The ADS101x-Q1 provide 12 bits of data in binary two's complement format that is left justified within the 16-bit data word. A positive full-scale (+FS) input produces an output code of 7FF0h and a negative full-scale (–FS) input produces an output code of 8000h. The output clips at these codes for signals that exceed full-scale. Table 3 summarizes the ideal output codes for different input signals. Figure 18 shows code transitions versus input voltage.
VIN = (VAINP – VAINN)
|IDEAL OUTPUT CODE(1)(1)|
|≥ +FS (211 – 1)/211||7FF0h|
Single-ended signal measurements, where VAINN = 0 V and VAINP = 0 V to +FS, only use the positive code range from 0000h to 7FF0h. However, because of device offset, the ADS101x-Q1 can still output negative codes in case VAINP is close to 0 V.