I am running a SPICE simulation (in Altium Designer) using the supplied model for the ADA4857. If I load the output of the amplifier with anything less than 1Meg or so the output sags very significantly - but I get reasonable performance with a 1Meg load. In the data sheet it mentions performance into a 1K load. I am down 20dB when I drive a 1K load. I have checked and double checked my connections and everything looks correct. Suggestions of what might be wrong or how to go about troubleshooting this issue would be most welcome. Thanks!
Here is the pertinent connection info:
From the model
*Node Assignments* Non-Inverting Input* | Inverting Input* | | Positive supply* | | | Negative supply* | | | | Output* | | | | | FB* | | | | | | PD* | | | | | | |.Subckt ADA4857 100 101 102 103 104 105 106
From the netlist
XU1 P_IN N_IN PLUS5 MINUS5 VOUT N_IN GND ADA4857