A 65-nm CMOS Temperature-Compensated Mobility-Based Frequency reference for wireless sensor networks

For the first time, a temperature-compensated CMOS frequency reference based on the electron mobility in a MOS transistor is presented. Over the temperature range from -55°C to 125 °C, its frequency spread is less than ±0.5% after a two-point trim and less than ±2.7% after a one-point trim. These results make it suitable for use in Wireless Sensor Network nodes. Fabricated in a baseline 65-nm CMOS process, the 150 kHz frequency reference occupies 0.2 mm2 and draws 42.6 μA from a 1.2-V supply at room temperature.\ud \u

A 1.2-V 10- µW NPN-Based Temperature Sensor in 65-nm CMOS With an Inaccuracy of 0.2 °C (3σ) From 70 °C to 125 °C

An NPN-based temperature sensor with digital output transistors has been realized in a 65-nm CMOS process. It achieves a batch-calibrated inaccuracy of ±0.5 ◦C (3¾) and a trimmed inaccuracy of ±0.2 ◦C (3¾) over the temperature range from −70 ◦C to 125 ◦C. This performance is obtained by the use of NPN transistors as sensing elements, the use of dynamic techniques, i.e. correlated double sampling and dynamic element matching, and a single room-temperature trim. The sensor draws 8.3 μA from a 1.2-V supply and occupies an area of 0.1 mm2

A Low-Voltage Mobility-Based Frequency Reference for Crystal-Less ULP Radios

The design of a 100 kHz frequency reference based on the electron mobility in a MOS transistor is presented. The proposed low-voltage low-power circuit requires no off-chip components, making it suitable for application in wireless sensor networks (WSN). After a single-point calibration, the spread of its output frequency is less than 1.1% (3 ) over the temperature range from -22 C to 85 C. Fabricated in a baseline 65 nm CMOS technology, the frequency reference circuit occupies 0.11 mm

High-resolution Wideband continuous-time Σ Δ modulators

The signal bandwidth of delta-sigma analog-to-digital converters has been greatly extended during the last few decades from a few tens of kHz bandwidth for audio to several hundred MHz to date for wireless applications. To enable a wideband and filterless RF radio front-end, high dynamic range and very high linearity of the wideband delta-sigma modulator is required as well. In this chapter the design aspects of high-resolution and wideband continuous-time delta-sigma modulators are presented, from architectural choices to implementation and circuit design examples

High speed and wide bandwidth delta-sigma ADCs

This book describes techniques for realizing wide bandwidth (125MHz) over-sampled analog-to-digital converters (ADCs) in nanometer-CMOS processes.  The authors offer a clear and complete picture of system level challenges and practical design solutions in high-speed Delta-Sigma modulators.  Readers will be enabled to implement ADCs as continuous-time delta-sigma (CT∆Σ) modulators, offering simple resistive inputs, which do not require the use of power-hungry input buffers, as well as offering inherent anti-aliasing, which simplifies system integration. The authors focus on the design of high speed and wide-bandwidth ΔΣMs that make a step in bandwidth range which was previously only possible with Nyquist converters. More specifically, this book describes the stability, power efficiency, and linearity limits of ΔΣMs, aiming at a GHz sampling frequency.   • Provides overview of trends in Wide Bandwidth and High Dynamic Range analog-to-digital converters (ADCs); • Enables the design of a wide bandwidth, high dynamic range modulator with state-of-the-art power efficiency; • Includes introduction to Continuous-Time Delta-Sigma Modulators and its system level modeling; • Explains issues relating to stability of Continuous-Time Delta-Sigma Modulators; • Includes discussion of system level non-idealities in Continuous-Time Delta-Sigma Modulators; • System level design of  CT∆Σ modulators at GHz sampling frequencies; • Practical implementation details of high speed CT∆Σ ADCs; • Overview of static and dynamic error correction techniques in ∆Σ ADCs; • Dynamic error correction techniques that are suitable for high speed CT∆Σ ADCs

Mobility-based Time References for Wireless Sensor Networks

 This book describes the use of low-power low-cost and extremely small radios to provide essential time reference for wireless sensor networks.  The authors explain how to integrate such radios in a standard CMOS process to reduce both cost and size, while focusing on the challenge of designing a fully integrated time reference for such radios. To enable the integration of the time reference, system techniques are proposed and analyzed, several kinds of integrated time references are reviewed, and mobility-based references are identified as viable candidates to provide the required accuracy at low-power consumption. Practical implementations of a mobility-based oscillator and a temperature sensor are also presented, which demonstrate the required accuracy over a wide temperature range, while drawing 51-uW from a 1.2-V supply in a 65-nm CMOS process. Provides system analysis to understand requirements for time/frequency accuracy in wireless sensor networks; Describes system optimization for time references in wireless sensor networks, with ad-hoc modulation schemes and system duty-cycle techniques; Includes an overview of different physical principles for integrated time references; Shows a practical alternative for integrated time-references; Details a competitive solution for temperature compensation of integrated references

Method and system for impulse radio wakeup

Communication networks are implemented using a variety of devices and methods. In a particular embodiment for use in a communication network having RF-communication devices that communicate using a RF protocol, an RF-communication device is implemented with an RF transceiver (110) to communicate over the network using the RF protocol and being controllable in a reduced power-consumption mode in which the RF transceiver does not communicate over the network. The device also includes an RF receiver (104, 106) including an envelope detector (104) and a pulse generator circuit (106).; The envelope detector circuit (104) providing an envelope-based signal to a pulse generator circuit (106) that, in response to the envelope-based signal and after generating a number of pulses that exceeds a predetermined number of pulses, prompts the RF transceiver (110) to transition out of the reduced power-consumption mode