Side-Power 8981 Manual de usuario descargar pdf (Pagina 6)

Advanced Power

Electronics Corp. APE8981

FUNCTION DESCRIPTION

Current-Limit

Thermal Shutdown

APPLICATION INFORMATION

Capacitor Selection

A thermal shutdown circuit limits the junction temperature of APE8981. 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.

Normally, use a MLCC capacitor on the input and output of the APE8981. 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.

The APE8981 monitors the current via the output NMOS and limits the maximum current to

prevent load and APE8981 from damages during overload or short circuit conditions.

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Side-Power 8981 Manual de usuario Pagina 6