Hi, AD Team!
I am measuring the dynamic parameters of AD7779 and I have some questions.
1) This is the spectrum I got. I use Pseudo Differential input and follow the InputRange excel guide. The frequency of input sine on AIN+ is 60 Hz, the amplitude is 1,5 V, offset voltage is 1,65 V. Ain- = 1,65 V.
Dynamic parameters are worse than those which are presented in datasheet. Which test conditions (frequency, amplitude of input sine) correspond to the parameters in datasheet? It is said that frequency = 60 Hz for SFDR. Is it the same for THD and SINAD?
Are there any reasons of such bad parameters?
2) Also INL is worse than supposed to be. What can be a reason for it?
3) What are the requirements for jitter?
4) What are the requirements for input resistance?
5) I use PXI-4110 as a source of external REF. Is it appropriate? Should I use a buffer for it?
6) The last question is about SAR ADC: Which input range does it have? When I use AIN+ = 0..3,3, AIN- = 0 I get only a half of its transfer function.