Riad KACED
Community Member
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Posts: 93
Swindon, UK
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Hi,
There are many ways to simulate the stability. The most common one for your BG is to run an AC analysis and look at the open loop gain and phase along with the gain and phase margins. All what you need is a testbench where you put your design and a stimulus with 1V AC DC source (1V to directly read the gain without any divisions). In the old days, we used to open the AC loop and leave the DC loop closed in order to keep all the devices at the right operating point around which you exercise the small signal anaylsis. Nowadays (with Spectre at least), you don't really need to
My advice for you is:
1. Look at your Analog Design book to learn things about feedback analysis, gain, phase ... etc 2. Look at the Hspice doc for more details about the AC analysis. I'm a Spectre user as far as I'm concerned.
If you are really in a hurry, then run a quick transient and if it the output oscillates then it is instable :-[
Cheers, Riad.
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