unisonic technologies co., ltd l3012 linear integrated circuit www.unisonic.com.tw 1 of 5 copyright ? 2015 unisonic technologies co., ltd qw-r125-025.d 1a high power led driver with 4.5~40v input ? description the utc l3012 is a step-down pwm control led driver with a built-in power switch. it achieves 1a continuous output current in 4.5~40v input voltage range. it has high efficiency up to more than 96%, with the excellent current accuracy within 1%. ? features * 4.5~40v input voltage range * maximum 1a output current * 0.15 ? built-in power mosfet * 280khz fixed frequency * excellent constant cu rrent accuracy 1% * thermal shutdown * cycle-by-cycle over current protection * pwm dimming function ? ordering information ordering number package packing L3012G-S08-R sop-8 tape reel (1) r: tape reel (2) s08: sop-8 (3) g: halogen free and lead free L3012G-S08-R (1)packing type (2)package type (3)green package ? marking
l3012 linear integrated circuit unisonic technologies co., ltd 2 of 5 www.unisonic.com.tw qw-r125-025.d ? pin configuration 1 2 3 4 8 7 6 5 sw gnd sense v in adj v dd pwm comp ? pin description pin no. pin name description 1 sw power switch output. 2 gnd ground. 3 sense current sense pin. 4 v in input supply voltage. 5 comp compensation pin, connec ts to external capacitor. 6 pwm pwm dimming pin. 7 v dd 5v ldo output 8 adj thermal compensation pin or linear dimming pin. ? block diagram 4 v in 3 sense 5 comp 7 v dd 8 adj 6 pwm 3 gnd 1 sw s q r + - current comparator osc + - current setting internal reference driver vgate m1 + - pwm control osc vsense slope compensation
l3012 linear integrated circuit unisonic technologies co., ltd 3 of 5 www.unisonic.com.tw qw-r125-025.d ? absolute maximum rating (t a =25c, unless otherwise specified ) parameter symbol ratings unit supply voltage v in 40 v switch voltage v sw -1~v in +1 v comp voltage v comp -0.3~6 v sense voltage v sense -0.3~v in v input voltage v in 4.5~40 v junction temperature t j 150 c operating temperature t opr -40 ~ +125 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. ? electrical characteristics (t a =25c, unless otherwise specified, v in =12v, i out =700ma) parameter symbol test conditions min typ max unit supply voltage v in 6 36 v operating current i in v cc =4/40v (switch off) 2.2 5 ma upper switch leakage i l v sw =40v 0 5 a current limit i lim v in =sense=12v 1.7 2 3 a maximum duty cycle d max 3led, v in =9v 94 96 % oscillator frequency f osc 250 280 350 khz comp clamp voltage v comp open without load 2.6 v switch transistor on resistance r on 1led, i out =1a 0.15 0.5 ? sampling voltage threshold v in -v sense drop voltage between v in and sense 100 mv thermal shutdown threshold tsd 160 c thermal shutdown hysteresis tsd-hys 30 c
l3012 linear integrated circuit unisonic technologies co., ltd 4 of 5 www.unisonic.com.tw qw-r125-025.d ? function description the utc l3012 is a current mode and fixed frequency (280khz) led driver. 1. output current setting the output current is determined by the sampling resistor (r s ) and setting voltage (v in -v sense a built-in fixed 100mv). s sense in out r v v i ? ? =100mv/rs 2. current limiting utc l3012 has internal current limiting function, and the voltage on comp is clamped at about 2v, the output current of the power mosfet is limited at about 2a by current comparator. 3. diode selection utc l3012 driver led need a schottky diode. if output current is 700ma or smaller then ss14w (1n5819) is ok. the average current through the diode is i d : i d = (1-d) i led i led is the current of led 4. pwm dimming utc l3012 has internal pwm dimming function. when pwm voltage is connects to high level, the chip is working normally, when pwm voltage is open or connects to low level, the comp pin voltage will k eep normal state, so can improve the startup speed of the chip. adjust the output current by control the duty of external pwm signal. the minimum setup time of utc l3012 pwm dimming is less than 20 s, and the maximum pwm dimming ratio is up to 500:1. when high dimming ratio is needed, the dimming frequency is recommended 500hz below, or else the dimming frequency can be up to 2khz. when pwm pin is low, output is shutdown. ? typical application circui 1 2 3 4 8 7 6 5 sw gnd sense v in adj v dd pwm comp sbd v in rs cout l 10f 1f 100nf
l3012 linear integrated circuit unisonic technologies co., ltd 5 of 5 www.unisonic.com.tw qw-r125-025.d 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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