ad8426 Analog Devices, Inc., ad8426 Datasheet - Page 14

• Manufacturer Part Number: ad8426
• Description: Wide Supply Range, Rail-to-rail Output Instrumentation Amplifier
• Manufacturer: Analog Devices, Inc.

AD8426
limiting resistors and low leakage diode clamps such as the
BAV199, the FJH1100s, or the SP720 should be used.
RADIO FREQUENCY INTERFERENCE (RFI)
RF interference is often a problem when amplifiers are used in
applications where there are strong RF signals. The precision
circuits in the
appear as a dc offset voltage error. To avoid this rectification,
place a low-pass RC filter at the input of the instrumentation
amplifier (see Figure 13). The filter limits both the differential
and common-mode bandwidth, as shown in the following
equations:
where C
FilterFreq
FilterFreq
D
 10 C
AD8426
uency
uency
C
.
DIFF
CM
can rectify the RF signals so that they


π 2
π 2
RC
1
R
2 (
C
C
1
D

C
C
)
Rev. PrD | Page 14 of 20
C
mode signal. Values of R and C
RFI. Any mismatch between the R × C
and the R × C
AD8426. By using a value of C
than C
is improved.
D
affects the differential signal, and C
C
, the effect of the mismatch is reduced, and performance
4.02kΩ
4.02kΩ
R
R
C
at the negative input degrades the CMRR of the
Preliminary Technical Data
C
1nF
C
10nF
C
1nF
Figure 13. RFI Suppression
C
D
C
R
0.1µF
0.1µF
G
+IN
–IN
D
C
one order of magnitude larger
should be chosen to minimize
AD8426
+V
–V
S
S
C
C
at the positive input
affects the common-
REF
10µF
10µF
V
OUT