Mr Katchashkin -
[quote user="Sergey Katchashkin"]1. Document SBAS561A-JUNE, 2012. Page 2. ABSOLUTE MAXIMUM RATINGS table. The string AGND to DGND -0.3 to +0.3 V. (The latest version of the row is deleted.) My question is: What limits can be at the voltage AVSS to DGND?[/quote]
Check out the Power-Supply Requirements of the spec table on the bottom of page 4 and top of page 5. More specifically the AVDD-DVDD spec should allow you to determine the power levels you are interested in.
[quote user="Sergey Katchashkin"]2. Sample chips ADS131E08, which we have, is behaving strangely. When reading the ID Control Register, 2 least significant bits of it sometimes read as 10b and sometimes as 00b. In the latest case it corresponds to the 4-channel version ADS131E04. In this case, if we try to read data stream all 8 channels, we read correct the first 4 channels only. Latest 4 channels reads as 0 (Exactly ADS131E04). This chip marking as 23AEWKWG4 ADS131E08. ID Control Register reads as 0xC0 (0xC2 - it right).[/quote]
Do you follow the startup procedure as documented in Figure 49 on page 51? If not, you might try this to see if you get consistent readings.