unisonic technologies co., ltd us3x77 cmos ic www.unisonic.com.tw 1 of 10 copyright ? 2011 unisonic technologies co., ltd qw-r502-568.b power distribution switch ? description the utc us3x77 is a power distribution switch and particularly designed for self-powered and bus-powered universal serial bus (usb) applications. the utc us3x77 incorporates protection circuits including current limiting circuit with foldback function, thermal shutdown circuit designed to prevent catastrophic switch failure due to increasing power dissipation when continuous heavy loads or short circuit occurs. besides, a built-in charge pump is used to drive the n-channel mosfet that is free of parasitic body diode to eliminate any reversed current flow across the switch when it is powered off. the r ds(on) of the mosfet switch is as low as 100m ? . oc is open-drain output report over-curr ent or over-temperature event which has deglitch typical 9ms timeout period typically 9ms. the utc us3x77 is applied in high-side power protection switch, usb power management, usb host and self-powered bubs, usb bus-powered hubs, hot plug-in power supplies, battery-charger circuits. ? features * 100m ? high-side mosfet * supply current: switch on : 65 a(typ) switch off : 1 a (max) * accurate current li mit with foldback * deglitched open-drain over-c urrent flag output (oc) * no reverse current when power off * under voltage lockout * operating range: 2.7v ~ 5.5v * output shutdown pull-low resistor ? ordering information ordering number lead free halogen free package packing us3x77xl-s08-r us3x77xg-s08-r sop-8 tape reel us3x77xl-s08-t us3x77xg-s08-t sop-8 tube us3x77xl-sm1-r us3x77xg-sm1-r msop-8 tape reel US3X77XL-SM1-T us3x77xg-sm1-t msop-8 tube
us3x77 cmos ic unisonic technologies co., ltd 2 of 10 www.unisonic.com.tw qw-r502-568.b ? pin configuration out out nc oc gnd in in en(en) 1 2 3 4 8 7 6 5 ? pin description pin no. pin name description 1 gnd ground 2, 3 in input supply: output mosfet drain, which also supplies ic's internal circuitry. connect to positive supply. 4 en(en) enable: logic level enable i nput. make sure en pin never floating. 5 oc over-current: open-drain oc output. 6 nc no connection. 7, 8 out switch output: output mosfet source of sw itch. typically connect to switched side of load.
us3x77 cmos ic unisonic technologies co., ltd 3 of 10 www.unisonic.com.tw qw-r502-568.b ? block diagram
us3x77 cmos ic unisonic technologies co., ltd 4 of 10 www.unisonic.com.tw qw-r502-568.b ? absolute maximum rating (t a = 25c, unless otherwise specified) parameter symbol ratings unit supply voltage v in 6 v output voltage v out 6 v enable input v en -0.3 ~ 6 v output current i out internally limited a storage temperature t stg -65~ +150 reflow temperature (soldering, 10sec) 260 esd protection 2 kv 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. ? operating ratings parameter symbol ratings unit supply voltage v in +3 ~ +5.5 v operating temperature t a -40 ~ +85 c ? electrical characteristics (v in = 5v, c in =1f, c out =1f, r l =10 ? , t a = 25c, unless otherwise specified) parameter symbol test conditions min typ max unit input voltage v in 2.7 5.5 v us3477, i out =1.5a us3377, i out =1.0a us3277, i out =0.5a output mos r ds(on) us3177, i out =0.3a 100 115 m ? supply current i in 65 a output turn-on rising time r l =10 ? , 90% settling 400 s us3477 2 2.5 3.3 us3377 1.6 2 2.6 us3277 1.2 1.5 1.9 current limit threshold i thd(limit) us3177 v out =4v 0.75 1 1.45 a us3477 0.2 1.7 2.3 us3377 0.2 1.3 1.7 us3277 0.2 1 1.3 short-circuit current i sc us3177 v out =0v, 2.7v us3x77 cmos ic unisonic technologies co., ltd 5 of 10 www.unisonic.com.tw qw-r502-568.b ? functional description overcurrent protection when the output load exceeds the current-limit threshol d, the over current protec tion will be triggered. the typical current limit value of utc us3077/us3277/us3377/us3477 is 1a, 1.5a, 2a, 2.5a. there is foldback of current limit when short-circuit being encountered. oc response the oc open-drain output is asserted (active low) when an over current or over-tem perature shutdown condition is encountered after a 9-ms deglitch timeout. the output re mains asserted until the over-c urrent or over-temperature condition is removed. thermal shutdown thermal shutdown protects utc us3x77 from excessive power dissipation. if the die temperature exceeds 135c, the mosfet switch is shut off. 20c of hysteresis preven ts the switch from turning on until the die temperature drops to 115c. thermal shutdown circuit functions only when the switch is enabled. undervoltage lockout (uvlo) uvlo (under-voltage lockout) prevents the output mosfet from turning on until in (input voltage) exceeds 2.5v typically. after the switch turns on, if the voltage drops below 2.3v typica lly, uvlo shuts o ff the output mosfet.
