unisonic technologies co., ltd USR1021 preliminary linear integrated circuit www.unisonic.com.tw 1 of 4 copyright ? 2013 unisonic technologies co., ltd qw-r103-073.a 3a synchronous buc k regulator ? description the utc USR1021 is a high efficiency, 3a synchronous buck regulator. the utc USR1021 works from a 6v to 18v input voltage range, and provides up to 3a of continuous output current with an output voltage adjustable down to 0.8v. the utc USR1021 comes in an sop-8 packages and is rated over a -40c~+85c ambient temperature range. ? features * 6v~18v operating input voltage range * high ef ciency * internal soft start * 1.5% initial output accuracy * output voltage adjustable to 0.8v * 3a continuous output current * cycle-by-cycle current limit * 500khz pwm operation * thermal shutdown * short-circuit protection sop-8 ? ordering information ordering number package packing lead free halogen free USR1021l-s08-r USR1021g-s08-r sop-8 tape reel USR1021l-s08-t USR1021g-s08-t sop-8 tube note: xx: output voltage, refer to marki ng information.
USR1021 preliminary linear integrated circuit unisonic technologies co., ltd 2 of 4 www.unisonic.com.tw qw-r103-073.a ? pin configuration ? pin description pin no. pin name description 1 pgnd power ground 2 v in supply voltage input 3 agnd reference connectio for controller section 4 fb feedback voltage 5 comp compensation pin 6 en enable pin 7, 8 lx switch pin ? block diagram
USR1021 preliminary linear integrated circuit unisonic technologies co., ltd 3 of 4 www.unisonic.com.tw qw-r103-073.a ? absolute maximum rating parameter symbol ratings unit supply voltage v in 18 v lx to agnd -0.7~v in +0.3 v en to agnd -0.3~v in +0.3 v fb to agnd -0.3~6.0 v comp to agnd -0.3~6.0 v pgnd to agnd -0.3~+0.3 v junction temperature t j +150 c storage temperature t stg -65~+150 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. ? thermal data parameter symbol ratings unit junction to ambient (note 2) ja 87 /w ? recommended operating condiions parameter symbol ratings unit supply voltage v in 6~18 v output voltage range 0.8~v in v ambient temperature t a -40~+85 c ? electrical characteristics (t a =25c, v in =v en =12v, v out =3.3v, unless otherwise specified) (note 3) parameter symbol test conditions min typ max unit supply voltage v in 6 18 v supply current (quiescent) i in i out =0, v fb =1.2v, v en >2v 3.5 5 ma shutdown supply current i off v en =0v 1 10 a feedback voltage v fb t a =25 c 0.788 0.8 0.812 v load regulation 0.5 % line regulation 1 % feedback voltage input current i fb 200 na en input threshold v en off threshold 0.6 v on threshold 2 v ss time c ss =16nf 2 ms modulator frequency f o 400 500 600 khz maximum duty cycle d max 85 % controllable minimum on time t min 150 ns current sense transconductance 7 a/v error amplifier transconductance 180 a/v protection current limit i limt 3.5 4.5 a over-temperature shutdown limit t j rising 150 c t j falling 100 c notes: 1. devices are inherently esd sensitive, handling precautions are required. human body model rating: 1.5 k ? in series with 100pf. 2. the value of ja is measured with t he device mounted on a 1-in 2 fr-4 board with 2oz. copper, in a still air environment with t a =25c. the value in any given applicatio n depends on the user?s specific board design. 3. specification in bold indicate an ambient temperature range of -40 c~+85c. these s pecifications are guaranteed by design.
USR1021 preliminary linear integrated circuit unisonic technologies co., ltd 4 of 4 www.unisonic.com.tw qw-r103-073.a ? typical application circuit agnd pgnd lx comp en fb v in v in 22f c1 r c c c l1 4.7h r1 r2 v out 22f c2, c3 utc USR1021 ceramic ceramic 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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