1FEATURES

2• VERSATILE:

– Low-Pass, High-Pass

– Band-Pass, Band-Reject

• SIMPLE DESIGN PROCEDURE

• ACCURATE FREQUENCY AND Q:

– Includes On-Chip 1000pF ±0.5% Capacitors

APPLICATIONS

• TEST EQUIPMENT

• COMMUNICATIONS EQUIPMENT

• MEDICAL INSTRUMENTATION

• DATA ACQUISITION SYSTEMS

• MONOLITHIC REPLACEMENT FOR UAF41

DESCRIPTION

The UAF42 is a universal active filter that can be

configured for a wide range of low-pass, high-pass,

and band-pass filters. It uses a classic state-variable

analog architecture with an inverting amplifier and two

integrators. The integrators include on-chip 1000pF

capacitors trimmed to 0.5%. This architecture solves

one of the most difficult problems of active filter

design—obtaining tight tolerance, low-loss capacitors.

A DOS-compatible filter design program allows easy

implementation of many filter types, such as

Butterworth, Bessel, and Chebyshev. A fourth,

uncommitted FET-input op amp (identical to the other

three) can be used to form additional stages, or for

special filters such as band-reject and Inverse

Chebyshev.

The classical topology of the UAF42 forms a

time-continuous filter, free from the anomalies and

switching noise associated with switched-capacitor

filter types.

The UAF42 is available in 14-pin plastic DIP and

SOIC-16 surface-mount packages, specified for the

–25°C to +85°C temperature range.