At this week’s International Solid State Circuit Conference, IMEC and Holst Centre report a 2.4 GHz/915 MHz wake-up receiver which consumes only 51 µW power. This record low power achievement opens the door to battery-less or energy-harvesting based radios for a wide range of applications including long-range RFID and wireless sensor nodes for logistics, smart buildings, healthcare etc.
Today’s battery-operated wireless communication systems consume a lot of power at times when the radio does not have to transmit or receive data. This means that most of their time Bluetooth or WLAN radios on mobile phones are taking energy from the battery without adding functionality. Imec and Holst Centre’s wake-up receiver with ultra-low power consumption and fast response time can be put in parallel with the conventional radio to switch it on when data needs to received or transmitted.
Test board of IMEC and Holst Centre’s wake up receiver.
IMEC, a semiconductor maker based in Leuven, Belgium, and Holst Centre, an independent R&D center located on the High Tech Campus Eindhoven, developed an innovative radio architecture based on double sampling to overcome the 1/f noise problem. This noise affects most low data rate (10-100 kbps) radios. As a consequence, these radios traditionally have a higher power budget than higher data rate radios achieving the same performance. By using a double-sampling technique the offset and 1/f noise is reduced and consequently the sensitivity of the receiver improves proportionally as data-rate scales.
The wake-up receiver chip was implemented in a 90nm digital CMOS technology and occupies an area of 0.36 mm2. Measurements on silicon show a sensitivity of -75 dBm (SNR>12 dB) for the 915 MHz receiver at 100 kbps OOK (on off keying) modulation. When scaling the data rate to 10kbps and filtering the out-of-band noise, the sensitivity is improved by 5 dB. For the 2.4 GHz receiver, the sensitivity is -64 dBm and -69 dBm for 100 kbps and 10 kbps data rate respectively.
“Within our wireless autonomous sensor system research, we aim to develop wireless sensor systems powered by energy harvested from the environment instead of using batteries. The power budget of such systems is only 100 µW for the DSP, radio and sensor. This ultra-low power radio of only 51 µW with small form factor is a major step forward to achieve our goal. It opens the door to many new battery-less applications such as long-range RFID, smart lighting, and sensor tags.” said Bert Gyselinckx, general manager, IMEC at the Netherlands at Holst Centre.
Original release
Title of original paper: 11.5: A 2.4GHz/915MHz 51μW Wake-Up Receiver with Offset and Noise Suppression.
International Solid State Circuit Conference
