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Axelite Confidential Materials, do not copy or distribute without written consent.

Rev.2.1 Nov.12, 2019

AX6617

Under-Voltage Protection (UVP)

The AX6617 monitors the voltage on FB pin after soft-start process is finished.

Therefore the UVP is disabling during soft-start. When the voltage on FB pin falls below

the under-voltage threshold, the UVP circuit shuts off the output immediately. After a while,

the AX6617 starts a new soft-start to regulate output.

Thermal Shutdown

A thermal shutdown circuit limits the junction temperature of AX6617. When the

junction temperature exceeds +160°C, a thermal sensor turns off the output NMOS,

allowing the device to cool down. The regulator regulates the output again through

initiation of a new soft-start cycle after the junction temperature cools by 40°C, resulting in

a pulsed output during continuous thermal overload conditions. The thermal shutdown

designed

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APPLICATION INFORMATION

Capacitor Selection

Normally, use a MLCC capacitor on the input and output of the AX6617. Larger input

capacitor values provide better supply-noise rejection and transient response. A higher-

value output capacitor may be necessary if large, fast transients are anticipated and the

device is located several inches from the power source. The X5R and X7R type in MLCC is

recommended. For aluminum electrolytic capacitor application, 100uF in input capacitor

and 220uF in output capacitor (30mΩ < ESR < 200mΩ) are recommended. Output

capacitor of larger capacitance can reduce noise and improve load transient response,

stability, and PSRR.