US107

Preliminary

LINEAR INTEGRATED CIRCUIT

UNISONICTECHNOLOGIESCO.,LTD

6 of 8

www.unisonic.com.tw

QW-R129-004.d

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FUNCTIONAL DESCRIPTION

Input and Output

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

is the source of the output MOSFET. In a typical application, current flows through the switch from IN to OUT toward

the load. Both OUT pins must be connected together to the load.

Thermal Shutdown

The thermal shutdown circuit is used to prevent damage occurs when the die temperature becomes higher than

approximately 140°C. After 20°C of hysteresis, the switch will automatically restart if it enabled. When these devices

are disabled or the fault is removed, the output and OC signal will continue to cycle on and off.

Undervoltage Lockout

UVLO (Under-voltage Lockout) turns off the MOSFET switch once the input voltage falls below 2.2V, and the

OC is in active. If the input voltage exceeds approximately 2.4V, the switch will be turned on. Under-voltage

detection functions only when the switch is enabled.

Over Current Trigger Point

The typical over current trigger point of UTC US107 is 2.5A, 2A, 1.5A. There is foldback of current limit when

Output Reverse-Voltage Protection

The output reverse-voltage protection turns off the MOSFET switch whenever the output voltage is higher than

the input voltage by 20mV (typ) for 5ms (typ) and the MOSFET switch will turn on when output reverse-voltage

condition is removed for 5ms (typ).

OC Function

The OC open-drain output is asserted (active low) when an over current condition is encountered after a 9ms

deglitch timeout. The output remains asserted until the overcurrent condition is removed. Over temperature condition

is also reported immediately by OC open-drain output. In addition, OC is also asserted (active low) in output

reverse-voltage condition with typical 5ms deglitch timeout period until the output reverse-voltage condition is

removed.