LMH6723MF National Semiconductor, LMH6723MF Datasheet - Page 12

• Manufacturer Part Number: LMH6723MF
• Description: OP AMP, 1MA WIDEBAND CFB, POWERWISE
• Manufacturer: National Semiconductor

Specifications of LMH6723MF

• Op Amp Type: Wideband
• No. Of Amplifiers: 1
• Bandwidth: 370MHz
• Slew Rate: 600V/µs
• Supply Voltage Range: 4.5V To 12V
• Amplifier Case Style: SOT-23
• No. Of Pins: 5
• Operating Temperature Range: -40°C To
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

www.national.com
Application Section
GENERAL INFORMATION
The LMH6723/LMH6724/LMH6725 is a high speed current
feedback amplifier manufactured on National Semiconduc-
tor’s VIP10
polar process. LMH6723/LMH6724/LMH6725 offers a
unique combination of high speed and low quiescent supply
current making it suitable for a wide range of battery pow-
ered and portable applications that require high perfor-
mance. This amplifier can operate from 4.5V to 12V nominal
supply voltages and draws only 1mA of quiescent supply
current at 10V supplies (
LMH6724/LMH6725 has no internal ground reference so
single or split supply configurations are both equally useful.
EVALUATION BOARDS
National Semiconductor provides the following evaluation
boards as a guide for high frequency layout and as an aid in
device testing and characterization. Many of the datasheet
plots were measured with these boards. For availability and
ordering details refer to the national web site at WWW.Na-
tional.com. Use the search box to locate the product folder.
An evaluation board is shipped when a sample request is
placed with National Semiconductor.
FEEDBACK RESISTOR SELECTION
One of the key benefits of a current feedback operational
amplifier is the ability to maintain optimum frequency re-
sponse independent of gain by using appropriate values for
the feedback resistor (R
Typical Performance plots specify an R
+2V/V and
specified). Generally, lowering R
value will peak the frequency response and extend the band-
width while increasing the value of R
quency response to roll off faster. Reducing the value of R
too far below it’s recommended value will cause overshoot,
ringing and, eventually, oscillation.
Device
LMH6723MA
LMH6723MF
LMH6724MA
LMH6725MA
™
±
5V or
(Vertically Integrated PNP) complimentary bi-
±
2.5V power supplies (unless otherwise
Package
SOIC-8
SOT-23
SOIC-8
SOIC-14
F
). The Electrical Characteristics and
±
5V typically). The LMH6723/
F
from it’s recommended
Board Part #
CLC730227
CLC730216
CLC730036
CLC730231
F
F
of 1200Ω, a gain of
will cause the fre-
F
12
The plot labeled "Frequency Response vs. R
LMH6723/LMH6724/LMH6725’s frequency response as R
is varied (R
800Ω results in peaking. An R
bandwidth and gain flatness with good stability. Since each
application is slightly different it is worth some experimenta-
tion to find the optimal R
value of R
compromise between stability and maximal bandwidth. Note
that it is not possible to use a current feedback amplifier with
the output shorted directly to the inverting input. The buffer
configuration of the LMH6723/LMH6724/LMH6725 requires
a 2000Ω feedback resistor for stable operation. For other
gains see the charts "R
Inverting Gain". These charts provide a good place to start
when selecting the best feedback resistor value for a variety
of gain settings.
For more information see Application Note OA-13 which
describes the relationship between R
quency response for current feedback operational amplifiers.
The value for the inverting input impedance for the
LMH6723/LMH6724/LMH6725 is approximately 500Ω. The
LMH6723/LMH6724/LMH6725 is designed for optimum per-
formance at gains of +1 to +5V/V and −1 to −4V/V. Higher
gain configurations are still useful, however, the bandwidth
will fall as gain is increased, much like a typical voltage
feedback amplifier.
FIGURE 1. Frequency Response vs. R
F
L
= 100Ω, A
that produces ~ 0.1 dB of peaking is the best
V
F
= +2). This plot shows that an R
vs. Non Inverting Gain" and "R
F
for a given circuit. In general a
F
of 1200Ω gives near maximal
F
and closed-loop fre-
F
20078922
" shows the
F
F
F
vs.
of
F