MX674A MAXIM [Maxim Integrated Products], MX674A Datasheet - Page 14

• Manufacturer Part Number: MX674A
• Description: Industry-Standard, Complete 12-Bit ADCs
• Manufacturer: MAXIM [Maxim Integrated Products]

Figure 11. MAX174 to HA5320 Sample-and-Hold Interface
The unipolar transfer function and input connections are
shown in
Because all internal resistors of the MAX174/MX574A/
MX674A are trimmed for absolute calibration, additional
trimming is not necessary for most applications. The
absolute accuracy for each grade is given in the speci-
fication tables.
If the offset trim is not needed, BIPOFF can be tied direct-
ly to AGND. The two resistors and trimmer for BIPOFF
can then be discarded. A 50ω ±1% metal film resistor
should be attached between REFOUT and REFIN.
For a 0 to +10V input range, the analog input is con-
nected between AGND and 10V
range, the analog input is connected between AGND
and 20V
beyond the supplies. If full-scale trim is not needed, the
gain trimmer, R2, should be swapped with a 50ω resis-
tor. Should a 10.24V input range be selected, a 200ω
trimmer should be inserted in series with 10V
scale input range of 20.48V, use a 500ω trimmer in series
with 20V
5kω and 10kω for 20V
IN
IN
Figures 12
. These ADCs can easily handle an input signal
. The nominal input impedance into 10V
+15V
-15V
4.7µF
4.7µF
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and 13.
ANALOG
IN
Industry-Standard, Complete 12-Bit ADCs
INPUT
0.1µF
0.1µF
.
Unipolar Input Operation
*ADDITIONAL PINS OMITTED FOR CLARITY
IN
+V
-V
+V
S
S
IN
. For a 0 to +20V input
HA5320*
GND
VOUT
S/H
-V
IN
IN
. For a full-
IN
50I
50I
is
MAX174/MX574A/MX674A
In applications where the offset and full-scale range
have to be adjusted, use the circuit shown in
The offset should be adjusted first. Apply 1/2 LSB at the
analog input and adjust R1 until the digital output code
flickers between 0000 0000 0000 and 0000 0000 0001.
To adjust the full-scale range, apply FS - 3/2 LSB at the
analog input and adjust R2 until the output code changes
between 1111 1111 1110 and 1111 1111 1111.
The bipolar transfer function is shown in
input connections are shown in
of the trimmers can be exchanged with a 50ω ±1% fixed
resistor if the offset and gain specifications suffice.
To begin bipolar calibration, a signal 1/2 LSB above neg-
ative full-scale is applied. R1 is trimmed until the digital
output flickers between 0000 0000 0000 and 0000 0000
0001. Next, a signal 3/2 LSB below positive full scale
is applied. Then, R2 is trimmed until the output flickers
between 1111 1111 1110 and 1111 1111 1111.
STS
20V
10V
BIPOFF
REFOUT
REFIN
IN
IN
AGND
MAX174*
Offset and Full-Scale Adjustment
Offset and Full-Scale Adjustment
DGND
V
V
CC
V
EE
L
Bipolar Input Operation
0.1µF
0.1µF
0.1µF
Figure
4.7µF
4.7µF
4.7µF
CONTROL
INPUTS
D0 –11
+15V
-15V
+5V
15. One or both
Figure
Figure
14, and
12.