ams3109 micropower 700ma lo w noise fast transient response ldo 02/11/2010 www.advanced-monolithic.com phone (925) 443-0722 1 fax (925) 443-0723 general description the ams3109 is a high performance linear regulator with very low dropout voltage and excellent transient response. it is designed to operate with wide input voltage range of 1.5 ? 12volts making it ideal for two step conversion while maintaining high efficiency for many power sensitive applications. the device is capable of supplying 700ma of output current with a typical dropout voltage of 550mv. the product is available in adjustable output voltage. the linear regulator has been optimized for noise sensitive applications. the device includes an enable pin for electrical on/off of the regulator. forcing the enable pin to logic low shuts down the ldo and reduces the supply current below 1a. the product includes complete shor t-circuit and thermal protection. the co mbination of these two internal protection circuits gives the device a comprehensive safety system to safe guard against extreme adverse operating conditions. the ams3109 is available in a thermally enhanced soic-8 edp package, and it is rated for -40c to +125c temperature range. features ? v in range: 1.5 ? 12v ? adjustable output voltage as low as 0.6v ? 700ma maximum output current ? 550mv typical dropout voltage at 700ma ? low self noise ? enable (en) pin for ldo on/off ? 120a typical supply current ? bypass (c byp ) pin for low psrr and output noise ? psrr > 40db at 10khz ? stable with electrolytic, tantalum or ceramic capacitors ? current limit protection ? over-temperature shutdown ? -40 to +125c temperature range ? thermally enhanced soic-8 exposed paddle package ? rohs & weee compliant applications ? asic power supplies in: ? set-top boxes, desktops, notebooks ? graphic cards, printers and copiers ? dvd, blue-ray dvd writers ? lcd tvs and lcd monitors ? infotainment ? wireless & rf: applications ? dsp and fpga power supplies ? medical instrumentation ? smps post-regulator typical application
ams3109 micropower 700ma lo w noise fast transient response ldo 02/11/2010 www.advanced-monolithic.com phone (925) 443-0722 2 fax (925) 443-0723 pin description (soic-8 edp package) pin # symbol description 1 byp reference bypass pin. connect an external capacitor from c byp to ground to bypass the noise generated by the inter nal bandgap. this improves power supply rejection ratio and output noise. 2 nc no connection 3 gnd ground 4 v in input supply voltage. it powers the internal control circuitry and the internal power switch. bypass v in with at ceramic capacitor from this pin to ground. 5 v out output voltage 6 adj provides feedback to error amplifier from the resistive divider that sets the output voltage. 7 nc no connection 8 en enable pin. it controls the electrical on/o ff of the device. when connected to logic low, the device shuts off and consumes less than1 a of current. logic high will resume normal operation. 9 gnd expose pad. connected to pcb ground plane for good thermal dissipation. pin configuration soic-8edp (top view)
ams3109 micropower 700ma lo w noise fast transient response ldo 02/11/2010 www.advanced-monolithic.com phone (925) 443-0722 3 fax (925) 443-0723 absolute maximum ratings (1) maximum input supply voltage (v in )???....??..? -0.3v to 15v enable voltage (en)?????..?..????.??? -0.3v to 15v adjustable voltage (adj).??...?????????? -0.3v to 3v bypass voltage (byp)????..?..???????? -0.3v to 3v storage temperature range?????................. -65 ? c to 150 ? c lead temperature???????..????...?????? 260 ? c junction temperature???...??????..?..????? 125 ? c recommended operating conditions (2) input voltage???????????..???.???.. 