ZHCSGU6A september 2017 – july 2023 ADS8588H
PRODUCTION DATA
The ADS8588H features an optional digital averaging filter that can be used in slower throughput applications requiring lower noise and higher dynamic range. As explained in Table 7-1, the oversampling ratio of the digital filter is determined by the configuration of the OS[2:0] pins. The overall throughput of the ADC decreases proportionally with increases in the oversampling ratio.
OS[2:0] | OS RATIO | SNR ±10-V INPUT (dB) |
SNR ±5-V INPUT (dB) |
3-dB BANDWIDTH ±10-V INPUT (kHz) |
3-dB BANDWIDTH ±5-V INPUT (kHz) |
MAX THROUGHPUT PER CHANNEL (kSPS) |
---|---|---|---|---|---|---|
000 | No OS | 92.7 | 92.2 | 24 | 16 | 500 |
001 | 2 | 93.4 | 92.7 | 23.9 | 15.9 | 250 |
010 | 4 | 94.0 | 93.2 | 23.2 | 15.7 | 125 |
011 | 8 | 94.7 | 93.7 | 20.6 | 14.9 | 62.5 |
100 | 16 | 95.8 | 94.5 | 13.7 | 12.2 | 31.25 |
101 | 32 | 96.9 | 95.8 | 7 | 6.9 | 15.625 |
110 | 64 | 98.3 | 97.4 | 3.5 | 3.5 | 7.8125 |
111 | Invalid | — | — | — | — | — |
In oversampling mode (see the Oversampling Mode of Operation section), the ADC takes the first sample for each channel at the rising edge of the CONVSTA, CONVSTB signals. After converting the first sample, the subsequent samples are taken by an internally generated sampling control signal. The samples are then averaged to reduce the noise of the signal chain as well as to improve the SNR of the ADC. The final output is also decimated to provide a 16-bit output for each channel. Table 7-1 lists the typical SNR performance for both the ±10-V and ±5-V input ranges, including the –3-dB bandwidth and proportional maximum throughput per channel. When the oversampling ratio increases, there is a proportional improvement in the SNR performance and decrease in the bandwidth of the input filter.