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Technical Product Overview
December 2020
Breakthrough Performance of UnitedSiC 750V Gen 4 SiC FETs
Complementing its already strong portfolio of industry-leading SiC FETs, UnitedSiC has released its
(Gen 4) SiC FETs, offering breakthrough performance levels designed to accelerate WBG adoption
in automotive and industrial charging, telecom rectifiers, datacenter PFC DC-DC conversion as well
as renewable energy and energy storage applications.
The new series has expanded UnitedSiC FET offerings to include a 750V rating allowing additional
design margin for 400V or 500V battery/bus voltage applications. Despite the increased voltage
rating, Gen 4 devices employ advanced cell density to reduce the R
DS(on)
per unit area, delivering the
industry’s lowest resistance products in all packages. In addition, high current ratings are achieved
by the devices’ advanced sintered die attach technology offering improved thermal performance.
Figure 1 shows the new 750V specific on-resistance versus 650V rated SiC competitors, offering
substantially lower conduction losses across the full temperature range.
Figure 1. 750V Gen 4 UnitedSiC FET On-resistance per unit area compared to 650V rated SiC competitors
Design ease-of-use will again be featured with UnitedSiC Gen 4 switches. All devices can be safely
driven with standard 0V to 12V or 15V gate drive voltage. Good threshold noise margin is
maintained with a true 5V threshold voltage. Like previous generations, these new SiC FETs can be
Breakthrough Performance of UnitedSiC 750V Gen 4 SiC
FETs
Page 2 of 4
Technical Product Overview
December 2020
operated from all the typical Si IGBT, Si MOSFET and SiC MOSFET drive voltages and includes a
built-in ESD gate protection clamp.
Along with low on-resistance, these new SiC FETs offer improved efficiency in both hard and soft-
switched circuits. In hard-switched circuits such as Totem-Pole PFC or standard 2-level inverters,
the low on-resistance per unit-area and low output capacitance along with the near-zero stored
charge in the low-voltage Si MOSFET combine to offer superior reverse recovery charge (Q
rr
) and
low E
oss
/Q
oss
. The devices exhibit a superior and robust integral diode with low voltage drop V
F
(<1.75V).
Figure 2 illustrates the advantage of the 750V UnitedSiC FETs versus their 650V rated SiC
competitors when represented as a hard-switching Figure-of-Merit (FoM) of R
DS(on)
x E
oss
. The
UJ4C075018K3S (in TO247-3L package) and UJ4C075018K4S (in TO247-4L package) features a
low on-resistance of 18mohm, which is 50% less at 25
o
C and almost 40% less at 125
o
C compared to
its closest competitor.
Figure 2. Hard-Switching Figure of Merit advantage of UnitedSiC 750V FETs compared to 650V rated SiC competitors
These new devices also offer improved performance in high-frequency, soft-switched resonant
converter topologies such as LLC or PSFB. The breakthrough performance of the 750V UnitedSiC
FETs comes as the on-resistance has been substantially reduced, while at the same time, offering
lower output capacitance, C
oss(tr)
. In Figure 3, the benefit is illustrated with the proposed resonant
or soft-switching FoM, R
DS(on)
x C
oss(tr)
.