RX8900CE (built-in DTCXO, high precision, built-in power switch I) ² Real time clock module for C-Bus interface

Mar 18,2024
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The RX8900CE real-time clock module can easily achieve various functions. The built-in 32.768kHz crystal unit ensures high-precision timing, allowing the device to run more accurately. At the same time, the operating voltage range is between 2.5V and 5.5V, which allows the equipment to operate more stably and effectively extends its service life. In addition to precise timing function, the RX8900CE real-time clock module also supports a variety of functions, which can easily achieve functions such as full calendar, alarm, timer, and temperature sensor. This real-time clock module can work stably in temperatures ranging from -40 to 85 ° C, with a frequency tolerance of ± 5 ppm.

·Built in 32.768kHz crystal unit

(Frequency accuracy adjustment completed) and DTCXO

·Interface type: I ² C-Bus interface (400kHz)

·Working voltage range: 2.5V~5.5V

·Temperature compensation voltage: 2.0V~5.5V

·Timing (holding) voltage range: 1.6V~5.5V

·You can choose an output frequency of 32.768 kHz, 1024 Hz, or 1Hz

·Different functions include full calendar, alarm, timer, and temperature sensor

Circuit diagram

Overview

High Stability
- UA ± 3.4 x 10^-6 / -40 °C to +85 °C ( Equivalent to ±9 seconds of month deviation )
- UB ± 5.0 x 10^-6 / -40 °C to +85 °C ( Equivalent to ±13 seconds of month deviation )
- UC ± 5.0 x 10^-6 / -30 °C to +70 °C ( Equivalent to ±13 seconds of month deviation )
32.768 kHz frequency output function
- FOUT pin output (C-MOS output), CL=30 pF
- Output selectable: 32.768 kHz, 1024 Hz, 1 Hz
Available automatic battery backup switch-over function
- Charge from VDD to backup battery connected to VBAT is possible.
  VDD voltage drop(VDET3) detection and automatically switches to the backup battery.
  This circuit is optimal to backup with a secondary battery and a large capacitor.
Timer function
- Timer period is adjustable in 1/4096 second from 4095 minutes
Alarm function
- Available dual-alarm, weekly and monthly
Temp. sensor function
- Available readout temperature data from embedded temp sensor. (Bank.2_Add17h)