Design Resources

Application Notes

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Switching Characteristics of UnitedSiC Gen 3 SiC FETs at Elevated Temperatures

One unique characteristic of UnitedSiC Gen 3 SiC FETs is that its switching losses and Qrr decrease at
elevated temperature, making the device more efficient once it heats up. This paper explains in detail the
reason behind this characteristic.

Through-Hole Lead Bending

It is often necessary for board assemblers to bend the leads of a through-hole technology (THT) device
when constrained by heat sink orientation, board and system space, etc. While the package may be formed
into different configurations for board mounting, care must be taken in order avoid damage such as plating
strip-off, cracked package, or delamination. This application note contains options and guidelines for
reliable lead bending.

Gate Drive and Protection of Three-Level Inverters

There are multiple variants of three-level neutral point clamped inverters. Most are derivatives of
two circuit topologies: one with four series-connected FETs and two clamp diodes, the other with two
series-connected FETs and two clamp FETs. The first one is diode neutral point clamped but simply called
neutral point clamped (NPC). The second one is transistor neutral point clamped (TNPC), and the phase leg
schematic resembles a sideways letter T. There are different tradeoffs between these two topologies, but
in the end the gate drive requirements and implementation are very similar.

Switching Fast SiC FETs with a Snubber

The emergence of fast switching WBG devices has dramatically enhanced power density in a
range of power conversion circuits such as active rectifiers, LLC bridges, Phase shifted full bridges,
Dual active bridges to name a few. These circuits form the backbone of efficient AC-DC and DC-DC
stages in battery chargers for EVs, forklifts, solar inverters and power supplies, especially where
power density is key.

From Continuous-Time Domain to Microcontroller Code

Control theory is one of the many aspects of electronic theory required for power electronic
design. With the ever increasing popularity of digital control, it is important to have a good
understanding of the basics of digital control. Many textbooks have been written about system
modeling and control theory, but what can be difficult to find is a clear explanation of how to
take an existing continuous-time model and convert it to something that can actually be programmed
into a microcontroller.

650V Cascode in LLC Second Stage Power Conversion for Servers

The 80 Plus certification program is used to classify power supplies in terms of efficiency and power factor.
Supplies with the highest overall efficiency and power factor can be certified to the 80 Plus Titanium level.
Titanium power supplies have the lowest energy cost, and are one of the pieces in improving operational
computer efficiency.

SiC in Solar Inverter Topologies

The design of a renewable energy inverter involves many tradeoffs, including cost, electrical specifications,
efficiency, features, reliability, installation cost, etc. Adding to these assorted considerations is the radically
improved performance of SiC versus silicon-based semiconductors and their cost differences, which makes
evaluating various topology options like comparing apples to oranges and pears.

UnitedSiC JFET in Active Mode Applications

Power MOS devices, which include power MOSFETs of various construction materials and gate structures, as well
as JFETs and IGBTs are three-terminal devices with current flow controlled by the gate. In most power electronic
applications, the gate is driven to either block current flow with the device fully off; or fully on with minimal
conduction loss.

Soldering and Rework of UnitedSiC THT Devices

This document provides recommendations for soldering and rework of UnitedSiC through-hold technology (THT)
devices, including (but not limited to) TO-247 with three or four leads, and TO-220. Included are recommendations
for production assembly soldering as well as rework.

1.5 kW Totem-pole PFC Using 650V UnitedSiC SiC Cascodes

Bridgeless totem-pole PFC can be used to improve efficiency over conventional boost PFC by reducing the number
of semiconductor devices in the conduction path from three to two. Silicon based totem-pole PFC have been
limited to critical conduction mode (CrM) due to the high Qrr of silicon switches.

High Voltage Phase Shift Full Bridge Design with SiC Cascode

The unique combination of features of the silicon carbide (SiC) cascode opens possibilities for new circuits, or for
expanding the operating boundaries of existing circuits. The phase shift full bridge (PSFB) is a perfect example,
now capable of operating efficiently and economically with 800 V input.

