ap1621 pwm/pfm dual mode step -down dc/dc controller 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 may.27, 2004 1/5 ? features - input voltage range:2.2v~8v v out type - adjustable version 2.5% - oscillator freq uency: 270khz 15% - high efficiency: 92% typ . - stand-by capability: i stb 2a. max . - soft-start time set-up externally type possible - output voltage type possible fb - package: sot23-5 ? applications electronic information organizers palmtops cellular and portable phones portable audio systems various multi-function power supplies ? general descriptions the ap1621 series are multi-functional step-down dc/dc converters with built-in speed, low on resistance drivers. a more than 1a output current is possible using an externally connected transistor, coil, diode and capacitor. output voltage is set-up by external resistor. 2.5% accuracy . with a 270khz switching frequency, the size of the external components can be reduced. control switches from pwm to pfm during light loads with the ap1621 pwm/pfm switchable and the series is highly efficient from light loads to large output currents. in relation to soft-start time external capacitor regulated types. during stand-by time ce pin ?low? ,current consumption is reduced to less than 0.5a. with u.v.l.o internal, the external mosfet. will be forcibly switched off if used below the stipulated voltage. ? pin assignment 1 3 2 5 4 ce v out v dd gnd fb ap1621a 1 3 2 5 4 ce v out v dd gnd sot23-5 fb (top view) ap1621b ? pin descriptions pin no. a b pin name function 14v out external pmosfet connection 2 2 gnd ground 35 v dd power supply 41 ce chip enable soft-start capacitor connection 5 3 fb feedback pin
ap1621 pwm/pfm dual mode step-d own dc/dc controller anachip corp. www.anachip.com.tw rev.1.1 may.27, 2004 2/5 ? ordering information ap1621x x x x w : sot23-5 packing a : taping package lead free blank : normal l : lead free package version a : a version b : b version ? block diagrams phase compensation vref with soft start ce + - pwm/pfm controller + - ramp wave generator, osc buffer, driver v out ce gnd v dd pwm comparator fb ? absolute maximum ratings ta=25c parameter symbol rating unit v in pin voltage v dd -0.3 ~ 8.5 v v out pin voltage v out -0.3 ~ v in +0.3 v fb pin voltage v fb -0.3 ~ v in +0.3 v ce pin voltage v ce -0.3 ~ v in +0.3 v v out pin current v out 100 ma continuous total power dissipation pd 250 mw operating ambient temperature topr -30 ~ +80 c storage temperature tstg -40 ~ +125 c
ap1621 pwm/pfm dual mode step-d own dc/dc controller anachip corp. www.anachip.com.tw rev.1.1 may.27, 2004 3/5 ? electrical characteristics ap1621 v out 3.3v, f osc 270khz ta=25c parameter symbol conditions min. typ. max. unit fb v fb 1.17 1.2 1.23 v maximum input voltage v in 8 v uvlo voltage min. operating voltage v uvlo same as i dd , voltage required to maintain h at v out 2.2 v supply current i dd no external components, ce=v in , v out =0v 35 102 a stand-by current i stb no external components, ce=v in , v out =0v 2 a oscillator frequency fosc measuring of ext/waveform, v in =output voltage+0.3v 230 270 310 khz maximum duty ratio maxdty 100 % pfm duty ratio pfmdty no load (ap1621 only) 15 25 35 % ce?high? voltage v ceh no external components, v fb =0v, apply 0.65v (min.) to ce, determine v out ?low? 0.5 vcc ce?low? voltage v cel same as v ceh , determine ext/?high? 0.20 v efficiency effi 92 % soft-start time tss use a 33 nf capacitor 5 15 msec measuring conditions: unless otherwise specified, connect external components. v in =5.0v,l out =220ma series amendment: ap1621 external components: css 0.033 f, rss 470k ? the following para meter applies: soft start time tss :connect rss,css. ce, 0v 3.0v when v in <3.0v, v in 3.0v
ap1621 pwm/pfm dual mode step-d own dc/dc controller anachip corp. www.anachip.com.tw rev.1.1 may.27, 2004 4/5 ? typical application circuit ap1621 v dd ce fb gnd r l v out +c l l sd pmos v in +c in c fb r fb1 r fb2 v out r ss c ss ? marking information sot23-5l xx : identification code (see appendix) y : year: 0-9 m : month: a~l x : blank: normal l: lead free package sot23-5l xx y m x 7 12 3 4 5 appendix part number package identification code ap1621a sot23-5 ex ap1621b sot23-5 eu
ap1621 pwm/pfm dual mode step-d own dc/dc controller anachip corp. www.anachip.com.tw rev.1.1 may.27, 2004 5/5 ? package information package type: sot23-5l gauge plane 0.25 mm l l1 e1 e e1 d 123 4 5 b e b1 b c c1 base metal with plating a2 a1 a seating plane 0.10 c 5x 2(4x) 1(4x) dimensions in millimeters dimensions in inches symbol min. nom. max. min. nom. max. a 1.05 1.20 1.35 0.041 0.047 0.053 a1 0.05 0.10 0.15 0.002 0.004 0.006 a2 1.00 1.10 1.20 0.039 0.043 0.047 b 0.25 - 0.55 0.010 - 0.022 b1 0.25 0.40 0.45 0.010 0.016 0.018 c 0.08 - 0.20 0.003 - 0.008 c1 0.08 0.11 0.15 0.003 0.004 0.006 d 2.70 2.85 3.00 0.106 0.112 0.118 e 2.60 2.80 3.00 0.102 0.110 0.118 e1 1.50 1.60 1.70 0.059 0.063 0.067 l 0.35 0.45 0.55 0.014 0.018 0.022 l1 0.60 ref. 0.024 ref. e 0.95 bsc. 0.037 bsc. e1 1.90 bsc. 0.075 bsc. 0 o 5 o 10 o 0 o 5 o 10 o 1 3 o 5 o 7 o 3 o 5 o 7 o 2 6 o 8 o 10 o 6 o 8 o 10 o
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