ISSCC Emerging Wireless and Memory Technology
February 19, 2013, ISSCC, San Francisco—Session 11 was a catchall of various technologies that focused on energy efficiency. The integration of non-volatile memory with logic for data retention from TI and Mit, integration of a timing micro-system including crystal oscillators from CSEM in Switzerland, and integration of NEMS resonators from Aalto University in Finland are some of the novelties presented.
A vertical directional coupler from Keio University in Japan address the need for inter-PCB connections that can handle high data rates without burning a lot of power. This non-contact coupler is built into the facing boards and is capable of data rates up to 4.6 Gb/s on a balanced signal. The nominal signaling distance is 75 microns. The energy per bit is about 1.5 pJ/b andis fairly constant over data rates from 0.6 to 2.4 Gb/s.
Similar work from KAS in Korea achieved a 1 Gb/s data rate over a 1 mm distance at 3.9 pJ/b for the transceiver and 0.39 pJ/b for the clock recovery function. This design also uses balanced pulses to minimize DC offsets and EMI. The variable pulse transmission achieves a BER of 10 -11 at 1.2 Gb/s. the whole chip consumes 6.4 mW at 1.2 V
A wireless, self-powered sensor interface allows rotating shafts to transmit data to instrumentation in a design from Keio. The interface uses a 2-D waveguide sheet that is formed around the shaft to supply power and interrogate the sensors. Power is on the 2.4 GHz band and sensors are measured at 1.2 GHz. A reference oscillator on the sheet is used to calibrate the transducers for maximum power transfer and signal capture.
Wearable sensor arrays come from MIT and Masdar Institute of Technology in UAE. Groups of parallel inductors form sub-networks of sensors and power transfer nodes. Each sub-network has its own analog interface which handles power and data transfer. Power is transmitted at 27.12 MHz.
The sensors need a custom MAC to handle the automatic network configuration, and the end points can be fixed TDMA timeslots or a ACK scheme for slower data. The base station consumes 2.9 mW while powering and communicating with the sub-nets at a 2 cm link. The sensor interface circuits consume about 14 ?W, leaving 20 ?W available for the actual sensors.
