I am using the MAX6035 as a 5V reference that draws 5mA load current. To protect the input from transient spikes, I thought a simple resistor and zener diode circuit would work well. I noticed that the circuit was drawing more current than expected so I did a little digging. With a 1kOhm series resistor to the input and a 1kOhm load resistor (to simulate 5mA of load current), I was seeing oscillations at the IN pin of the MAX6035. Even in the simulation below, the oscillations occur until I bump up the input capacitance.
The current solution is to add more capacitance to the input pin (1uF vs. 0.1uF) and that seemed to fix the issue at room temperature. However, when running it at -55degC, the oscillations show up again, but to a lesser degree.
I am not necessarily looking for a solution to this specific issue, but an understanding to how a series resistor affects the operation/stability of a series reference. Any references (no pun intended) to reading material is greatly appreciated.