®
®
ADS-942
ZERO/OFFSET
ADJUST
20k
Ω
+15V
–15V
+5V
4.7µF
0.1µF
10
DIGITAL
11 GROUND
5
OFFSET
ADJUST
31 BIT 1 OUT (MSB)
30 BIT 1 OUT (MSB)
29 BIT 2 OUT
28 BIT 3 OUT
27 BIT 4 OUT
26 BIT 5 OUT
25 BIT 6 OUT
24 BIT 7 OUT
23 BIT 8 OUT
22 BIT 9 OUT
21 BIT 10 OUT
20 BIT 11 OUT
19 BIT 12 OUT
18 BIT 13 OUT
17 BIT 14 OUT (LSB)
7 OVERFLOW
16 EOC
4.7µF
+
+
+15V
12
0.1µF
6, 14, 15 ANALOG
GROUND
13
4.7µF
–15V
0.1µF
GAIN ADJUST
ADS-942
3 ANALOG INPUT
0 to +10V
100
Ω
4 SIGNAL GROUND
CODING SELECT
8
+5V
START CONVERT 32
0.1µF
4.7µF
1 +10V REF. OUT
ENABLE
BIPOLAR
9
2
Figure 3. ADS-942 Connection Diagram
Removing System Errors
Use external potentiometers to remove system errors or to
reduce the small initial errors to zero. Use a 100Ω trimpot in
series with the analog input for gain adjustment. Use a fixed
50Ω resistor instead of the trimpot for operation without
adjustment. Use a 20kΩ trimpot with the wiper tied to OFFSET
ADJUST (pin 5) for zero/offset adjustment. Connect pin 5 to
ANALOG GROUND (pin 6) for operation without zero/offset
adjustment.
Table 3. Output Coding
STRAIGHT BIN.
UNIPOLAR
SCALE
INPUT VOLT.
0 TO +10V
MSB
LSB
COMP. BINARY
OUTPUT CODING
MSB
LSB
MSB
LSB
INPUT VOLT.
±5V
BIPOLAR
SCALE
+FS – 1 LSB
+7/8 FS
+3/4 FS
+1/2 FS
+1/4 FS
+1/8 FS
+1 LSB
0
+9.999390
+8.750000
+7.500000
+5.000000
+2.500000
+1.250000
+0.000610
0.000000
11 1111 1111 1111
11 1000 0000 0000
11 0000 0000 0000
10 0000 0000 0000
01 0000 0000 0000
00 1000 0000 0000
00 0000 0000 0001
00 0000 0000 0000
OFF. BINARY
00 0000 0000 0000
00 0111 1111 1111
00 1111 1111 1111
01 1111 1111 1111
10 1111 1111 1111
11 0111 1111 1111
11 1111 1111 1110
11 1111 1111 1111
COMP. OFF. BIN.
01 1111 1111 1111
01 1000 0000 0000
01 0000 0000 0000
00 0000 0000 0000
11 0000 0000 0000
10 1000 0000 0000
10 0000 0000 0001
10 0000 0000 0000
TWO'S COMP.
+4.999390
+3.750000
+2.500000
0.000000
–2.500000
–3.750000
–4.999390
–5.000000
+FS – 1LSB
+3/4FS
+1/2FS
0
–1/2FS
–3/4FS
–FS+1LSB
–FS
4
MURATA-PS [ MURATA POWER SOLUTIONS INC. ]
