LMC6484AIMX Datasheet, PDF (15/24 Pages) Texas Instruments – LMC6484 CMOS Quad Rail-to-Rail Input and Output Operational Amplifier

Application Information (Continued)
7.0 Offset Voltage Adjustment
Offset voltage adjustment circuits are illustrated in Figures
13, 14. 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 = ±5V.
DS011714-25
FIGURE 12. Inverting Configuration
Offset Voltage Adjustment
DS011714-26
FIGURE 13. Non-Inverting Configuration
Offset Voltage Adjustment
8.0 Upgrading Applications
The LMC6484 quads and LMC6482 duals have industry
standard pin outs to retrofit existing applications. System
performance can be greatly increased by the LMC6484’s
features. The key benefit of designing in the LMC6484 is
increased linear signal range. Most op-amps have limited
input common mode ranges. Signals that exceed this range
generate a non-linear output response that persists long
after the input signal returns to the common mode range.
Linear signal range is vital in applications such as filters
where signal peaking can exceed input common mode
ranges resulting in output phase inversion or severe distor-
tion.
9.0 Data Acquisition Systems
Low power, single supply data acquisition system solutions
are provided by buffering the ADC12038 with the LMC6484
(Figure 14). Capable of using the full supply range, the
LMC6484 does not require input signals to be scaled down
to meet limited common mode voltage ranges. The
LMC6484 CMRR of 82 dB maintains integral linearity of a
12-bit data acquisition system to ±0.325 LSB. Other
rail-to-rail input amplifiers with only 50 dB of CMRR will
degrade the accuracy of the data acquisition system to only
8 bits.
www.national.com
14