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TIDA-060029: Can TIIDA-060029 support 2MHz bandwidth?

Part Number: TIDA-060029
Other Parts Discussed in Thread: OPA2810, BUF802, BUF634A, OPA656, THS4631

Hi team,

Can TIIDA-060029 support 2MHz bandwidth? If not
Do we need to make any changes? Or does TI have a higher frequency LCR reference design?

  • Hello Jimmy,

      The impedance measurement methods are shown in the user guide under Table 1.1 which includes the applicable frequency range:

      The auto balancing method is used in the design which can be applicable for 20Hz to 120MHz. It depends on the type and how high your impedance range is under test. Also, above 100kHz, the AOL of the amplifiers decrease which will impact accuracy of the measurement. A general rule-of-thumb is to ensure that the amplifier has >60- dB AOL at the highest frequency of interest for high accuracy measurements

       The compensation of the unknown impedance is explained on pages 5 to 9 of the reference design user-guide. The application brief at this link also explains zero/pole balancing act in comparison to the AOL of the amplifier. 

       The range would have to be less than shown in the red outline box with the same design. Otherwise, a higher GBW part is necessary. 

    Thank you,



  • Hi team,

    So, I want to upgrade operation BW to 2MHz. It needs to change OPA2810. Maybe find a High BW device. like BUF802 right?

  • Hello Jimmy,

      I wouldn't use a buffer, since you need access to the feedback path of the amplifier to be altered and compensate for the unknown impedance at the input. The BUF634A used in the LCR reference design is optional, but can be used in a composite loop with the main amplifier, OPA2810, to increase the output current capabilities of the overall application. I do agree it should be a FET-input amplifier due to needing a very low input bias current. 

    Here is a list of potential parts (except the THS4631: there is a known issue with the leakage current that we are working on fixing). I would suggest the OPA656, but ultimately will depend on other customer parameters.

    Thank you,