LMC6064EP Datasheet, PDF (13/18 Pages) Texas Instruments – Precision CMOS Quad Micropower Operational Amplifier

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(Input pins are lifted out of PC board and soldered directly to components. All other pins connected to PC board).
FIGURE 6. Air Wiring
Typical Single-Supply
Applications
(V⁺ = 5.0 V_DC)
The extremely high input impedance, and low power con-
sumption, of the LMC6064EP make it ideal for applications
that require battery-powered instrumentation amplifiers. Ex-
amples of these types of applications are hand-held pH
probes, analytic medical instruments, magnetic field detec-
tors, gas detectors, and silicon based pressure transducers.
Figure 7 shows an instrumentation amplifier that features high
differential and common mode input resistance (>10¹⁴Ω),
0.01% gain accuracy at A_V = 100, excellent CMRR with 1
kΩ imbalance in bridge source resistance. Input current is
less than 100 fA and offset drift is less than 2.5 μV/°C. R₂
provides a simple means of adjusting gain over a wide range
without degrading CMRR. R₇ is an initial trim used to maxi-
mize CMRR without using super precision matched resistors.
For good CMRR over temperature, low drift resistors should
be used.
If R₁ = R₅, R₃ = R₆, and R₄ = R₇; then
  
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∴A_V ≈ 100 for circuit shown (R₂ = 9.822k).
FIGURE 7. Instrumentation Amplifier
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201144 Version 2 Revision 3 Print Date/Time: 2011/08/30 23:14:26