There is an occasional caution that even unity-gain stable Voltage Feedback Amplifiers (VFAs) risk instability in inverting attenuator applications
Here, model testing steps will be shown for the VFA then external adjustments to match reported data sheet numbers will be shown
The most recent VFA FDAs focus on lower power, precision, solutions more aimed at Successive Approximation Register (SAR) and delta sigma ADC support. Those will be focus in this FDA stability discussion - but the concepts are backward compatible to the earliest VFA FDAs.
Here, an updated Loop Gain (LG) simulation approach will be first detailed and then used to show paths into, and out of, low Phase Margin (PM) conditions for a current feedback amplifier.