Low power Sub-GHz RF transceiver suits secure IoT applications

The ZL70550 is well-suited for wireless applications operating on coin-cell batteries or energy harvesters, such as electronic shelf labels, retail asset tracking, process control, wearable monitoring, medical diagnostics and ECG.

With annual chipset volumes reaching 450m in 2015, the wireless sensor market is experiencing 'hypergrowth' according to On World Inc.’s recent market study. Although this market is dominated by WiFi, Bluetooth and Zigbee solutions, many applications require much lower power characteristics in order to operate for years on very small batteries.

“Many medical and industrial customers have applications where changing the battery is a complex and expensive operation that often exceeds the cost of the system itself,” said Francois Pelletier, Product Line Director, Microsemi. “By leveraging the same intellectual property we have successfully developed for implantable pacemakers and hearing aids where power consumption cannot be compromised, we are able to provide the lowest power wireless link in an extremely small form factor that is easy to deploy.”

Operating in the 779-965MHz unlicensed Industrial, Scientific and Medical (ISM) frequency bands, the ZL70550 consumes only 2.8mA while transmitting at -10dBm output power and a similar 2.5mA during reception. It offers the industry’s lowest sleep state current of 10nA, making it suitable for low-duty cycle applications. As a flexible solution that can be tailored to various application requirements, the ZL70550 operates between 1.7 to 3.6V and offers variable output power and data rates up to 200kbps. For applications that require extended wireless range, the transmitter output power, receiver input sensitivity and data rate can be adjusted to give a link budget up to -107dBm while minimally increasing the power consumption of the device.

“Working with the Microsemi team to implement its ZL70550 into our medical devices has been groundbreaking, as the product’s extremely low power, RF input sensitivity and small size provide the optimal solution for our specific needs,” said John Walmsley, vice president product development at Starfish Medical in Victoria, B.C. “We are leveraging the unique capabilities of this solution to ensure successful deployment of our latest innovations and we look forward to future advancements from Microsemi as Starfish Medical continues to create breakthrough products for a number of medical specialty areas.”

The ZL70550 is highly integrated and offered in a very small 3x2 mm chip scale package. Other than the antenna and, in some cases, its matching network, only a crystal, resistor and two coupling capacitors are required.

The device includes an advanced Media Access Controller (MAC) that performs most link support functions, Received Signal Strength Indications (RSSI), clear channel assessment, Sniff, preamble and synchronisation, packetisation, whitening and forward error correction (FEC). The Microsemi optional Z-Star protocol enables rapid product development and offers a full star configuration to allow a full network to be deployed.

Microsemi offers a Wireless Sensor Network (WSN) evaluation kit and an Application Development Kit (ADK) to ease and accelerate hardware and software development. The evaluation kit includes one USB hub and one accelerometer sensor node and demonstrates a wireless sensor network application using the ZL70550’s built-in Z-Star protocol. The ADK provides all the necessary hardware and software to demonstrate the performance of the ZL70550 and is intended to be used as a tool to support prototype development.