Designing a Low-Power IoT Device: What to Look for in a Wireless SoC

Battery life is one of the biggest challenges when designing connected IoT devices. Sensors, asset trackers, smart-home devices, remote controls, wearables, and other wireless products may need to operate for months or even years without frequent battery replacement.

Choosing the right wireless System-on-Chip (SoC) can have a significant impact on achieving that goal.

However, selecting a low-power wireless SoC involves more than checking a single current-consumption value in a datasheet. Developers need to understand how the processor, radio, memory, peripherals, firmware, and application work together.

Here are the main areas developers should consider when designing a low-power connected device.

Start With the Device's Operating Cycle

Before selecting hardware, understand how the product will operate.

Consider a wireless temperature sensor. It might spend most of its time sleeping, wake periodically to collect a measurement, process the data, transmit it, and then return to sleep.

An interactive device such as a wireless mouse behaves differently because it may need to respond immediately to user input.

These differences matter because average power consumption depends heavily on how frequently the device wakes and how long it remains active.

Developers should therefore estimate the product's duty cycle before comparing wireless SoCs.

Evaluate Active and Sleep Power

Active current is important, but it tells only part of the story.

For many battery-powered IoT devices, the processor and radio remain inactive for much longer than they remain active. In these applications, sleep current can significantly influence total battery life.

A useful evaluation should consider processor activity, radio transmission and reception, standby modes, deep-sleep behavior, wake-up time, and peripheral power consumption.

The lowest active-current device is not automatically the best choice if another device provides more efficient sleep behavior for the actual application.

Choose the Right Wireless Technology

Different wireless technologies have different power and performance characteristics.

Bluetooth Low Energy is commonly used in battery-powered products because it supports efficient short-range communication and can interact directly with smartphones and other Bluetooth-enabled devices.

Wi-Fi can provide higher throughput and direct network connectivity, but its power profile must be carefully evaluated for battery-operated applications.

Smart-home products may require technologies such as Matter, Thread, or Zigbee. Other applications might use proprietary 2.4 GHz communication, UWB, or GNSS.

The best technology depends on communication range, data throughput, latency, interoperability, network architecture, and power requirements.

Processor Efficiency Matters

Developers sometimes assume that a slower processor automatically consumes less energy.

In practice, efficiency is more complicated.

A higher-performance processor may complete a task faster and return to sleep sooner, while a lower-performance processor may remain active longer.

The important measurement is therefore not simply clock frequency or active current. Developers should consider the energy required to complete the application's typical workloads.

Processor architecture, hardware accelerators, clock management, and firmware efficiency can all affect the final result.

Check Flash and SRAM Requirements

Memory should also be considered early in the design.

Wireless protocol stacks, application firmware, security functionality, sensor processing, device configuration, and over-the-air updates all require memory.

Selecting an SoC with too little Flash or SRAM can create problems later in development.

At the same time, choosing significantly more resources than the application requires may increase cost or complexity.

Developers should estimate current memory requirements while leaving reasonable space for future firmware growth.

Pay Attention to Peripheral Interfaces

IoT devices rarely operate independently of external components.

A wireless SoC may need to communicate with temperature sensors, accelerometers, displays, external Flash, LEDs, buttons, microphones, or other devices.

Interfaces such as SPI, I²C, UART, GPIO, ADC, PWM, USB, and I²S can therefore influence SoC selection.

Developers should also consider whether peripherals can be disabled or placed into low-power states when they are not required.

An external sensor consuming power continuously can reduce battery life even when the wireless SoC itself is highly optimized.

Optimize Radio Activity

Wireless transmission is often one of the more energy-intensive operations in a connected device.

Reducing unnecessary communication can therefore improve efficiency.

Instead of transmitting every measurement immediately, some applications can collect multiple readings and send them together. Developers can also optimize advertising intervals, connection parameters, transmit power, and communication frequency according to application requirements.

The objective is not simply to minimize radio usage. It is to use the radio efficiently while maintaining the required responsiveness and reliability.

Don't Ignore Development Support

Power optimization requires both suitable hardware and effective software.

A good wireless development platform should provide an SDK, example applications, debugging tools, reference designs, documentation, evaluation hardware, and support for relevant wireless protocols.

Reference designs can be particularly valuable because RF layout, antenna implementation, component selection, and power architecture all influence real-world performance.

T2M SEMI provides wireless SoC solutions covering technologies including Bluetooth LE, Wi-Fi, Matter, Thread, Zigbee, UWB, GNSS, and multi-protocol connectivity for a range of connected-device applications.

Final Thoughts

Building a low-power IoT product requires system-level optimization.

Processor efficiency, sleep behavior, wireless technology, radio activity, memory, peripherals, firmware architecture, and RF design all contribute to total energy consumption.

The best wireless SoC is therefore not necessarily the device with the lowest number on a datasheet. It is the platform that best matches how the product actually operates.

By understanding the complete operating cycle before selecting hardware, developers can make better design decisions and build connected products that balance battery life, wireless performance, functionality, and user experience.