
5
Motorola TMOS Power MOSFET Transistor Device Data
COMMUTATING SAFE OPERATING AREA (CSOA)
The Commutating Safe Operating Area (CSOA) of Figure
12 defines the limits of safe operation for commutated sour-
ce-drain current versus re-applied drain voltage when the
source-drain diode has undergone forward bias. The curve
shows the limitations of IFM and peak VDS for a given rate of
change of source current. It is applicable when waveforms
similar to those of Figure 11 are present. Full or half-bridge
PWM DC motor controllers are common applications requir-
ing CSOA data.
Device stresses increase with increasing rate of change of
source current so dIs/dt is specified with a maximum value.
Higher values of dIs/dt require an appropriate derating of IFM,
peak VDS or both. Ultimately dIs/dt is limited primarily by de-
vice, package, and circuit impedances. Maximum device
stress occurs during trr as the diode goes from conduction to
reverse blocking.
VDS(pk) is the peak drain–to–source voltage that the device
must sustain during commutation; IFM is the maximum for-
ward source-drain diode current just prior to the onset of
commutation.
VR is specified at rated BVDSS to ensure that the CSOA
stress is maximized as IS decays from IRM to zero.
RGS should be minimized during commutation. TJ has only
a second order effect on CSOA.
Stray inductances in Motorola’s test circuit are assumed to
be practical minimums.
Figure 11. Commutating Waveforms
15 V
VGS
0
90%
IFM
dls/dt
IS
10%
trr
IRM
ton
VDS
Vf
VdsL
dVDS/dt
VDS(pk)
MAX. CSOA
STRESS AREA
VR
0.25 IRM
Figure 12. Commutating Safe Operating
Area (CSOA)
200
0
20
40
60
80
15
12
9
6
0
3
VDS, DRAIN-TO-SOURCE VOLTAGE (VOLTS)
+
+
–
Figure 13. Commutating Safe Operating Area
Test Circuit
VR
VGS
IFM
20 V
RGS
DUT
IS
Li
VR = 80% OF RATED BVDSS
VdsL = Vf + Li
dls/dt
–
TJ
≤
175
°
C
IS = 12 A
dIs/dt
≤
100 A/
μ
s
VR
≤
100 V
100
120
140
160
180
I
VDS
Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding
the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit,
and specifically disclaims any and all liability, including without limitation consequential or incidental damages. “Typical” parameters can and do vary in different
applications. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. Motorola does
not convey any license under its patent rights nor the rights of others. Motorola products are not designed, intended, or authorized for use as components in
systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of
the Motorola product could create a situation where personal injury or death may occur. Should Buyer purchase or use Motorola products for any such
unintended or unauthorized application, Buyer shall indemnify and hold Motorola and its officers, employees, subsidiaries, affiliates, and distributors harmless
against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death
associated with such unintended or unauthorized use, even if such claim alleges that Motorola was negligent regarding the design or manufacture of the part.
Motorola and
are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal Opportunity/Affirmative Action Employer.