unisonic technologies co., ltd us205 preliminary cmos ic www.unisonic.com.tw 1 of 5 copyright ? 2011 unisonic technologies co., ltd qw-r502-609.a 100m , 2a slew rate controlled load switch ? description the utc us205 is a cost-effective, low-voltage, low switch-on resistance (typ. 100m ? ) high-side power switch ic. it has a 20 a low quiescent supply current t hat meets the requirements of battery-powered portable equipment. the utc us205 incorporates protection circuits, such as an over-current protection circuit, a short fold back circuit, a thermal shutdown circuit and an under-voltage lockout circuit for overall protection. besides, a slew rate controlled function is embedded for turn-on rising time control. the utc us205 can be usedin applications, such as cellular phones, digital still camera, hot swap supplies, notebook computers, personal communication devices, personal digital assistants and so on. the utc us205 is available in sop-8 package. ? features * high-side nmosfet: 100m ? (typ) * input voltage varies from 2.7v to 5.5v * low supply current: 20 a * over current protection * short circuit protection * under voltage lockout * thermal protection with foldback * slew rate limited turn-on time 3ms (5v) * reverse blocking current * rohs compliant ? ordering information ordering number lead free halogen free package packing US205XL-S08-R us205xg-s08-r sop-8 tape reel
us205 preliminary cmos ic unisonic technologies co., ltd 2 of 5 www.unisonic.com.tw qw-r502-609.a ? pin configuration ? pin description pin no. pin name description 1 nc no internal connection. 2 v out power-switch output. 3 en chip enable (active high). 4 gnd ground. the exposed pad must be soldered to a large pcb and connected to gnd for maximum power dissipation. 5, 6, 7, 8 v in power input voltage. ? block diagram
us205 preliminary cmos ic unisonic technologies co., ltd 3 of 5 www.unisonic.com.tw qw-r502-609.a ? absolute maximum rating (t a =25c, unless otherwise specified) parameter symbol ratings unit supply voltage v in 6 v enable input voltage en -0.3~6 v power dissipation, @t a =25c p d 0.3 w junction temperature t j 150 c 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. note: ? recommended operating conditions (t a =25c, unless otherwise specified) (note) parameter symbol ratings unit supply voltage v in 2.7~5.5 v enable input voltage en 0~5.5 v junction temperature t j -40~100 c ambient temperature t a -40~85 c the device is not guaranteed to func tion outside its operating conditions. note: ? electrical characteristics (v in =5v, c in =1uf, c out =0.1uf, t a =25c, unless otherwise specified) parameter symbol test conditions min typ max unit operation voltage v in 2.7 5 v under voltage lookout v uvlo v in falling 1.3 1.7 2.1 v under voltage lockout hysteresis v uvlo 50 mv quiescent current i q en=high 20 70 a off supply current i shdn en=low, v out =open 1 a off switch current i leakage en=low, v out =0 1 a on-resistance r ds(on) v in =3.3v, i out =1.3a 100 120 m ? current limiting i lim v in =3.3v, v out =2.3v 1.5 2 2.5 a short circuit current i sc_fb v out =0v, measured prior to thermal shutdown 0.4 0.8 1.5 a thermal shutdown threshold t sd 130 c thermal shutdown hysteresis t sd 20 c low v il v in =2.7v ~ 5.5v 0.8 v en threshold high v ih v in =2.7v ~ 5.5v 2 v enable input leakage i en v en =5.5v 1 a output turn-on delay time t d_on v in =5v, r load =10 ? 60 100 s output turn-on rise time t on v in =5v, r load =10 ? 1 3 ms output turn-off fall time t d_off v in =5v, r load =10 ? 4 10 s output pull-down resistance during off r discharge en=low 150 ?
us205 preliminary cmos ic unisonic technologies co., ltd 4 of 5 www.unisonic.com.tw qw-r502-609.a ? application information the utc us205 is an enable input single n-mosfet high-side power switches, optimized for self-powered and bus-powered universal serial bus (usb) applications. a char ge pump circuitry is contained to drive the internal mosfet switch, the switch on resistance is 100m ? , meets usb voltage droop requirements. input and output v in (input) is both the power supply connection for the inter nal circuitry driving the switch and the input (drain connection) of the power mosfet switch. v out (output) is the source connecti on of the mosfet and supplies power to the load. in a typical circuit, current flows from v in to v out toward the load. since the switch is bidirectional when enabled, if v out is greater than v in , current will flow through the switch from v out to v in . there is no parasitic body diode betwe en drain and source of the mosfet, prevents reverse current flow if v out is externally forced to a higher voltage than v in when the chip is disabled (v en < 0.8v). d s g normal mosfet d s g utc us205 chip enable input if the en pin is in a logic low condition the utc us205 switch will be disabled. during this case, mosfet and the internal circuitry will be turned off, and the supply curren t is reduced to 0.1ua typical. when the en is floating, unpredictable operation may be caused. en goes negative with respect to gnd should not be allowed. the en pin can be directly tied to v in . soft start for hot plug-in applications the utc us205 ?soft-start? feature eliminates the upstream vo ltage droop caused by the large inrush current during hot-plug events, and effectively is olates the power source from extrem ely large capacitive load, meets the usb voltage droop requirements. under-voltage lockout the utc us205 internal under-voltage lockout (uvlo) circuit pr events the mosfet switch from turning on until the input voltage exceeds approximately 1.75v. the internal mosfet switch wi ll be turned off if input voltage drops below approximately 1.7v. under-voltage detect ion functions only when the chip is enabled. current limiting and short-circuit protection the utc us205 protects the power supply and the load from damage by the current limit circuitry, but can deliver load current up to the current limit threshold (typically 2a). if an enabled switch encounters a heavy load or short circuit case, a large transient current may flow until the current limit circuitry responds. once this current limit threshold level is exceeded, the device enters constant current m ode until the fault is remov ed or thermal shutdown occurs. supply filter/bypass capacitor to prevent the input voltage droopi ng during hot-plug events, a 1uf low-esr ceramic capacitor from v in to gnd is strongly recommended. but higher capacitor values will fu rther reduce the voltage droo p on the input. furthermore, without the bypass capacitor, an output short may cause sufficient ringing on the input (from source lead inductance) to destroy the internal circuitry. the input voltage trans ient must not exceed the abs olute maximum supply voltage 6v even for a short duration.
us205 preliminary cmos ic unisonic technologies co., ltd 5 of 5 www.unisonic.com.tw qw-r502-609.a ? application information(cont.) output filter capacitor a low-esr 150uf aluminum electrolytic or tantalum between v out and gnd is strongly recommended to meet the 330mv maximum droop requirement in the hub v bus (per usb 2.0, output ports must have a minimum 120 f of low-esr bulk capacitance per hub). the bypass capacitor itself should have a low dissipation factor to allow decoupling at higher frequencies. thermal shutdown thermal shutdown is used to turn off the output mosfet when the if the temperature is higher than130c, 20c of hysteresis prevents the switch turn on until the die temperat ure drops to 110c. ? typical application circuit 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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