1.7 kV JFET Eases High Voltage Utility Power Supply Design

Systems that incorporate High Voltage Rails (~ 800 V) are typically controlled by circuitry that utilizes much lower
voltages. Microprocessors, communication protocols, and sensors require a variety of voltages. A common
approach to generate these voltages is with the flyback topology. In this design, a 1.7kV JFET in the cascode
configuration is used as the main power switch in a flyback utility power supply.

Turn-Off Characteristics of SiC JBS Diodes

SiC junction barrier schottky (JBS) diodes, as majority carrier devices, have very different turn-off characteristics
from conventional Si PiN diodes. The specification data presented in the datasheets are not enough to fully cover
the turn-off characteristics of SiC JBS diodes. This application note presents comprehensive experimental results to
reveal the turn-off behavior of SiC JBS diodes and serves as a supplement to the datasheets.

Importing UnitedSiC Models into LTSPICE – LTSPICE Model File: ZIPTAR

United Silicon Carbide provides standard text based SPICE models to all their commercially released products. To
fully utilize these models they need to be imported into a circuit simulator. This application note details the
process to add UnitedSiC models to LTSPICE, and apply them to a simple example.

Overview of UnitedSiC Normally-On JFETs

The performance improvements of Silicon Carbide switching devices compared against standard Silicon devices are
well documented. What can be confusing are the drive requirements for the various SiC devices and the variation
between suppliers. This document is designed to be used in conjunction with the data sheet to enable designers
to confidently design with United Silicon Carbide (UnitedSiC) normally on xJ Series 1.2kV JFETs.

Cascode Configuration Eases Challenges of Applying SiC JFETs

The high switching speeds and low RDS(ON) of high-voltage SiC JFETs can significantly improve the efficiency and
power density of many power conversion applications. However, the conventional view of these devices is that,
despite the parametric advantages, JFETs are difficult to implement due to non-standard drive voltages and a lack
of an intrinsic diode when switching inductive loads.

SiC Cascode in 440 VAC – 800 VDC Power Factor Correction

With the introduction of wide bandgap switching devices, good efficiencies at higher switching frequencies become
attainable, while producing more cost effective solutions by lowering the required inductance. This article will
explore the design tradeoffs for efficiency and power factor in implementing designs at higher frequencies (>75

Utilizing Silicon Carbide in 80 Plus Current Average Power Factor Correction

In an attempt to improve the efficiency and power factor of computing power supplies, the computer industry has
created a voluntary certification program called “80 Plus”.  In this application note, a silicon carbide cascode switch
and boost diode will be evaluated in a 1 kW hard switch Power Factor Correction (PFC) board with respect to its
suitability in 80 Plus applications.

Cascode Facilitates Simple Startup

Offline converters present a challenge in starting up, due to the mismatch between the high voltage input, and the
low voltage power supply requirements of the controller IC. A typical application uses a string of resistors, Zener
diodes and a high voltage BJT combination to generate ~ 12 V to power the controller until the feedback winding
can generate enough energy to power the IC at an operational voltage. This application note will describe a self-
generated startup voltage that can be used by taking advantage of a cascode configuration.


White Papers

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Practical considerations when comparing SiC and GaN in power applications

Silicon Carbide (SiC) and Gallium Nitride (GaN) semiconductor technologies are promising great performance for the
future. SiC devices in a cascode configuration enable existing systems to be easily upgraded to get the benefits of
wide band-gap devices right now.

Anup Bhalla

Status of SiC Products and Technology

The benefits of silicon carbide (SiC) devices for use in power electronics are driven by
fundamental material benefits of high breakdown field and thermal conductivity, and over 25 years
of sustained development in materials and devices has brought adoption to a tipping point.

