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TPA2006D1: Enabling the device causes a power rail drop

Nir Dvash1
Intellectual 470 points
Part Number: TPA2006D1

Hey,

This device is connected to a 3.6V power rail. When enabling the device, it causes a voltage drop pulse causing the voltage to drop to about 1.88V in less than 380uS.

This pulse then generates a reset on the microcontroller controlling the shutdown pin and the whole process repeats itself.

It should be noted that:

1. It does not matter if the inputs to the amp have audio running on them or if they are disabled.

2. The output of the amp is connected to an 8 ohm/0.5W speaker.

3. When disconnecting one of the wires going to the speaker, the problem stops and yes, I have replaced the speaker. it is not a bad speaker issue.

4. As long as the device is disabled, this problem does not show up. 

I am attaching the schematics related to the device. 

Does anyone have a clue as of what might be causing this "short circuit" behavior when enabling the device?

TPA2006.pdf

Thank you!

Nir.

  • 0
    TI__Guru** 109055 points

    Hi Nir,

    Looking at your schematic I noticed the input gain setting resistors are missing. Can you try modifying your circuit such that you have R at the inputs instead of capacitors? You may replace C2 and C6 with resistors temporarily just to test this.

    Here's a circuit reference from data sheet:

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Intellectual 470 points

    Thank you Ivan,

    I understand that R2 can not serve as a gain setting resistor since it is "behind" the C2 capacitor?

    Also, what value would you recommend the gain resistors should be set to?

    Nir.

  • +1 in reply to Nir Dvash1
    TI__Guru** 109055 points

    Nir,

    Correct, being the resistor behind the capacitor it does not work as gain setting resistor. Please notice you need the same resistor/capacitor on both inverting and non-inverting inputs, regardless of using differential or single-ended input.

    As for the resistor value, you may try 300k or 150k to keep the gain low for now.

    Best regards,
    -Ivan Salazar
    Applications Engineer