800 V depletion-mode MOSFET in modified SOT-223 package provides extra creepage distance

The new CPC3981Z from Littelfuse provides a compact solution for high-voltage power circuits that require extra drain-gate pin spacing. The longer creepage helps to save cost and simplify board layouts.

Littelfuse has launched the CPC3981Z, an 800 V N-channel depletion-mode MOSFET with a novel pin arrangement that provides extended creepage distance in high-voltage applications.


A variation on the standard SOT-223 outline, the design of the CPC3981Z SOT-223-2L package removes a middle pin. This extends the drain-gate pin spacing from 1.386 mm to more than 4 mm. The longer creepage is beneficial in high-voltage applications such as switch-mode power supplies or power factor correction start-up circuits, because designers can avoid the need for costly conformal coating or potting while meeting the design requirement with a small, discrete device.


The increased distance between the depletion-mode MOSFET’s pins also simplifies the isolation management of wide input-voltage power supplies, and enables compact PCB layouts.


The 800 V blocking voltage rating of the CPC3981Z makes it the ideal choice for use in applications such as:

  • Normally on switches
  • Power supplies
  • Start-up circuits
  • Solid-state relays
  • Current regulators
  • Constant current sources


  • High input impedance
  • Low gate-source switch-off voltage
  • Normally closed with no power applied


  • Industrial equipment
  • Energy systems
  • Telecoms equipment
  • LED lighting

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