
4–810
Motorola TMOS Power MOSFET Transistor Device Data
SAFE OPERATING AREA INFORMATION
FORWARD BIASED SAFE OPERATING AREA
The FBSOA curves define the maximum drain–to–source
voltage and drain current that a device can safely handle
when it is forward biased, or when it is on, or being turned on.
Because these curves include the limitations of simultaneous
high voltage and high current, up to the rating of the device,
they are especially useful to designers of linear systems. The
curves are based on a case temperature of 25°C and a maxi-
mum junction temperature of 175°C. Limitations for repetitive
pulses at various case temperatures can be determined by
using the thermal response curves. Motorola Application
Note, AN569, “Transient Thermal Resistance–General Data
and Its Use” provides detailed instructions.
SWITCHING SAFE OPERATING AREA
The switching safe operating area (SOA) of Figure 9 is the
boundary that the load line may traverse without incurring
damage to the MOSFET. The fundamental limits are the
peak current, I
DM
and the breakdown voltage, BV
DSS
. The
switching SOA shown in Figure 9 is applicable for both turn–
on and turn–off of the devices for switching times less than
one microsecond.
The power averaged over a complete switching cycle must
be less than:
T
J(max)
– T
C
R
θJC
Figure 7. Resistive Switching Time
versus Gate Resistance
t,
M
ns
R
G
, GATE RESISTANCE (OHMS)
V
DD
= 50 V
I
D
= 12 A
V
GS
= 10 V
T
J
= 25°C
t
f
t
r
t
d(off)
t
d(on)
100010010
000
100
10
1
I
D
, DRAIN CURRENT (AMPS)
D
, D
A
N C
N
AMPS
V
DS
, DRAIN–TO–SOURCE VOLTAGE (VOLTS)
Figure 8. Maximum Rated Forward Biased
Safe Operating Area
V
DS
, DRAIN–TO–SOURCE VOLTAGE (VOLTS)
Figure 9. Maximum Rated Switching
Safe Operating Area
0 20 40 60 80 100
Figure 10. Thermal Response
r(t), NORMALIZED EFFECTIVE
TRANSIENT THERMAL RESISTANCE
0
30
0
0.1
100
R
DS(on)
LIMIT
THERMAL LIMIT
PACKAGE LIMIT
10
V
GS
= 20 V
SINGLE PULSE
T
C
= 25°C
1
1
10
000
0.1
dc
100 µs
1 ms
10 ms
20
10
R
θJC
(t) = r(t) R
θJC
R
θJC
= 1.9°C/W MAX
D CURVES APPLY FOR POWER
PULSE TRAIN SHOWN
READ TIME AT t
1
T
J(pk)
– T
C
= P
(pk)
R
θJC
(t)
P
(pk)
t
1
t
2
DUTY CYCLE, D = t
1
/t
2
t, TIME (ms)
1
0.01
D = 0.5
0.05
0.01
SINGLE PULSE
0.01
0.02
120
100
T
J
≤ 175°C
0.03
0.02
0.05
0.1
0.2
0.3
0.5
0.02 0.05 0.1 0.2 0.5 1 2 5 10 20 50 100 200 500 1000
OPERATION LIMITED IN THIS
AREA BY R
DS(on)
0.1
0.2