AN-733

APPLICATION NOTE

One Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106 • Tel

TT : 781/329-4700 • Fax: 781/326-8703 • www.analog.com

INTRODUCTION

The EVAL-PRAOPAMP-1RM is an evaluation board which

accommodates single op amps in MSOP packages. It is

meant to provide the user with multiple choices and

extensive flexibility for different application circuits

and configurations. This board is not intended to be

used with high frequency components or high speed

amplifiers. However, it provides the user with many

combinations for various circuit types, including active

filters, differential amplifiers, and external frequency

compensation circuits. A few examples of application

circuits are given in this application note.

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Figure 1. Simple Low-Pass Filter

Universal Precision Op Amp Evaluation Board in MSOP Package

by Giampaolo Marino, Soufiane Bendaoud, and Steve Ranta

LOW-PASS FILTER

Figure 1 is a typical representation of a first-order low-

pass filter. This circuit has a 6 dB per octave roll-off

this frequency is defined as the magnitude of R7 to R2.

The circuit might be considered as an ac integrator for

response is that of a single RC, rather than an integral.

Acl = –(R7/R2); close loop gain

R6 should be chosen equal to the parallel combination

between R7 and R2 in order to minimize errors due to

bias currents.

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Figure 2. Difference Amplifier

DIFFERENCE AMPLIFIER AND PERFORMANCE

OPTIMIZATION

Figure 2 shows an op amp configured as a difference

amplifier. The difference amplifier is the complement

of the summing amplifier, and allows the subtraction

of two voltages or the cancellation of a signal common

to both inputs. The circuit shown in Figure 2 is useful

as a computational amplifier in making a differential

to single-ended conversion or in rejecting a common-

two separate components:

short circuited to ground.)

short circuited to ground.)

REV. A