RX4901CE comes with SPI interface, suitable for use in devices that require high precision and fast response

Apr 11,2024
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The traditional simulation temperature compensation crystal oscillator uses thermistors and other components to detect environmental temperature, and the temperature information is transformed accordingly to control the output frequency of the crystal oscillator to achieve stable output. However, this method has limited accuracy in frequency compensation. With the increasing frequency of circuit calculations and the emergence of more industrial grade applications with high time accuracy and fast time response, the original analog temperature compensation crystal oscillator cannot meet the requirements. Real time clock modules for digital temperature compensation have emerged. By detecting temperature, simulating changes, AD conversion, converting analog signals to digital signals, adjusting frequency output, higher precision frequency compensation can be achieved.

Recently, EPSON has launched a digital temperature compensation real-time clock RX4901CE with SPI interface. This clock module comes with SPI interface and can work stably in temperature environments ranging from -40 ℃ to+105 ℃. When used in conjunction with computing chips, it can achieve high time accuracy and fast time response applications.

Figure 1 Internal structure diagram of RX4901CE

Supporting SPI digital interface, high communication speed, more suitable for high-precision and fast response clock applications

The RX4901CE clock module uses SPI bus to communicate with external computing chips. The bus is a synchronous serial communication protocol that supports point-to-point and point-to-point multi-point communication protocols, as shown in Figure 2. It uses four communication lines: CLK (clock), DI (input), DO (output), and CE (slave selection). Its advantages lie in fast transmission speed and strong real-time performance, making it particularly suitable for clock applications that require high-speed real-time response to clock signals. In industrial control products, it is necessary to actually analyze continuous signals and maintain the credibility of signal acquisition time accuracy, which will play an important role in the design of high-precision sensitive instruments and meters.

Figure 2 Schematic diagram of digital temperature compensation function of SPI interface

Frequency tolerance less than+8.0x10.6, operating at harsh ambient temperatures of+85 '℃~+105 ℃

The stable characteristics of the RX4901CE real-time clock module with temperature changes are shown in Figure 3. Its maximum startup time is 1 second, which is particularly suitable for various programmable instrument applications. At the same time, its frequency tolerance is less than ± 8.0x10-6 in ambient temperatures of -40 ℃~+105 ℃, and its performance is excellent, meeting the requirements of high-precision temperature compensation. In scenarios such as wind power, oil extraction, and other environments where temperature changes vary greatly, it ensures the reliable operation of equipment at any time. It can be used as a high-quality component selection option to provide component level technical support for high-precision time application design. At the same time, RX4901CE also offers XS sub model products, with a frequency tolerance of+3.0x10-6 in temperature environments ranging from -40 ℃ to+85 ℃, which is convenient for designers to further pursue accuracy. For example, in industries such as petrochemicals and steel smelting, where signal detection of rotating equipment requires high stability of instrument clocks.

Figure 3 Frequency characteristics of RX4901CE

Provide timestamp function, which can automatically switch between battery power and system power supply

As a highly integrated real-time clock module, RX4901CE integrates rich design functions internally. RX4901CE has a timestamp function, which can record information from 1/1024 second to second, minute, hour, day, month, and year through external event pin input configuration. The module can record up to 32 events internally, which can help users mark important signal events with high-precision timestamp information, effectively facilitating data traceability. At the same time, the module can detect the status of system power supply and battery power supply internally, and automatically switch to battery power supply in case of system power supply failure, ensuring the stable and reliable operation of the clock system.