IoT sensors timing solutions with Micro Crystal Real-Time Clock Modules

IoT sensors timing solutions with Micro Crystal Real-Time Clock Modules

By Andre Rousselot

Nowadays, smart factories, smart cities, smart buildings and connected individuals are using arrays of smart sensors to collect data for insights and decision-making.

In general, those ubiquitous smart sensors have three major components: a sensor that captures data from an environment; a microprocessor, which computes on the output of the sensor; and communications capabilities that enable the sensor to communicate the microprocessor’s output for action. Usually, an included wireless communication feature allows data collection through a global network – commonly the internet – defining connected smart sensors as IoT.

In our connected world, the importance of having a permanent link to the internet network can be seen as an obvious absolute requirement for IoT applications. While the first word of the acronym IoT is “Internet”, not all IoT devices need to be connected to the Internet, or — at least, not always.

Typically, an array of devices in a home or factory area will communicate via a non-IP bus such as ZigBee to a router – and the router alone will maintain the edge’s presence on the internet, allowing communication with the system’s remote cloud server. Small sensors benefit from eliminating the overhead of a high-performance IP-based network.

Key requirements for IoT devices are quick to fit, with no cabling required, offering an easy-to-install and low maintenance solution. Users today are looking at size and battery life as a key differentiator in IoT devices. A product that is small and lasts longer between charges is more desirable and likely to succeed in an ever-competitive marketplace.

Beside battery technology choice, using power management circuit (PMC) is key to ensure that product designer can chose between smaller battery and extended battery-life. Real-Time Clock Module (RTC) acts as a PMC. It has the ability to wake-up microprocessor to perform periodic sensor measurement and to power down the microcontroller when no task is required, resulting in significant power savings.

Ultra-low quiescent current in the order of tens of nanoamps achieved by today’s RTC modules allows a significantly extended battery life. Accurate timekeeping function guaranty scheduled operation over time with no need for frequent synchronization and connection to the server. Timers, alarms and external event detection can be active in the application while microcontroller is maintained in power saving mode.

With best accuracy of all temperature compensated RTC at ±2.5 ppm (± 0.22s/day) over the industrial temperature range; the new RV-3032-C7 has also an ultra-low current consumption of 160nA. The embedded accurate high-resolution temperature sensor, combined with programmable temperature window detection interrupt, enables also times stamp for temperature alarm event.

As most battery-operated devices have to be very small for portability, RTC modules from Micro Crystal are assembled in small size DFN package of only 3.2 x 1.5 x 0.8 mm. In the self-contained solutions, integrating the crystal resonator and the RTC circuit, the protection against pressure change, humidity or external chemical contamination, which might affect oscillator stability, is ensured through a perfect sealing under vacuum of the ceramic package with a metal lid.

The factory high time accuracy, as low as half a minute deviation per year, eliminates any need for oscillator design and adjustment phase, clock calibration during manufacturing and avoids frequent time adjustment over years of operation, reducing errors and maintenance costs.

Selecting and using a ready-to-go RTC module solution in your design reduce engineering effort and risk in building your next product.

With its Real-Time Clock Module product line, Micro Crystal masters the Art of Timing to meet extreme requirements in terms of size, power consumption, and performance; helping engineers in developing next generations of IoT and other smart products. Developers can now take products down to some of the smallest sizes imaginable. Wireless long-life battery powered devices can be used in places that were not previously possible.

To find more detailed information and to learn more about how Micro Crystal has the solution for you, please visit


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