RX-8581JE (I2C-Bus Interface Real Time Clock Module)


Complies with EU RoHS directive.

  • Built-in frequency adjusted 32.768kHz crystal unit.
  • Interface Type
    I2C-Bus Interface(400kHz)
  • Operating voltage range
    1.8V to 5.5V
  • Wide Timekeeper voltage range
    1.6V to 5.5V
  • Low backup current
    0.45µA / 3V(Typ.)
  • 32.768kHz frequency output function
    C-MOS output With Control Pin
  • The various functions include full calendar, alarm, timer.
    * The I2C-Bus is a trademark of NXP Semiconductors

Block diagram

Block diagram


  • Interface Type
    • I2C-Bus interface. (Hi-speed bus specifications 400kHz)
      * I2C-Bus slave address : read A3h and write A2h
  • 32.768kHz frequency output function
    • FOUT pin output (C-MOS output ), CL=30pF
    • 32.768kHz clock frequency output. (Duty 50 ±5 %)
  • Timer function
    • Timer interrupt function can be set up between 1/4096second and 4095minutes.
    • It is recorded automatic to TF-bit at the time of event
      occurrence,and possible to output with /TIRQ pin output
      (N-ch open-drain output).
  • Interrupt function
    • Alarm interrupt function, Time update interrupt function.

Terminal connection / External dimensions

Terminal connection External dimensions

(Unit: mm)

Metal may be exposed on the top or bottom of this product. This will not affect any quality, reliability or electrical spec.

Specifications *Refer to application manual for details.

Recommend Operating Conditions

Item Symbol Condition Min. Typ. Max. Unit
Power voltage VDD - 1.8 3.0 5.5 V
Clock voltage VCLK - 1.6 3.0 5.5 V
Operating temperature TOPR - -40 +25 +85 °C

Frequency characteristics

Item Symbol Condition Rating Unit
Frequency tolerance Δ f/f Ta=+25°C
5±23 * ×10-6
FOUT output Duty tw/t Ta=-40°C to +85°C
VDD=2.4V to 5.5V
50±5 %

* Please ask for tighter tolerance.( Equivalent to 1 minute of monthly deviation )

Current consumption characteristics

Item Symbol Conditions Min. Typ. Max. Unit
lBK fSCL=0Hz

FOUT;output OFF(LOW)
VDD=5V - 0.65 1.2 µA
VDD=3V - 0.45 0.8
l32k fSCL=0Hz

FOUT;32.768kHz output ON
VDD=5V - 8.0 20.0 µA
VDD=3V - 5.0 12.0
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