A nA crystal - less oscillator for internet of things

This work presents an ultra-low power oscillator designed to target different contexts, such as crystal-assisted time keeping, reference oscillator to optimize the always on domain of a microcontroller or wake-up timer. This oscillator enables ultra-low power operation in 0.18 μm CMOS technology; the core oscillator consumes 2.5 nW at room temperature, with a temperature stability of 14 ppm/°C [-40°C - 60°C] and 0.07 %/V supply sensitivity.

[1]  F. Ayazi,et al.  Process and temperature compensation in a 7-MHz CMOS clock oscillator , 2006, IEEE Journal of Solid-State Circuits.

[2]  M. Berroth,et al.  Reduction of CMOS Inverter Ring Oscillator Close-in Phase Noise by Current Mode Instead of Voltage Mode Supply , 2006, 2006 Ph.D. Research in Microelectronics and Electronics.

[3]  Benton H. Calhoun,et al.  A 150nW, 5ppm/o C, 100kHz On-Chip clock source for ultra low power SoCs , 2012, Proceedings of the IEEE 2012 Custom Integrated Circuits Conference.

[4]  R. M. Swanson,et al.  Ion-implanted complementary MOS transistors in low-voltage circuits , 1972 .

[5]  Nobuo Fujii,et al.  Tuning Analysis of a CMOS Current Controlled Ring Oscillator , 2006 .

[6]  Manoj Sachdev,et al.  A method to derive an equation for the oscillation frequency of a ring oscillator , 2003 .

[7]  J. Fellrath,et al.  CMOS analog integrated circuits based on weak inversion operations , 1977 .

[8]  David Blaauw,et al.  A 5.8nW, 45ppm/°C on-chip CMOS wake-up timer using a constant charge subtraction scheme , 2014, Proceedings of the IEEE 2014 Custom Integrated Circuits Conference.

[9]  Zeying Ren,et al.  A real-time 32.768-kHz clock oscillator using a 0.0154-mm2 micromechanical resonator frequency-setting element , 2012, 2012 IEEE International Frequency Control Symposium Proceedings.

[10]  Urs Denier,et al.  Analysis and Design of an Ultralow-Power CMOS Relaxation Oscillator , 2010, IEEE Transactions on Circuits and Systems I: Regular Papers.

[11]  Eric A. Vittoz,et al.  High-performance crystal oscillator circuits: theory and application , 1988 .

[12]  François Krummenacher,et al.  Silicon Resonator Based 3.2 $\mu$W Real Time Clock With $\pm$10 ppm Frequency Accuracy , 2010, IEEE Journal of Solid-State Circuits.

[13]  H.J. De Man,et al.  Adaptive biasing CMOS amplifiers , 1982, IEEE Journal of Solid-State Circuits.

[14]  Keng-Jan Hsiao,et al.  A 32.4 ppm/°C 3.2-1.6V self-chopped relaxation oscillator with adaptive supply generation , 2012, 2012 Symposium on VLSI Circuits (VLSIC).

[15]  G. Dundar,et al.  Modeling phase noise and jitter in subthreshold region and assessing the randomness performance of CMOS ring oscillators , 2012, 2012 International Conference on Synthesis, Modeling, Analysis and Simulation Methods and Applications to Circuit Design (SMACD).