- #1
Firefox123
- 183
- 1
Circuit Design help...
Hi all...
I had a question about a little audio circuit I am working on...its pretty simple it just consists of an audio amplifier (OPA134PA), an audio balanced line driver (DRV134), a audio differential receiver (INA137), and a few caps and resistors.
When I hook this circuit up on a bread board everything works fine...the op amp gives a gain of 8 and the line driver outputs two signals 180 degrees out of phase with virtually the same peak to peak voltage.
I am inputting a .5 volt peak to peak signal into the amplifier and getting 4 volts peak to peak out of the amplifier. Then the line driver provides me with two out of phase signals each 4 volts peak to peak.
But on my PCB something seems to be wrong...the audio line driver (DRV134) outputs are not equal...the positive output is around .30 volts higher than the negative input which is out of specs for the DRV134. I called Texas instruments and they said I might have a bad chip, but since it works on a breadboard I am convinced it is a issue with the final PCB circuit.
Any ideas what could cause the difference in the two outputs?
I have attached the ORCAD files I used for the circuit for reference...any help would be appreciated.
Regards.
Hi all...
I had a question about a little audio circuit I am working on...its pretty simple it just consists of an audio amplifier (OPA134PA), an audio balanced line driver (DRV134), a audio differential receiver (INA137), and a few caps and resistors.
When I hook this circuit up on a bread board everything works fine...the op amp gives a gain of 8 and the line driver outputs two signals 180 degrees out of phase with virtually the same peak to peak voltage.
I am inputting a .5 volt peak to peak signal into the amplifier and getting 4 volts peak to peak out of the amplifier. Then the line driver provides me with two out of phase signals each 4 volts peak to peak.
But on my PCB something seems to be wrong...the audio line driver (DRV134) outputs are not equal...the positive output is around .30 volts higher than the negative input which is out of specs for the DRV134. I called Texas instruments and they said I might have a bad chip, but since it works on a breadboard I am convinced it is a issue with the final PCB circuit.
Any ideas what could cause the difference in the two outputs?
I have attached the ORCAD files I used for the circuit for reference...any help would be appreciated.
Regards.