unisonic technologies co., ltd p1686 linear integrated circuit www.unisonic.com.tw 1 of 6 copyright ? 2008 unisonic technologies co., ltd qw-r103-039.c 600khz, 3a step-down current mdoe switching regulator ? description as a current mode switching regulator with an integrated switch, the utc p1686 is operating at 600khz with separate sync and enable functions. in order to avoid frequency beating in noise sensitive applications the sync function allows customers to synchronize to a faster clock. cost effective low power solutions is considered in the integrated switch ,and so peak switch current 3 amps. very small passive components is considered in high frequency of operation. current mode operation: fast dynamic response and instantaneous dut y cycle adjustment as the input changes, as a ideal for cpe applications where the input is a wall plug power. the low shutdown current as ideal for portable applications when battery life is important. the utc p1686 is synchronizable to a frequency from 750khz to 1.2mhz. ? features * integrated 3 amp switch * 600khz frequency of operation * current mode controller * synchronizable to higher frequency up to 1.2mhz * 6 a low shutdown current *pb-free plating product number: p1686l ? ordering information ordering number normal lead free plating package packing p1686-s08-r p1686l-s08-r sop-8 tape reel p1686-s08-t p1686l-s08-t sop-8 tube P1686-SH2-R p1686l-sh2-r hsop-8 tape reel p1686-sh2-t p1686l-sh2-t hsop-8 tube
p1686 linear integrated circuit unisonic technologies co., ltd 2 of 6 www.unisonic.com.tw qw-r103-039.c ? pin configuration sop-8 hsop-8 5 6 7 8 4 3 2 1 en fb comp sync gnd sw in bst 5 6 7 8 4 3 2 1 en fb comp sync gnd sw in bst ? pin description pin no. pin name pin function 1 bst providing power to the internal npn switch. to turn on for this switch the lowest voltage is 2.7v. 2 in this pin delivers all control and power circuitry?s power, and sees high di/dt during switching. a decoupling capacitor is better to be attached to this pin very closely. 3 sw this pin is the emitter of the internal sw itch and should be connected with the external freewheeling diode very closely. 4 gnd almost all voltages are measured with respect to this pin. the decoupling capacitor and the freewheeling diode is better to be connected to this pin as short as possible. 5 fb input of feedback for adjustable output controllers. 6 comp output of the internal error amplifier and al so input of the peak current comparator. to achieve the specified performance a compensati on network is connected to this pin. 7 en chip enable input. en is high: the regulator switched on; en is low: off. en is low: the regulator is in standby mode, and the in put supply current is reduced to a few microamperes. 8 sync synchronous control pin used to synchronize t he internal oscillator to an external pulse control signal. but it should be connected to gnd when not used.
p1686 linear integrated circuit unisonic technologies co., ltd 3 of 6 www.unisonic.com.tw qw-r103-039.c ? block diagram + + i s slope + in bs isen + pwm - ea s r q 1v uvlo ol 0.7v reference soft start hiccup oscillator slope comp frequency slope fb i s sw gnd power transistor clk en sync fb comp 40m 2 1 3 4 6 5 7 8
p1686 linear integrated circuit unisonic technologies co., ltd 4 of 6 www.unisonic.com.tw qw-r103-039.c ? absolute maximum ratings parameter symbol ratings units input supply voltage v in -0.3 ~ +28 v boost pin above v sw (v bst -v sw ) 16 v boost pin voltage v bst -0.3 ~ +32 v en pin voltage v en -0.3 ~ +16 v fb pin voltage v fb -0.3 ~ +6 v fb pin current i fb 1 ma sync pin current i sync 1 ma junction temperature t j 150 c operating temperature t opr -40 ~ +85 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 units junction to ambient ja 36.5 c/w ? electrical characteristics (v in = 12v, v comp = 0.8v, v bs = v in + 5v, en = tied to v in , sync = 0, sw = open. t a = t j = -40c ~ 85c.) parameter symbol test conditions min typ max units operating input voltage v in 16 (note 1) v maximum switch current limit i sw 3.0 a oscillator frequency f osc 550 600 750 khz switch on voltage drop v d(sw) i sw = 3a 330 mv v in undervoltage lockout v uvlo t a = 25 c 2.60 3 v v in supply current i q v fb = v out(nom) + 17% 1.0 5 ma standby current i q(off) v en = 0v, v in = v boost = 16v, v sw = 0v 5 45 a fb input current i fb -0.25 -0.50 a feedback voltage 1.176 1.2 1.224 v feedback voltage line regulation 3v < v in < 16v (note 2) +3 mv/v fb to v comp voltage gain (note 3) 0.4v v comp 0.9v 150 350 fb to v comp transconductance (note 3) i comp = 10 a 500 850 1300 mho v comp pin source current v fb = v out(nom) -17% 70 110 a v comp pin sink current v fb = v out(nom) + 17% 70 110 a v comp pin to switch current trans conductance 2.5 a/v v comp pin maximum switching threshold duty cycle = 0% 0.35 v v comp pin threshold i sw = 3a 0.9 v maximum switch duty cycle v comp = 1.2v, i sw = 400ma 85 % minimum boost voltage above switch (note 3) v boost i sw = 3a, 0c t a 85c i sw =2.5a, t a < 0c 1.8 2.7 v i sw = 1a 10 15 boost current i boost i sw = 3a, 0c t a 85c i sw =2.5a, t a < 0c 30 45 ma v ih 3 v enable input threshold voltage v il 0.4 v i il en = 60mv above threshold 2.5 a enable input bias current i ih en = 100mv below threshold 5 15 a
p1686 linear integrated circuit unisonic technologies co., ltd 5 of 6 www.unisonic.com.tw qw-r103-039.c ? electrical characteristics(c ont .) parameter symbol test conditions min typ max units sync threshold voltage 1.5 v sync input frequency (note 4) 750 1200 khz sync pin resistance v sync = 0.5v 20 k ? note: 1 . the device may not function properly out side its operating input voltage range. 2 . the required minimum input voltage for a regulat ed output depends on the output voltage and load condition. 3 . guaranteed by design. 4 . for sync applications, please contact factory.
p1686 linear integrated circuit unisonic technologies co., ltd 6 of 6 www.unisonic.com.tw qw-r103-039.c ? typical application circuit d 1 ? application circuit design example: 16v to 5v at 2a 1 2 7 8 3 5 6 4 sw fb comp sync en in utc p1686 r 3 3.4k d 2 c 4 3.3n c 5 180p l 1 8.2uh r 1 31.6k r 2 10k gnd bs c 2 10u v o =5v d 3 c 1 0.22u r 4 4.75k c 3 10u v in =16v 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 writ ten 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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