New-Tech Europe Magazine | July 2016 | Digital edition

Fast, Accurate, Economical Testing of Low- Power Devices Will Be Crucial to the Growth of the Internet of Things

Robert Green, Keithley Instruments, a Tektronix Company

line cycles along with filtering can result in a measurement time well into the seconds and often tens of seconds. This extended measurement period runs in opposition to the need for high speed to increase throughput and reduce the cost of test for each part. In addition to making slow, sensitive measurements of the sleep or standby currents of IoT devices, the instrumentation must make very fast current measurements when an IoT device is active, such as when it is transmitting data. The challenge is to capture and measure a load current pulse that might last for only a few hundred microseconds. The instrumentation must respond quickly to make a measurement in this very short time interval. In this situation, the test system designer must trade

Characterizing the power consumption of these devices demands instrumentation capable of making both sensitive measurements and high speed measurement. For example, when characterizing load currents, the test system must be capable of measuring low currents, sometimes down to tens of microamps or less, when the device is in its sleep and standby modes. To produce stable and accurate measurements of these low-level currents, test systems are generally configured to make many measurements over a long measurement interval in order to average out electrical noise created in the device and noise from the external environment. Filtering can also be used to ensure quality measurements. However, a measurement period that extends over a number of AC power

It has been predicted that, within a decade, the Internet of Things (IoT) will grow to encompass billions or even trillions of wireless devices and sensors. However, that growth will depend to some degree on the ability of their manufacturers to drive down the cost of each of these devices. At the same time, however, these devices must be thoroughly characterized during their design and development, then tested quickly, accurately, and cost-effectively during production. To operate reliably for extended periods on a finite amount of battery power, these tiny wireless devices must consume power sparingly. This requires characterizing a device’s power consumption in all of its operating states so developers can understand where to focus their efforts.

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