CPWR-AN08 CREE [Cree, Inc], CPWR-AN08 Datasheet - Page 2

• Manufacturer Part Number: CPWR-AN08
• Description: Application Considerations for Silicon Carbide MOSFETs
• Manufacturer: CREE [Cree, Inc]

2
CPWR-AN08, REV -
Application Considerations for SiC MOSFETs -
January 2011
The modest transconductance and short
device. The CMF20120D needs to be driven with a higher gate voltage swing than what is customary
with SJMOSFETS or IGBTs. Presently,
with SJMOSFETS or IGBTs. Presently, a +20V and -2V to -5V negative bias gate drive is recommended
for the CMF20120D. Care needs to be taken not to exceed
of gate voltage will have a greater effect on the rate of rise of the drain current due to the
of gate voltage will have a greater effect on the rate of rise of the drain current due to the
of gate voltage will have a greater effect on the rate of rise of the drain current due to the lower
transconductance. Therefore, the gate drive needs to supply a fast rise and fall time gate pulse to
transconductance. Therefore, the gate drive needs to supply a fast rise and fall time gate pulse to
transconductance. Therefore, the gate drive needs to supply a fast rise and fall time gate pulse to
maximize switching speed. The CMF20120D
(2V nominal). Like the Si SJMOSFET, consideration
(2V nominal). Like the Si SJMOSFET, considerations need to be made for the lower threshold voltage,
especially at high temperatures.
The rather large triode region can have
active de-saturation circuits. Some of these designs assume t
impedance constant current and/or tran
CMF20120D , the output impedance is lower and the
region during this type of over-current fault
drain to source voltage will not increase as much
carefully considered in fault protection schemes.
carefully considered in fault protection schemes.
The forward conduction characteristics of the
The forward conduction characteristics of the CMF20120D along with the Si SJMOSFET,
IGBTs are presented in Figure 2. T
R
were somewhat similar. At 150 ° C,
° C to 150 ° C, whereas both the Si SJMOSFET and Si MOS8 devices
significant effect on system thermal design. The obvious advantage is that a smaller device can be used
significant effect on system thermal design. The obvious advantage is that a smaller device can be used
significant effect on system thermal design. The obvious advantage is that a smaller device can be used
at higher operating temperatures.
DS(on)
has a considerable effect on its conduction losses.
saturation circuits. Some of these designs assume that the switching device enters a fairly high
considerable effect on its conduction losses. At 25 ° C, the Si SJMOSFET and
, the output impedance is lower and the device does not go into a clean constant current
whereas both the Si SJMOSFET and Si MOS8 devices increase by 250%.
SiC MOSFET
Care needs to be taken not to exceed -5V in the negative direction
Figure 1: O
ance and short-channel effects are important to consider when applying the
needs to be driven with a higher gate voltage swing than what is customary
needs to be driven with a higher gate voltage swing than what is customary
not increase as much. These characteristics of the SiC MOSFET need
and/or transconductance saturation region during over-current
current fault, especially under moderate over-currents. Therefore, the
: Output characteristics comparison (T
CMF20120D also has a threshold voltage similar to the Si SJMOSFET
have an impact on certain types of fault detection schemes, chiefly the
The Si SJMOSFET’s relatively high positive temperature coefficient of
the R
This document is provided for informational purposes only and is not a warranty or a specification.
For product specifications, please see the data sheets available at www.cree.com/power. For warranty
information, please contact Cree Sales at [e-mail].
channel effects are important to consider when applying the
DS(on)
impact on certain types of fault detection schemes, chiefly the
Application Considerations for SiC MOSFETs
January 2011
of the CMF20120D increases by only about 20% from 25
also has a threshold voltage similar to the Si SJMOSFET
. These characteristics of the SiC MOSFET need to be
2
s need to be made for the lower threshold voltage,
device does not go into a clean constant current
5V in the negative direction. The rate of rise
hat the switching device enters a fairly high
J
Si SJMOSFET and CMF20120D
= 150 ° C)
Si SJMOSFET, TFS, and NPT
ase by 250%. This has a
Si NPT IGBT
Si NPT IGBT
gate drive is recommended
temperature coefficient of
only about 20% from 25
current faults. For the
. Therefore, the