Ultra FRFET™

Ultra FRFET™ family - optimizes designs by providing best-in-class reverse recovery time (trr) of 35 ns ~ 65 ns and the industry's smallest reverse recovery current (1.8 A ~ 3.1 A). Some inverter applications use MOSFETs with two fast recovery diodes (FRDs) and two blocking diodes in a half-bridge circuit to initiate the non-zero voltage switching. The FRDs are used to reduce the reverse recovery current. The blocking diodes prevent the built-in diode of the MOSFET from turning on and eliminate the large reverse recovery current of the diodes. Fairchild's breakthrough solution eliminates the need for two blocking diodes and two FRDs in the half-bridge circuit, saving board space and cost .

Requirements

Application specific MOSFET for Non-ZVS(Zero Voltage Switching) bridge circuit in Dimmable ballast, Motion and Solar system

Advantages

  • Lower switching loss due to smaller trr and Qg
  • Remove external blocking diodes and FRDs in bridge typed circuit
  • High reliability in high temperature and frequency (arrow_left high diode dv/dt immunity > 20V/ns)
  • Better EMI Characteristic (arrow_left small reverse recovery current and soft recovery characteristics)

Circuit Diagram

Turn-on peak current of MOSFET

UltraFRFETLandingPage-Graphic1_rev1
The small reverse recovery current reduces the turn on loss of other side MOSFET in half bridge circuit.

Trr Comparison (Typical Value)

UltraFRFETLandingPage-Graphic2_rev1
The soft reverse recovery characteristics of Ultra FRFET improves EMI performance.

Diode dv/dt immunity comparison (typical value)

 FDPF12N50T
Normal MOSFET
FDPF12N50FT
FRFET
FDPF12N50UT
Ultra FRFET
#16.7V/ns25V/ns32V/ns
#26.8V/ns24V/ns33V/ns
#36.7V/ns25V/ns30V/ns
#46.5V/ns26V/ns32V/ns
#56.5V/ns26V/ns32V/ns

The good diode dv/dt immunity of Ultra FRFET improves the reliability at high temperature and high frequency operation.