BCW33LT1

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6

Figure 16A.

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DESIGN NOTE: USE OF THERMAL RESPONSE DATA

A train of periodical power pulses can be represented by the model

as shown in Figure 16A. Using the model and the device thermal

response the normalized effective transient thermal resistance of

Figure 16 was calculated for various duty cycles.

Example:

The MPS3904 is dissipating 2.0 watts peak under the following

conditions:

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

For more information, see AN-569.

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+ 20 + 40 + 60 + 80 + 100 + 120 + 140 + 160

AND