Fairchild UniFET II MOSFETs Optimize Consumer Power Converters

New Products Jan 23, 2011 by Jeff Shepard

According to Fairchild Semiconductor, designers of switch mode power supplies need high voltage MOSFETs that can withstand reverse recovery current spikes and can reduce switching losses. Fairchild has developed an optimized power MOSFET, the UniFET™ II MOSFET, which features an improved body diode, reduced switching losses and the capability of withstanding double the current stress during diode recovery dv/dt mode.

Fairchild states that its UniFET II MOSFETs deliver 50% better reverse recovery than alternate solutions. A slow reverse recovery can lead to the inability to handle the high reverse recovery current spike, more switching losses and the heating up of the power MOSFET. Fairchild’s solution can handle more than double the current stress than existing solutions.

These UniFET II MOSFETs are based on Fairchild’s advanced Planar technology, which offers a better Figure of Merit (FOM). With lower input and output capacitances and best-in-class reverse recovery, these MOSFETs offer high efficiency. And, by packing a high amount of power in a small package without excessive heat, this improves the overall efficiency of applications such as SMPS for LCD TVs and PDP TVs, SMPS for lighting systems, PC Power, and Server and Telecom power supplies.

Initial products offered in the UniFET II MOSFET series include the FDPF5N50NZ and the FDPF8N50NZ N-channel MOSFETS. The FDPF5N50NZ is a 500V, 4.5A, 1.5O device, featuring an RDS(ON) of 1.38O (Typ.) @VGS = 10V, ID = 2.25A; and a low gate charge (Typ. 9nC). The FDPF8N50NZ is a 500V, 8A, 0.85O device that features an RDS(ON) of 0.77O (Typ.) @ VGS = 10V, ID = 4A, as well as a low gate charge of 14nC (Typ.).

According to Fairchild, these devices are one of the few in the industry to have robust ESD capability of 2kV HBM. This strong ESD capability is instrumental in protecting the application from adverse electrostatic events.

The units are priced (in 1,000 piece quantities) as follows: FDPF5N50NZ at $0.69; FDPF8N50NZ at $0.86, with a delivery of 10 weeks ARO.