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TLV320AIC3120: TLV320AIC3120: settings for the MIC1LP Using Mono MIC

Si Yoon Kim
Intellectual 690 points
Part Number: TLV320AIC3120

Dear team,

I am using the TLV320AIC3120 AUDIO CODEC, and I would like to inquire about the settings for the MIC1LP.

Using Mono Mic (Low Impedance), I set the resistor to RIN=10kohm to use the maximum gain based on Single Ended.

If the value of the coupling capacitor is determined as 100nF , 1uF , and 4.7uF respectively, the cut-off frequency becomes f=1/2πRC ≒ 159Hz , 15.91Hz , 3.38Hz by the RC High Pass Filter.

(1). When testing according to our standard, the signal frequency entering the MIC IN starts from 500Hz.
As above, if the cut-off frequency is less than 500Hz, is it good to think that there is almost no attenuation of the MIC IN signal with respect to the cut-off frequency?


(2). Assume that the signal frequency entering the MIC IN is 0Hz or higher.
Can the setting of 3.38Hz be advantageous in terms of not attenuating the signal, and setting of 159Hz in terms of noise rejection?

(3). Can the same concept used in MIC1LP be used in MIC1RP and MIC1LM?

I always appreciate your kind replies.

  • +1
    TI__Mastermind 31690 points

    Hi Si Yoon,

    1) If your design requirement is such that only frequencies above 500Hz are important, then yes there won't be any attenuation done by the high pass filter within the band.

    2) If your important signals now include down to 0Hz, yes fc = 3.38Hz would be better for reducing attenuation at the input. 159Hz obviously attenuates part of your desired band, but it also attenuate low frequency noise if any is present. I recommend designing your input filter to attenuate anything outside of the desired input frequencies.

    3) Yes this applies to the other input pins.

    Best regards,

    Jeff