"RTC", short for Real Time Clock, is an electronic component used to measure time. The "RTC module" is a single packaged module that integrates RTC IC, oscillation circuit and master clock, without the need to design the oscillation circuit and adjust the frequency.

Are you struggling with below problems? Let's learn one by one.

1. Backup current consumption cannot meet specifications

In many ioT applications, there is a growing trend to reduce current consumption. In equipment such as smart utility meters, it is usually necessary to have the function of anti-demolition detection. However, if the microcontroller is operating for tamper detection every time, the system current consumption can be quite high. RTC is able to take over many house maintenance functions with lower power consumption.

2. When the backup battery is used, data retention of time information is too short

Maintaining accurate time information becomes especially important during power outages. Due to space and cost constraints, choosing a larger capacity battery may not always be feasible. At this time, the RTC module can effectively solve the problem that data retention of time information is too short under the backup battery.

3. The accuracy of the clock will deteriorate under extreme temperature conditions

Smart utility meters are increasingly requiring high-precision clocks, especially in scenarios where power companies are using time-base to charge customers. Because smart utility meters often operate in extreme weather conditions, and RTC modules need to maintain high clock accuracy over a wide temperature range. In industrial applications, RTC modules must own a high operating temperature to accommodate the potentially higher temperature inside the equipment.

With its high precision and low power consumption characteristics, the Epson RTC module, especially RX8901CE, has excellent performance in solving these three types of problems.

Main features of RX8901CE:

Back-up battery ensures a long operation

Low current consumption (240nA Typ.)

Time stamps of up to 3 sensors can be recorded

Time stamps can be recorded up to 32 times and up to 3 inputs can be supported.

Maintains high accuracy time information at high temperatures (up to 105° C).

With the D-TCXO function, it can operate with high precision over a wide temperature   range (-40 ~105 ° C).

Versatility - interface selection (I2C/SPI) and multiple other functions.

Supports I2C-bus or SPI-bus interface standards. Various configurations of multiple event pins, time stamps, and other features are also supported.

3 reasons for using RTC modules:

1. Reduce standby power consumption and lower system power consumption

The time stamp function stores time information when an event (signal) is detected. The RTC module enables the MCU to enter a low-power sleep state, thus reducing the power consumption of the entire system.

2. Power switch function for efficient use of backup power supply

The RTC module can detect the voltage drop of the main power supply and automatically switch to the backup power supply. Compared to diodes or circuits, MOS switches can suppress leakage current and voltage drops, enabling efficient power management of the entire system.

3. Provide high-precision time information when temperature changes

The RTC module is installed with DTCXO (Digital Temperature Compensated Xtal Oscillator) to enable it to provide high-precision time information of up to 105 ° C under a large temperature change.