Manuel Carmona, quality director, Johanson Technology
The design goal for the next generation of low-cost, battery operated, wireless internet-of-things (IoT) products is to provide exceptional radiofrequency (RF) signal range and stability, while also reducing power consumption, in a miniaturised package. As a result, manufacturers of RF chipsets and components are increasingly fine-tuning and improving their products to do just that.
According to Semtech’s website, its LoRa (long range) wireless RF technology is “the de facto technology for IoT networks”. Together, the company’s LoRa devices and LoRaWAN (wide area networking) protocol have several hundred known use cases for smart cities, smart homes and buildings, smart agriculture, smart metering, smart supply chain and logistics, and more. To accomplish the printed circuit board (PCB) effective-area reduction task, chipset manufacturers such as Semtech create technical blueprints of a system, known as reference designs, that third parties can adapt and modify as required for their products’ applications. The reference design serves as proof of the platform concept and is usually targeted for specific uses. Johanson Technology provides front-end solutions that reduce risk in the OEM’s integration project and therefore allow products to be fast-tracked to market.
The starting point is the chipset, but the chipset requires specific RF circuitry to connect to the antenna. In the case of Semtech’s LoRa chipsets, integrating all the RF components into a much smaller, low-profile package known as an integrated passive device (IPD) increases their attractiveness for miniaturised, battery powered IoT products. It means that OEMs do not have to design the entire capacitor/inductor scheme and mount many separate components onto the PCB. They simply use the IPD in place of the traditional discrete capacitor and inductor components. An IPD makes the final PCB size smaller and simpler. Moreover, it prevents changes in the geometry of the layout that can affect the output performance, battery life and signal range.
The RF circuitry required in LoRa chipsets is used to convert the signal from differential to single-ended in a specific impedance ratio using an impedance matching network and a balun. Most chipsets require this type of conversion due to the differential, two-pin input/output configuration to connect with the single-ended antenna. The output straight out of a chipset is usually not matched to 50 ohms, which requires an impedance matching network that is designed to avoid loss of power signal, reduced battery life and decreased signal range. To meet this requirement, Johanson Technology collaborated with Semtech to develop an IPD that serves as an impedance-matched-balun-filter.
IPDs are manufactured using low-temperature cofired ceramic (LTCC) technology, which allows the passive components to be layered three-dimensionally and deliver the same functionality as 10–40 individual RF components. This means that the entire front-end between the chipset and the antenna is produced as a single, ultra-low-profile package that is less than 40 percent of the total size of the same circuit comprised of discrete components.
Johanson Technology’s impedance-matched-balun-filter IPD combines an impedance matching network, a balun and a filter, and the entire front-end RF circuitry is reduced to a single, EIA 0805 (2.0 x 1.25 mm) surface-mount technology (SMT) component. It pairs seamlessly with Semtech’s LoRa smart home RF transceivers—namely SX1261, SX1262 and LLCC68—operating within the licence-free 868 MHz RF band used in Europe and the 915 MHz band for Australia and the Americas.
The IPD is a plug-and-play solution for OEMs utilising the Semtech LoRa chipsets. Johanson Technology works with chipset manufacturers, completing all the R&D to ensure that the IPD is optimised for a specific chipset and meets Federal Communications Commission (FCC) and European Telecommunications Standards Institute (ETSI) regulatory emission requirements.
Another significant benefit afforded by IPDs is increased reliability. By creating a literal circuit within a small LTCC package, variability and potential points of failure are all but eliminated when compared with mounting many discrete components.
Johanson Technology must guarantee that the performance of this much smaller solution is equal or better than the larger discrete solution. Therefore, each integrated package is thoroughly RF tested to ensure all the components are integrated together and working properly.
Johanson Technology’s background in material development has been key to being able to create the entire circuit in such a small package. The product utilises a proprietary ceramic material in an LTCC manufacturing process that is designed to improve its performance to high Q-factor levels. Johanson Technology is constantly developing new ceramic materials that will better integrate circuits, reduce power consumption and eliminate power loss.
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Don Komarechka
The Johanson integrated passive device (IPD) plug-and-play solution for OEMs utilising the Semtech LoRa chipsets. It combines an impedance matching network, balun and filter, thus reducing the entire front-end radio frequency (RF) circuitry to a single EIA 0805 surface-mount technology (SMT) component.
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Don Komarechka
The Johanson integrated passive device (IPD) plug-and-play solution for OEMs utilising the Semtech LoRa chipsets. It combines an impedance matching network, balun and filter, thus reducing the entire front-end radio frequency (RF) circuitry to a single EIA 0805 surface-mount technology (SMT) component.
The process for manufacturing IPDs is similar to that already used to create multi-layer SMD component parts, such as capacitors and inductors. However, LTCC technology allows the circuits to be embedded in as many as 40 separate layers in a 3D package that is still very low profile.
Since IPDs require much less PCB space, IoT devices with RF circuitry can be designed in much smaller form factors. The size and placement of passive components are critical because as everything gets smaller, it becomes increasingly difficult to fit more components on the board. Design engineers are therefore looking to component manufacturers to deliver miniaturised solutions that occupy next to no real board space.
A smaller PCB not only allows for increased functionality of the product but improves its appearance, allowing for slim, low profiles. Moreover, the elimination of components on a 10:1 or greater basis reduces the overall weight of the product, which is significant even if it is only tenths of grams.
Johanson Technology