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 UAF42 is a universal active filter that can be configured for low‑pass, high‑pass, band‑pass, and band‑reject applications. It uses a classic state‑variable architecture with on‑chip 1000 pF capacitors trimmed to ±0.5 %.
The datasheet includes absolute maximum ratings, electrical characteristics, ordering and packaging information, and design equations for filter implementation. It also describes a DOS‑compatible design program that assists in calculating component values for various filter types.
| Frequency Range | 0 to 100 kHz |
|---|---|
| Frequency Accuracy | 1 % vs Temperature 0.01 %/°C |
| Maximum Q | 400 |
| Maximum Q·Frequency Product | 500 kHz |
| Q vs Temperature | 0.01 %/°C |
| Input Offset Voltage | ±5 mV |
| Resistor Accuracy | 0.5 %–1 % |
| Input Voltage Noise Density (10 Hz) | 25 nV/√Hz |
| Short‑Circuit Output Current | ±25 mA |
| Specified Operating Voltage | ±15 V |
| Operating Voltage Range | ±6 V to ±18 V |
| Supply Current | 6 mA–7 mA |
| Specified Temperature Range | –25 °C to +85 °C |
| Storage Temperature Range | –40 °C to +125 °C |
| Thermal Resistance (θJA) | 100 °C/W |
The maximum Q value is 400.
The UAF42 is available in a 14‑pin PDIP package and a 16‑pin SOIC surface‑mount package.
The device operates from ±6 V to ±18 V.
The input offset voltage is specified as ±5 mV.