1 (9) da9485.001 7 march, 2001 mas9485 ldo voltage regulator ic ? 100ma very low dropout voltage regulator ? low noise ? regulator enable/disable control ? stable even with low-esr output capacitor description the mas9485 is a low dropout voltage regulator with an enable/disable pin, which allows device to be turned off or on by pulling control to low or high. due to the low noise level of only 30 vrms, mas9485 is suitable for sensitive circuits, e.g., in portable applications. in addition to the noise levels, mas9485 excels in dropout voltage (150 mv typical at 100 ma) and rise time (15 s typical without bypass capacitor. a very wide range of values of equivalent series resistance (esr) of output capacitors can be used with mas9485. this esr range from a few m ? up to a couple of ten ohms combined with no minimum output current requirement makes the usage of mas9485 easier and low in cost. in order to save power the device goes into sleep mode when the regulator is disabled. an internal thermal protection circuit prevents the device from overheating. also the maximum output current is internally limited. features application ? output accuracy < 2% ? low noise ? internal thermal shutdown ? short circuit protection ? sot23-5 package ? pin compatible with lp2985 ? output voltage options: 3.3 v, 2.8 v, and 2.4 v ? cellular phones ? cordless phones ? pagers ? battery powered systems ? portable systems ? radio control systems ? low voltage systems pin configuration and description pin name pin type function vin 1 p power supply voltage gnd 2 g ground ctrl 3 i enable/disable pin for regulator (push down) bypass 4 i pin for bypass capacitor vout 5 o output 123 4 5 vin vout ctrl gnd bypass top view g = ground, i = input, o = output, p = power for top marking information see p. 9 ordering information
2 (9) da9485.001 7 march, 2001 block diagram absolute maximum ratings all voltages with respect to ground. parameter symbol conditions min max unit supply voltage v in -0.3 6 v esd rating human body model, hbm 1.5 kv junction temperature t jmax +170 (limited) c operating junction temperature t j - 40 +125 c storage temperature t s -55 +150 c operating ambient temperature t a -40 +85 c stresses beyond those listed may cause permanent damage to the device. the device may not operate under these conditions, but i t will not be destroyed. ctrl vin vout gnd over current / over temperature protection voltage reference + bypass 80k ?
3 (9) da9485.001 7 march, 2001 electrical characteristics t a = 27 c, v in = typ v out + 1.0 v, i out = 1.0 ma, c in = 1.0 f, c out = 1.0 f, v ctrl = v in , unless otherwise specified thermal protection parameter symbol conditions min typ max unit threshold high t h 140 155 170 c threshold low t l 130 145 160 c the hysteresis of 10 o c prevents the device from turning on too soon after thermal shut-down. control terminal specifications parameter symbol conditions min typ max unit control voltage off state on state v ctrl 1.6 0.55 v control current i ctrl v ctrl = v in v ctrl = 0 v 5 0 10 a voltage parameters parameter symbol conditions min typ max unit output voltage tolerance v out 2.76 2.88 v operating supply voltage v in 2.5 6 v dropout voltage v drop i out = 1 ma i out = 50 ma i out = 100 ma 15 70 150 mv current parameters parameter symbol conditions min typ max unit continuous output current i out 100 ma short circuit current i max r l = 0 ? 250 ma peak output current i pk v out > 95%*v out typical 210 ma ground pin current i gnd i out = 0 ma i out = 10 ma i out = 50 ma i out = 100 ma v ctrl < 0.3 v 100 125 170 230 0.01 a
