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TPA3136D2: schematic review

Part Number: TPA3136D2

The input to the TPA3136D2 is coming from the analog headphone output of the SGTL5000 audio codec.

I have used a combination of the TPA3136D2EVM schematic and Fig 19 from the TPA3136D2 datasheet

to put this schematic together. The class D amplifier drives one 4 Ohm 3W loudspeaker. Let me know your

feedback on this circuit.

Edited to add: The SGTL5000 codec is on the Toradex iMX7 Colibri SOM board. Only the analog

headphone outputs are available.

Thanks,

Priya

AUDIO_INTERFACE.pdf

  • Hi Priya,

    I reviewed the SCH and have the following comments:

    1. 100kOhm resistor can be used for R40 to achieve a lower idle power loss.

    2. I guess C140, C64 and C65 are used for PVCC(Pin #27, #28), right? But in the SCH, they are connected to the wrong net.

    3. Can't see the value of C140 and C141, please use 100uF or larger capacitors for them.

    4. To improve EMI performance, you could add 1nF+68Ohm snubbers on the output after the output filters. Please refer to our EVM design:

    4. From the SCH, single-ened input mode is used. Please make sure the balance beteetwen RINN and RINP, which means there shouldn't be any other components/device between DAC/Codec output and RINP except 1uF capacitor. In this way, pop noise can be minimized.

    5. There is one switch on the output traces, please make sure the balance between the two output(P and N) is good and the delay between them during switching is short. Becasue a DC signal on the speaker could damage it.  

    Best regards,

    Shawn Zheng 

  • Shawn,
    I had one question about your feedback:
    5. There is one switch on the output traces, please make sure the balance between the two output(P and N) is good and the delay between them during switching is short. Becasue a DC signal on the speaker could damage it.  

    What components on the schematic impact the switching delay and balance?

    Thanks,
    Priya
  • Hi Priya,

    K1 and K2 are switch, please make sure the balance between the two channels are good and the delay between them are small.

    Best regards,

    Shawn Zheng 

  • The only switch associated with the class D is K2. K2 selects the speaker and K1 the intercom. They probably will never go active at the same time. But I will confirm to be sure.
    Thanks,
    Priya