1.5v to 12v ambient operating temperature?????.??? -40 ? c to 125 ? c thermal information 8l soic ep ja (3) ????????????.???.?...45 ? c/w electrical characteristics unless otherwise noted: v in =3.3v, v out =1.8v, c in =10 f, c out =22f, -40 ? c t a =t j 85 ? c, t j(max.) = 125 c, typical values are t a = 25 c parameter symbol conditions min. typ. max. units output voltage accuracy v out -3 3 % adjustable voltage v adj 0.588 0.600 0.612 v adjustable bias current i adj_bias 10 100 na maximum output current i out_max 700 ma load regulation i out = 0 ? 700ma 0.6 % line regulation v in =3.0 ? 12v; i out =100ma 0.15 % supply current i sup v in =3.3v, io=0a 120 150 a shutdown current i shdn v in =3.3v, v en =0v <1 a current limit i lim 800 ma dropout voltage v do i out =100ma; v out =95% of v out(nom) 220 mv i out =250ma; v out =95% of v out(nom) 300 i out =500ma; v out =95% of v out(nom) 425 i out =750ma; v out =95% of v out(nom) 600 psrr v out / v in f=10khz io=20ma 33 db output noise voltage e n bw: 100hz?100 khz c out = 22f i load = 150ma no c byp 118 v(rms) c byp = 10nf 33 enable threshold low v en(l) 1 v enable threshold high v en(h) 1.1 v input enable low current i en(l) v en = 0v 0 10 na input enable high current i en(h) v en = 1.5v 150 300 na thermal shutdown t sd 145 c thermal shutdown hysteresis t sd_hys 15 c notes: 1. stresses above those listed in absolute maximu m ratings may cause permanent damage to the device. 2. measured on approximately 1? square of 1 oz. copper. 3. the total power dissipation for so-8 ed p package is recommended to 2.5w rated at 25 ? c ambient temperature. the thermal resistance junction to case is 45 ? c/w. total power dissipation for the switching regulator and the ldo should be taken in consideration when calculating the outp ut current capability of each regulator
t y adjust voltage (v) ground current (ma) 02/11/201 0 y pical perf o 0.600 0.602 0.604 0.606 -50 adjust voltage (v) a d v a r 0 5 10 15 20 25 30 0 1 ground current (ma) i gnd v s 0 o rmance c -25 0 ambient d just (adj) v r iation (adju s 1 00 200 3 outp u s . output cu r ot tvlt ch (%) mi c c haracteri s 25 50 7 temperatur e v oltage tem s table volta g 3 00 400 5 u t current ( a r rent v o =1.8 v 25c -0.6 -0.4 -0.2 0 0.2 0.0 o u t pu t v o lt age ch ange (%) c ropower 7 www.a d s tics (t a = 2 7 5 100 1 2 e (oc) perature g e option) 00 600 7 0 a ) v , vin=2.5 v \ 50c 100c ou t lo a 7 00ma lo w d vanced-mon o 4 2 5c unless o 2 5 0 0 output voltage error (%) shutdown current (a) 0.1 t put current a d regulatio n w noise f a o lithic.com o therwise s p -0.2 -0.1 0.0 0.1 0.2 3 line r 0 10 20 30 40 50 01 2 shut d (a) n a a st transi e p ecified) 6 input v r egulation v o 2 345 input v o d own curre n 1.0 a ms 3 e nt respo n phone (925 ) fax (925 ) 9 oltage (v) o = 1.8v, i o = 678 9 o ltage (v) n t vs. input v 125c 25c 3 109 n se ldo ) 443-0722 ) 443-0723 12 = 100ma 9 10 11 12 v oltage
t y 5 dropout voltage (mv) 02/11/201 0 y pical perf o 0ma to 550m a 0 100 200 300 400 500 600 700 0 1 dropout voltage (mv) 0 o rmance c load tr a a , v out =1.8v, 1 00 200 3 outpu t v do vs. o mi c c haracteri s nsient v in =3.3v c in = 3 00 400 5 t current (m a o utput curre n 100c \ 50c 25c c ropower 7 www.a d s tics (t a = 2 c out =4.7f 5 00 600 7 a ) n t v out = 1.8v 7 00ma lo w d vanced-mon o 5 2 5c unless o i out = 00 2 3 4 5 6 7 dropout voltage (mv) w noise f a o lithic.com o therwise s p = 0 to 350ma, v 2 00 3 00 4 00 5 00 6 00 7 00 -50 -2 v do a a st transi e p ecified) enable sta r v out = 1.8v, v 50 a mbient te m vs. temper a a ms 3 e nt respo n phone (925 ) fax (925 ) r t-up v in = 3.0v, c in = 25 50 m perature ( a ture (i o = 7 0 3 109 n se ldo ) 443-0722 ) 443-0723 = c out =10f 75 100 c) 0 0ma)
ams3109 micropower 700ma lo w noise fast transient response ldo 02/11/2010 www.advanced-monolithic.com phone (925) 443-0722 6 fax (925) 443-0723 functional block diagram figure 1: block diagram of ams 3109
