TL441CN Datasheet, PDF (14/20 Pages) Texas Instruments – LOGARITHMIC AMPLIFIER

TL441
LOGARITHMIC AMPLIFIER
SLVS328 – OCTOBER 2000
Input
A
2 kΩ
Origin
20 kΩ
APPLICATION INFORMATION
2 kΩ
Slope
–
+
+
–
A1 _1/2 Y
A2 ^TL441 Y
Output
W
2 kΩ
2 kΩ
NOTE: Adjust the slope to correspond to the base “a”.
Exponential to any base: W = a.
Figure 18. Raising a Fixed Number to a Variable Power
Input
1
50 Ω
Input
2
50 Ω
TL592
+
–
50 Ω
Open
0.2 µF
Gain Adj. = 400 Ω
For 30 dB
TL592
+
–
50 Ω
Open
0.2 µF
A1
Y
A2
Y
TL441
Z
B1
B2
Z
CA2 CA2’ CB2 CB2’
10
10
kΩ
kΩ
Gain Adj. = 400 Ω
For 30 dB
2.2 kΩ
20 kΩ
2.2 kΩ
2.2 kΩ
20 kΩ
2.2 kΩ
TL592
+
–
0.2 µF
0.2 µF
Output
1
1 kΩ
Gain Adj.
TL592
+
–
0.2 µF
0.2 µF
1 kΩ
Output
2
1 kΩ
Gain Adj.
1 kΩ
VCC _–
Figure 19. Dual-Channel RF Logarithmic Amplifier With 50-dB Input Range Per Channel at 10 MHz
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