TABLE OF CONTENTS For active semiconductor devices:
| (B.1) |  |
| where | T J is the junction temperature, |
| T A is the ambient temperature, | |
| P is the power dissipation, and | |
| ? JA is the junction to ambient thermal resistance. |
If the junction temperature of a semiconductor device remains constant, then the performance of the device should not change. The power dissipation of a device is often a function of some electrical parameter (for example: operating voltage, frequency); thus a trade-off can thus be made between ambient temperature and an electrical parameter. From Equation 6, a higher ambient temperature is allowed if the power dissipation is reduced sufficiently to keep the junction temperature constant. The steps to be followed in stress balancing are listed in B.3.1 through B.3.6, and shown schematically in Figure 15.
The goal of this step is to determine which electrical parameters can be derated [3], and by how much, and to calculate the amount by which the dissipated power must be reduced in the proposed application, in order to uprate the device.
| Note | Various factors, such as device technology, device family, and electrical function, must be considered in selecting the parameters that most significantly affect power dissipation, and therefore should be selected for reduction. As examples, the relationship between power dissipation and effective operating frequency is essentially linear for CMOS devices; and changing the device operating voltage may reduce... |
