IXYS/Littelfuse Depletion-Mode D2™ MOSFETs feature unique characteristics that cannot be replicated by their commonly used enhancement-mode counterpart. Unlike the regular N-channel enhancement-mode type, depletion-mode power MOSFETs require zero gate bias to turn-on and negative gate bias to turn-off but otherwise have similar characteristics. The “normally-on” operational mode of these devices combined with an enhanced linear operating capability allows for an ideal device selection in current sources, current regulators, solid-state relays, level shifting, active loads, start-up circuits, and active power filters.

These devices are available with blocking voltages between 500 V to 1000 V, on-resistance (Rdson) as low as 500 mΩ (max), and drain current ratings of up to 6 A. They can provide simplified control and reduced line voltage dissipation when used for line interface in off-line applications. Since these devices require no energy or gate voltage for turn-on, high-energy efficiency can be achieved through device implementation in zero power “normally-on” load switch applications. With the high degree of current regulation, these devices can also act as active inductors with high dynamic impedance in power filter applications to limit voltage and current noise and spikes. Furthermore, these devices can provide active circuit protection to limit the surge of current during short-circuit or overload conditions.