california micro dev ices preliminary cm 350 3 ? 200 3 california micro devices corp. all rights reserved. c0970500 09/10/03 430 n. mccarthy blvd, milpitas, california 95035 tel: (408) 263 - 3214 fax: (408) 263 - 7846 www.calmicro.com 1 usb 5v single 1.4a overcurrent switch features high - side high current switch with active low enable very low on - resistance switch (0.07 ? typ.) up to 1.4a continuous current on the output over - current limits at 1.4a min 10msec min fault blanking delay on oc# output prevents false overcurrent alarms prevents backdrive current when host powered off low operating current (95 m a typ.) low quiescent current when disabled (<1 m a max) small 8 - lead soic package applications 2 usb port s 5v supply overcurrent pro tection pin diagram product description california micro devices? cm3503 is a usb overcurrent power switch that provides power to two usb ports. the device has a very low on - resistance power switch that provides the v bus voltage at the usb output ports with minimal voltage drop. when the en# pin is logic low, the power switch is on, and v cc is connected to the output v out . when the en# pin is logic high, the power switch is off, and no power is available at the o utput. the power switch has full over - current protection. whenever the current limit of the switch is exceeded, the device enters a constant - current mode, where the output voltage is progressively reduced to prevent the current from increasing further. t he oc# output becomes active low only if the overcurrent condition exceeds at least 10ms. this fault blanking delay prevents false alarms from being reported to the host usb controller. if the overcurrent condition is severe enough that the part heats up to the thermal limit t max , then the switch will be turned off and the temperature cools down. at t min the switch then turns on again, and the device heats up again, and so on, until the fault is removed. the cm3503 also prevents backdrive current flowing into the host from the connected peripheral. this can occur when v cc is removed as the host powers down, and the peripheral still has normal power applied. the 5v from the peripheral can therefore be linked to the host?s v bus , potentially causing backdriv e current into the host and overloading the peripheral power supply. typical application circuit simplified electrical schematic soic - 8 v cc en# gnd v cc v out v out oc# v out en# oc# v out v cc over current protect 1 usb port v bus v bus 1 usb port v cc en# gnd v cc v out v out oc# v out v cc obsolete product
california micro dev ices preliminary cm 350 3 note: this is a preliminary datasheet only. data subject to change at a ny time. ? 200 3 california micro devices corp. all rights reserved 09/10/03 430 n. mccarthy blvd, milpitas, california 95035 tel: (408) 263 - 3214 fax: (408) 263 - 7846 www.calmicro.com 2 absolute maximum ratings parameter rating unit esd protection ( all pins, hbm) 2 000 v v cc input voltage + 5. 6 , gnd - 0.5 v storage temperature range operating ambient operating junction - 55 to +150 - 40 to +85 - 40 to +1 50 * c output curre nt loading in ternally limited a package power dissipation 0.5 w *internal ly limited operating conditions (unless specified otherwise) parameter range unit v cc input voltage 4.5 to 5.5 v ambient tempe rature - 40 to +85 c i load v cc 0 to 1 4 00 ma electrical operating characteristics (over operating conditions unless specified otherwise) symbol parameter conditions min typ max unit uvlo v cc voltage under which ci rcuit locks out - will not operate t=25 c 2. 2 2. 5 v r sw switch on - resistance i load = 0 to 1 4 0 0ma ; v cc = 5v , t = 25 c 0. 07 0. 1 w r sw a switch on - resistance i load = 0 to 1 4 00ma; v cc = 5v, t = 0 to +85 c 0.1 25 w r sw b switch on - resistance i load = 0 to 1 4 00ma; v cc = 5v, t = - 40 to +85 c 0.1 25 w v out output voltage i load = 10 00ma, v cc = 5.0v, en # = 0 v , t=25 c 4. 9 v i lim o ver - current limit v cc = 5v t=25 c 1 4 0 0 2 0 00 2 6 00 m a t fbd time delay from overcurrent detection to oc # output indication (fault blanking delay) 10 20 30 ms t max temperature at which switch turn s off during overcurrent 150 c t min temperature at which switch turns on, after cooling from t max 125 c i rcc reverse leakage from output to input v cc = 0v, v out = 5v , en # = high , t=25 c 10 m a i cc operating supply current en# = low 95 m a i ccq qui escent c urrent en # = high 1 m a v ih - en en# input logic - 1 threshold v cc = 5v 2 v v il - en en# input logic - 0 threshold v cc = 5v 0.8 v v ol - oc oc# output logic - 0 threshold i oc = 1ma to v cc 0 .4 v obsolete product
