Datasheet
© 2011 Microchip Technology Inc. DS25073A-page 9
MCP6N11
1.4 DC Test Circuits
1.4.1 INPUT OFFSET TEST CIRCUIT
Figure 1-6 is used for testing the INA’s input offset
errors and input voltage range (V
E
, V
IVL
and V
IVH
; see
Section 1.5.1 “Input Offset Related Errors” and
Section 1.5.2 “Input Offset Common Mode Non-
linearity”). U
2
is part of a control loop that forces V
OUT
to equal V
CNT
; U
1
can be set to any bias point.
FIGURE 1-6: Test Circuit for Common
Mode (Input Offset).
When MCP6N11 is in its normal range of operation, the
DC output voltages are (where V
E
is the sum of input
offset errors and g
E
is the gain error):
EQUATION 1-1:
Table 1-5 gives the recommended R
F
and R
G
values
for different G
MIN
options.
1.4.2 DIFFERENTIAL GAIN TEST CIRCUIT
Figure 1-7 is used for testing the INA’s differential gain
error, non-linearity and input voltage range (g
E
, INL
DM
,
V
DML
and V
DMH
; see Section 1.5.3 “Differential Gain
Error and Non-linearity”). R
F
and R
G
are 0.01% for
accurate gain error measurements.
FIGURE 1-7: Test Circuit for Differential
Mode.
The output voltages are (where V
E
is the sum of input
offset errors and g
E
is the gain error):
EQUATION 1-2:
To keep V
REF
, V
FG
and V
OUT
within their ranges, set:
EQUATION 1-3:
Table 1-6 shows the recommended R
F
and R
G
. They
produce a 10 kΩ load; V
L
can usually be left open.
TABLE 1-5: SELECTING R
F
AND R
G
G
MIN
(V/V)
Nom.
R
F
(Ω)
Nom.
R
G
(Ω)
Nom.
G
DM
(V/V)
Nom.
G
DM
V
OS
(±V)
Max.
BW
(kHz)
Nom.
1 100k 499 201.4 0.60 2.5
2 0.40 5.0
5 100k 100 1001 0.85 2.5
10 0.50 5.0
100 0.35 35
R
L
V
CM
100 nF
V
DD
2.2 µF
V
REF
V
L
12.7 kΩ
V
M
100 nF
C
CNT
U
1
MCP6N11
U
2
MCP6H01
V
CNT
63.4 kΩ
R
G
R
F
R
CNT
63.4 kΩ
V
OUT
10 nF
1kΩ
1kΩ
G
DM
1R
F
R
G
⁄
+=
V
OUT
V
CNT
=
V
M
V
REF
G
DM
1g
E
+()V
E
+=
TABLE 1-6: SELECTING R
F
AND R
G
G
MIN
(V/V)
Nom.
R
F
(Ω)
Nom.
R
G
(Ω)
Nom.
G
DM
(V/V)
Nom.
10Open1.000
2 4.99k 4.99k 2.000
5 8.06k 2.00k 5.030
10 9.09k 1.00k 10.09
100 10.0k 100 101.0
R
L
6.34 kΩ
1kΩ
1kΩ
V
CM
+V
DM
/2
+
100 nF
V
OUT
R
F
R
G
V
M
–
100 nF
V
DD
2.2 µF
6.34 kΩ
V
REF
V
FG
V
L
V
CM
–V
DM
/2
0.01%
0.01%
U
1
MCP6N11
G
DM
1R
F
R
G
⁄
+=
V
M
V
OUT
V
REF
–=
V
OUT
V
REF
G
DM
1g
E
+()V
DM
V
E
+()+=
G
DM
1g
E
+()V
DM
V
E
+()=
V
REF
V
DD
G
DM
V
DM
–()2
⁄
=