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Pre-Amplifier/Headphone Amplifier frequency response

Icy
Intellectual 265 points
Other Parts Discussed in Thread: INA217, INA163, OPA344, TINA-TI

I want to create a microphone amplifier circuit that has a frequency response of 10 Hz- 20 kHz. I'm planning to use the Knowles Analog MEMS microphone SPU1410LR5H-QB, which has a frequency response of 10 Hz-10 kHz. The purpose of the circuit is to listen to the microphone output through headphones, so I will need a pre-amplifier stage with a headphone amplifier. Is there an op-amp for the pre-amplifier and a headphone amplifier that would meet the specification of a 10 Hz- 20 kHz frequency response? As for the pre-amplifier, is there a specialized IC that could be a substitute for an op-amp based pre-amplifier circuit, that would also meet that frequency response spec?

  • 0
    TI__Guru** 104455 points
    Hi Icy,

    Regarding the preamplifier I think you could take a look at INA163 or INA217. You can find a typical application circuit for microphone preamplifier in its datasheets.
    And for the headphone amplifier I think you could choose one of the TPA613xA2 devices.

    Best regards,
    -Ivan Salazar
    Texas Instruments
  • 0 in reply to Ivan Salazar
    Intellectual 265 points

    Hi Ivan,

    The microphone application circuit in the preamplifier datasheet involves "phantom power"...can you explain how this circuit would be simplified if a MEMs microphone is used? I'm not familiar with phantom power but I read that it is used for dynamic and condenser microphones. How do the pre-amplifiers you suggested have an advantage over a single op amp based pre-amplifier such as this: www.sparkfun.com/.../ADMP401-Breakout-v13.pdf. This is a circuit I used that is based on the OPA344 op amp using a different MEMs microphone.

    Also, can the expected frequency response of the amplifiers be determined without having to test them?


    Thank you.

  • 0 in reply to Icy
    TI__Guru** 104455 points
    Icy,

    Sorry I missed the MEMS spec of your microphone.
    You can select from several options of general purpose opamps.
    Your OPA344 circuit looks good, you can simulate it in WEBENCH, TINA-TI and there is also a P-SPICE model available of this device.
    TPA613xA2 should not have any problem operating in the audible frequencies range.

    Best regards,
    -Ivan Salazar
    Texas Instruments