Anup Bhalla




Designing with UnitedSiC FETs

Chris Dries Discusses Analog Device’s Strategic Investment in UnitedSiC at PCIM Europe 2019

PSDtv – UnitedSiC on Our Silicon Carbide FETs and More at APEC 2019

Chris Dries, President and CEO of UnitedSiC talks about the company’s progress at APEC

Understanding UnitedSiC Cascode Switches (English)


Understanding UnitedSiC Cascode Switches (Mandarin)


Anup Bhalla, Ph.D., Vice President of Engineering, discusses new 650 V and 1200 V series of devices


Chris Dries, President and CEO of United Silicon Carbide, talks about our latest wide-bandgap devices



Magazine Articles

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Paralleling SiC Cascodes for High Performance, High Power Systems
Matt O’Grady, Mike Zhu, Xueqing Li, John Bendel
Bodo’s Power Systems, September, 2015

Robustness of SiC JFETs and Cascodes
Anup Bhalla, Xueqing Li, John Bendel
Bodo’s Power Systems, May 2015

Using “Normally-On” JFETs in Power Systems
John Bendel & Xueqing Li
Bodo’s Power, March 2015

SiC Research and Development at United Silicon Carbide Inc. – Looking Beyond 650-1200V Diodes and Transistors
J. C. Dries
IEEE Power Electronics Magazine, March 2015


UnitedSiC Publications References


Gate Driving Strategies of SiC Cascode
Xueqing Li, Shirley Zhang, and Anup Bhalla
PCIM Europe 2016

Medium Voltage Power Switch Based on SiC JFETs
Xueqing Li, Shirley Zhang, Peter Alexandrov, Anup Bhalla
APEC 2016 conference 2016

SiC JFET Cascode Enables Higher Voltage Operation in a Phase Shift Full Bridge DC-DC Converter
Jonathan Dodge, P.E.
PCIM Europe 2016




6.5kV Enhancement Mode SiC JFET Based Power Module
John. L. Hostetler, Xueqing Li, Peter Alexandrov, Xing Huang, Anup Bhalla ,Martin Becker, Joseph Colombo, Derrick Dieso, Jerry Sherbondy
Wide Bandgap Power Devices and Applications (WiPDA), 2015 IEEE Workshop on , Nov. 2015

Series-Connection of SiC Normally-on JFETs
Xueqing Li, Anup Bhalla, Petre Alexandrov, John Hostetler, and Leonid Fursin,
Proceedings of the 27th ISPSD, Kowloon Shangri-La, Hong Kong, pp. 221-224. May, 2015

Correlation of Lifetime Mapping of 4H‐SiC epilayers with Structural Defects Using Synchrotron X‐ray Topography
Ouloide Goue, Yu Yang, Jianqiu Guo, Balaji Raghothamachar, Michael Dudley, John Hostetler, Rachael L. Myers‐Ward, Paul B. Klein, D. Kurt Gaskill
ICSCRM, Sicily, Italy October 2015

Understanding the basis of laterally varying minority carrier lifetimes in epitaxial 4H‐SiC
D.Kurt Gaskill, Rachael L. Myers‐Ward, Anthony B. Boyd, Kevin M. Daniels, Paul B. Klein, John Hostetler
ICSCRM, Sicily, Italy October 2015

Breakthrough Analog and Logic SiC Integrated Circuits Enable Ultra High Temperature Control Applications
Peter Alexandrov, Xueqing Li, Matt O’Grady, John Hostetler
PCIM Europe, May 2015




Market Penetration of Wide-Bandgap SiC and GaN technology in light of Silicon Superjunction and IGBT technology evolution
Anup Bhalla
CS Mantech May 19, 2014

6.5 kV SiC Normally-Off JFETs — Technology Status
John. L. Hostetler, Peter Alexandrov, Xueqing Li, Leonid Fursin, Anup Bhalla
Wide Bandgap Power Devices and Applications (WiPDA), 2015 IEEE Workshop on , Oct. 2014

Investigation of SiC Stack and Discrete Cascodes
Xueqing Li, Anup Bhalla, Petre Alexandrov, John Hostetler, and Leonid Fursin
PCIM 2014 conference, Nuremberg, Germany, pp.448-455 May 20-22, 2014

Study of SiC Vertical JFET Behavior during Unclamped Inductive Switching
Xueqing Li, Anup Bhalla, Peter, Alexandrov, Leonid Fursin
APEC Conference, Fort Worth, TX, pp. 2588-2592.March 16-20, 2014




