US3076-US3376

Preliminary

CMOS IC

UNISONICTECHNOLOGIESCO.,LTD

8 of 8

www.unisonic.com.tw

QW-R502-424.d

FUNCTIONAL DESCRIPTION

Input and Output

IN pin (Input) is the power supply connection to the logic circuitry and the drain of the output MOSFET. OUT pin

(Output) is the source of the output MOSFET. Current flows through the switch from input to output toward the load

in a typical application. Both OUT pins must be connected together to the load.

Thermal Shutdown

Thermal shutdown is designed to prevent this device from being damaged due to excessive power dissipation. It is

used to turn off the output MOSFET when the if the temperature is higher than135°C, 20°C of hysteresis prevents

the switch turn on until the die temperature drops to 115°C. Thermal shutdown circuit functions only when the switch

is enabled.

Under-Voltage Lockout

UVLO (Under Voltage Lockout) turns off the MOSFET switch once the input voltage falls below 2.3V (TYP.) and if

the input voltage exceeds 2.5V (TYP.), the switch will be turned on. UVLO detection functions only when the switch

is enabled.

Current Limiting

The current limit value is fixed internally, typically 2A, 1.5A, 1A, 0.75A for US3376/ US3276/ US3176/ US3076

OC Function

The OC open-drain output is asserted (active low) when an over-current or over-temperature shutdown condition

is encountered after a 9-ms deglitch timeout. The output remains asserted until the over current or over temperature

condition is removed.

APPLICATION INFORMATION

Supply Filtering

To avoid supply transients, 1μF bypass capacitor is strongly recommended to located between IN to GND.

Without a bypass capacitor, an output short may cause sufficient ringing on the input (from supply lead inductance)

to damage internal control circuitry.

short duration.

EN, the Enable Input

The enable pin, EN, must be driven logic high or logic low for a clearly defined input. The input is not allowed to

float, or unpredictable operation may be occurs. EN should not be allowed to go negative with respect to GND.

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.