OPA548: Does this part operate below -40 deg C?

Hi Michael, 

Michael Wellborn said:

if I try and operate this part at -41C will it stop working or only partially work? 

IC generally handles cold a lot better than the elevated temperature, say above 85C as in this part. As in this part, it should work below -40C, and it looks like to the quiescent current should be operate unaffected at -40C vs. -50C . 

Most IC is designed with enough thermal margin, which it should not stop working as soon as below a recommended operating temperature, say -40C in this case. Typically, an normal IC should have ±10-15C built-in thermal margin, where the minimum cold/heat performance of the IC will not be affected significantly, especially at low temperature. As power amplifier, there are plenty dissipated heat internally, which it will keep the Si die warm for operating normally under a cold condition.  

One particular test can indicate if the part is able to handle lower temperature below -40C is this scenario. Say the lowest application requirement is -50C for your application. you should cold soak the circuit at -50C overnight, and power-up after the IC's Tj reached thermal equilibrium at -50C. If the IC is able to power-up normally, it should be good. Of course, you should monitor the critical voltage and current load requirements per your test configuration, and make sure the OPA548 can start at the coldest temperature for the application. 

Assume an power amplifier is unable to have a normal startup after a cold soak overnight, the part may be still able to work, if you are able to power it up at an elevated temperature, and decrease the operating temperature to a coldest setpoint. The residual heat generated within the package will still keep the die warm and maintain the normal operation.

Anyway, OPA548 should pass the cold soak temperature at -50C or -55C and the performance should not be affected significantly if the internal Tj temperature is kept at approx. -40C or higher.  

I am going to close this inquiry. Please let me know if you have other questions. 

Best,

Raymond

Hi Raymond,

Thanks for your response.    We are seeing a ~20% failure rate of this part on our product when we test the circuit card at -40 C.    Could you please have someone contact me who is very familiar with this exact component so we can discuss next steps to determine the root cause?  Thank you.

Hi Michael, 

Can you be more specific about the ~20% failure rate when the DUT is tested at -40C? I would need to know how these tests are performed. 

The public E2E forum is not the best place to discuss the issues. Please contact me, and send me the schematic as well. 

I am going to leave my contact information for now. I will remove it once we are establishing the contact. 

Best,

Raymond

Hi Michael, 

I am going to close this inquiry, since we have established communication via TI's email. 

If you have other questions, we can discussed via emails. 

Raymond