Hi,
for my next course about PSRR, I try to simulate the AD8031 PSRR with LTspice.
The used schematic is :
Result is :
This is very different from the datasheet graph (i.e. figure 35).
How explain that ?
Best regards.
Eric PERONNIN
AD8031
Production
The AD8031 (single) is a single supply voltage feedback amplifier that features high speed performance with 80 MHz of small signal bandwidth, 30 V/µs slew...
Datasheet
AD8031 on Analog.com
Hi,
for my next course about PSRR, I try to simulate the AD8031 PSRR with LTspice.
The used schematic is :
Result is :
This is very different from the datasheet graph (i.e. figure 35).
How explain that ?
Best regards.
Eric PERONNIN
Hi,
as a complement, I've done a time domain analysis with that schematic :
It uses a BV source with 5V plus decade sinus (for 1k, 10k, 100k and 1MHz). Each spectral lines has a weight of -23dB in the FFT analysis. FFT on the output has given that result :
As you can see, this result is consistent with the AC analysis : the -88dB at 1MHz plus 23dB give -65dB which is the result at 1MHz with the AC analysis and so one for the other spectral lines.
Hi Eric,
Since you are using single supply, add a DC offset in the non-inverting input to use the whole range of input common-mode voltage range. Below is the PSRR graph obtained when I add 2.5V in non-inverting input. It resembles Figure 35 in the data sheet. Simulations are dependent on the part modeling and may present some limitations thus the low accuracy in the low frequencies.
Thanks a lot for you answer. You are totally right. I'm an idiot... I forgot the DC source which I already use in my final schematic.
Have a good day.
Eric