8143 Datasheet, PDF (18/24 Pages) Maxwell Technologies – 12-Bit Serial Daisy Chain D/A Converter

12-Bit Serial Daisy-Chain D/A Converter
FIGURE 19. MULTIPLE 8143S WITH THREE WIRE INTERFACE
8143
Analog/Digital Division
The transfer function for the 8143 connect is the multiplying mode as shown in Figures 16 and 17 is:
where AX assumes a value of 1 for an “ON” bit and 0 for an “OFF” bit.
The transfer function is modified when the DAC is connected in the feedback of an operational amplifier as shown in
Figure 20 and is:
The above transfer function is the division of an analog voltage (VREF) by a digital word. The amplifier goes to the
rails with all bits “OFF” since division by zero is infinity. With all bits “ON”, the gain is 1 (±1 LSB). The gain becomes
4096 with the LSB, Bit 12, “ON”.
07.23.03 REV 3
All data sheets are subject to change without notice 18
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