A charge-pump-controlled MOSFET-C single-amplifier biquad

Author

Schmid, Hanspeter ; Moschytz, George S.

Author_Institution

Inst. for Signal & Inf. Process., Swiss Fed. Inst. of Technol., Zurich, Switzerland

Volume

2

fYear

2000

fDate

2000

Firstpage

677

Abstract

The spurious-free dynamic range (SFDR) of a MOSFET-C filter can be increased greatly by generating its tuning voltage with a charge pump. In this paper, we apply this technique to build a Sallen-and-Key lowpass filter with a pole frequency of 24 MHz and a pole Q of 3. It has an SFDR better than 50 dB and consumes 16 mW from a 3.3 V supply. Implemented with a double-poly triple-metal 0.6-μm CMOS process, it covers an area of only 0.11 mm². In addition to a description of the filter and the charge pump, we also discuss linear and non-linear clock feed-through from the charge pump´s own ring oscillator, and derive a formula for the optimum voltage swing at the MOSFET-C network nodes

Keywords

CMOS analogue integrated circuits; MOSFET circuits; Q-factor; biquadratic filters; circuit tuning; low-pass filters; 16 mW; 24 MHz; 3.3 V; CMOS chip; MOSFET-C single-amplifier biquad filter; Q-factor; Sallen-and-Key low-pass filter; charge pump control; clock feedthrough; ring oscillator; spurious-free dynamic range; tuning voltage; CMOS process; Charge pumps; Clocks; Dynamic range; Frequency; MOSFET circuits; Nonlinear filters; Ring oscillators; Tuning; Voltage;

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems, 2000. Proceedings. ISCAS 2000 Geneva. The 2000 IEEE International Symposium on

Conference_Location

Geneva

Print_ISBN

0-7803-5482-6

Type

conf

DOI

10.1109/ISCAS.2000.856419

Filename

856419