Texas Instruments SoundPlus INA1651EVM, User Manual, Page: 4 / 20

0
f
1
c _ VMID
2 250k C
1
S u : u
R
3
Attenuation
R R
2 3
8
f
1
c _ out
2 (R R ) C
2 3
S u u
n
f
1
c _ in
C R
7 i
S u u
Modifications
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4 SBOU212 – September 2018
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INA1651EVM SoundPlus™ High Common-Mode Rejection Line Receiver
Evaluation Module
3.1 AC-Coupled Corner Frequency
Capacitors C7 and C9 provide the option to ac couple the input of the INA1651 and capacitor C8 provides
the option to ac couple the output of the INA1651.
Equation 1 calculates the high pass corner frequency of
input A and input B due to capacitors, C7 and C9 on the input.
where
• C
7
= C
9
• R
IN
is the differential input impedance of the INA1651 (1)
Equation 2 calculates the high-pass corner frequency due to capacitor C8 and resistors R2 and R3 on the
output.
(2)
Resistors R2 and R3 form a voltage divider on the output of the INA1651 and will attenuate the output
signal.
Equation 3 calculates the attenuation on the INA1651 output.
(3)
3.2 Filtering the VMID (IN) Pin
Capacitor C10 provides an option to filter the input to the internal reference buffer, VMID (IN). Equation 4
calculates the cut-off frequency due to C10.
(4)