california micro dev ices preliminary cm 350 3 note: this is a preliminary datasheet only. data subject to change at a ny time. ? 200 3 california micro devices corp. all rights reserved 09/10/03 430 n. mccarthy blvd, milpitas, california 95035 tel: (408) 263 - 3214 fax: (408) 263 - 7846 www.calmicro.com 3 pin functions v cc is the power source. pins 2 & 3 must be connected together externally v out provides the power for the load s . the internal mosfet switch i s designed for very low voltage drops from the voltage input pins at the full rated current . pins 6, 7 & 8 must be connected together externally. current loads of up to 1. 4 a are allowed. current loads above 1. 4 a may cause the constant - current limiting circuit to operate ? reducing the output voltage. continuous over - current loads will cause the part?s internal temperature to rise. if the internal temperature exceeds 150?c then the switch immediately turn s off. once the part has cooled to 125?c then the switch automatically turn s on again. during the cold - start interval when the input is initially applied, internal circuitry provides a soft turn - on for the switch, which limits peak in - rush current. e n # is the active low logic input pin that is used to control the power switch . set en # high (>2v) to de select v out , and set en # low (<0.8v) to select v out . oc # is an active low open - drain output voltage , indicating an overcurrent fault condition has been detected at v out . there is a built - in 10msec (min.) fault blanking delay aft er the overcurrent fault condition has been detected, before th i s output become s active low . t he oc # output deasserts only when both the overcurrent condition stops and when the voltage drop across the switch is less than 1 v . an external pull - up resistor of 10k - 100k is required if the oc # output is used. gnd is the negative reference for all voltages. pin descriptions pin no. symbol description 1 gnd negative reference for all voltages. 2 v cc power primary high current positive supply input. 3 v cc power s upply input connected to pin 2 4 en # active low enable p in 5 oc # active low when v out is in overcurrent mode . e xternal pull - up resistor required . 6 v out output connected to pins 7 and 8 7 v out output connected to pins 6 and 8 8 v out output connected to pins 6 and 7 standard part ordering information pins package ordering part number 1 part marking 8 soic cm3503 - 0 2 sn cm3503 - 02sn note 1: parts are shipped in tape & reel form unless otherwise specified. obsolete product
california micro dev ices preliminary cm 350 3 note: this is a preliminary datasheet only. data subject to change at a ny time. ? 200 3 california micro devices corp. all rights reserved 09/10/03 430 n. mccarthy blvd, milpitas, california 95035 tel: (408) 263 - 3214 fax: (408) 263 - 7846 www.calmicro.com 4 response to momentary overcurrent fault i out v out oc# temp. >1400ma <150?c v out drops to reduce i out oc# goes inactive as soon as overcurrent condition stops <1300ma oc# goes active after 10ms (min) 20ms (typ.) delay i out v out oc# temp. t max = 150?c t min = 125?c 150?c response to continuous overcurrent fault v out drops to reduce i out total powerdown when over-temperature limit reached re-powers when temperature drops to 125?c oc# goes active after 10ms (min) 20ms ( typ .) delay oc# stays low >1400ma obsolete product
california micro dev ices preliminary cm 350 3 note: this is a preliminary datasheet only. data subject to change at a ny time. ? 200 3 california micro devices corp. all rights reserved 09/10/03 430 n. mccarthy blvd, milpitas, california 95035 tel: (408) 263 - 3214 fax: (408) 263 - 7846 www.calmicro.com 5 typical operating characteristics cm3503 quiescent supply current vs. supply voltage 0 20 40 60 80 100 120 4 4.2 4.4 4.6 4.8 5 5.2 5.4 5.6 v cc [v] i cc [ua] oc# fault blanking delay 0 10 20 30 40 50 60 3.5 4 4.5 5 5.5 6 v cc [v] delay [msec] cm3503 v out - i out characteristic 0 1 2 3 4 5 6 0 1 2 3 4 5 6 i out [a] v out [v] obsolete product
california micro dev ices preliminary cm 350 3 note: this is a preliminary datasheet only. data subject to change at a ny time. ? 200 3 california micro devices corp. all rights reserved 09/10/03 430 n. mccarthy blvd, milpitas, california 95035 tel: (408) 263 - 3214 fax: (408) 263 - 7846 www.calmicro.com 6 soic - 8 package dimensions obsolete product
|
