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Trouble implementing PCM1798 application circuit

Michael Gosselin
Prodigy 100 points
Other Parts Discussed in Thread: PCM1798, NE5534, OPA604

Hi, I have constructed the PCM 1798 (same pinout as PCM 1794) recommended application circuit on a solderless breadboard, using the recommended op-amps and component values from the data sheet.  I am using the output of a PCM2707 to supply i2s to the PCM1798 at 48KHz, 16bits.  I am using +/- 15V regulated DC supply for the analog section (for the op amps), +5VDC regulated supply for the DAC's analog side, and +3.3VDC regulated supply for the DAC's digital side.  It is configured in hardware mode, for mono output (I am testing with only one channel at this time).

However, I accidentally applied power backwards to the breadboard.  When I connected everything and checked the output of the analog section, there was nothing...except a bit of noise.  I suspect all the op amps were destroyed when the power was connected backwards.  What do you recommend I replace first, in order to trouble shoot this issue?

Thanks, 

Michael

  • 0
    TI__Guru**** 189399 points

    Hi, Michael,

    I suggest that you replace all the ICs as they are all probably damaged.

    Funny thing, I did the same thing in State College about 25 years ago... Doh!

    -d2

  • 0 in reply to Don Dapkus
    Prodigy 100 points

    Ok, thanks Don.

    I think all the voltage regulators survived, since they all seem to be still regulating correctly.  I will replace the DAC IC and the op-amps, as you have suggested.

    One further question - in order to save cost, can I replace the recommended op-amps in the application circuit with OPA604?  (the recommended ones are NE5534 and LT1028)   I happen to already have some 604's in the correct package.  I don't mind if my application circuit doesn't meet the target specifications initially, I just want to verify that my circuit is indeed assembled and working in the way that is recommended in the datasheet.

    Thanks, 

    Michael