ARF477FL

Figure 5b, TRANSIENT THERMAL IMPEDANCE MODEL

0

0.05

0.10

0.15

0.20

0.25

10

1.0

-1

0.3

D = 0.9

SINGLE PULSE

RECTANGULAR PULSE DURATION (SECONDS)

Figure 5a, Maximum Effective Transient Thermal Impedance, Junction-To-Case vs Pulse Duration

0.5

0.1

0.05

Peak TJ = PDM x ZθJC + TC

Duty Factor D =

2

t2

t1

Note:

0.7

Dissipated Power

(Watts)

T

T

Z

impedances: Case to sink,

sink to ambient, etc. Set to

zero when modeling only

the case to junction.

.0915

.108

.0111F

.133F

Freq. (MHz)

Z

40

60

80

1.5 - j 10

1.9 - j 1.3

2.2 - j 0.82

24 - j 37

13 - j 29

7.9 - j 24

Z

I

Z