LMC6482QML_16 Datasheet, PDF (15/29 Pages) Texas Instruments – LMC6482QML CMOS Dual Rail-To-Rail Input and Output Operational Amplifier

www.ti.com
LMC6482QML
SNOSAR9A – DECEMBER 2010 – REVISED MARCH 2013
Figure 55. R_I Input Current Protection for
Voltages Exceeding the Supply Voltages
RAIL-TO-RAIL OUTPUT
The approximated output resistance of the LMC6482 is 180Ω sourcing and 130Ω sinking at V_S = 3V and 110Ω
sourcing and 80Ω sinking at Vs = 5V. Using the calculated output resistance, maximum output voltage swing can
be estimated as a function of load.
CAPACITIVE LOAD TOLERANCE
The LMC6482 can typically directly drive a 100pF load with V_S = 15V at unity gain without oscillating. The unity
gain follower is the most sensitive configuration. Direct capacitive loading reduces the phase margin of op-amps.
The combination of the op-amp's output impedance and the capacitive load induces phase lag. This results in
either an underdamped pulse response or oscillation.
Capacitive load compensation can be accomplished using resistive isolation as shown in Figure 56. This simple
technique is useful for isolating the capacitive inputs of multiplexers and A/D converters.
Figure 56. Resistive Isolation
of a 330pF Capacitive Load
Figure 57. Pulse Response of
the LMC6482 Circuit in Figure 56
Improved frequency response is achieved by indirectly driving capacitive loads, as shown in Figure 58.
Copyright © 2010–2013, Texas Instruments Incorporated
Product Folder Links: LMC6482QML
Submit Documentation Feedback
15