AS1543/44
Data Sheet - Detailed Description
Transfer Functions
Output coding and transfer function depend on the control register bits RANGE (page 14), SE/FDN (page 14) and
CODING (page 14).
Figure 24. Straight Binary Transfer Function for
SE/FDN = 1 and CODING = 1
Figure 25. Straight Binary Transfer Function for
SE/FDN = 0 and CODING = 1
RANGE = 1; VREF=VREFIN
RANGE = 0; VREF=2xVREFIN
Full Scale
(FS)
Transition
RANGE = 1; VREF=VREFIN
RANGE = 0; VREF=2xVREFIN
Full Scale
(FS)
Transition
11...111
11...110
11....101
11...111
11...110
11....101
Full Scale = VREF
Zero Scale = 0
1LSB = VREF/4096
Full Scale = +VREF/2
Zero Scale = -VREF/2
1LSB = VREF/4096
00...011
00...010
00...001
00...000
00...011
00...010
00...001
00...000
0
1
2
3
FS - 3/2LSB
ZS ZS+1LSB
FS - 3/2LSB
Input Voltage VINx (LSB)
Input Voltage VINx - VINy (LSB)
Figure 26. Two’s Complement Transfer Function for
SE/FDN = 1 and CODING = 0
Figure 27. Two’s Complement Transfer Function for
SE/FDN = 0 and CODING = 0
RANGE = 1; VREF=VREFIN
RANGE = 1; VREF=VREFIN
RANGE = 0; VREF=2xVREFIN
RANGE = 0; VREF=2xVREFIN
011....111
011....111
Full Scale = +VREF/2
-Full Scale = -VREF/2
Zero Scale = 0
Full Scale = VREF
-Full Scale = 0
Zero Scale = VREF/2
1LSB = VREF/4096
011...110
011...110
1LSB = VREF/4096
000...010
000...001
000...000
111...111
111...110
111...101
000...010
000...001
000...000
111...111
111...110
111...101
100...001
100...000
100...001
100...000
-FS
ZS
Input Voltage VINx (LSB)
+FS - 1LSB
-FS
ZS
+FS - 1LSB
Input Voltage VINx - VINy (LSB)
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