Cascade amplifier stability using TINA TI AC Analysis plots

Hi Vinay

   Usually we need to test the Gain and the Phase at the output side, reference to your input signal. For amplifier, the working area should be larger than 0dB Gain, and there's delay cause the phase the negative value. We need to check at the position the Gain decrease to 0dB, and the phase value difference to -180deg is the phase margin. 

   Your test results seems not expected, can you double check if you are testing at output and reference to the input?

The simulation test circuit is:

Hi Vinay

   From your system, there's not a feed back after you cascade these Filter and Gain. So there's not stability issue from system level. As long as each of the Filter and Gain could remain stable, then your system could stable. You could consider to check each block one by one, seems shouldn't be a problem actually, as they are quite basic structures.