us3x77 cmos ic unisonic technologies co., ltd 6 of 10 www.unisonic.com.tw qw-r502-568.b ? test circuits in en gnd out oc utc us3x77 chip enable a v in c i r fg v flg s1 i out c o r l i l v out turn-on & off response, flag response
us3x77 cmos ic unisonic technologies co., ltd 7 of 10 www.unisonic.com.tw qw-r502-568.b ? typical application circuit supply voltage 5v ferrite beades 1f 0.1f 150f v bus d+ d- gnd data in en gnd out oc utc us3x77 chip enable r fg pull-up resistor (10k ~ 100k) over - current flag transient filtering usb controller 0.1f 10k note. a low-esr 150 f aluminum electrolytic or tantalum between v out and gnd is strongly recommended to meet the 330mv maximum droop requirement in the hub v bus . power supply considerations a 1 f bypass capacitor on in pins, a high value capacitor and a 0.1uf bypass capacitor on out pins are strongly recommended because this precaution can reduce a poor risk that an output short may cause sufficient ringing on the input to damage internal control circuitry. input transients must not exceed t he absolute maximum supply voltage (6v) even for a short duration. enable input en must be driven logic high or logic low for a clearly defined input. floating the input may cause unpredictable operation. en should not be allowed to go negative with respect to gnd.
us3x77 cmos ic unisonic technologies co., ltd 8 of 10 www.unisonic.com.tw qw-r502-568.b ? typical characteristics (t a =25c, v in = 5v, 3275h, c in =1 f, c out =1 f, v en =0v, unless otherwise specified.) time (400 s/div) 5v 0 0 2v 4v turn on delay ti me and rise time 10v 6v 8v 0 2000 4000 time (1ms/div) 5v 0 0 2v 4v turn off delay time and fall time 10v 6v 8v 0510 v in =5v c l =120 f r l =5 v in =5v c l =120 f r l =5 5v 0 v en 0 5v v oc inrush current with different load capacitance 0 2000 4000 time (400 s/div) i out 0 0.5a 1a 5v 0 v en 0 5v v oc 0 2000 4000 time (400 s/div) i out 0 0.5a 1a c l =10 f inrush current with different load capacitance c l =120 f 10v 10v v in =5v r l =5 v in =5v r l =5 5v 0 v en 0 5v v oc 0510 time (1ms/div) i out 0 0.5a 1a inrush current with different load capacitance 10v c l =220 f v in =5v r l =5 v in =5v c l =47 f r l =1 thermal shutdown response v en v oc i out v out
us3x77 cmos ic unisonic technologies co., ltd 9 of 10 www.unisonic.com.tw qw-r502-568.b ? typical characteristics (cont.) v in v out v in v out 5v 0 v in 0 500 1000 time (100ms/div) i out 0 1a 2a short circuit response at start up 10v 5v 0 v en 0 2000 4000 time (400ms/div) 0 5v 0 short-circuit current, device enable into short 2a 10v v oc i out c l =47 f v in =5v c in =47 f c l =47 f v in i out v out v in i out v out v oc
us3x77 cmos ic unisonic technologies co., ltd 10 of 10 www.unisonic.com.tw qw-r502-568.b ? typical characteristics (cont.) v in i out v out v oc 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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