4 (9) da9485.001 7 march, 2001 power dissipation parameter symbol conditions min typ max unit junction to case thermal resistance r jc 81.0 c/w junction to ambient thermal resistance r ja 260 c/w maximum power dissipation p d any ambient temperature ja a (max) j max d r t t p ? = mw note 1 note 1: t j(max) denotes maximum operating junction temperature (+125 c), t a ambient temperature, and r ja junction-to-air thermal resistance (+260 c/w). line and load regulation parameter symbol conditions min typ max unit line regulation v out + 1 v < v in < 6 v i out = 60 ma 3.0 mv load regulation i out = 1.0 to 50 ma i out = 1.0 to 100 ma 5 10 15 20 mv noise and ripple rejection parameter symbol conditions min typ max unit output noise voltage v rms 300hz < f < 50khz, c bypass = 10 nf 30 vrms noise density v n c bypass = 10 nf, i out = 50 ma, f = 1.0 khz 250 nv sqrt(hz) psrr c bypass = 10 nf f = 1khz f = 10 khz f = 100 khz 55 45 23 db dynamic parameters parameter symbol conditions min typ max unit rise time (10% ? 90%) v ctrl = 0 to 2.4 v, i out = 30ma c bypass = 10 nf w/o c bypass 3 15 ms s overshoot v ctrl = 0 to 2.4 v w/o c bypass 35 % start-up delay v ctrl to v out 60 s
5 (9) da9485.001 7 march, 2001 application information ctrl vin vout over current / over temperature protection voltage reference + c bypass 80k ? c in c out gnd bypass 1 2 3 4 5
6 (9) da9485.001 7 march, 2001 load transient vs. vout capacitor esr load current changes from 10ma to 90ma during 1 s. load current changes from 90ma to 10ma during 1 s. typical load transient for battery supply and ceramic capacitor, esr 0.1 ? 0.2 ? . typical load transient for battery supply and tantalum capacitor, esr 1 ? 3 ? parameter symbol min max unit comment output capacitor capacitance c out 0.22 f effective series resistance esr 0.05 20 ? good capacitor value is 0.47 ? 2 f. to have load transient overshoot/undershoot small it is recommended to use capacitor with esr no less than 1 ? . with smaller esr the regulator is stable, but load transients can get worse. bypass capacitor c bypass typically 10 nf using this capacitor decreases noise on regulator output. dc leakage of capacitor should be below 100na. input capacitor c in 1 f any type of capacitor can be used. small capacitor esr and bigger capacitor value will make load transient better. when selecting capacitors, tolerance and temperature coefficient should be considered to make sure the requirements are met.
7 (9) da9485.001 7 march, 2001 package (sot-23-5) outline dimension min max unit a 2.60 3.00 mm b 1.45 1.75 mm c 2.80 3.10 mm d 0.00 0.15 mm e 0.90 1.30 mm f 0.25 0.50 mm g 0.95ref mm h 1.90ref mm j 0.09 0.20 mm k010 l 0.35 0.55 mm dimensions do not include mold flash, protrusions or gate burrs. h j l k e d f pin 1 (top view) a b g c seating plane
8 (9) da9485.001 7 march, 2001 tape specifications feeding direction 8 mm 4 mm sot23 5ld tape other dimensions according to eia-481 standard
9 (9) da9485.001 7 march, 2001 ordering information product code product top marking package comments MAS9485AST2-T 2.8 v voltage regulator ic 85a2 sot23-5 tape and reel for more voltage options contact micro analog systems oy. local distributor micro analog systems oy contacts micro analog systems oy kamreerintie 2, p.o.box 51 fin-02771 espoo, finland http://www.mas-oy.com tel. (09) 80 521 tel. int. +358 9 80 521 telefax +358 9 805 3213 e-mail: info@mas-oy.com notice micro analog systems oy reserves the right to make changes to the products contained in this data sheet in order to improve the design or performance and to supply the best possible products. micro analog systems oy assumes no responsibility for the use of any circ uits shown in this data sheet, conveys no license under any patent or other rights unless otherwise specified in this data sheet, an d makes no claim that the circuits are free from patent infringement. applications for any devices shown in this data sheet are for illust ration only and micro analog systems oy makes no claim or warranty that such applications will be suitable for the use specified without furthe r testing or modification.
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