opa2673: opa2673

Hi Paul,

Sorry for missing this post.

I think you might run into thermal issues with the OPA2673 if the amplifier power specs are exceeded. Do you know whether the junction temperature (Tj) of the part could go beyond 150'C while operating the device in low duty cycle pulses with 10nF cap? Also, lower duty cycle of the pulses often results in the part dissipating more heat for longer time compared to the short duty cycle pulses. I would recommend that you take a look at the Thermal Analysis section in the device datasheet to understand a bit more about any thermal issues you might encounter.

Best Regards,
Rohit

Rohit,

Thanks for your reply. The opamp is nun at low average power levels so the junction temperatures would be well below operating limits (<80C). The data set does not give any time dependent information e.g. thermal time constants. Is it ok to assume that the thermal time constants are much greater than 1us? If that is the case the temperature rise during each pulse will be small and there will be time for the junction to cool down between pulses. Thats why I think it will be ok to exceed the internal 2W power dissipation limit for short times ~20 ns. However I am not very confident my assumptions are correct so any further insight would be welcome.

Paul

Paul,

You are right that the thermal time constants on the device are much greater than 1us. If you are running pulses for short times of ~20ns which allows the junction to cool down in-between pulses, then I think it should be ok to exceed the internal 2W power dissipation intermittently.

Best Regards,
Rohit

Thanks Rohit,

If you know of any publication (especially by TI) relevant to this topic could you please send me a reference?

Paul