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Greetings,
My customer is planning to use the TPA3138D2 amplifier with the PCM2704 DAC and they have a question regarding the series capacitors to use between the DAC and the amplifier.
"On the PCM2704 datasheet, 100uF and 1uF are used, but on the PCM2704 EVM, only a 100uF is used in reverse polarity.
On the TPA3138D2 datasheet, a 1uF ceramic capacitor is used.
In our design, the DAC and the amplifier will be on the same PCB and everything willl be powered using the USB +5V power.
Could you please give me more information on the capacitors value/polarity that we should use in our design?"
PCM2704 datasheet:
PCM2704 EVM:
TPA3138D2 datasheet:
Our audio team has confirmed for the TPA3138, a 1uF DC cap is fine. Looking forward to your response.
Best,
Steven
Hi Steven, The value of C is more critical for the TPA3138 , as it directly affects the bass (low-frequency) performance of the amplifier you are attaching to PCM. The TPA3138 has a fixed input Z. I think a 1uf should be okay for PCM too . It is all depending on frequency response you need. For polarity please use the below diagram (fig 33, page 29 of data sheet)
