc01 input voltage (v) output voltage (v) 3.0 2.4 1.8 1.2 0.6 1.35 1.40 1.45 1.50 1.55 1.60 1.30 03.6 t a = -40 c to +85 c output voltage vs. load current max8516/17/18 toc02 load current (ma) output voltage (v) 800 600 400 200 1.492 1.494 1.496 1.498 1.500 1.502 1.490 0 1000 1200 t a = +85 c t a = +25 c t a = -40 c ground current vs. input voltage max8516/17/18 toc03 input voltage (v) ground current ( a) 3.0 2.4 0.6 1.2 1.8 100 200 300 400 500 0 03.6 i load = 1a i load = 0.5a i load = 0a
max8516/MAX8517/max8518 1.425v to 3.6v input, 1a, 0.2v dropout ldo regulators 4 _______________________________________________________________________________________ ground current vs. load current max8516/17/18 toc04 load current (ma) ground current ( a) 1000 800 600 400 200 275 300 325 350 375 250 0 1200 t a = +25 c t a = -40 c t a = +85 c dropout voltage vs. load current max8516/17/18 toc05 load current (ma) dropout voltage (mv) 800 600 400 200 25 50 75 100 125 0 0 1000 line input transient (v in = +1.8v to +2.5v, i load = 1a) max8516/17/18 toc06 100 s/div v out ac-coupled 20mv/div v in ac-coupled 0.5v/div load-transient response (i load = 0.1a to 1a) max8516/17/18 toc07 40 s/div v out ac-coupled 50mv/div i load 1a/div c in = 220 f electrolytic cap close to in psrr vs. frequency (max8516) max8516/17/18 toc09 frequency (khz) psrr (db) 100 10 1 0.1 10 20 30 40 50 60 70 80 0 0.01 1000 i load = 100ma shutdown response max8516/17/18 toc08 100 s/div v out 1v/div en 2v/div i in 1a/div typical operating characteristics (continued) (circuit of figure 1, v in = +1.8v, v out = +1.5v, i out = 1a, c out = 4.7?, c in = 1?, t a = +25?.)
max8516/MAX8517/max8518 1.425v to 3.6v input, 1a, 0.2v dropout ldo regulators _______________________________________________________________________________________ 5 fb voltage vs. temperature max8516/17/18 toc10 temperature ( c) fb voltage (mv) 60 35 10 -15 499 500 501 502 498 -40 85 i load = 10ma output ripple voltage max8516/17/18 toc11 100 s/div v out ac-coupled 1mv/div overcurrent threshold vs. temperature max8516/17/18 toc12 temperature ( c) overcurrent threshold (a) 60 35 10 -15 1.80 1.85 1.90 1.95 1.75 -40 85 short-circuit current max8516/17/18 toc13 100 s/div v out 1v/div i out 2a/div case temperature vs. load current max8516/17/18 toc14 load current (ma) case temperature ( c) 800 600 400 200 15 30 45 60 75 0 0 1000 v in = 2.5v; t a = +25 c typical operating characteristics (continued) (circuit of figure 1, v in = +1.8v, v out = +1.5v, i out = 1a, c out = 4.7?, c in = 1?, t a = +25?.)
max8516/MAX8517/max8518 1.425v to 3.6v input, 1a, 0.2v dropout ldo regulators 6 _______________________________________________________________________________________ pin description pin max8516 MAX8517 max8518 name description 111en enable input. set low to place the device in low-current shutdown mode. set high for normal operation. 2, 3 2, 3 2, 3 in regulator input. v in can range from +1.425v to +3.6v. bypass with a 1? or higher ceramic capacitor to gnd. 4, 5, 10 5, 10 4, 10 n.c. no connection. pin 10 is internally pulled down to gnd with a 10k ? resistor. leave floating. 6 6 6 gnd ground 7 7 7 fb feedback pin. connect to output through a voltage-divider to set the output. 8, 9 8, 9 8, 9 out regulator output. bypass with a 4.7? ceramic capacitor to gnd (a smaller capacitor can be used if maximum load is less than 1a, i.e., c out = i out (max) ? (1?/200ma). ? pok power-ok output (MAX8517 only). open-drain output. connect to a positive supply with a pullup resistor. if not used, leave pin unconnected. see the detailed description. 5por power-on reset output. open-drain output. connect to a positive supply with a pullup resistor. if not used, leave pin unconnected (see the detailed description for more details). ep gnd exposed pad on the underside of the package. solder to the ground plane for proper heat dissipation. max8516 MAX8517 max8518 pok (MAX8517 only) por (max8518 only) gnd ref overthermal protection overthermal protection en in undervoltage lockout threshold 0.55v 0.45v 0.50v error amp with soft-start mos driver with i limit out fb functional diagram
detailed description the max8516/MAX8517/max8518 are low-input, low- dropout, pmos regulators capable of delivering up to 1a of output current with as little as 200mv of headroom from input to output. the pmos output stage can be dri- ven from input voltages down to +1.425v without sacri- ficing stability or transient performance. since these regulators have a pmos output device, supply current is not a significant function of load or input headroom. internal p-channel pass transistor the max8516/MAX8517/max8518 feature a 100m ? (typ) p-channel mosfet pass transistor. unlike similar designs using pnp 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 use high base-drive currents under large loads. the max8516/ MAX8517/max8518 do not suffer from these problems and consume only 340? (typ) of quiescent current under heavy loads, as well as in dropout. short-circuit/thermal fault protection the max8516/MAX8517/max8518 are fully protected from a short circuit at the output through current-limiting and thermal-overload circuitry. in the fault condition when the output is shorted to ground, the output current is limited to 2a. under these conditions, the part quickly heats up. when the junction temperature reaches +165?, the thermal-overload circuitry turns off the output, allowing the part to cool down. when the junction temperature