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Please refer to the Typical Applications Circuit, and to set the circuit parameters please refer 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 AP3403 output node is shorted to GND, as VFB drops under 0.3V, the chip will enter hiccup mode to protect itself, when short circuit is
removed, and VFB rises over 0.4V, the AP3403 recovers to normal operation again. If the AP3403 reaches OCP threshold while short circuit, the
AP3403 will enter cycle by cycle current limit mode until the current under OCP threshold.
Input Over Voltage Protection
When input voltage of AP3403 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.
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 +140ºC, it shuts down the internal control circuit and switching power MOSFET.
The AP3403 will restart automatically under the control of soft start circuit when the junction temperature decreases to +100ºC.
AP3403 FLJ - 7
FLJ : U-DFN1616-6
7 : Tape & Reel
7” Tape and Reel
Part Number Suffix
3000/Tape & Reel
U-DFN1616-6 (Type G)
XX : Identification Code
Y : Year : 0~9
W : Week : A~Z : 1~26 week;
a~z : 27~52 week; z represents
52 and 53 week
X : Internal Code
Document number: DS36839 Rev. 3 - 2
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