LMC662AMD NSC [National Semiconductor], LMC662AMD Datasheet - Page 5

• Manufacturer Part Number: LMC662AMD
• Description: CMOS Dual Operational Amplifier
• Manufacturer: NSC [National Semiconductor]

Typical Performance Characteristics
CMRR vs Frequency
Non-Inverting Large Signal
Pulse Response
Application Hints
AMPLIFIER TOPOLOGY
The topology chosen for the LMC662, shown in Figure 1 , is
unconventional (compared to general-purpose op amps) in
that the traditional unity-gain buffer output stage is not used;
instead, the output is taken directly from the output of the in-
tegrator, to allow rail-to-rail output swing. Since the buffer
traditionally delivers the power to the load, while maintaining
high op amp gain and stability, and must withstand shorts to
either rail, these tasks now fall to the integrator.
As a result of these demands, the integrator is a compound
affair with an embedded gain stage that is doubly fed forward
(via C
driver. In addition, the output portion of the integrator is a
push-pull configuration for delivering heavy loads. While
sinking current the whole amplifier path consists of three
gain stages with one stage fed forward, whereas while
sourcing the path contains four gain stages with two fed
forward.
f
and C
ff
) by a dedicated unity-gain compensation
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Open-Loop Frequency
Response
Stability vs
Capacitive Load
Note: Avoid resistive loads of less than 500 ,
as they may cause instability.
V
5
S
=
The large signal voltage gain while sourcing is comparable
to traditional bipolar op amps, even with a 600
gain while sinking is higher than most CMOS op amps, due
to the additional gain stage; however, under heavy load
(600 ) the gain will be reduced as indicated in the Electrical
Characteristics.
±
FIGURE 1. LMC662 Circuit Topology (Each Amplifier)
7.5V, T
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A
= 25˚C unless otherwise specified (Continued)
Frequency Response vs
Capacitive Load
Stability vs
Capacitive Load
Note: Avoid resistive loads of less than 500 ,
as they may cause instability.
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load. The
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