HI Brian,
The OPAx209 can be compensated to drive a large 100µF bypass capacitor, but will require increasing the resistors from 0.7Ω to ~3Ω. Also, the issue is the OPAx209 input common-mode range requires a 1.5V headroom from the positive rail. In the circuit above, the reference is 4.096V and the supply is +5V, with 904mV headroom, therefore this is outside the allowed linear range of the OPAx209:
The OPA354 can certainly work on the circuit above, nevertheless, this is a much higher bandwidth amplifier, where the OPA350 GBW is 38-MHz, and OPA354 is 250-MHz.
You could consider using the OPA328, which is stable in the circuit above driving the (100µF+0.7Ω )|| (10µF+0.7Ω) load, without modifications. The OPAx328 is a newer amplifier offering a bandwidth of 40-MHz, and lower offset and offset drift, offering better accuracy driving the reference of the DDC264.
OPAx328 reference driver Circuit:
OPAx328 Open-Loop Stability Analysis driving the (100µF+0.7Ω )|| (10µF+0.7Ω) load : Stable with 87-degrees of phase margin (phase-margin >> 45-degrees)
Thank you and Regards,
Luis Chioye
