This document discusses PSRR (Power Supply Rejection Ratio) and CMRR (Common Mode Rejection Ratio), which are measures of a circuit's ability to reject noise or interference from the power supply or inputs. It provides examples of how to calculate PSRR and CMRR and explains factors that affect their values, such as input/output impedances, capacitors, and voltage levels. The document is intended to help designers understand and optimize PSRR and CMRR in their circuits.

1. PSRR CMRR
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PSRR CMRR
PSRR
CMRR
PSRR
CMRR
PSRR CMRR PSRR
1
Vo1 Vo2
1/2VDD Vo1 Vo2
180 BTL

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(2)
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PSRR
PSRR
PSRR 2
10Ω GND
Ci1 Ci2
PSRR
GND
100mVpp 500mVpp
VDD
VDD BTL
PSRR
(FFT)
1 PSRR dB
CMRR
dB 2
3 CMRR
2 CMRR dB
CMRR
CMRR
PSRR
dB 1

3. (3)
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CMRR
VDD/2
1 Vcmi=0V
3
Ri Rf
(Rf1
Rf2) Ri1 Ri2)
Ri1=Ri2 Rf1=Rf2
Ri1=Ri2=R
Rf1=0.8R Rf21.2R, 20%
8Ω
0.45V 46mA
4
0.4
CMRR 23dB PSRR
1

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" " CB
1/2VDD
PSRR
5
PSRR 70dB
0.1uF 1uF PSRR
20dB PSRR 70dB PSRR
PSRR
0Vdc
PSRR

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6. AN-1447PSRRCMRR
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