Analog Devices Leverages Precise Current Profiling for Optimized IoT Devices

The Internet of Things (IoT) is revolutionizing healthcare, factories, cities, agriculture, infrastructure, and more. IoT devices use sensors to convert information such as temperature, humidity, acceleration, and light into electric signals that are sent to the cloud. In addition to the sensor, a typical IoT device consists of a microcontroller unit, power management integrated circuits, and RFICs, and operates on a small battery. Obtaining reliable high-performance IoT devices, while preserving battery life and avoiding defects, remains one of industry’s biggest challenge.

Analog Devices, Inc. (ADI), a global leader in analog and mixed signal devices used Keysight Technologies’ CX3300A Automatic Current Profiler to analyze its current profiles in a fraction of the time and optimize both the design and reliability of its IoT solutions.

IoT Device Design and Development Challenges

ADI faced two major challenges with its IoT design and development: how to achieve high-performance with low-power consumption, and how to adhere to strict design and validation requirements. The difficulty in achieving both low-power consumption and high performance is that they each come with trade-offs. Striking the optimal balance is critical.

Additionally, IoT solution companies such as ADI need to provide customers with reference designs that maximize IoT device performance. The challenge here is to evaluate and analyze dynamic operation of the entire system, including software, in a time efficient manner.

A Clear Process Forward

To overcome these challenges, ADI’s R&D engineers first had to focus on 4 key steps:

1. Sensor selection - It was important to select sensors that offered accuracy for ADI’s measurement target and were able to operate with low-power consumption in both active and sleep modes.

2. Optimize data processing - If all raw data generated by ADI’s IoT devices were sent to the cloud for analysis, the sheer volume of data would increase cost substantially. To find the optimal balance between data processing performance and power consumption, all data had to be processed and compressed prior to sending it to the cloud.

3. Appropriate wireless technology - ADI had to select wireless technology based on requirements such as data throughput, range of network, mesh or star networking, and power consumption.

4. Optimize power modes - To minimize power consumption, ADI needed to better manage and optimize the power modes in its IoT devices, such as stand-by in sleep mode and wake-up in active mode.

Next, ADI had to devise a plan to provide its customers with reference designs, but to do that it needed to evaluate and analyze the dynamic operation of its IoT devices, including software. Accomplishing this task requires the dynamic current characteristics of the power rails for each component and circuit to be precisely measured and analyzed. The resulting current profile shows the actual operation of a circuit and enables engineers to optimize performance and power consumption, and capture spikes, noise, and other unexpected signals that cause problems. Additionally, it validates software control of power modes and detects potential defects at an earlier stage.

A digital multimeter (DMM) or an oscilloscope with a current probe or shunt resistor are the most common ways to measure the current waveform. However, these instruments cannot precisely capture the waveform due to their limited bandwidth, dynamic range, and sensitivity. As a result, these tools cannot access sufficient information to describe the actual operation from a current waveform. With such limited information, validation and debug can take a long time.

Evaluate Dynamic Operation of the Entire System

To precisely measure and analyze the current profile of its IoT devices with a single instrument, ADI turned to Keysight’s CX3300 Series Device Current Waveform Analyzer. With up to 200-MHz bandwidth, wide current range from 150 pA to 100 A, wide 14 bit/16 bit dynamic range, and deep memory depth up to 256 Mpts/ ch, the CX3300 captures the detailed transition current (from sleep to active mode, fast inrush/spike, current, and low noise) that cannot be seen with a single measurement (Figure 1). Because the CX3300 quickly generates current profiles, it enables quick characterization, validation, and debug of IoT devices.

Utilizing the CX3300, ADI was able to quickly validate the power mode transitions in its reference boards. With just a single measurement, it precisely captured the transient characteristics during RF communication—from sleep current on the order of μA to active current of just mA. Additionally, ADI analyzed the current profile of its devices using Keysight’s embedded Automatic Current Profiler (Figure 2). It accomplished this task in just 1/10th of the time it normally takes with the conventional method.

Using the CX3300, ADI was also able to efficiently optimize its devices’ power consumption and validate software control. It even identified a defect in the power mode control much earlier in the R&D phase.

A Proven Powerful IoT Device Solution

With billions of IoT devices expected to come online in the near future, the device market represents a big opportunity for IoT manufacturers everywhere. Accordingly, IoT device manufacturers like ADI will increasingly look to optimize power consumption, shorten time-to-market, and improve device reliability.

Using the CX3300 and its sophisticated current profiling capabilities, ADI was able to greatly cut the analysis time of its IoT solutions and efficiently optimize them in just a fraction of the time.