Title :
High-frequency fully differential filter using operational amplifiers without common-mode feedback
Author :
Nicollini, Germano ; Moretti, Francesco ; Conti, Mauro
Author_Institution :
ST Microelectron., Milano, Italy
fDate :
6/1/1989 12:00:00 AM
Abstract :
A technique for realizing a fully differential filter using an operational amplifier (op amp) without common-mode feedback (CMFB) is presented. This technique results in a smaller area, a reduced power dissipation, and an improved speed and dynamic range of the filter. Experimental results of a biquad switched-capacitor bandpass filter with a center frequency of 3.5 MHz and a Q of 24 are presented. The op amp has an open-loop unity-gain bandwidth of 230 MHz, a phase margin greater than 50°, and a DC gain of 76 dB. The prototype filter occupies only 0.26 mm2 and dissipates 6 mW with a 5-V supply
Keywords :
active filters; band-pass filters; switched capacitor filters; 230 MHz; 35 MHz; 6 mW; 76 dB; DC gain; biquad switched-capacitor bandpass filter; center frequency; dynamic range; fully differential filter; open-loop unity-gain bandwidth; operational amplifiers; phase margin; power dissipation; speed; Band pass filters; Bandwidth; Differential amplifiers; Dynamic range; Feedback; Frequency; Gain; Operational amplifiers; Power dissipation; Prototypes;
Journal_Title :
Solid-State Circuits, IEEE Journal of
