Summary:

I am able to realize ~8 kHz UGF with ~60 degrees of phase margin on the CARM loop OLTF (combination of analog and digital signal paths).

Details:

• Attachment #1 shows the measured OLTF.
• The measurement is made by using the "EXC A" bank on the CM board, with an SR785. With this technique, the measurement will be poor where the loop gain is high, as the excitation will be squished. Nevertheless, we can estimate the behavior in those regimes by using a model, and fitting it to the regions where the measurement is valid (in this case, above ~1 kHz).
• This measurement was made with IN1 Gain = +4 dB, AO gain = 0 dB, and IMC IN2 gain = 0 dB.
• The regular boost has been enabled, but no super-boosts yet, mainly because I think they consume too much phase close to the UGF. 
• The modeling/fitting of this, including a more thorough characterization of the crossover, will follow...