Hello I’m using your software When I use an ADC\AD4000 example circuit 1st I provide different types of signals sinewave, exp, rectangular Vin voltage contains some errors due to resistance so this ADC gives incorrect OUTPUT How can I solve this problem?

Hi Muhammed82,

Thank you for sharing your concern here. I think we would be able to help you better if you can provide more information like sharing your circuit file here.
Thank you.

AD4000 sine Last.asc

I need to check this adc model to get it's response and because we have imperfect i\p signa will get wrong o\p 

AS YOU SEE there is a difference between the original i\p before resistance of 10kohm

and after this resistance 

can i use zero ohm?

The step on the input is caused by the sample and hold capacitor dumping a load on the 10 Ohm resistor, so the input voltage drops. You need an ADC driver and possibly a small RC filter after the ADC driver just to absorb this kick back from the sample and hold capacitor. 

The attached works much better, although you will have to play with the RC filter to get the best response. Make the C large compared with the 6pF sampling capacitor, then increase the R from zero until the op amp is no longer unstable. Alternatively reduce the 10 Ohms in your original circuit, if you can

I also added the '.option' statement to remove compression on the LTspice simulation. This makes the simulation more accurate, especially when looking for small ac disturbances on large dc common modes AD4000 sine Last_SB.asc

Muhammed82 You can also use https://tools.analog.com/en/adcdriver/ to better understand ADC kickback, and the tradeoffs with the driver and RC filter.

many thanks

many thanks ..... i'll check it

many thanks ..... i'll check it