unisonic technologies co., ltd p1595 preliminary linear integrated circuit unisonic technologies co., ltd 1 of 6 www.unisonic.com.tw qw-r103-047.b 200khz, 1.5a pwm buck dc/dc converter ? description the utc p1595 is a monolithic integrat ed circuit intended for the use of a step-down dc/dc converte r and it can drive a 1.5a load without additional transistors. the internal compensation makes feedback control having good line and load regulation without external design. the external shutdown function can be controlled by logic level and then enter the standby mode. the utc p1595 features a guaranteed +3% tolerance on output voltage under specified in put voltage and output load conditions. thermal shutdown protecti on is designed to prevent over temperature operating from damage while current limit protection is against over current operating of the output switch. the switching frequency will be reduced if current limit function occurs and feedback voltage (v fb ) drops below 0.5v. the utc p1595 works at a 200khz switching frequency so it allows smaller sized filter components. ? features * output voltage in adju stable output version. * adjustable version output voltage range: 0.75v ~ 22v with+3% accuracy. * short circuit protect * fixed switching frequency: 200khz. * on/off shutdown control input. * voltage mode non-synchronous pulse width modulation (pwm) control. * thermal-shutdown and current-limit protection. * operating voltage can be up to 24v. * 1.5a output load current . * low power standby mode. * built-in switching transistor ? ordering information ordering number package packing P1595G-AB5-R sot-89-5 tape reel
unisonic technologies co., ltd p1595 preliminary linear integrated circuit unisonic technologies co., ltd 2 of 6 www.unisonic.com.tw qw-r103-047.b ? pin configuration 4 3 2 1 5 en v cc sot-89-5 sw fb gnd ? pin description pin no. pin name description 1 sw switching output 2 gnd ground 3 fb feedback voltage 4 en on/off pin 5 v cc operating voltage input
unisonic technologies co., ltd p1595 preliminary linear integrated circuit unisonic technologies co., ltd 3 of 6 www.unisonic.com.tw qw-r103-047.b ? block diagram current source bias start up 200khz osc. thermal shutdown comp. pwm ea 2.5v regulator 0.75v reference v cc en sw gnd fb latch driver 0.4v + - + + + - - -
unisonic technologies co., ltd p1595 preliminary linear integrated circuit unisonic technologies co., ltd 4 of 6 www.unisonic.com.tw qw-r103-047.b ? absolute maximum rating parameter symbol ratings unit maximum supply voltage v cc +26 v on/off pin input voltage v en -0.3 ~ v cc v feedback pin voltage v fb -0.3 ~ 12 v operating supply voltage v op 4.5~24 v output voltage to ground v out -0.8 v power dissipation (note 1) ta=25c p d 690 mw operating temperature t opr -20 ~ +125 c storage temperature t stg -65 ~ +150 c note: absolute maximum ratings are those values beyo nd 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 1) ja 180 c/w junction to case (note 1) jc 38 c/w note: 1. it?s measured with the pcb copper area (need connect to v ss pins) of approximately 1.5 in 2 (multi-layer) ? electrical characteristics (ta=25c, v cc =12v, i load =0.2a, unless otherwise specified,) parameter symbol test conditions min typ max unit feedback voltage v fb i out =0.2a 0.728 0.750 0.773 v saturation voltage v sat i out =1.5a, no outside circuit v fb =0v force driver on 1.2 1.5 v quiescent current i q v fb =1.2v force driver off 4 8 ma feedback bias current i fb i out =0.1a -10 -50 na shutdown supply current i sd v en =0v 2 10 a current limit i (limit) pear current, no outside circuit v fb =0v force driver on 1.8 a sw pin=0v no outside circuit v fb =1.0v force driver off -50 a sw pin leakage current sw pin=-0.8v i sw(leak) v cc =24v force driver off -5 ma oscillator frequency f osc 140 200 260 khz oscillator frequency circuit protect of short f scp (adjustable) when v fb < 0.5v 80 khz max. duty cycle (on) v fb =1.2v force driver off 0 % min. duty cycle (off) dc v fb =0v force driver on 100 % v ih high (regulator on) 1.2 2.0 v en pin logic input threshold voltage v il low (regulator off) 0.5 1.2 v en pin logic input current i h v en =2.5v (on) 20 a en pin input current i l v en =0.3v (off) -5 a thermal shutdown temp tsd 135 c
unisonic technologies co., ltd p1595 preliminary linear integrated circuit unisonic technologies co., ltd 5 of 6 www.unisonic.com.tw qw-r103-047.b ? typical application circuit adjustable output voltage version v out =v fb ? ? ? ? ? ? + r2 r1 1, v fb =0.75v. r2=0.75k~4k resistor select for output voltage setting v out r2 r1 5v 1.2k 6.8k 3.3v 2k 6.8k 2.5v 2k 4.7k 1.8v 2k 3k 1.5v 2k 2k 1.3v 2k 1.5k 1.2v 2k 1.2k l1 recommend value (v in =12v, i out =1.5a,) v out 1.8 v 2.5v 3.3v 5v l1 value 22 h 22 h 33 h 33 h
unisonic technologies co., ltd p1595 preliminary linear integrated circuit unisonic technologies co., ltd 6 of 6 www.unisonic.com.tw qw-r103-047.b ? function descriptions pin functions vcc it provides the ic switching regulator with positive input supply. this pin is used to supply the switching currents needed by the regulator and a suitable input bypass capacitor must be connected at this pin. gnd circuit ground. sw internal switch. the voltage at this pin switches between (+v cc -v sat ) and approximately-0.5v, with a duty cycle of approximately v out / v cc . to minimize coupling to sensitive circuitry, you should minimize the pc board copper area connected to this pin. feedback senses the regulated output voltage to complete the feedback loop. en using logic level signals to allow the switching regulator circuit to be shutdown, which dropping the total input supply current to approximately 10ua. shut the regulator down through pulling this pin below a threshold voltage of approximately 0.5v, turn the regulator on through pulling this pin above 2.0v (up to v cc max). 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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