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OPA192: about Precision Reference Buffer

toshi-e2e
Genius 4850 points
Part Number: OPA192


Hi all,
OPA192 datasheet described an  application of the Precision Reference Buffer on page of 34.
Are there detailed calculation methods and materials that can understand the operation of this circuit?

Regards,
Toshi

  • 0
    Guru 140200 points

    Hi Toshi,

    you can do a phase stability analysis by yourself like shown below:

    Hhm, a phase lag of 82° between 100Hz and 1kHz looks not very convincing...

    I would use this circuit:

    toshi.TSC

    Kai

  • 0
    TI__Guru* 93105 points

    Hello Toshi,

    The OPA192 precision reference buffer shown in datasheet Fig. 69 uses dual feedback and an Riso to help stabilize the circuit when driving the 10 uF load capacitance. This method is presented in the Section 10.6 of the TI Precision Labs - Op Amps: Stability. It is helpful to view the preceding sections because they build upon each other. You can find the Precision Labs information here:

    I made a quick TINA Spice simulation of the small-signal transient response of the OPA192 precision reference buffer circuit. The resulting output signal overshoot is small indicating that the phase margin is quite sufficient and the circuit is stable while driving the 10 uF load.

    Regards, Thomas

    Precision Amplifiers Applications Engineering