Part Number: ADS4126
Other Parts Discussed in Thread: ADS4126
Hello,
I am working on interface between analogue to digital converter ads4126 and differential amplifier driving it.
I can't find two information.
1. What is the acquisition time?
I guess about 50 % of cycle time but am I right?
2. What happens to the charge of sampling capacitor during conversion phase? As it is charged to the potential (or almost?) of signal at the end of acquisition phase. But what is its charge / potential at the end of conversion phase?
a. It is untouched?
b. It is only slightly changed with the charge injected from the switch and roughly known – estimated.
c. It is seriously changed according to the bit code from the MSB pipeline stage?
d. It is seriously changed but in unpredictable or complicated manner?
e. It is reset to zero or other constant potential (like Vref, Vcom, ...).
f. Other scenarios.......
Does anybody know?
This converter is very fast, so the time to charge the sampling capacitor is very short.
At 12bit resolution we need 8.3 x TimeConstant to set it. Unfortunately the filter capacitor we usually put at ADCs input influences this TimeConstant. So it is worth to know from what level this charging starts at the beginning of the acquisition phase.
Thank you for help.
Regards
Robert
