ZHCSHP3 February 2018 DAC8771
PRODUCTION DATA.
The current output stage consists of a pre-conditioner and a precision current source as shown in Figure 97. This stage provides a current output according to the DAC code. The output range can be programmed as 0 mA - 20 mA, 0 mA - 24 mA, 4 mA - 20 mA, 3.5 mA - 23.5 mA, or ±24 mA. In the current output mode, the maximum compliance voltage on pin IOUT is between (-|VNEG_IN| + 3 V) ≤ |VIOUT| ≤ (VPOS_IN – 3 V). When in unipolar current output modes the low-side of the compliance voltage limit is replaced by GND. This compliance voltage is automatically maintained when the Buck-Boost converter is used to generate these supplies (see Buck-Boost Converter section). However, when using an external supply for VPOS_IN pin (Buck-Boost converter disabled), the VPOS_IN and VNEG_IN supplies should be chosen such that this compliance voltage is maintained.
The 16 bit data can be written to DAC8771 using address 0x05 (DAC data register, Table 4 and Table 5).
For a 0-mA to 20-mA output range:
For a 0-mA to 24-mA output range:
For a 3.5-mA to 23.5-mA output range:
For a 4-mA to 20-mA output range:
For a -24-mA to 24-mA output range:
Where: