Everything You Need to Know About Real Time Clocks

Learn More About RTCs and How They Are Used

To understand what a real time clock (RTC) is and how it functions, it is important to begin with frequency. When a resonating surface, such as quartz crystal, is agitated mechanically (as in oscillation) frequency is created.

When designed correctly, a quartz crystal oscillator can generate a frequency of 32.768 kHz. This frequency is ideal because – with the help of quality engineering – it allows for a precise, one-second-long pulse. Therefore, a crystal oscillator can create a reliable clock when designed correctly. This engineering configuration is used most famously, of course, in the quartz watch.

However, a significant use of the 32.768 kHz frequency for a broad number of applications is the real time clock. A real time clock is essentially a component used in an electronic device that faithfully accounts for “real time” even when the device is off or in a low-power mode.

Why Are RTCs Important for Electronic Components?

A real time clock operates much like the brain at night – it stays awake even when you’re at rest. When you’re sleeping, you may not be aware of your surroundings, but your mind is still assessing your environment and performing vital functions. Your mind can tell your body to wake up when it needs to. A real time clock functions similarly.

An RTC accurately tracks time inside an electronic device, even if the device is shut down, loses power, or has an energy-saving “sleep mode” function. The most familiar application of an RTC is how time is kept on a wearable, such as a fitness tracker. These products will eventually go into low-power mode because they have a limited battery life.

However, a low battery should not prevent a fitness tracker from providing accurate time for the user. A real time clock, in this case, provides a timing solution while consuming a minimal amount of energy, so that there is no interruption in one of the product’s key features, even if the wearable has not been charged for an extended period of time.

Since so many products are built with batteries so that they can operate away from a power source and provide the benefits of remote use (after all, a fitness tracker wouldn’t be useful at all if it was plugged into a wall) RTCs provide significant value as electronic components in many battery-powered devices.

What Other Key Functions Do RTCs Provide?

Real time clocks do more than keep time in the background. A second analogy for this timing solution comes from football. On the football field, the quarterback calls the plays and – on his signal – the players spring into action.

Similarly, a real time clock can activate important device functions from power-saving or sleep mode. Consider an office printer or copier that by all appearances is in a cool-down mode when not in use. However, once a signal is sent from a remote device, the office printer starts back up and can even log the precise time that a document was printed. In devices that are deployed in places where they can’t be charged, integrating a timing solution among other electronic components is an essential tool.

What Applications Use RTCs as a Timing Solution?

A vast number of industries benefit from real time clocks. The products that use RTCs are wide-ranging, and, in some cases, these timing solutions are modified for different environments. Considering our examples above, the RTC used in a wearable – which is a battery-powered device – is different from one that is used in a printer, which has a continuous power supply.

Applications for RTCs include:

• GPS
• Building Management Systems (BMS)
• Weather stations
• Printers and copiers
• IoT devices
• Wearable devices
• Medical products
• Automotive electronics, including infotainment technology

Where Can You Learn More About RTCs?

For further information on real time clocks, access the following resources, which provide additional insights on how RTCs are used in many applications, as well as information on how to select the timing solution that will be most effective for your frequency-based use-case.

• “What Is a Real Time Clock (RTC)?”
  This white paper defines real time clocks from an in-depth engineering perspective.
• “Considerations for Choosing the Right Real Time Clock”
  This article guides engineers in the design community through various kinds of real time clocks that provide specific support for certain applications, including GPS, building management systems, remotely deployed devices and more.
• “What You Should Know About Frequency Control Products, Including Real Time Clocks, in Wearable Devices
  A comprehensive analysis of real time clocks and other crystal-based products in wearable devices.

In addition, engineers are encouraged to contact their preferred manufacturer of electronic components for a full list of available RTCs on the market today, as well as for engineering support throughout the design process.