LM6171AIMX National Semiconductor, LM6171AIMX Datasheet - Page 12

• Manufacturer Part Number: LM6171AIMX
• Description: High Speed Low Power Low Distortion Voltage Feedback Amplifier
• Manufacturer: National Semiconductor

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Typical Performance Characteristics
Undistorted Output Swing
vs Frequency
LM6171 Simplified Schematic
Application Information
LM6171 Performance Discussion
The LM6171 is a high speed, unity-gain stable voltage feed-
back amplifier. It consumes only 2.5 mA supply current while
providing a gain-bandwidth product of 100 MHz and a slew
rate of 3600V/µs. It also has other great features such as low
differential gain and phase and high output current. The
LM6171 is a good choice in high speed circuits.
The LM6171 is a true voltage feedback amplifier. Unlike cur-
rent feedback amplifiers (CFAs) with a low inverting input im-
pedance and a high non-inverting input impedance, both in-
puts of voltage feedback amplifiers (VFAs) have high
impedance nodes. The low impedance inverting input in
CFAs will couple with feedback capacitor and cause oscilla-
tion. As a result, CFAs cannot be used in traditional op amp
circuits such as photodiode amplifiers, I-to-V converters and
integrators.
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Undistorted Output Swing
vs Frequency
Unless otherwise noted, T
12
LM6171 Circuit Operation
The class AB input stage in LM6171 is fully symmetrical and
has a similar slewing characteristic to the current feedback
amplifiers. In the LM6171 Simplfied Schematic, Q1 through
Q4 form the equivalent of the current feedback input buffer,
R
ers the inverting input. The triple-buffered output stage iso-
lates the gain stage from the load to provide low output im-
pedance.
LM6171 Slew Rate Characteristic
The slew rate of LM6171 is determined by the current avail-
able to charge and discharge an internal high impedance
node capacitor. The current is the differential input voltage
divided by the total degeneration resistor R
E
the equivalent of the feedback resistor, and stage A buff-
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Total Power
Dissipation vs
Ambient Temperature
A
= 25˚C (Continued)
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E
. Therefore, the
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