SBAS533E March 2011 – February 2023 ADS4222 , ADS4225 , ADS4226 , ADS4242 , ADS4245 , ADS4246
PRODUCTION DATA
The ADS424x/422x include gain settings that can be used to get improved SFDR performance (compared to no gain). The gain is programmable from 0 dB to 6 dB (in 0.5-dB steps). For each gain setting, the analog input full-scale range scales proportionally, as shown in #GUID-DC643BCA-2FFC-4EF1-97B8-AC146A7A6515/SBAS4832188.
The SFDR improvement is achieved at the expense of SNR; for each gain setting, the SNR degrades approximately between 0.5 dB and 1 dB. The SNR degradation is reduced at high input frequencies. As a result, the gain is very useful at high input frequencies because the SFDR improvement is significant with marginal degradation in SNR. Therefore, the gain can be used as a trade-off between SFDR and SNR. Note that the default gain after reset is 0 dB.
GAIN (dB) | TYPE | FULL-SCALE (VPP) |
---|---|---|
0 | Default after reset | 2 |
1 | Fine, programmable | 1.78 |
2 | Fine, programmable | 1.59 |
3 | Fine, programmable | 1.42 |
4 | Fine, programmable | 1.26 |
5 | Fine, programmable | 1.12 |
6 | Fine, programmable | 1 |