These normally on devices are well-suited for very fast-acting circuit breakers and circuit protection

By Heather Hamilton, contributing writer

UnitedSiC has expanded its portfolio of
normally on silicon-carbide (SiC) junction
field-effect transistors (JFETs
) with the launch of its Generation 3 1,200-V
and 650-V SiC JFETs. The new devices are normally on with zero-voltage gate
drive. These devices are well-suited for applications such as very fast-action,
solid-state circuit breakers and circuit protection where a default to on-state
is required in the absence of gate power.

They may also be useful for electronic loads, wireless
charging synchronous rectification, and power switches in low-power flyback
converters in which the JFET in cascode configuration provides for easy

UnitedSiC also noted that the devices are
frequently used in series connection with a Si-MOSFET as “supercascodes,”
providing the benefits of wide band-gap technology with high operating voltages
and easy gate drive.

SiC JFETs offer an extremely good RDSA figure
of merit (normalized on-resistance with die area), which provides for low
insertion loss in circuit protection applications, said the company. Thanks to
a positive temperature coefficient of RDSON and flat gate threshold
voltage curve over temperature, the parts can also be paralleled.

SiC JFETs can be operated in linear mode,
which offers a wide safe operating area (SOA) free of current crowding and
current filament formation that are often present in other technologies.
Because of this, they’re great for electronic loads and current limiters. The
absence of a gate oxide provides the benefits of radiation hardness and

In addition, the company’s proprietary 6-inch wafer process with advanced
wafer-thinning and die-attach techniques in the fabrication of the devices
results in excellent junction-to-case thermal resistance, said UnitedSiC.

Here are datasheet links to the new Gen 3

Application notes are available here. The Gen-e JFETs, available in TO-247-3L
packages, are available through the company’s distribution network. Prices
start at $5.00 in quantities of 1,000.

Learn more about UnitedSiC