AP3402 datasheet(7/10 Pages) DIODES

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AP3402

Document number: DS36623 Rev. 3 - 2

7 of 10

www.diodes.com

August 2015

AP3402

Application Information

Typical application circuit is shown in the application circuit and for the circuit parameters setting please refers to the following descriptions.

Under Voltage Lockout (UVLO) Circuit

When the VIN drops lower than the UVLO detector threshold, the UVLO circuit starts to operate, VREF stops, and high-side switch and low-side

switch built-

in switch transistors turn “OFF”. As a result, VOUT drops according to the COUT capacitance value and the load. When the VIN is rising

higher than UVLO released voltage, the IC will restart the operation.

Short Circuit Protection and Recovery

When the AP3402 output node is shorted to GND that VFB drops under 0.3V, AP3402 will enter hiccup mode to protect itself. If short circuit is

removed, and VFB rises over 0.3V, the AP3402 recovers to normal operation again. If the AP3402 reaches OCP threshold while short circuit, the

AP3402 will enter cycle by cycle current limit mode until the current under OCP threshold.

Power Good

The PG pin output is an open drain MOSFET. The output is pulled low when the FB voltage enters the fault condition by falling below 80% or

rising above 120% of the nominal internal reference voltage. When the FB voltage rises to the good condition above 90% or falls below 110% of

the internal voltage reference PG output MOSET is turned off. It is recommended using a pull-up to VIN.

Over Temperature Protection

The internal thermal temperature protection circuitry is provided to protect the integrated circuit in the event that the maximum junction

temperature is exceeded. When the junction temperature exceeds +160

OC, it shuts down the internal control circuit and switching power

MOSFET. The AP3402 will restart automatically under the control of soft start circuit when the junction temperature decreases to +130

OC.

Input Over Voltage Protection

When input voltage of AP3402 is near 6.25V, the IC will enter Input-Over-Voltage-Protection. It would be shut down and there will be no output

voltage in this state. As the input voltage goes down below 6V, it will leave input OVP and recover the output voltage.

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