MMSF7P03HD

6

Motorola TMOS Power MOSFET Transistor Device Data

t, TIME

Figure 11. Reverse Recovery Time (trr)

di/dt = 300 A/

µs

Standard Cell Density

High Cell Density

tb

trr

ta

trr

SAFE OPERATING AREA

The Forward Biased Safe Operating Area curve (Figure

12) defines the maximum simultaneous drain–to–source vol-

tage 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 pro-

cedures discussed in AN569, “Transient Thermal Resistance

– General Data and Its Use.”

Switching between the off–state and the on–state may tra-

verse any load line provided neither rated peak current (IDM)

nor rated voltage (VDSS) is exceeded, and that the transition

time (tr, tf) does not exceed 10 µs. In addition the total power

averaged over a complete switching cycle must not exceed

(TJ(MAX) – TC)/(R

θJC).

A power MOSFET designated E–FET can be safely used

in switching circuits with unclamped inductive loads. For reli-

able operation, the stored energy from circuit inductance dis-

sipated in the transistor while in avalanche must be less than

the rated limit and must be 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 non–linearly with an

increase of peak current in avalanche and peak junction tem-

perature.

Although many E–FETs can withstand the stress of drain–

to–source avalanche at currents up to rated pulsed current

(IDM), the energy rating is specified at rated continuous cur-

rent (ID), in accordance with industry custom. The energy rat-

ing must be derated for temperature as shown in the

accompanying graph (Figure 13). Maximum energy at cur-

rents below rated continuous ID can safely be assumed to

equal the values indicated.

Figure 12. Maximum Rated Forward Biased

Safe Operating Area

0.1

VDS, DRAIN–TO–SOURCE VOLTAGE (VOLTS)

1.0

10

RDS(on) LIMIT

THERMAL LIMIT

PACKAGE LIMIT

VGS = 12 V

SINGLE PULSE

TA = 25°C

10

0.01

dc

10 ms

1.0

100

100

1 ms

TJ, STARTING JUNCTION TEMPERATURE (°C)

0

25

45

65

85

105

3000

145

2000

500

4000

Figure 13. Maximum Avalanche Energy versus

Starting Junction Temperature

5000

0.1

125

2500

1500

3500

4500

1000

ID = 7.0 A