
Applications Information
Figure 1 shows a simple implementation of a non-inverting
buffer amplifier of unity gain. Popular industry standard op-
erational amplifiers such as LF156, LF351, LF411, LF441,
LM11, LM741, etc. can be used in this configuration. Due to
the high bandwidth of the LH4001, it is suitable for use with
most monolithic op amps.
Figure 2 shows an implementation of an inverting amplifier
with output current capability in excess of
g
100 mA. The
gain of this amplifier is determined by the values of R
F
and
R
IN
. The resistor between the non-inverting input and
ground is used to minimize the output offset voltage result-
ing from the input bias current.
Because of its high current drive capability, the LH4001
buffer amplifier is suitable for driving terminated or untermi-
nated co-axial cables, and high current or reactive loads.
Figure 3 shows a co-axial cable drive circuit. The 43
X
resis-
tor matches the driving source to the cable, however, its
inclusion rarely will result in substantial improvement in
pulse response into a terminated cable. If the 43
X
resistor
is included, the output voltage to the load is about half what
it would be without the near end termination.
Figure 4 shows a non-inverting amplifier with gain and out-
put current capability in excess of
g
100 mA. It is capable of
providing
g
10 mA into a 1 k
X
load or
g
100 mA into a
100
X
load (
g
10V swing). Figures 5 and 6 show two differ-
ent methods of providing current limit or short circuit protec-
tion for the LH4001. In Figure 6, the 10
X
resistor limits the
output current to approximately 70 mA. This circuit is highly
recommended if there is a potential for a short circuit to
occur.
TL/K/8628–4
FIGURE 1. Non-Inverting Buffer Amplifier
V
OUT
V
IN
e b
R
F
R
IN
TL/K/8628–6
FIGURE 2. Inverting Buffer Amplifier with Current Limit
3