unisonic technologies co., ltd uc3552 cmos ic www.unisonic.com.tw 1 of 7 copyright ? 2013 unisonic technologies co., ltd qw-r502-134.b pwm dc-dc converter with internal switch and soft-start ? description the utc uc3552 is a step-up pwm dc-dc converter with a internal switch which is 1.6a, 0.23 ? . utc uc3552 offers users flexibility in determining loop dynamics and adjusting operating frequency cause it?s equipped with an external compensation pin ,and it also allows the use of small, low equivalent resistance (esr) ceramic output capacitors. utc uc3552 is capable of converting a standard input of 3. 3v to multiple outputs of 8v, ? 8v , and 23v. otherwise, filtering and loop performance are enhanced and facilitated by a high switching frequency of either 640 khz or1.3mhz. as a power-smart design in shutdown mode a soft-start with an external capacitor that sets the in put current ramp rate, reduces the current consumption to 0.1 a. a mere 2.6v input yields an impressive output voltage to 12v when operating. ? features * 1.6a, 0.23 ? , internal switch * high efficiency: 90% * adjustable output: v dd to 12v * adjustable frequency: 640khz or 1.3mhz * wide input range: +2.6v ~ +5.5v * low shutdown current: 0.1 a * programmable soft-start ? ordering information ordering number package packing lead free halogen free uc3552l-s08-r UC3552G-S08-R sop-8 tape reel uc3552l-s08-t uc3552g-s08-t sop-8 tube uc3552l-sm1-r uc3552g-sm1-r msop-8 tape reel uc3552l-sm1-t uc3552g-sm1-t msop-8 tube
uc3552 cmos ic unisonic technologies co., ltd 2 of 7 www.unisonic.com.tw qw-r502-134.b ? pin configuration ? pin description pin no. pin name i/o description 1 eo i compensation pin for error amplifier 2 in i feedback pin with a typical reference voltage of 1.24v 3 shdn i shutdown control pin. the device will turn off when shdn is low 4 gnd ground 5 sw o switch pin 6 v dd power supply pin 7 freq i frequency select pin. switch oscillator frequency to 640khz when freq is low, and 1.3mhz when freq is high 8 ss i soft-start control pin. no soft-start when the pin is left open
uc3552 cmos ic unisonic technologies co., ltd 3 of 7 www.unisonic.com.tw qw-r502-134.b ? block diagram
uc3552 cmos ic unisonic technologies co., ltd 4 of 7 www.unisonic.com.tw qw-r502-134.b ? absolute maximum ratings parameter symbol ratings unit sw to gnd -0.3 ~ +14 v in, shdn , v dd , freq to gnd -0.3 ~ +6 v ss, eo to gnd -1.3v ~ (v dd +0.3v) v rms sw pin current i sw 1.2 a continuous power dissipation (t c = 70c) sop-8 p d 350 mw msop-8 300 mw junction temperature t j +125 c operating temperature t opr -20 ~ +85 c storage temperature t stg -45 ~ +125 c note: absolute maximum ratings are those values beyond which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device oper ation is not implied. ? electrical characteristics t c = +25c, v dd =shdn = 3v, freq = gnd, unless otherwise specified.) parameter symbol test conditions min typ max unit input supply voltage v dd 2.6 5.5 v v dd under voltage lockout uvlo when v dd is rising, typical hysteresis is 40mv; sw remains off below this level 2.25 2.38 2.52 v quiescent current i dd v dd = 1.3v, not switching 0.21 0.35 ma v dd = 1.0v, switching 1.2 5.0 shutdown current i sc shdn = gnd 0.1 10.0 a error amplifier feedback voltage v in level to produce v eo = 1.24v 1.22 1.240 1.258 v v dd input bias current i i ( bias ) v in = 1.24v 0 40 na feedback-voltage line regulation level to produce v eo = 1.24v, 2.6v < v dd < 5.5v 0.05 0.15 %/v transconductance g m i = 5a 70 105 240 a/v voltage gain g v 1500 v/v oscillator frequency f osc freq = gnd 540 640 740 khz freq = v dd 1100 1320 1600 maximum duty cycle t duty freq = gnd 79 85 92 % freq = v dd 85 n-channel switch current limit i limit v dd = 1v, duty cycle = 65% 1.2 1.6 2.3 a on-resistance r on i sw = 1.2a 0.23 0.50 ? leakage current i leak v sw = 12v 0.01 20.00 a soft-start reset switch resistance 300 ? charge current v ss = 1.2v 1.5 4.0 7.0 a control inputs input low voltage v il shdn , freq; v dd = 2.6v ~ 5.5v 0.3v dd v input high voltage v ih shdn , freq; v dd = 2.6v ~ 5.5v 0.7v dd v hysteresis shdn , freq 0.1v dd v freq pull-down current i freq 1.8 5.0 9.0 a shdn input current i shdn 0.001 1.000 a
uc3552 cmos ic unisonic technologies co., ltd 5 of 7 www.unisonic.com.tw qw-r502-134.b ? typical application circuit v dd 2.6v~5v sw in ss gnd freq r eo shdn on/off l d1 r2 r1 c2 c out v out c1 c ss 1.2mhz 640khz v dd utc uc3552 c eo c eo2 eo 3.3 f 0.47 f 33 f 44.2k ? 274k ? 6.8 h 27nf 33pf 47k ? 1.3nf
uc3552 cmos ic unisonic technologies co., ltd 6 of 7 www.unisonic.com.tw qw-r502-134.b ? in a sepic configuration
uc3552 cmos ic unisonic technologies co., ltd 7 of 7 www.unisonic.com.tw qw-r502-134.b ? multiple-output tft lcd power supply utc uc3552 shdn eo ss in freq sw v dd gnd l1 d1 c3 c4 v1 d2 d3 v2 v3 d4 c1 c2 v dd c5 6.8 h 0.47 f 3.3 f 3.3 f 3.3 f 3.3 f +26v 5ma 1 f 1 f 0.1 f 0.1 f 1 f 3.3 f 274k 44.2k 18pf 150k 27nf 3.0v ~ 3.6v utc assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all utc products described or contained herein. utc products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. the information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.
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