ZHCSNC4B February 2021 – September 2022 ADC3661 , ADC3662 , ADC3663
PRODUCTION DATA
The digital output interface uses a flexible output bit mapper as shown in Figure 8-40. The bit mapper takes the 16 bit output directly from the ADC or from digital filter block and reformats it to a resolution of 14, 18 or 20-bit. The output serialization factor gets adjusted accordingly for 2-, 1- and 1/2-wire interface mode. The maximum output data rate can not be exceeded independently of output resolution and serialization factor.
For 14-bit output resolution, the LSBs is truncated during the reformatting. With 18 and 20-bit output, in bypass mode 0s are added 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 14-bit, 2-wire mode for example would result in DCLKIN = FS * 3.5 instead of * 4.
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 (default) | 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 | 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 Table 8-8.