AD829 stability

Question

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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krisf · Answer

Hi Mathieu, 
 I apologize for the delay on this response. As I mentioned, the AD829 is a very old part, and unfortunately, I would not trust the SPICE model to be reliable in simulation. However, I revisited my circuit and we are now getting the same results on our circuit, i.e. no oscillation. In addition, I brought the capacitive load up to 560pF without seeing any oscillation at the output. One of the other methods I tried to get an idea of the stability of the circuit was to apply a step input and see how much overshoot was present at a 150pF load. 
 
 I calculated the overshoot to be about 10%, which looks to be an acceptable figure. Hopefully, this figure will be enough to properly satisfy your requirement. 
 Regards, 
 Kris

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AD829 stability