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OPA2210: Query regarding phase delay

Nitesh Bhurke
Intellectual 260 points
Part Number: OPA2210


Tool/software:

Hello,

We are using 'OPA2210IDGKR' opamp in one of our designs. We are using this opamp as anti alias filter before ADC. I have attached the image of anti-alias filter and its TINA simulation file. The filter is designed for cut off frequency around 38KHz. The sensor output is provided to the anti alias filter with some MUX IC such as (TMUX1204DQAR) and opamp (OPA192IDBVR) are present in the path. The signal flow is as below,

Sensor ---> 'ADG5419BCPZ-RL7' MUX ---> 'OPA192IDBVR' as non inverting buffer ---> 'TMUX1204DQAR' MUX ---> 'OPA2210IDGKR' as 2nd order LPF anti alias filter.

So, we want to calculate total delay for signal from sensor output to anti alias filter output. Can you please provide the required calculations to find out the time delay and phase shift if any caused due to anti alias filter designed using 'OPA2210IDGKR' IC.

Note: sensor signal amplitude will not be greater than 5V it will be 0-5V.

Regards,

Nitesh

OPAx210 - ANTI-ALIAS Filter.TSC

  • 0
    TI__Guru* 77541 points

    Hi Nitesh,

    Nitesh Bhurke said:
    The filter is designed for cut off frequency around 38KHz. The sensor output is provided to the anti alias filter with some MUX IC such as (TMUX1204DQAR) and opamp (OPA192IDBVR) are present in the path.

    The 2nd order filter has slightly Q near the cutoff frequency. Typically, cutoff frequency at 38kHz implies the phase starts at 3.8kHz or a decade early (phase delay ~5.7 degree). But the Q per the filter created a sharper drop and the phase delay gauge may be shifted. 

    At 3.8kHz, the phase is delayed approx. 8 degree. 

    OPAx210 - ANTI-ALIAS Filter 03192025.TSC

    I do not know what is the sensor's max. operating frequency in  your application. In addition, the phase delay can be measured directly from the filter simulation. However, I do not know what is overall phase delay from sensor to final output stage. This is the really concerns. 

    If you have additional questions, please let me know. 

    Best,

    Raymond

  • 0 in reply to Raymond Zhang1
    TI__Guru* 77541 points

    Hi Nitesh, 

    I am going to close this query, since I have not heard from you. 

    If you have other questions, please let me know. 

    Best,

    Raymond

  • +1 in reply to Raymond Zhang1
    Intellectual 260 points

    Hello Raymond,

    Thanks for the response, we can close the query now.