Title :
Substrate noise immune design of an LC-tank VCO using sensitivity functions
Author :
Soens, C. ; Van der Plas, G. ; Wambacq, P. ; Donnay, S.
Author_Institution :
IMEC, Leuven, Belgium
Abstract :
Substrate noise is a major concern for the realization of radios on a mixed-signal chip. This paper presents a method for substrate noise immune VCO design. A sensitivity analysis is proposed to investigate and reduce the impact of substrate noise on a 900 MHz LC-tank VCO. The proposed method provides a designer with the necessary insight to control the performance degradation by substrate noise. Impact via the on-chip current reference is explained and solved reducing the overall impact with 10 dB. The VCO on-chip ground is recognized as a major entry point for substrate noise. Guarding is used to attenuate coupling of substrate noise into the VCO ground up to - 90 dB in this 0.18 μm design on a lightly doped substrate. In this way a high immunity for substrate noise is achieved.
Keywords :
CMOS analogue integrated circuits; UHF integrated circuits; UHF oscillators; integrated circuit design; integrated circuit noise; sensitivity analysis; substrates; voltage-controlled oscillators; 0.18 micron; 900 MHz; LC-tank VCO design; lightly doped substrate; on-chip current reference; on-chip ground; performance degradation; sensitivity analysis; sensitivity functions; substrate noise immunity; CMOS technology; Circuit noise; Degradation; Frequency modulation; Integrated circuit noise; Noise reduction; Programmable logic arrays; Radio frequency; Sensitivity analysis; Voltage-controlled oscillators;
Conference_Titel :
Custom Integrated Circuits Conference, 2005. Proceedings of the IEEE 2005
Print_ISBN :
0-7803-9023-7
DOI :
10.1109/CICC.2005.1568710
