Op Amp Applications Handbook

SECTION 7-5

Thermal Considerations

Walt Jung

For reliability reasons, op amp systems handling appreciable power are increasingly called upon to observe thermal management. All semiconductors have some specified safe upper limit for junction temperature (T_J), usually on the order of 150°C (sometimes 175°C). Like maximum power supply voltages, maximum junction temperature is a worst-case limitation which shouldn’t be exceeded. In conservative designs, it won’t be approached by less than an ample safety margin. Note that this is critical, since semiconductor lifetime is inversely related to operating junction temperature. Simply put, the cooler op amps are, the more they can approach their maximum life.

This limitation of power and temperature ...