Dr Harry Zervos recently interviewed Mr Mauricio Peres, product marketing director with Microsemi, an $840 Million company specializing in high performance, high quality analog devices, ICs, all the way to complete subsystems for a variety of industry sectors.
Quick overview of Zarlink-Microsemi
Through the acquisition of Zarlink Semiconductor, Microsemi expanded its activities into implant grade (400MHz) and wearable (ISM band 779-965MHZ covering most countries) ultra low-power radios. "The medical products group (MPG) was a growing segment of Zarlink's revenue." Mr Peres says. "Due to high industry interest level in ultra low power radios, Microsemi kept the group intact". And he continues: "In the summer prior to its acquisition, Zarlink was expanding to applications outside of medical. So now the same products for ISM band are being promoted into other vertical markets too, such as commercial/industrial wireless sensors that require ultra low-power".
Products - ZL 70250
Power consumption of Microsemi radios is very low, due to requirements from past customers that really needed compact size and low power, which translates to market interest from companies in various segments. "Putting some numbers into it, you have a 2mmx3mm radio chip, that is very thin- around 250micron thickness. With an added 120microns you now have chip scale packaging option too. This allows most of our customers to use common, regular, manufacturing flow".
ZL 70250, the lowest power radio transceiver according to customer testimonials, consumes 2mW to transmit a packet in a few milliseconds. Once the CPU initializes the radio, the CPU can duty cycle it at a required frequency bringing the average power consumption in the 100's of μA, depending on the size of the data packet being sent, frequency, etc.
"That is up to 5 times lower power consumption than what other companies have available out there so far".
The device works with a variety of off-the shelf CPUs. Voltage supply varies from 1.2 to 1.8V which can be very beneficial when you have a harvester that gives tiny currents to a boost converter and some form of energy storage (e.g. a capacitor). "There's an added benefit in reducing power consumption when you can bring CPU voltage and radio voltage at the same level , which has been acknowledged by different Microsemi customers".
Integration - applications
Microsemi has been quite active in supporting our customers to understand ways to integrate multiple components in energy harvesting based sensors. Working with Perpetua Power for example, they developed a wearable thermoelectric generator complete with a current booster and radio connectivity. Just by strapping the device around someone's arm, one could go up to a 15-meter distance and still transmit data packets via the radio.
Other applications include integrating ultra slim radio from MIcrosemi in PV cell based harvesting sensors with the complete device being the size of a credit card: Embedded in it you have CPUs, sensors of different types, the radio or even an LCD display. "The thin form factor makes all these components easily embeddable with applications envisaged in security badges, tracking temperature or other parameters in any asset, etc" says Mauricio.
Market growth
Discussing the potential for the market to grow, Mauricio mentioned: "Large market growth is something that is expected. Customers are waiting for devices to get to the right price points to deploy WSNs (Wireless Sensor Networks)". The transducer, thin film battery storage, sensor, power management, CPU and radio make up multiple nodes and added to them is one base station. "The real volume is in the nodes. Their cost is critical. Medical, industrial, commercial (water, gas metering, oil flow, pressure metering) are getting close to the right price point, consumer applications (laptops, computers) are still 2-3 years away".
That difference is due to the fact that the medical, industrial and some commercial applications have a more immediate benefit in energy harvesting sensor deployment, increasing the end user motivation to pay a premium as they have a more immediate ROI (as a minimum, they are able to pay 3 times more than what consumer apps would pay for)."In these sectors a cost of $10-20 for the sensors can be tolerated due to the benefits. In consumer applications, harvesters should be at a level of just a few cents".
For Microsemi in specific, the energy harvesting/WSN volumes are still relatively low. By the end of 2013, the company expects to have a good market share of the multi-million unit solar & ambient - light energy driven credit card-sized market. As an example, we see great potential in Cold Chain Tracking for cold storage of medical products.
Currently the medical radio part of Microsemi is already shipping 1,000,000 radios per year in non EH related apps to customers using various types of batteries. Volume scale up to much higher capacities of up to 2-3, 5 Million is easily achievable by sharing common infrastructure and manufacturing equipment within Microsemi.
Are there any obstacles for commercialization? Asks Dr Zervos and Mauricio responds: "Cost has been the biggest barrier. The technology is there. With costs going down too, there's going to be few limitations as performance has also improved. But a potential issue is interoperability of communication protocols. Standards committees must be able to address that. Of course, more interoperability means more lines of code which translates to bigger power consumption"
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"That's of course a drawback" says Mauricio and he continues: "We need minimization of data packets. That's one of the success factors of the EnOcean alliance, using their own protocol with low power consumption. What's important is to continue looking to improve what is out there and make sure new technologies are added in order to make the alliance stronger and give more option to customers".
For more information on Microsemi/Zarlink products, please visit www.zarlink.com 
