TLE2027 Datasheet, PDF (31/35 Pages) Texas Instruments – EXCALIBUR LOW-NOISE HIGH-SPEED PRECISION OPERATIONAL AMPLIFIERS

TLE2027, TLE2037, TLE2027A, TLE2037A, TLE2027Y, TLE2037Y
EXCALIBUR LOW-NOISE HIGH-SPEED
PRECISION OPERATIONAL AMPLIFIERS
SLOS192 – FEBRUARY 1997
APPLICATION INFORMATION
input offset voltage nulling
The TLE2027 and TLE2037 series offers external null pins that can be used to further reduce the input offset
voltage. The circuits of Figure 55 can be connected as shown if the feature is desired. If external nulling is not
needed, the null pins may be left disconnected.
10 kΩ
VCC ₊
IN – –
IN + +
OUT
VCC _–
(a) STANDARD ADJUSTMENT
4.7 kΩ
IN –
–
1 kΩ
4.7 kΩ
IN +
+
VCC ₊
OUT
VCC _–
(b) ADJUSTMENT WITH IMPROVED SENSITIVITY
Figure 55. Input Offset Voltage Nulling Circuits
voltage-follower applications
The TLE2027 circuitry includes input-protection diodes to limit the voltage across the input transistors; however,
no provision is made in the circuit to limit the current if these diodes are forward biased. This condition can occur
when the device is operated in the voltage-follower configuration and driven with a fast, large-signal pulse. It
is recommended that a feedback resistor be used to limit the current to a maximum of 1 mA to prevent
degradation of the device. Also, this feedback resistor forms a pole with the input capacitance of the device.
For feedback resistor values greater than 10 kΩ, this pole degrades the amplifier phase margin. This problem
can be alleviated by adding a capacitor (20 pF to 50 pF) in parallel with the feedback resistor (see Figure 56).
CF = 20 to 50 pF
RF
VCC
–
IF ≤ 1 mA
VO
VI
+
VCC _–
Figure 56. Voltage Follower
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