LMC6484AIMX Datasheet, PDF (17/24 Pages) Texas Instruments – LMC6484 CMOS Quad Rail-to-Rail Input and Output Operational Amplifier

Application Information (Continued)
A 2 op-amp instrumentation amplifier designed for a gain of
100 is shown in Figure 16. Low sensitivity trimming is made
for offset voltage, CMRR and gain. Low cost and low power
consumption are the main advantages of this two op-amp
circuit.
Higher frequency and larger common-mode range applica-
tions are best facilitated by a three op-amp instrumentation
amplifier.
DS011714-30
FIGURE 16. Low-Power Two-Op-Amp Instrumentation Amplifier
11.0 Spice Macromodel
A spice macromodel is available for the LMC6484. This
model includes accurate simulation of:
• input common-mode voltage range
• frequency and transient response
• GBW dependence on loading conditions
• quiescent and dynamic supply current
• output swing dependence on loading conditions
and many more characteristics as listed on the macromodel
disk.
Contact your local National Semiconductor sales office to
obtain an operational amplifier spice model library disk.
Typical Single-Supply Applications
DS011714-31
FIGURE 17. Half-Wave Rectifier with
Input Current Protection (RI)
DS011714-32
FIGURE 18. Half-Wave Rectifier Waveform
The circuit in Figure 17 use a single supply to half wave
rectify a sinusoid centered about ground. R_I limits current
into the amplifier caused by the input voltage exceeding the
supply voltage. Full wave rectification is provided by the
circuit in Figure 19.
www.national.com
DS011714-33
FIGURE 19. Full Wave Rectifier
with Input Current Protection (R_I)
16