The power dissipation on this application condition

is about 1.3W and Figures 10 and 11 show two

ways of heatsinking.

In the first case, a PCB copper area is used as a

heatsink L= 65mm while in the second case, the

device is soldered to an external heatsink ; in both

examples, the thermal resistance junction ambient

is 35°C/W.

The presence of thermal shut-down circuit does

mean that the heatsink can have a smaller factor

of safety compared with that of a conventional

circuit.

If for any reason, the junction temperature in-

creases up to 150°C, the thermal shut-down simply

switches off the device.

L

Copper Area 35

µ Thickness

Figure 10 : Example of Heatsink using

P.C. Board Copper (L = 65mm)

Figure 11 : Example of an External Heatsink

TDA8140

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