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TAD5212: Schematic review

Stone Zeng
Intellectual 780 points

Part Number: TAD5212
Other Parts Discussed in Thread: TAA5212, TAC5212

Hi Team,

 

my customer is using TAD5212 on PDA, could you help review the schematic as below

 

 

188a2048-1cdf-41e4-8340-33ab2a40be09.jpg

Regards,

Stone

  • 0
    TI__Mastermind 21996 points

    Hi Stone,

    VREF should have a 1uF capacitor to GND, and should not be connected elsewhere in the design as a voltage source.

    I would also add pull-ups on SCL and SDA.

    Best,

    Garret

  • 0
    Prodigy 10 points

    Hi Stone

    The following table is the content on page 8 of the DEMO board manual. Looking at this table,

    1. Is it true that tad5212 material only supports electret MIC in IN1 and IN2 analog MIC in IN2? Is this just an example or a fixed configuration?

    2. For the electret single-ended AC coupling mode, there is a pull-up bias in front of the isolation capacitor. Is this resistor 10k? Still needs to be adjusted? Also, is it necessary to reserve a pull-up resistor at the back end of the DC-blocking capacitor, that is, at the input terminal of the chip?

    3. For the electret single-ended AC coupling mode, what is the bias voltage of the signal? Do I need to configure it myself? If so, what bias voltage should a general analog headset be configured with?

    4. For the board-level analog MIC AC coupling method, as shown in the following figure, only 10uF capacitors need to be connected in series with positive and negative terminals, and there is no need to pull them up and down, right? If it is a single-ended input, the front end of the IN2M DC blocking capacitor doesn't need to be grounded either, right?

  • 0 in reply to Garret Godfrey
    TI__Intellectual 780 points

    Hi  Team,

    Add the picture, could you give a hand on the question of Sean Peng.

    Regards,

    Stone

  • 0 in reply to Stone Zeng
    TI__Mastermind 21996 points

    Hi Sean,

    First, keep in mind that the TAD5212 does not have an ADC path. Analog inputs are only supported in the analog bypass path.

    1. Is it true that tad5212 material only supports electret MIC in IN1 and IN2 analog MIC in IN2? Is this just an example or a fixed configuration?

    This is just an example based on how the EVM is connected. There are actually no mics connected on the TAD5212 board. This is only available on the TAC5212 and TAA5212 board.

    2. For the electret single-ended AC coupling mode, there is a pull-up bias in front of the isolation capacitor. Is this resistor 10k? Still needs to be adjusted? Also, is it necessary to reserve a pull-up resistor at the back end of the DC-blocking capacitor, that is, at the input terminal of the chip?

    On the EVM, this resistor is 1.1k. It is not necessary to have pull-up on the chip side, as this device has an internal pull-up for quick-charge of the coupling capacitor.

    3. For the electret single-ended AC coupling mode, what is the bias voltage of the signal? Do I need to configure it myself? If so, what bias voltage should a general analog headset be configured with?

    The bias voltage from MICBIAS is configurable in register 0x4D. The default is 2.75V. This should be suitable for most applications, but you can read more about headset detection here:  https://www.ti.com/lit/an/slaaeg7/slaaeg7.pdf

    4. For the board-level analog MIC AC coupling method, as shown in the following figure, only 10uF capacitors need to be connected in series with positive and negative terminals, and there is no need to pull them up and down, right? If it is a single-ended input, the front end of the IN2M DC blocking capacitor doesn't need to be grounded either, right?

    The front end of the AC coupling capacitor should be grounded in single-ended mode.

    Best,

    Garret