ap1603 step-up dc/dc converter this datasheet contains new product information. anachip corp. reserves the rights to modify the product specification without notice. no liability is assumed as a result of the use of this product. no rights under any patent accompany the sale of the product. rev.1.1 feb. 14, 2005 1/8 ? features -a guaranteed start-up from less than 0.9 v. -high efficiency. -low quiescent current. -less number of external components needed. -low ripple and low noise. -space saving pb-free packages: sot23-6 ? applications -pagers. -cameras. -wireless microphones. -pocket organizers. -battery backup suppliers. -portable instruments. ? general description the ap1603 is a high efficiency step-up dc/dc converter for applications using 1 to 2 nimh battery cells. only three external components are required to deliver a fixed output voltage of 3.3v. the ap1603 starts up from less than 0.9v input with 1ma load. pulse frequency modulation scheme brings optimized performance for applications with light output loading and low input voltages. the output ripple and noise are lower compared with the circuits operating in psm mode. the pfm control circuit operating in 150khz (max.) switching rate results in smaller passive components. the space saving sot23-6 packages make the ap1603 an ideal choice of dc/dc converter for space conscious applications, like pagers, electronic cameras, and wireless microphones. ? pin assignments 1 2 3 7 4 6 lx gnd out ref sot23-6l ap1603 5 shdn fb ? pin descriptions name description ref 1.2v reference voltage. bypass with a 0.1f capacitor. out power output. out provides bootstrap power to the ic. lx n-channel and p-channel power mosfet drain gnd ground shdn shutdown input. drive high (>80% of v out ) for operating mode. drive low (<20% of v out ) for shutdown mode. connect to out for normal operation. fb feedback ? ordering information package ap1603 x x packing blank : tube a : taping w: sot23-6l
ap1603 step-up dc/dc converter anachip corp. www.anachip.com.tw rev.1.1 feb. 14, 2005 2/8 ? block diagram + - + - s q r f/f trig one-shot q one-shot q trig maximum on-time one-shot error amplifier current-limit amplifier zero crossing amplifier minimum off-time one-shot + - + - out lx gnd fb ref 0.1uf 22uh 0.1uf + 47uf + 47uf + shdn p n v in en fb ? absolute maximum ratings symbol parameter rating unit v cc supply voltage (out to gnd) -0.3 to 5.5 v v ref ref to gnd -0.3 to v out +0.3 v v sw switch voltage (lx to gnd) -0.3 to v out +0.3 v i out output current (o ut) -0.8 to 0.2 a i sw switch current (l x) -0.8 to 0.2 a t st storage temperature range -65 to +150 o c t ot operation temperature range -40 to +80 o c
ap1603 step-up dc/dc converter anachip corp. www.anachip.com.tw rev.1.1 fe b. 14, 2005 3/8 ? electrical characteristics (v in =2v, fb=v out , r l = , t a = 0c to +85c , unless otherwise noted. typical values are at t a = +25c.) symbol parameter conditions min. typ. max. unit minimum input voltage - 0.9 - v v in operating voltage t a = +25c 1.1 - 5.5 v start-up voltage t a = +25c, rl = 3k ? (note 1) - 0.9 1.1 v start-up voltage tempco - -4 - mv/c output voltage range 2 - 5.5 v fb=v out =3.3v 100 150 - i out steady-state output current (note2) v in =2.4v, fb=gnd, v out =5v - 80 - ma v ref reference voltage i ref =0 1.196 1.22 1.244 v fb=v out 3.17 3.3 3.43 v out output voltage fb=gnd 4.8 5 5.2 v tempco reference voltage tempco - 0.05 - mv/c v ref_load reference voltage load regulation i ref =0 to 20 a - 15 80 mv v ref_line reference voltage line regulation v in =1.1v to 3.6v - 0.08 1.5 mv/v r ds(on) internal nfet, pfet on-resistance i lx =100ma - 0.6 1.0 ? i lim lx switch current limit (nfet) 0.3 0.35 0.4 a i leak lx leakage current v lx =0, 5.5v; v out =5.5v - 0.05 1 a operating current into out v out =3.3v - 16 35 a shutdown current into out shdn =gnd - 0.1 1 a efficiency v out =3.3v, i load =100ma - 90 - % t on lx switch on-time 3 4 7 s t off lx switch off-time 1.0 1.2 1.4 s i shdn shdn input current v shdn =0 or v out - 0.07 50 na v il - - 0.2 v ih shdn input voltage based on v out voltage 0.8 - - v out note 1: start-up voltage operation is guaranteed with the addition of a schottky 1n5819 external diode between the input and output. note 2: steady-state output current indicates that the device maintains output voltage regulation under load.
