lm7341mfx National Semiconductor Corporation, lm7341mfx Datasheet - Page 15

• Manufacturer Part Number: lm7341mfx
• Description: Lm7341 Rail-to-rail Input/output ?15v, 4.6 Mhz Gbw, Operational Amplifier In Sot-23 Package
• Manufacturer: National Semiconductor Corporation

Typical Applications
HANDHELD REMOTE CONTROLS
The LM7341 offers outstanding specifications for applications
requiring good speed/power trade-off. In applications such as
remote control operation, where high bandwidth and low pow-
er consumption are needed. The LM7341 performance can
easily meet these requirements.
OPTICAL LINE ISOLATION FOR MODEMS
The combination of the low distortion and good load driving
capabilities of the LM7341 make it an excellent choice for
driving opto-coupler circuits to achieve line isolation for
modems. This technique prevents telephone line noise from
coupling onto the modem signal. Superior isolation is
achieved by coupling the signal optically from the computer
modem to the telephone lines; however, this also requires a
low distortion at relatively high currents. Due to its low distor-
tion at high output drive currents, the LM7341 fulfills this need,
in this and in other telecom applications.
REMOTE MICROPHONE IN PERSONAL COMPUTERS
Remote microphones in Personal Computers often utilize a
microphone at the top of the monitor which must drive a long
cable in a high noise environment. One method often used to
reduce the nose is to lower the signal impedance, which re-
duces the noise pickup. In this configuration, the amplifier
usually requires 30 dB–40 dB of gain, at bandwidths higher
than most low-power CMOS parts can achieve. The LM7341
offers the tiny package, higher bandwidths, and greater out-
put drive capability than other rail-to-rail input/output parts can
provide for this application.
LM7341 AS A COMPARATOR
The LM7341 can also be used as a comparator and provides
quite reasonable performance. Note however that unlike a
typical comparator an op amp has a maximum allowed dif-
ferential voltage between the input pins. For the LM7341, as
stated in the Absolute Maximum Ratings section, this maxi-
mum voltage is V
for a short time, damage to the device may occur.
As an inverting comparator at V
there is typically 12 μs of propagation delay. At V
50 mV of overdrive there is typically 17 µs of propagation de-
lay.
IN
Differential = ±15V. Beyond this limit, even
S
= 30V and 1V of overdrive
S
= 30V and
15
Similarly a non-inverting comparator at V
overdrive there is typically 12 µs of propagation delay. At
V
propagation delay.
COMPARATOR WITH HYSTERESIS
The basic comparator configuration may oscillate or produce
a noisy output if the applied differential input voltage is near
the comparator's offset voltage. This usually happens when
the input signal is moving very slowly across the comparator's
switching threshold. This problem can be prevented by the
addition of hysteresis or positive feedback.
S
= 30V and 50 mV of overdrive there is typically 17 μs of
FIGURE 2. Non-Inverting Comparator
FIGURE 1. Inverting Comparator
S
= 30V and 1V of
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