Optimizing PCBs for better IoT design: Manufacturer’s guide

Article By : Suresh Patel, Mer-Mar Electronics

With a growing demand to access new internet technologies, IoT applications are now influencing PCB design, fabrication, and assembly process for optimization.

Internet of Things (IoT) is a network of smart objects that gather and share data in real-time, over the internet or any communication network. These smart devices include sensors to collect data and software, with associated technology to process the acquired data.

IoT applications cover a wide range from consumer electronics like smartphones, wearables up to Industrial IoT (IIoT) like manufacturing, Healthcare monitoring equipment, etc. The ability to connect smart sensors with traditional electronic equipment has opened up various opportunities in the fields of agriculture, biomedical, automobile industries. The connected sensors provide data and are controlled remotely. This improves the efficiency and yield of the IoT product to a great extent.

With a growing demand to access new internet technologies, IoT applications are now influencing the PCB design, PCB fabrication and manufacturing process for optimization.

It is important to understand the internal circuitry requirements for different form factors of IoT products. Flex PCBs and high-density Interconnect (HDI) PCBs are the best choices in these applications. They meet high-power requirements in compact board sizes along with constant device stress endurance.

We shall discuss some of the design requirements of an IoT PCB:

• Size is the critical requirement for any IoT product. Physical restrictions like flexibility and size have to be addressed during IoT PCB design.
• Since IoT products are always connected over a communication network, the associated battery design needs optimization in power consumption.
• The IoT devices exchange data over the internet seamlessly. This user information has to be protected and the design should meet the security requirements.
• As the dependency on IoT devices increase, the reliability standards also shoot up, to build and maintain the trust of the consumers. Hence exhaustive prototyping and simulations are required in IoT PCB design.

Considering the above unique design requirements, we shall list out the recommendations for an optimized IoT PCB Design:

1. The small size requirement has left no excess board space other than the calculated placement of components, tracks, and vias. The functionality of such a compact design is possible only by using Flex PCBs or HDI PCBs with features like dense wiring, small connection pads, and miniatured vias.
2. Right component selection is the key in an IoT PCB design. Since the application involves a lot of internet access for collecting and processing sensitive data, it is important to choose the correct RF components, Wireless modules, etc. The network range and speed of such components have to be evaluated during the component selection stage.
3. Power management is essential for the prolonged battery requirement in an IoT design. This calls for a strict power budgeting of each circuit block. In the case of wireless transceivers, it is noted to have considerable energy absorptions during transitions. The power requirements of the Integrated circuits (IC) in sleep mode also determine the battery life. So, prior testing of the power requirements is suggested in an IoT PCB design.
4. Security and Traceability are of prime importance in a design involving access to a shared network. The IoT design involves the detection and measurement of sensitive data. The software security has to be supported with necessary safety strategies during PCB design also. Certain low-cost microcontrollers are available with encryption algorithms that can be used for this purpose. Traceability can be improved using modern PCBs that support encoded identifiers at each physical layer, apart from the single barcode used as a standard procedure.
5. IoT products have varied requirements when it comes to product fitting. Ensure thorough prototyping for easy incorporation of your design in the intended IoT product form.
6. In IoT designs targeted for consumer wearables, it is suggested to simulate the design mechanics that might be affected by human contacts like body temperature, continuous movement, or dampness. It is necessary to analyze the thermal effects of such products and a sufficient cooling option has to be provided in the PCB design.
7. Choosing newer packaging technologies like multi-chip modules (MCM) or System-in-package (SiP) for IoT components is recommended for low-space and high-efficiency purposes.
8. Following certain layout practices can assist in optimizing an IoT PCB design like:

• • PCB stack-up design for efficient thermal performance
  • stitching vias to enable sufficient current return paths
  • appropriate grounding for safety
  • strategic antenna selection and placement for effective performance

Some exclusive features of Flex PCBs and HDI PCBs enable them to be the best fit for IoT applications. Flex PCBs allow components to fit in a small space reducing the product weight. Flex PCBs remove the need for mechanical connectors and this simple wiring circuit turns out to be a great advantage in IoT applications. HDI PCBs provide speed and reliability that are critical in IoT applications. They offer excellent wiring density and tiny trace width which makes them smaller in size and distinct in circuit routing. The combination of Flex PCBs and HDI PCBs shall bring out an exceptional IoT PCB design with good signal integrity and lesser thermal stress.

Many IoT applications work at very high frequencies and the massive growth of consumer IoT applications has choked the RF spectrum. This has led to unwanted interference and safety issues. Designing an IoT PCB for User Safety is very important. PCB designer has to include shielding for sensitive devices to reduce the EMI hazards. A good grounding scheme provides immunity against interference issues.

Based on the IoT applications, the PCB design guidelines have to be optimized to deliver a high-performance IoT product. We have discussed the design, layout, and safety requirements to build a successful IoT PCB. You can contact a PCB assembly provider to assist you in bringing out your next IoT product into the market.

About the Author

Suresh Patel has worked as a Sales Engineer and other management roles at Mer-Mar Electronics. He brings 25 years of experience in printed-circuit-board sales and technical client service and managing business. You can connect with him on Twitter.

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