LMC6001-MIL Datasheet, PDF (11/18 Pages) Texas Instruments – Ultra, Ultra-Low Input Current Amplifier

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Application Information (continued)
LMC6001-MIL
SNOSD60 – JUNE 2017
Figure 20. LMC6001 Noninverting Gain of 10 Amplifier, Compensated to Handle Capacitive Loads
In the circuit of Figure 20, R1 and C1 serve to counteract the loss of phase margin by feeding the high frequency
component of the output signal back to the inverting input of the amplifier, thereby preserving phase margin in
the overall feedback loop.
Capacitive load driving capability is enhanced by using a pullup resistor to V⁺ (Figure 21). Typically a pullup
resistor conducting 500 µA or more will significantly improve capacitive load responses. The value of the pullup
resistor must be determined based on the current sinking capability of the amplifier with respect to the desired
output swing. Open-loop gain of the amplifier can also be affected by the pullup resistor. See DC Electrical
Characteristics for LMC6001AI.
Figure 21. Compensating for Large Capacitive Loads with a Pullup Resistor
7.2 Typical Application
The extremely high input resistance, and low power consumption, of the LMC6001 make it ideal for applications
that require battery-powered instrumentation amplifiers. Examples of these types of applications are hand-held
pH probes, analytic medical instruments, electrostatic field detectors and gas chromotographs.
R2
R1
V_IN
±
LMC6001
+
V_OUT
Figure 22. Typical Application Schematic, LMC6001
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