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OPERATING PRINCIPLES
R4 may be optionally populated with a resistor equivalent
to R
||R
for increased precision over temperature. R4
G
FB
will cancel out I
and potential parasitic thermocouples
B
at the inputs.
NON-INVERTING GAIN
R
FB
A
=1 +
V
R
G
To set the board up for non-inverting gain with split sup-
plies (see Figure 5):
1. Populate R5 with the desired R
2. Populate R2 with the desired R
3. Tie –IN turret to GND (or populate Z3 with 0Ω)
4. Connect the input signal to the +IN turret
R5
R
FB
R2
R1
R
0
G
–IN
R4*
R3
R
||R
0
G
FB
+IN
V
*OPTIONAL
Figure 5. Non-Inverting Gain
R4 may be optionally populated with a resistor equivalent
to R
||R
for increased precision over temperature. R4
G
FB
will cancel out I
and potential parasitic thermocouples
B
at the inputs.
FB
G
+
V
R6
R7
0
49.9
S
C10
0.1µF
–
V
2
R8
1k
3
1
J1
–
ENABLED
DC2837A-B F05
DC2837A-A/DC2837A-B
ADDING DC BIASES
To add a DC bias using a resistor divider, populate Z1 and
R9/R10 with the same value resistor to set the same DC
offset at both inputs. To keep total power consumption in
the microwatts, choose R
kilohm to single-digit megohm range.
The circuit in Figure 6 level shifts an input signal's com-
mon mode voltage from 0V to mid-rail (V
ing gain of –R
FB
divider Z1 and R1, and the DC bias added to +IN is set by
divider R9 and R3.
+
V
JP1
Z1
V
= 0
R
CM
G
JP2
R1
R
G
–IN
R3
R
G
+IN
OUT
+
R9
V
R
G
+
JP3
V
Figure 6. Inverting Gain with DC Bias
To build the Figure 6 level shift circuit with DC2837A:
1. Remove default R1 – R5 and R9
2. Stuff R1, R3, R9, and Z1 with desired R
3. Stuff R2, R4, Z5 with 0Ω
4. Stuff R5 with desired R
5. Tie +IN turret to GND (or populate Z4 with 0Ω)
6. Jumper settings: JP1 to 1 (V
JP2 installed
7. Connect the –IN turret to input signal
DEMO MANUAL
and R
values in the 100's of
G
FB
+
/R
. The DC bias added to –IN is set by
G
–
V
R5
R
FB
+
V
R2
0
R6
0
R4
S
0
+
V
Z5
0
+
ENABLED (JP6 TIED TO V
)
R10
0
–
V
FB
+
), JP3 to 1 (R9),
/2), with invert-
+
V
= V
/2
CM
R7
49.9
OUT
DC2837A-B F06
G
Rev. 0
5
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