ZHCSN12B December 2020 – October 2022 ADC3681 , ADC3682 , ADC3683
PRODUCTION DATA
The digital output interface uses a flexible output bit mapper (Figure 8-40). The bit mapper takes the 18-bit output directly from the ADC or from the digital decimation filter block and reformats it to a resolution of 14,16,18 or 20-bit. The output serialization factor is adjusted accordingly for 2-, 1- and 1/2-wire interface modes. The maximum SLVDS interface output data rate can not be exceeded independent of output resolution or serialization factor.
For 14 and 16-bit output resolution, the LSBs are truncated during the reformatting. With 20-bit output, in bypass mode two 0s are added in place of the two LSBs while in decimation mode and the digital averaging mode the full 20-bit output is used.
Table 8-6 provides an overview for the resulting serialization factor depending on output resolution and output modes. Note that the DCLKIN frequency needs to be adjusted accordingly as well. Changing the output resolution to 16-bit, 2-wire mode for example results in DCLKIN = FS * 4 instead of * 4.5.
OUTPUT RESOLUTION | Interface | SERIALIZATION | FCLK | DCLKIN | DCLK | D0/D1 |
---|---|---|---|---|---|---|
14-bit | 2-Wire | 7x | FS/2 | FS* 3.5 | FS* 3.5 | FS* 7 |
1-Wire | 14x | FS | FS* 7 | FS* 7 | FS* 14 | |
1/2-Wire | 28x | FS | FS* 14 | FS* 14 | FS* 28 | |
16-bit | 2-Wire | 8x | FS/2 | FS* 4 | FS* 4 | FS* 8 |
1-Wire | 16x | FS | FS* 8 | FS* 8 | FS* 16 | |
1/2-Wire | 32x | FS | FS* 16 | FS* 16 | FS* 32 | |
18-bit (default) | 2-Wire | 9x | FS/2 | FS* 4.5 | FS* 4.5 | FS* 9 |
1-Wire | 18x | FS | FS* 9 | FS* 9 | FS* 18 | |
1/2-Wire | 36x | FS | FS* 18 | FS* 18 | FS* 36 | |
20-bit | 2-Wire | 10x | FS/2 | FS* 5 | FS* 5 | FS* 10 |
1-Wire | 20x | FS | FS* 10 | FS* 10 | FS* 20 | |
1/2-Wire | 40x | FS | FS* 20 | FS* 20 | FS* 40 |
The programming sequence to change the output interface and/or resolution from default settings is shown in Section 8.3.5.4.