TLE206X_07 Datasheet, PDF (57/78 Pages) Texas Instruments – EXCALIBUR JFET-INPUT HIGH-OUTPUT-DRIVE uPOWER OPERATIONAL AMPLIFIERS

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TLE206x, TLE206xA, TLE206xB
EXCALIBUR JFETĆINPUT HIGHĆOUTPUTĆDRIVE
µPOWER OPERATIONAL AMPLIFIERS
SLOS193B − FEBRUARY 1997 − REVISED MAY 2004
APPLICATION INFORMATION
input characteristics
The TLE206x, TLE206xA, and TLE206xB are specified with a minimum and a maximum input voltage that if
exceeded at either input could cause the device to malfunction. Because of the extremely high input impedance
and resulting low bias current requirements, the TLE206x, TLE206xA, and TLE206xB are well suited for
low-level signal processing. However, leakage currents on printed-circuit boards and sockets can easily exceed
bias current requirements and cause degradation in system performance. It is good practice to include guard
rings around inputs (see Figure 44). These guards should be driven from a low-impedance source at the same
voltage level as the common-mode input.
VI
+
−
R2
R1
VO
VI
R3
+
+
VO
VO
−
VI
−
R4
Where
R3
R4
+
R2
R1
Figure 44. Use of Guard Rings
TLE2061 input offset voltage nulling
The TLE2061 series offers external null pins that can be used to further reduce the input offset voltage. The
circuit of Figure 45 can be connected as shown if the feature is desired. When external nulling is not needed,
the null pins may be left unconnected.
IN −
−
IN +
+
OUT
N2
N1 _{100 kΩ}
5 kΩ
VCC _−
Figure 45. Input Offset Voltage Nulling
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