SBOS671D September 2018 – December 2022 OPA2828 , OPA828
PRODUCTION DATA
Through normal operation, the OPAx828 self-heat. Self-heating is a natural increase in the die junction temperature that occurs in every amplifier. This self-heating is a result of several factors, including quiescent power consumption, package thermal resistance, PCB layout, and device operating conditions.
To make sure that the amplifier operates without entering thermal shutdown, use Equation 7 to calculate the approximate junction (die) temperature:
As an example, Equation 8 calculates the approximate junction temperature for the OPA828 (D package) while unloaded with an ambient temperature of 25°C.
For high-voltage, high-precision amplifiers, such as the OPAx828, the junction temperature can easily be tens of degrees higher than the ambient temperature in a quiescent (unloaded) condition. As shown by Equation 7 and Equation 8, the junction temperature depends on the thermal properties of the package, as expressed by the junction-to-ambient thermal resistance (RϴJA). If the device then begins to drive a heavy load, the junction temperature can rise and trip the thermal-shutdown circuit. For such loading cases, the DGN package includes a thermal pad that significantly reduces RϴJA. Proper PCB layout is essential to realize this improved thermal behavior. Figure 8-7 and Figure 8-8 show the maximum output voltage of the OPAx828 without entering thermal shutdown versus ambient temperature in both a loaded and unloaded condition for the different package versions.