US3075-US3375

CMOS IC

UNISONICTECHNOLOGIESCO.,LTD

6 of 9

www.unisonic.com.tw

QW-R502-423.E

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. In a typical application, current flows through the switch from input to

output toward the load. 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 US3375/ US3275/ US3175/ US3075

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 keeps 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.