A switched‐capacitor programmable gain amplifier using dynamic element matching

Abstract

This paper discusses the effect of capacitor mismatch errors on gain accuracy of switched‐capacitor programmable gain amplifier (SC PGA). To improve gain deviations caused by mismatch errors, the dynamic element matching (DEM) algorithm is applied to the SC PGA circuits. It uses digital gain‐control signal to dynamically vary the matched capacitor combinations so that the effective capacitances of the sampling and feedback capacitor arrays are averaged, and thus the gain deviations due to capacitor mismatch errors are eliminated to a significant extent. The distortion caused by mismatch errors shift to certain frequency bands, and could be reduced or removed by subsequent processing such as lowpass filtering. A 4‐bit SC PGA using DEM was designed in 0.25 µm CMOS process with 2.5 V voltage supply, including offset cancellation and clock bootstrapped circuits operating at a sampling frequency of 10 MHz. Test results have indicated that gain deviations due to mismatch errors are substantially reduced. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

A Design of 0.7-V 400-MHz All-Digital Phase-Locked Loop for Implantable Biomedical Devices

“…A thermometer coder employing dynamic element matching (DEM) is used to convert the input digital bit. DEM effectively eliminates component mismatches [17]. Thus, the influence of capacitor mismatch can be reduced by changing the capacitor selection [18].…”

A Design of 0.7-V 400-MHz Digitally-Controlled Oscillator

“…5 causes distortion in the oscillation signal. The DEM effectively eliminates component mismatches [13]. This technique rearranges the interconnections of the mismatched components to nearly equalize the time averages of the equivalent components at each of the component positions.…”

Low-Voltage Wireless Analog CMOS Circuits toward 0.5 V Operation

“…Even in Δ-Σ A/D modulators, SR may help to enhance resolution [44]. Whereas dynamic element matching, which is applied for the improvement of D/A converters and programmable gain amplifiers [45], [46], relaxes the influence of device mismatches on circuit precision, this technique instead utilizes device mismatches.…”