This is with reference to LT1991 configuration discussed in datasheet on page no. 24, figure 17, VCM = –56V TO 53.2V .
I tried simulation with same configuration with different input combinations. Please note, this configuration is having gain =1.
Observations as below:
|#2||5V||10KHz||2.8V with delay|
|#3||1V||10KHz||1V with Delay|
Case#1: with 1KHz frequency and 5V input =>Gain 1
Case#2 : if we increase the frequency to 10KHz=> Gain reduced and Vout = 2.8 V with phase difference.
Case 3: With Increased frequency of 10KHz if Vin is reduced to 1V, Gain approx =1 with phase delay.
Gain is changing with input voltage and frequency (just 10KHz)
Please find attached simulation result. The input frequency of my design is 1KHz to 10KHz.
Is this the desired behavior of LT1991? It seems there is problem with Spice model.
[edited by: AshishRai at 12:37 PM (GMT 0) on 18 Nov 2019]