SPECIFIC ADVANTAGES OF 5-Pin SOT23 (TinyPak)
The obvious advantage of the 5-pin SOT23, TinyPak, is that
it can save board space, a critical aspect of any portable or
miniaturized system design. The need to decrease overall
system size is inherent in any handheld, portable, or
lightweight system application.
Furthermore, the low profile can help in height limited designs,
such as consumer hand-held remote controls, sub-notebook
computers, and PCMCIA cards.
An additional advantage of the tiny package is that it allows
better system performance due to ease of package place-
ment. Because the tiny package is so small, it can fit on the
board right where the op amp needs to be placed for optimal
performance, unconstrained by the usual space limitations.
This optimal placement of the tiny package allows for many
system enhancements, not easily achieved with the con-
straints of a larger package. For example, problems such as
system noise due to undesired pickup of digital signals can
be easily reduced or mitigated. This pick-up problem is often
caused by long wires in the board layout going to or from an
op amp. By placing the tiny package closer to the signal
source and allowing the LM7301 output to drive the long wire,
the signal becomes less sensitive to such pick-up. An overall
reduction of system noise results.
Often times system designers try to save space by using dual
or quad op amps in their board layouts. This causes a com-
plicated board layout due to the requirement of routing several
signals to and from the same place on the board. Using the
tiny op amp eliminates this problem.
Additional space savings parts are available in tiny packages
from National Semiconductor, including low power amplifiers,
precision voltage references, and voltage regulators.
LOW DISTORTION, HIGH OUTPUT
DRIVE CAPABILITY
The LM7301 offers superior low-distortion performance, with
a total-harmonic-distortion-plus-noise of 0.06% at f = 10 kHz.
The advantage offered by the LM7301 is its low distortion
levels, even at high output current and low load resistance.
Please refer to STABILITY CONSIDERATIONS for methods
used to ensure stability under all load conditions.
Typical Applications
HANDHELD REMOTE CONTROLS
The LM7301 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 LM7301 performance can
easily meet these requirements.
OPTICAL LINE ISOLATION FOR MODEMS
The combination of the low distortion and good load driving
capabilities of the LM7301 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 LM7301 fulfills this need,
in this and in other telecom applications. Please refer to STA-
BILITY CONSIDERATIONS for methods used to ensure sta-
bility under all load conditions.
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 LM7301
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.
Ordering Information
Package Part Number Package Marking Transport Media NSC Drawing
8-Pin SOIC LM7301IM LM7301IM 95 Units/Rail M08A
LM7301IMX 2.5k Units Tape and Reel
5-Pin SOT23 LM7301IM5 A04A 1k Units Tape and Reel MF05A
LM7301IM5X 3k Units Tape and Reel
11 www.national.com
LM7301