Evaluation of SiC Stack Cascode for 200°C Operation
Xueqing Li, Petre Alexandrov, John Hostetler, and Anup Bhalla,
ICSCRM Conference, Materials Science Forum, Vol. 778-780, p879-882, 2013

The Outlook for SiC Vertical JFET Technology
Anup Bhalla, Xueqing Li, Petre Alexandrov, and J. Christopher Dries
Wide Bandgap Power Devices and Applications (WiPDA), 2015 IEEE Workshop on , Oct. 2013

SiC JFETs Reduce the Balance-of-System for Stationary Energy Storage Power Conversion Systems
John Hostetler, Xueqing Li, Peter Alexandrov, Leonid Fursin, Anup Bhalla, Frank Hoffmann, D. Kurt Gaskill, Rachael Myers-Ward and Bob Stahlbush,
Biennial International Conference on Electrical Energy Storage Applications and Technologies, EESAT 2013, San Diego, California, USA 2013

Development of high-voltage 4H-SiC GTOs for grid-tied solar inverters
Leonid Fursin, Frank Hoffmann, John Hostetler, Xueqing Li, Matthew Fox, Petre Alexandrov, Mari-Anne Gagliardi, Mark Holveck,
Materials Science Forum Vols. 740-742 (2013) pp 982-985, 2013

High Voltage, High Frequency Lateral SiC JFET for Next Generation DC-DC Power Supply Peter Alexandrov, Xueqing Li, John Hostetler
PCIM – Europe Conference, Nuremberg, Germany, 2013

7.5 kV 4H-SiC GTO’s for Power Conversion
Leonid Fursin, John L. Hostetler, Xueqing Li, Matt Fox, Peter Alexandrov, Frank Hoffmann, Mark Holveck,
28th Annual IEEE APEC Conference p222-5, 2013

Breakthrough SiC GTOs Enable Efficient & Compact Next Generation High Voltage Grid Conversion
Leonid Fursin, John L. Hostetler, Xueqing Li, Anup Bhalla, Frank Hoffmann, Matthew Fox
PCIM Europe Conference Proceedings, p 43-48, 2013



2009 – 2012

SiC Solid-State Disconnect for High Power System Applications
X. Li, P. Alexandrov, L. Fursin, C. Dries, J. Zhao,
Materials Science Forum, Vols. 717-720, pp. 1249-1252, 2012

Optically Triggered Power Switch Based on 4H-SiC Vertical JFET
P. Alexandrov, X. Li, J. Zhao
Materials Science Forum, Vols. 679-680, pp. 625-628, 2011

Solid-State Disconnects Based on SiC Power JFETs
P. Alexandrov, X. Li, L. Fursin, C. Dries, J. Zhao2, T. Burke,
Vehicle Power and Propulsion Conference, 2011

Development of Silicon Carbide High-Voltage Switches for Power Converters and Solid-State Disconnects
P. Alexandrov, J. Zhang, L. Fursin, X. Li, C. Dries, L. Lin, J. H. Zhao, T. Burke, F. Kub
COMACTEC Conference, March, 2011

High Voltage 4H-SiC BJTs with Deep Mesa Edge Termination
Zhang, Jianhui; Zhao, Jian H; Wang, Xiaohui; Li, Xueqing; Fursin, Leonid; Alexandrov, Peter; Gagliardi, Mari-Anne; Lange, Mike; Dries, Chris
ICSCRM, Materials Science Forum, v679-680, p 710-713, 2011

Development of High Temperature Lateral HV and LV JFETs in 4H-SiC
Zhang, Y. Sheng, K.; Su, M.; Zhao, J.H.; Alexandrov, P.; Fursin, L.
Materials Science Forum, v600-603, pt.2, p 1091-4, 2009

4H-SiC Bipolar Junction Transistors with Graded Base Doping Profile
Zhang, Jianhui, Fursin, Leonid, Li, Xueqing, Wang, Xiaohui, Zhao, Jian H., Vanmil, Brenda L. Myers-Ward, Rachael L., Eddy Jr., Charles R., Gaskill, D. Kurt
ECSCRM, Materials Science Forum, v 615 617, p 829-832, 2009