
MTB1306
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7
I S
,SOURCE
CURRENT
t, TIME
Figure 11. Reverse Recovery Time (trr)
Standard Cell Density
High Cell Density
tb
trr
ta
trr
SAFE OPERATING AREA
The Forward Biased Safe Operating Area curves define
the maximum simultaneous draintosource voltage and
drain current that a transistor can handle safely when it is
forward biased. Curves are based upon maximum peak
junction temperature and a case temperature (TC) of 25°C.
Peak repetitive pulsed power limits are determined by using
the thermal response data in conjunction with the procedures
discussed
in
AN569,
“Transient
Thermal
ResistanceGeneral Data and Its Use.”
Switching between the offstate and the onstate may
traverse any load line provided neither rated peak current
(IDM) nor rated voltage (VDSS) is exceeded and the
transition time (tr,tf) do not exceed 10 s. In addition the total
power averaged over a complete switching cycle must not
exceed (TJ(MAX) TC)/(RθJC).
A Power MOSFET designated EFET can be safely used
in switching circuits with unclamped inductive loads. For
reliable operation, the stored energy from circuit inductance
dissipated in the transistor while in avalanche must be less
than the rated limit and adjusted for operating conditions
differing from those specified. Although industry practice is
to rate in terms of energy, avalanche energy capability is not
a constant. The energy rating decreases nonlinearly with an
increase of peak current in avalanche and peak junction
temperature.
Although many EFETs can withstand the stress of
draintosource avalanche at currents up to rated pulsed
current (IDM), the energy rating is specified at rated
continuous current (ID), in accordance with industry
custom. The energy rating must be derated for temperature
as shown in the accompanying graph (Figure 12). Maximum
energy at currents below rated continuous ID can safely be
assumed to equal the values indicated.
TJ, STARTING JUNCTION TEMPERATURE (°C)
E AS
,SINGLE
PULSE
DRAINT
OSOURCE
Figure 12. Maximum Rated Forward Biased
Safe Operating Area
0.1
1.0
100
VDS, DRAINTOSOURCE VOLTAGE (VOLTS)
Figure 13. Maximum Avalanche Energy versus
Starting Junction Temperature
0.1
10
A
V
ALANCHE
ENERGY
(mJ)
I D
,DRAIN
CURRENT
(AMPS)
RDS(on) LIMIT
THERMAL LIMIT
PACKAGE LIMIT
0
25
50
75
100
125
80
40
ID = 75 A
1000
1.0
10
150
VGS = 10 V
SINGLE PULSE
TC = 25°C
240
120
280
dc
160
100
10 ms
1.0 ms
200