Analysis and Design of VCO-Based Phase-Domain ΣΔ Modulators

Analysis and Design of VCO-Based Phase-Domain ΣΔ Modulators

Sonmez, U. (TU Delft Electronic Instrumentation)
Sebastiano, F. (TU Delft (OLD)Applied Quantum Architectures)
Makinwa, K.A.A. (TU Delft Microelectronics)

Microelectronics

2017

VCO-based phase-domain ΣΔ modulators employ the combination of a voltage-controlled-oscillator (VCO) and an up/down counter to replace the analog loop filter used in conventional ΣΔ modulators. Thanks to this highly digital architecture, they can be quite compact, and are expected to shrink even further with CMOS scaling. This paper describes the analysis and design of such converters. Trade-offs between design parameters and the impact of non-idealities, such as finite counter length and VCO non-linearity, are assessed through both theoretical analysis and behavioral simulations. The proposed design methodology is applied to the design of a phase-to-digital converter in a 40-nm CMOS process, which is used to digitize the output of a thermal-diffusivity temperature sensor, achieving ± 0.2° (3σ) phase inaccuracy from -40 to 125 °C and a sensor-limited resolution of 57 m° (RMS) within a 500-Hz bandwidth. Measurements on the prototype agree quite well with theoretical predictions, thus demonstrating the validity of the proposed design methodology.

Phase-to-digital converter
quantization noise
time-to-digital converter
VCO-based sigma-delta modulator

http://resolver.tudelft.nl/uuid:c6a3dc66-7199-4ab1-85b6-9586a5aa7a9c

https://doi.org/10.1109/TCSI.2016.2638827

1549-8328

IEEE Transactions on Circuits and Systems Part 1: Regular Papers, 64 (5), 1075-1084

Accepted Author Manuscript

Institutional Repository

journal article

© 2017 U. Sonmez, F. Sebastiano, K.A.A. Makinwa