The importance of rtc real time clock with high precision crystal oscillator
Function of rtc real time clock:
① High-precision RTC is essential for countless applications (such as personal computers, spreadsheets,
portable cameras and vehicles). If there is no rtc real time clock, you need to set the time and date each time when you turn on the device.
② Nowadays electronic devices can access the Internet or GPS.When you connect the device,
you can easily get the most accurate time.Therefore, network servers need high-precision rtc real time clock to provide time calibration for these terminals.
More and more rtc real time clock are actually being used in many automation and Internet of Things applications.
Many remote Internet of Things sensors(such as weather stations) are powered by batteries and measure or complete tasks according to a preset schedule.
These devices cannot continuously enable the wireless transceiver because it will run out of power soon.
In most cases, these battery-powered devices (including micro-controller) operate in deep sleep mode to minimize wastage during task-free execution.
These applications benefit from very low-power rtc real time clock, which can wake up the system from time to time to perform assigned tasks.
Micro-controllers usually have built-in rtc real time clock. In addition to Internet of things applications, many medical devices also need nano power level rtc real time clock.
For example, Wearable ECG devices, hearing aids and medical labels. Most battery powered devices are designed to be very small and easy to carry or install.
Since the independent rtc real time clock is external to the micro-controller, a low-power rtc real time clock with a smaller package is preferred.
In addition to low power consumption and small package size, some applications also require high timing accuracy in a wide temperature range.
For example, this is an important consideration for field installed sensors. In this sensor, the temperature may fluctuate greatly during the day.
For these applications, the better choice is rtc real time clock wide temperature crystal oscillator, 32.768 kHz crystal oscillator,
and the operating temperature range is: - 40 ℃ to + 105 ℃. The most commonly used rtc real time clock is a 32.768 kHz crystal oscillator,
and 32768 is a power function of 2. When the signal is connected to a 15 stage trigger, the output is an accurate 1Hz signal.
The RTC uses this 1 Hz signal to drive the timing logic.Assuming that the ambient temperature is constant throughout the year at 25 ° C and ± 20ppm RTC,
the maximum annual error is calculated as follows:
PS: If the temperature varies, the cumulative error of 32.768 KHz crystal oscillator may increase.
In addition, the crystal oscillator is also affected by "aging" and matching of "external capacitance".