MOSFET designed for pre-bias supply circuitry

Zetex Semiconductors introduced a high-voltage MOSFET to handle the requirements of pre-bias supply circuitry. The new ZXMN0545G4 is a 450V enhancement mode n-channel device used in simple linear regulators to supply pulse width modulator ICs at start-up, and is disabled once the converter is fully on.

The new MOSFET has a maximum on-resistance of 50 ohms, supports continuous drain currents up to 140mA, and features pulsed currents of 600mA. Switching speed has turn-on and rise times specified at 7ns.

Zetex added that by disconnecting one of the two conventional drain pin positions, the device's leadframe design extends inter-pin spacing. Housed in a 4-pin SOT223-package to maximize resistance to high voltage creepage, the ZXMN0545G4 is priced at 32 cents in quantities of 10,000.