On-chip automatic tuning based on amplitude detection and its application in CMOS continuous-time filters

✍ Scribed by Aruna Ajjikuttira; K. A. Stromsmoe; I. M. Filanovsky

• Publisher: Springer
• Year: 1991
• Tongue: English
• Weight: 851 KB
• Volume: 1
• Category: Article
• ISSN: 0925-1030
• DOI: 10.1007/bf00195623

✦ Synopsis

This paper describes the results of investigation of a continuous-time CMOS voltage controlled IC filter using amplitude detectors in the tuning scheme in the form of an amplitude-locked loop. This tuning scheme is used to stabilize the filter characteristics. A prototype 20-kHz fifth-order Chebyshev low-pass filter with 0.1-dB passband ripple was realized to study the performance of the tuning scheme. Voltage controlled integrators were used as building blocks, and the design details of these integrators, whose unity-gain frequency can be varied from 8 to 32 kHz are given. Two amplitude detector circuits--a precision rectifier and an averaging rectifier--were used to test the tuning scheme. The filter cutoff frequency was held within 1% of its room temperature value over the temperature range of 0 ~ to 70 ~ All the circuits were fabricated in a standard 3-micron double-metal p-well CMOS process.