ap1603 step-up dc/dc converter anachip corp. www.anachip.com.tw rev.1.1 fe b. 14, 2005 4/8 ? typical application circuit (1) v out =5v shdn lx out ref 0.1uf 22uh 47uf + 47uf + v in on off fixed output ( 5v ) gnd 1.1v to 5.5v fb (2) v out =3.3v shdn lx out ref 0.1uf 22uh 47uf + 47uf + v in on off fixed output ( 3.3v ) gnd 1.1v to 3.6v fb (3) v out =adj shdn lx out ref 0.1uf 22uh 47uf + 47uf + v in on off output gnd 1.1v to 5.5v fb r2 r1 v out = v ref (1+ ) r1 r2
ap1603 step-up dc/dc converter anachip corp. www.anachip.com.tw rev.1.1 fe b. 14, 2005 5/8 ? typical performance characteristics reference voltage v.s. temperature 1.18 1.19 1.2 1.21 1.22 1.23 -40-20 0 20406080 temperature ( o c) reference voltage (v) steady state output current v.s. input voltage 0 80 160 240 320 400 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 input voltage (v) steady state output current (ma) start-up voltage v.s. load current 0.8 1 1.2 1.4 1.6 1.8 2 0 3 9 1839597999 load current (ma) start-up voltage (v) with diode without diode 1n5819 no load input current v.s. input voltage 50 75 100 125 150 175 0.89 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 input voltage (v) no load input current (ua)
ap1603 step-up dc/dc converter anachip corp. www.anachip.com.tw rev.1.1 fe b. 14, 2005 6/8 ? typical performance char acteristics (continued) efficiency v.s. input voltage=1.2v 82.00 83.00 84.00 85.00 86.00 87.00 88.00 89.00 90.00 91.00 2 .89 7.94 17.86 2 7 . 9 37 . 9 47. 9 5 7 . 9 67 . 9 77. 6 8 7 . 7 97 . 6 input voltage=1.2 (v) efficiency (%) efficiency v.s. input voltage=2.4v 80.00 81.00 82.00 83.00 84.00 85.00 86.00 87.00 88.00 89.00 90.00 91.00 92.00 2. 9 1 27.9 57 .9 8 7 .6 1 1 7.6 147.6 177.5 2 0 8 2 3 8 2 68 298 input voltage=2.4 (v) efficiency (%) shutdown current v.s. supply voltage -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1234 supply voltage (v) shutdown current (ua) shutdown threshold voltage v.s. supply voltage 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 11.522.533.54 supply voltage (v) shutdown threshold voltage (v) ? marking information identification code (see appendix) 1 2 3 6 7 4 xx y m 5 year: 0-9 month: a~l appendix part number package identification code ap1603 sot23-6 ey
ap1603 step-up dc/dc converter anachip corp. www.anachip.com.tw rev.1.1 fe b. 14, 2005 7/8 ? function descriptions general description ap1603 pfm (pulse frequency modulation) converter ic series combine a switch mode converter, power mosfet, and precision voltage reference in a single monolithic device. they offer both extreme low quiescent current, high efficiency, and very low gate threshold voltage to ensure start-up with low battery voltage (0.9v typ.). designed to maximize battery life in portable products, and minimize switching losses by only switching as needed service the load. pfm converters transfer a discrete amount of energy per cycle and regulate the output voltage by modulating switching frequency with the constant turn-on time. switching frequency depends on load, input voltage, and inductor value, and it can range up to 150khz. the sw on resistance is typically 1 to 1.5 w to minimize switch losses. when the output voltage drops, the error comparator enables 150khz oscillator that turns on the mosfet around 7.5us and 2.5ms off time. turning on the mosfet allows inductor current to ramp up, storing energy in a magnetic field and when mosfet turns off that force inductor current through diode to the output capacitor and load. as the stored energy is depleted, the current ramp down until the diode turns off. at this point, inductor may ring due to residual energy and stray capacitance. the output capacitor stores charge when current flowing through the diode is high, and release it when current is low, thereby maintaining a steady voltage across the load. as the load increases, the output capacitor discharges faster and the error comparator initiates cycles sooner, increasing the switching frequency. the maximum duty cycle ensure adequate time for energy transfer to output during the second half each cycle. depending on circuit, pfm converter can operate in either discontinuous mode or continuous conduction mode. continuous conduction mode means that the inductor current does not ramp to zero during each cycle. inductor selection to operate as an efficient energy transfer element, the inductor must fulfill three requirements. first, the inductance must be low enough for the inductor to store adequate energy under the worst case condition of minimum input voltage and switch on time. second, the inductance must also be high enough so maximum current rating of ap1603 and inductor are not exceed at the other worst case condition of maximum input voltage and on time. lastly, the inductor must have sufficiently low dc resistance so excessive power is not lost as heat in the windings. but unfortunately this is inversely related to physical size. minimum and maximum input voltage, output voltage and output current must be established before and inductor can be selected. capacitor selection a poor choice for a output capacitor can result in poor efficiency and high output ripple. ordinary aluminum electrolyzers, while inexpensive may have unacceptably poor esr and esl. there are low esr aluminum capacitors for switch mode dc-dc converters which work much better than general propose unit. tantalum capacitors provide still better performance at more expensive. os-con capacitors have extremely low esr in a small size. if capacitance is reduced, output ripple will increase. most of the input supply is supplied by the input bypass capacitor. the capacitor voltage rating should be at least 1.25 times greater than a maximum input voltage.
ap1603 step-up dc/dc converter anachip corp. www.anachip.com.tw rev.1.1 fe b. 14, 2005 8/8 ? package information package type: sot23-6l c b g a h (ref.) e 0.20 j (ref.) i (ref.) k (ref.) f d (typ.) ll 1 3 4 65 2 dimensions in millimeters dimensions in inches symbol min. nom. max. min. nom. max. a 2.70 2.90 3.10 0.106 0.114 0.122 b 2.60 2.80 3.00 0.102 0.110 0.118 c 1.40 1.60 1.80 0.055 0.063 0.071 d 0.30 0.43 0.55 0.012 0.017 0.022 e 0 0.05 0.10 0.000 0.002 0.004 f 0 o - 10 o 0 o - 10 o g 1.90 ref. 0.075 ref. h 1.20 ref. 0.047 ref. i 0.12 ref. 0.005 ref. j 0.37 ref. 0.015 ref. k 0.60 ref. 0.024 ref. l 0.95 ref. 0.037 ref.
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