Title :
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
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;
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
DOI :
10.1109/ISCAS.2000.856419