ams3109 micropower 700ma lo w noise fast transient response ldo 02/11/2010 www.advanced-monolithic.com phone (925) 443-0722 7 fax (925) 443-0723 device summary the ams3109 is a high voltage low drop out linear regulator with a current cap ability of up to 700ma. the ldo has an input voltage range of 1.5v to 12v with an output voltage as low as 0.6v and is stable with a wide range of ceramic, t antalum, and electrolytic output capacitors. shutdown/enable the enable (on/off) input threshold voltage is 1.1v. when disabled the ldo quies cent current decreases to a typical value of <1a. fault protection short circuit and over-tem perature shutdown disable the converter and ldo in the event of an overload condition. overtemp shut down disables the device when the junction temperature exceeds 145 oc. the output current is internally limited to 800ma. input capacitor an input bypass capacitor ranging from 1f to 10f is required. the capacitor should be placed as close as possible to the device and not be placed more than 1 inch from the ldo. output capacitor the output capacitor requirements range from the minimum value required to guarantee stability to a larger value required to meet the extreme transient response requirements. values range from 10 to 22f x5r ceramic capacitors. due to the extreme voltage coefficient of x5r ceramic capacitors, the voltage rating should be at least double the maximum applied voltage. bypass capacitor whether the ldo is configured to be in a fixed or adjustable voltage configuration, connecting a capacitor between the bypa ss (byp) pin and ground can significantly reduce output noise. values can range from 0pf to 10nf, depending on the sensitivity to output noise in the application. the start-up speed of the ams3109 is inversely proportional to the size of the bypass capacitor. applications requiring a slow ramp-up of output voltage should consider larger values of bypass capacitance. likewise, if rapid turn- on is necessary, consider omitting c byp . because the bypass (byp) pin is high-impedance, careful considering must be taken in the pcb layout to minimize noise pickup, and capacitors must be selected to minimize current leakage. current leakage into the byp pin w ill directly affect the regulator?s accuracy and should be kept low as possible. using high quality ceramic and film types capacitors are recommended for their low leakage characteristics. adjustable feedback resistor selection ams 3109 uses a 0.6v reference voltage at the positive terminal of the error amplifier. to set the output voltage a programming resistor from the adjust pin (adj) to ground must be selected (see pg.1). a 10k ? resistor is a good selection for a programming resistor r2. a higher value may result in an excessively sensitive feedback node while a lower value will draw more current and degrade the light load efficiency. the equation for selecting the voltage specific resistor is: r 1 = vout vref -1 r 2 = 1.8 v 0.6v -1 10k ? = 20k ? table 1: adjustable feedback resistor values v out (v) r1 (k ? ) (r2=10k ? ) 1.8 20.0 2.5 31.6 3.3 45.3 5.0 73.2 pcb layout the following guidelines should be followed to insure proper layout. 1. v in capacitor. a low esr ceramic bypass capacitor must be placed as close to the ic as possible. 2. adjustable (adj) feedback resistors. the adjustable feedback resistors should be placed as close as possible the ic. minimize the length of the trace from the feedback pin to the resistors. this is a high impedance node susceptible to interference from external rf noise sources. 3. ground. 4. for good thermal performance vias are required to couple the exposed tab of the so-8 package to the pcb ground plane. the via diameter should be 0.3mm to 0.33mm positioned on a 1.2mm grid.
