Designers of switch mode power supplies need high voltage MOSFETs that can withstand reverse recovery current spikes and can reduce switching losses. In response, Fairchild Semiconductor has developed the new UniFET II MOSFET, which the company reports features an improved body diode, reduced switching losses and the capability of withstanding double the current stress during diode recovery dv/dt mode.
According to Fairchild, UniFET II MOSFETs deliver 50 percent 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.
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, 1.5Ω device, featuring an RDS(ON) of 1.38Ω (Typ.) @VGS = 10V, ID = 2.25A; and a low gate charge (Typ. 9nC). The FDPF8N50NZ is a 500V, 8A, 0.85Ω device that features an RDS(ON) of 0.77Ω (Typ.) @ VGS = 10V, ID = 4A, as well as a low gate charge of 14nC (Typ.).
UniFET II MOSFETs are based on Fairchild’s Planar technology, which offers an improved Figure of Merit (FOM: RDS(ON) * Qg). With lower input and output capacitances and reverse recovery said to be best-in-class, these MOSFETs are well suited for applications such as SMPS for LCD TVs and PDP TVs, SMPS for lighting systems, PC Power, and Server and Telecom power supplies.
These devices also are said to be among 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.
Samples are available now. The FDPFN50NZ is priced at $0.69 (in 1K quantities) and FDPF8N50NZ at $0.86, again in 1K quantities.