cools to +150?, the output turns back on and tries to reestablish regulation. current limiting and thermal protection continue until the fault is removed. for continuous operation, do not exceed the absolute maxi- mum junction-temperature rating of t j = +150?. output voltage selection the max8516/MAX8517/max8518 feature an adjustable output voltage from 0.5v to 3.4v, using two external resistors connected as a voltage-divider to fb as shown in figure 1. the output voltage is set by the following equation: where typically v fb = 0.5v. choose r2 5k ? to opti- mize quiescent current, accuracy, and high-frequency power-supply rejection. to simplify resistor selection: soft-start inherent soft-start limits inrush current. peak inrush cur- rent is dependent on the value of c out and can be cal- culated as follows: shutdown mode the max8516/MAX8517/max8518 include an enable input. to shut down the device, pull en to gnd. for normal operation, connect the en to in. during shut- down, an internal 10k ? resistor pulls down the output. power-ok (MAX8517 only) the MAX8517 features a power-ok (pok) output to indicate the status of the output. pok remains high when the regulator output is within ?0% of its nominal output voltage. if the output voltage falls or rises out- side this range, pok transitions low. this open-drain output requires an external pullup resistor to in. an internal delay circuit prevents pok from switching for 50? (typ) after the trip threshold is initially reached. if the part is in shutdown mode, pok is low. power-on reset (max8518 only) the max8518 features a power-on reset (por) output that transitions high 140ms (typ) after the output has risen above 90% of its final value. this open-drain out- put requires an external pullup resistor to in. if the part is in shutdown mode, falls below 90% of the nominal output voltage, or experiences a short-circuit or thermal fault, por immediately transitions low. ii cf inrush load out () =+ ? ? ? ? ? ? 66 rr v v out fb 12 1 = ? ? ? ? ? ? ? vv r r out fb =+ ? ? ? ? ? ? 1 1 2 max8516/MAX8517/max8518 1.425v to 3.6v input, 1a, 0.2v dropout ldo regulators _______________________________________________________________________________________ 7 max8516 MAX8517 max8518 1 f 4.7 f enable shutdown in in pok (MAX8517) or por (max8518) en gnd fb out out 100k ? * r1 r2 adjustable output *for MAX8517 and max8518 +1.425v to +3.6v figure 1. typical application circuit
max8516/MAX8517/max8518 operating region and power dissipation the maximum power dissipation depends on the ther- mal resistance of the ic package and circuit board, the temperature difference between the die junction and ambient air, and the rate of airflow. the power dissipat- ed in the device is p = i out ? (v in - v out ). the package features an exposed thermal pad on its underside. this pad lowers the thermal resistance of the package by providing a direct heat conduction path from the die to the pc board. additionally, the ground pins (gnd) perform the dual function of providing an electrical connection to system ground and channeling heat away. connect the exposed backside pad and gnd to the system ground using a large pad or ground plane, or multiple vias to the ground plane layer. applications information capacitor selection and regulator stability capacitors are required at the max8516/MAX8517/ max8518 inputs and outputs for stable operation over the full temperature range and with load currents up to 1a. connect a 1? capacitor between in and ground and a 4.7? capacitor with low equivalent series resistance (esr) between out and ground for 1a output current. the input capacitor (c in ) lowers the source impedance of the input supply. if input-supply source impedance is high, place a larger input capacitor close to in to prevent v in sagging due to load transients. smaller output capac- itors can be used for output currents less than 1a. calculate c out as follows: noise, psrr, and transient response the max8516/MAX8517/max8518 are designed to operate with low dropout voltages and low quiescent currents while still maintaining good noise, transient response, and ac rejection (see the typical operating characteristics for a plot of power-supply rejection ratio (psrr) vs. frequency). when operating 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. the max8516/ MAX8517/max8518 load-transient response graphs (see the typical operating characteristics ) show two components of the output response: a dc shift from the output impedance due to the load current change, and the transient response. a typical transient overshoot for a step change in the load current from 20ma to 1a is 45mv. use larger output ceramic capacitors greater than 4.7? up to 50? to attenuate the overshoot. chip information transistor count: 2849 process: bicmos ci fma out out max ( / ) () = 1 200 1.425v to 3.6v input, 1a, 0.2v dropout ldo regulators 8 _______________________________________________________________________________________
max8516/MAX8517/max8518 1.425v to 3.6v input, 1a, 0.2v dropout ldo regulators maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 _____________________ 9 2004 maxim integrated products printed usa is a registered trademark of maxim integrated products. package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation, go to www.maxim-ic.com/packages .) 10l umax, exppads.eps c 1 1 21-0109 package outline, 10l umax, exposed pad
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