LESHAN RADIO COMPANY, LTD.

M17–6/6

T

Figure 15. Typical Collector Leakage Current

V

–4

–2

0

+20

+40

+60

+80

+100

+120

+140

+160

I

CBO

AND

I

I

CEO

DESIGN NOTE: USE OF THERMAL RESPONSE DATA

A train of periodical power pulses can be represented by

the model as shown in Figure 16. Using the model and the

device thermal response the normalized effective transient

thermal resistance of Figure 14 was calculated for various

duty cycles.

Example:

Dissipating 2.0 watts peak under the following conditions:

t

Using Figure 16 at a pulse width of 1.0 ms and D = 0.2, the

reading of r(t) is 0.22.

The peak rise in junction temperature is therefore

∆T = r(t) x P

For more information, see AN–569.

LMBT5087LT1