High-voltage MOSFET gets things started

A new high-voltage MOSFET is designed to handle the requirements of prebias supply circuitry.

A new high-voltage MOSFET from Zetex Semiconductors is designed to handle the requirements of prebias supply circuitry.

A 450V enhancement mode N-channel device, the ZXMN0545G4 is used in a simple linear regulator to supply PWM ICs at startup, and is disabled once the convertor is fully on.

Compared with alternative resistor dependent solutions, the MOSFET based approach improves system efficiency and reduces startup time.

To maximise resistance to high voltage creepage, the MOSFET is provided in a novel 4-pin SOT223-package.

By simply disconnecting one of the two conventional drain pin positions, the device's new leadframe design significantly extends inter-pin spacing, which helps designers comply with UL and CE creepage distance specifications.

Characterised by low on resistance - a maximum of 5ohm - and supporting continuous drain currents up to 140mA, and pulsed currents of 600mA, the transistor offers a highly efficient power handling capability.

Switching speed is also fast, with turn-on and rise times specified at 7ns.

The price of the ZXMN0545G4 is US $0.32 in quantities of 10,000.

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