LM6181IM-8 National Semiconductor, LM6181IM-8 Datasheet - Page 17

• Manufacturer Part Number: LM6181IM-8
• Description: Operational Amplifier (Op-Amp) IC
• Manufacturer: National Semiconductor

Specifications of LM6181IM-8

• No. Of Amplifiers: 1
• Bandwidth: 100MHz
• No. Of Pins: 8
• Peak Reflow Compatible (260 C): No
• Leaded Process Compatible: No
• Mounting Type: Surface Mount
• Package / Case: 8-NSOIC
• Number Of Channels: 1
• Common Mode Rejection Ratio (min): 50 dB
• Input Offset Voltage: 3 mV at +/- 5 V
• Operating Supply Voltage: 9 V, 12 V, 15 V, 18 V, 24 V, 28 V
• Supply Current: 8.5 mA at +/- 5 V
• Maximum Operating Temperature: + 85 C
• Maximum Dual Supply Voltage: +/- 16 V
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Typical Applications
SLEW RATE CONSIDERATIONS
The slew rate characteristics of current feedback amplifiers
are different than traditional voltage feedback amplifiers. In
voltage feedback amplifiers slew rate limiting or non-linear
amplifier behavior is dominated by the finite availability of the
1st stage tail current charging the compensation capacitor.
FIGURE 3. Increasing Compensation
FIGURE 4. Reducing R
Closed Loop Gains, R
with Increasing R
3b: R
3a: R
f
f
= 1640
= 820
(Continued)
f
f
for Large
= 500
f
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DS011328-16
DS011328-15
17
The slew rate of current feedback amplifiers, in contrast, is
not constant. Transient current at the inverting input deter-
mines slew rate for both inverting and non-inverting gains.
The non-inverting configuration slew rate is also determined
by input stage limitations. Accordingly, variations of slew
rates occur for different circuit topologies.
DRIVING CAPACITIVE LOADS
The LM6181 can drive significantly larger capacitive loads
than many current feedback amplifiers. Although the
LM6181 can directly drive as much as 100 pF without oscil-
lating, the resulting response will be a function of the feed-
back resistor value. Figure 5 illustrates the small-signal
pulse response of the LM6181 while driving a 50 pF load.
Ringing persists for approximately 70 ns. To achieve pulse
responses with less ringing either the feedback resistor can
be increased (see typical curves Suggested R
C
works well). Either technique, however, results in lowering
the system bandwidth.
Figure 6 illustrates the improvement obtained with using a
47
L
), or resistive isolation can be used (10 –51
isolation resistor.
Drive 50 pF of Load Capacitance with 70 ns
FIGURE 5. A
of Ringing Resulting in Pulse Response
V
= −1, LM6181 Can Directly
5b
5a
DS011328-18
f
www.national.com
and R
DS011328-19
typically
s
for