LMC6482_15 Datasheet, PDF (24/39 Pages) Texas Instruments – CMOS Dual Rail-to-Rail Input and Output Operational Amplifier

LMC6482
SNOS674E – NOVEMBER 1997 – REVISED APRIL 2015
Typical Applications (continued)
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Figure 64. Canceling the Effect of Input Capacitance
The effect of input capacitance can be compensated for by adding a feedback capacitor. The feedback capacitor
(as in Figure 64), C_f, is first estimated by:
(1)
or
R₁ C_IN ≤ R₂ C_f
(2)
which typically provides significant overcompensation.
Printed-circuit-board stray capacitance may be larger or smaller than that of a bread-board, so the actual
optimum value for C_f may be different. The values of C_f should be checked on the actual circuit. (Refer to the
LMC660 quad CMOS amplifier data sheet for a more detailed discussion.)
8.2.1.2.1.3 Offset Voltage Adjustment
Offset voltage adjustment circuits are illustrated in Figure 65 and Figure 66. Large value resistances and
potentiometers are used to reduce power consumption while providing typically ±2.5 mV of adjustment range,
referred to the input, for both configurations with V_S = ±5 V.
V+
R4
500 k:
V_IN
1 k:
500 k:
V-
R3
1 M:
499:
V-
5V
-
1
LMC6482
2
+
-5V
V_OUT
R4
=-
V_IN
R3
V_OUT
Figure 65. Inverting Configuration Offset Voltage Adjustment
Figure 66. Noninverting Configuration Offset Voltage Adjustment
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