TL441-EP_14 Datasheet, PDF (9/19 Pages) Texas Instruments – LOGARITHMIC AMPLIFIER

TL441ĆEP
LOGARITHMIC AMPLIFIER
SGLS268 − OCTOBER 2004
Output Levels
Differential-output-voltage levels are low, generally less than 0.6 V. As demonstrated in Figure 11, the output
swing and the slope of the output response can be adjusted by varying the gain by means of the slope control.
The coordinate origin also can be adjusted by positioning the offset of the output buffer.
Circuits
Figure 11 through Figure 18 show typical circuits using this logarithmic amplifier. Operational amplifiers not
otherwise designated are TLC271. For operation at higher frequencies, the TL592 is recommended instead of
the TLC271.
TYPICAL TRANSFER CHARACTERISTICS
1.4
1.2
Adjusted for Increased
1.0 Slope and Offset
0.8
0.6
0.4
0.2
0
Adjusted For Minimum
Slope With Zero Offset
− 0.2
10 ^{− 4} 10 ^−3 10 ^−2 10 ^−1
1
101
Input Voltage − V
Input
A1
Y
−+
1/2
TL441
A2 _GND Y
Origin
+
−
Slope
Output
Figure 11. Output Slope and Origin Adjustment
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