ams3109 micropower 700ma lo w noise fast transient response ldo 02/11/2010 www.advanced-monolithic.com phone (925) 443-0722 8 fax (925) 443-0723 output power and thermal limits the ams3109 junction temperature and current capability depends on the internal dissipation and the junction to case thermal resistance of the so-8 exposed paddle package. additionally, the paddle and pcb temperature will be elevated due to the total losses of the ldo and of other circuits mounted to the pcb. tjmax = pd jc + tpcb + tamb the internal losses contribute to the junction temperature rise above the paddle and pcb temperature.
ams3109 micropower 700ma lo w noise fast transient response ldo 02/11/2010 www.advanced-monolithic.com phone (925) 443-0722 9 fax (925) 443-0723 figure 2: ams3109 evaluation board top side figure 3: ams3109 evaluation board bottom side figure 4: ams3109 evaluation board schematic table 2: ams3109 evaluation board bill of materials component value manufacturer manufacturer part number c1 10f, 50v, x5r, 1210, ceramic taiyo yuden umk325bj106km-t c2 22f, 10v, x5r, 0805, ceramic taiyo yuden lmk212bj226mg-t c3 optional feedforward c4 10nf, 50v,20%,x7r,0603 murata grm188r71h103ma01 r1 1.2v 10.0k ? , 0.1w, 0603 1% various crcw0603xxkxfkea 1.8v 20.0k ? , 0.1w, 0603 1% various crcw0603xxkxfkea 2.5v 31.6k ? , 0.1w, 0603 1% various crcw0603xxkxfkea 3.3v 45.3k ? , 0.1w, 0603 1% various crcw0603xxkxfkea 5.0v 73.2k ? , 0.1w, 0603 1% various crcw0603xxkxfkea r2 10.0k ? , 0.1w, 0603 1% various crcw060310k0fkea u1 linear regulator ams ams3109 soic-8 edp vin vout c1 10uf r2 10.0k r1 gnd gnd c2 22uf 1 2 enable c3 n/a c4 10nf en 8 vin 4 gnd 3 nc 2 byp 1 adj 6 nc 7 vout 5 u1 ams3109
ams3109 micropower 700ma lo w noise fast transient response ldo 02/11/2010 www.advanced-monolithic.com phone (925) 443-0722 10 fax (925) 443-0723 ordering information device package ams3109s (1)(2) soic-8 edp notes: 1. available in tape and reel only. a reel contains 2,500 devices. 2. available in lead-free package only. de vice is fully weee and rohs compliant outline drawing and landing pattern soic-8 package dimensions are inches (millimeters) unless otherwise noted. 0-8 typ 0.010-0.020 (0.254 -0.508) s ( so- 8 ) ams drw # 042293 x 45 0.016-0.050 (0.406-1.270) 0.008-0.010 (0.203-0.254) 0.004-0.010 (0.101-0.254) 0.014-0.019 (0.355-0.483) 0.053-0.069 (1.346-1.752) 0.050 (1.270) typ 0.150-0.157** (3.810-3.988) 0.228-0.244 (5.791-6.197) 0.189-0.197* (4.801-5.004) 12 34 87 65 12 34 87 65 0.090 (2.28) 0.102 (2.59) 0.123 (3.12) 0.137 (3.48) 0.138 (3.50) 0.105(2.67) 0.213(5.41) 0.050(1.27) 0.024(0.61) 0.063(1.60) *dimension does not include mold flash. mold flash shall not exceed 0.006" (0.152mm) per side **dimension does not include interlead flash. interlead flash shall not exceed 0.010" (0.254mm) per side recommended layout pattern
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