AD829 stability

Hello,

Is the AD829 stable in the following conditions ? What is the Phase Margin ?

- CL=150pF capacitor load

- RL=~1kohms resistor load

- Vs = +/- 5V

- Ccomp = 15pF to inverted input

I attached the schematic (VEE = -5V and VCC = +5V).

Can I simulate the phase margin with PSPICE and how ? Is the model realistic in theses conditions ?

Thanks for your answer,

Mathieu

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  • Thanks a lot for your answer.

    I will do the same test to try to reproduce this oscillation.

    Could you tell me how did you choose 68pF Ccomp capacitor ? How could I choose the "good" capacitor value ?

    When connecting the Ccomp to the inverting input, the datasheet doesn't mention the capacitor to choose. There is some figures where Ccomp = 3pF/ 4pF or 3pF with inverting gains of -1V/V to -4V/V (pages 14 and 15).

    Ccomp = 68pF at the gain of +1V/V is mentionned when Ccomp is connecting to ground (Table 4 page 13).

    Do you have some news about stability simulation ? I hope I can use the model to choose the "good" capacitor value for stability, or that you will help me. Because when connecting Ccomp to inverting input, the capacitor value vs gain is not mentioned in the datasheet, contrary to the connection of Ccomp to ground (Table 4 page 13).

Reply
  • Thanks a lot for your answer.

    I will do the same test to try to reproduce this oscillation.

    Could you tell me how did you choose 68pF Ccomp capacitor ? How could I choose the "good" capacitor value ?

    When connecting the Ccomp to the inverting input, the datasheet doesn't mention the capacitor to choose. There is some figures where Ccomp = 3pF/ 4pF or 3pF with inverting gains of -1V/V to -4V/V (pages 14 and 15).

    Ccomp = 68pF at the gain of +1V/V is mentionned when Ccomp is connecting to ground (Table 4 page 13).

    Do you have some news about stability simulation ? I hope I can use the model to choose the "good" capacitor value for stability, or that you will help me. Because when connecting Ccomp to inverting input, the capacitor value vs gain is not mentioned in the datasheet, contrary to the connection of Ccomp to ground (Table 4 page 13).

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