AD1376 Datasheet, PDF (6/8 Pages) Analog Devices – Complete, High Speed 16-Bit A/D Converters

AD1376/AD1377
Code Under Test
MSB LSB
000 ……… 000*
Table III. Transition Values vs. Calibration Codes
Range
+Full Scale
± 10 V
+10 V
–3/2 LSB
Low Side Transition Values
±5 V
± 2.5 V
0 V to +10 V
+5 V
–3/2 LSB
+2.5 V
–3/2 LSB
+10 V
–3/2 LSB
0 V to +5 V
+5 V
–3/2 LSB
011……… 111
111……… 110
Mid Scale
–Full Scale
0–1/2 LSB 0–1/2 LSB
–10 V
–5 V
+1/2 LSB +1/2 LSB
*Voltages given are the nominal value for Transition to the code specified.
Note: For LSB value for range and resolution used, see Table IV.
0–1/2 LSB
–2.5 V
+1/2 LSB
+5 V–1/2 LSB +2.5 V–1/2 LSB
0V
0V
+1/2 LSB
+1/2 LSB
Table IV. Input Voltage Range and LSB Values
Analog Input
Voltage Range ± 10 V
Code
Designation
One Least
FSR
Significant
2ⁿ
Bit (LSB)
n=8
n = 10
n = 12
n = 13
n = 14
n = 15
±5 V
COB*
or CTC**
20 V
2ⁿ
78.13 mV
19.53 mV
4.88 mV
2.44 mV
1.22 mV
0.61 mV
± 2.5 V
COB*
or CTC**
10 V
2ⁿ
39.06 mV
9.77 mV
2.44 mV
1.22 mV
0.61 mV
0.31 mV
0 V to +10 V 0 V to +5 V
COB*
or CTC**
CSB***
CSB***
5V
10 V
5V
2ⁿ
2ⁿ
2ⁿ
19.53 mV
4.88 mV
1.22 mV
0.61 mV
0.31 mV
0.15 mV
39.06 mV
9.77 mV
2.44 mV
1.22 mV
0.61 mV
0.31 mV
19.53 mV
4.88 mV
1.22 mV
0.61 mV
0.31 mV
0.15 mV
NOTES
***COB = Complementary Offset Binary.
***CTC = Complementary Twos Complementary—achieved by using an inverter to complement the most significant bit to
product (MSB).
***CSB = Complementary Straight Binary.
CALIBRATION
(14-Bit Resolution Examples)
External ZERO ADJ and GAIN ADJ potentiometers, connected
as shown in Figures 4 and 5, are used for device calibration. To
prevent interaction of these two adjustments, Zero is always
adjusted first and then Gain. Zero is adjusted with the analog
input near the most negative end of the analog range (0 for
unipolar and –FS for bipolar input ranges). Gain is adjusted
with the analog input near the most positive end of the analog
range.
0 V to + 10 V Range
Set analog input to +1 LSB₁₄ = 0.00061 V. Adjust Zero for
digital output = 11111111111110.
Zero is now calibrated. Set analog input to +FSR – 2 LSB =
+9.99878 V. Adjust Gain for 00000000000001 digital output
code; full scale (Gain) is now calibrated. Half scale calibration
check: set analog input to +5.00000 V; digital output code
should be 01111111111111.
–10 V to + 10 V Range
Set analog input to 9.99878 V; adjust zero for 1111111111110
digital output (complementary offset binary) code. Set analog
input to 9.99756 V; adjust Gain for 00000000000001 digital
output (complementary offset binary) code. Half scale calibra-
tion check set analog input to 0.00000 V; digital output (com-
plementary offset binary) code should be 01111111111111.
Figure 11. Analog and Power Connections for Unipolar
0 V to +10 V Input Range
–6–
REV. B