OPA1632D heating up in a custom PCM1792A DAC

[keves]

ijzerpro - which capacitors are you referring to? even if I didn't get the filter right, I don't think it should result in super hot chips...

Samuel - Any idea how should I go around measuring that, assuming I don't have access to a spectrum/audio analyzer?

Thanks <3

 

[ijzerpro]

PCM1792A  , pdf, page 36,  C1,C2,C3 etc.

 

[keves]

I used some ceramic capacitors I had lying around (1000pF (C1/C2) / 2500pF (C3)) just to see if it makes a difference in temperature but it didn't. I'll try other values when I get a chance.

 

[Andy Peters]

Have you used it to generate both positive and negative rails? Did you follow the "Dual Output Flyback Converter with Overvoltage Protection" example from the datasheet? If yes, how hard is it to obtain an equivalent for that transformer? I have no experience with switching regulators, which is partly why I opted for the Murata module.

Yes, I followed that example, and modified it for a higher output voltage so I could follow the outputs with LM317 and LM337 linears. I used Eaton/Coilcraft VP-series transformers (readily available from Mouser and Digikey), and simulated the design with LTSpice. I am not convinced I need the post-regulators (need to test it). If I were to re-do the design I would opt for one of the newer very-low-noise LDOs from Linear Tech.