Does the negative supply to -Vs for amplifier plays any vital role ? I have grounded -Vs pin and following issue was faced,
Closed loop gain was reduced and virtual grounding not happened properly, so my output voltage was reduced.
But when i have given -5V to -Vs pin, then im getting good Closed loop gain and virtual grounding comparing to GND on -Vs pin.
The -Vs also dictates your Input Voltage Range or VCM.For an instance in your case, if you have used +/-5V for your supply, then your input voltage range would be -4.9 to 4.1V.Where as, if your supply is 5V/GND, then your VCM is 0.1 to 4.1V.Having said that, using different supplies means different VCM.
Please make sure your input is within the input range or you can use a Vcm to shift your input just to make sure that it is within the input voltage range.
Hope this helps.
Thanks and regards.
Below is example of simulation using single supply vs. dual supply (Vout 1 vs. Vout2).
As you can see, the closed-loop gain is affected.
But, ensuring that the input is within the VCM of single supply, the closed-loop gain is now the same to the dual supply (Vout1 = Vout3).
Thanks for the reply. I undershoot that total supply voltage (+Vs)-(-Vs) will decide the closed loop gain , not the dual supply voltage.
This circuit is transimpedance amplifier ADA4895-2 with photodiode as input.
First image - Gnd is connected to -Vs pin. Virtual grounding is not happening
Second image - -5V connected to -Vs pin. Virtual grounding is happening perfectly.
As you said closed loop gain may change due to total supply voltage, but why virtual grounding is affecting in first image?