7.3.4 Thermal Shutdown

The internal power dissipation of any amplifier causes the internal (junction) temperature to rise. This phenomenon is called self heating. The OPA2156 has a thermal protection feature that prevents damage from self heating.

This thermal protection works by monitoring the temperature of the output stage and turning off the op amp output drive for temperatures above approximately 170°C. Thermal protection forces the output to a high-impedance state. The OPA2156 is also designed with approximately 15°C of thermal hysteresis. Thermal hysteresis prevents the output stage from cycling in and out of the high-impedance state. The OPA2156 returns to normal operation when the output stage temperature falls below approximately 155°C.

The absolute maximum junction temperature of the OPA2156 is 150°C. Exceeding the limits shown in the Absolute Maximum Ratings table may cause damage to the device. Thermal protection triggers at 170°C because of unit-to-unit variance, but does not interfere with device operation up to the absolute maximum ratings. This thermal protection is not designed to prevent this device from exceeding absolute maximum ratings, but rather from excessive thermal overload.