TS4994 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
TS4994
STMicroelectronics
'TS4994' PDF : 31 Pages View PDF
Application Information
TS4994
With ∆R=1%, the minimum CMRR would be -53dB that give Voo=5.6mV and an maximum extra
consumption less than 700µA.
This example is of a worst case scenario where each resistor has extreme tolerance and illustrates the
fact that for CMRR, good matching is essential.
As with the PSRR, due to self-generated noise, the TS4994 CMRR limitation would be about -110dB.
Figures 75 and 76 show CMRR versus frequency and versus bypass capacitor Cb in worst-case condition
(∆R=0.1%).
Figure 75. CMRR vs. frequency worst case
condition
0
Vcc = 5V
-10 Vic = 200mVpp
Av = 1, Cin = 470µF
-20
∆R/R = 0.1%, RL ≥ 8Ω
Tamb = 25°C
-30
Figure 76. CMRR vs. frequency worst case
condition
0
Vcc = 2.5V
-10 Vic = 200mVpp
Av = 1, Cin = 470µF
∆R/R = 0.1%, RL ≥ 8Ω
-20 Tamb = 25°C
-30
-40
Cb=1µF
Cb=0
-50
-40
Cb=1µF
Cb=0
-50
-60
20
100
1000
Frequency (Hz)
10000 20k
-60
20
100
1000
Frequency (Hz)
10000 20k
Figures 77 and 78 show CMRR versus frequency for a typical application with four 0.1% tolerances and
a random choice for them.
Figure 77. CMRR vs. frequency with random
choice condition
0
-10 Vcc = 5V
Vic = 200mVpp
-20 Av = 1, Cin = 470µF
∆R/R ≤ 0.1%, RL ≥ 8Ω
-30 Tamb = 25°C
-40
-50
Cb=1µF
-60
Cb=0
-70
-80
-90
20
100
1000
Frequency (Hz)
10000 20k
Figure 78. CMRR vs. frequency with random
choice condition
0
-10 Vcc = 2.5V
Vic = 200mVpp
-20 Av = 1, Cin = 470µF
∆R/R ≤ 0.1%, RL ≥ 8Ω
-30 Tamb = 25°C
-40
-50
Cb=1µF
-60
Cb=0
-70
-80
-90
20
100
1000
Frequency (Hz)
10000 20k
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