Manual

CS5571
16 DS768PP1
3/25/08
10:56
3.5 Output Coding Format
The reference voltage directly defines the input voltage range in both the unipolar and bipolar configura-
tions. In the unipolar configuration (BP/UP
low), the first code transition occurs 0.5 LSB above zero, and
the final code transition occurs 1.5 LSBs below VREF. In the bipolar configuration (BP/UP
high), the first
code transition occurs 0.5 LSB above -VREF and the last transition occurs 1.5 LSBs below +VREF. See
Table 1 for the output coding of the converter.
NOTE: VREF = [(VREF+) - (VREF-)] / 2
Table 1. Output Coding, Two’s Complement
Bipolar Input Voltage
Two’s
Complement
>(VREF-1.5 LSB) 7F FF
VREF-1.5 LSB
7F FF
7F FE
-0.5 LSB
00 00
FF FF
-VREF+0.5 LSB
80 01
80 00
<(-VREF+0.5 LSB) 80 00
NOTE: VREF = [(VREF+) - (VREF-)] / 2
Table 2. Output Coding, Offset Binary
Unipolar Input Voltage
Offset
Binary
>(VREF-1.5 LSB) FF FF
VREF-1.5 LSB
FF FF
FF FE
(VREF/2)-0.5 LSB
80 00
7F FF
+0.5 LSB
00 01
00 00
<(+0.5 LSB) 00 00