RX-8571NB (Low Current Consumption I2C-Bus Interface Real Time Clock Module)

  • Built-in frequency adjusted 32.768kHz crystal unit.
  • Interface Type
    I2C-Bus Interface(400kHz)
  • Operating voltage range
    1.6V to 5.5V
  • Wide voltage for timekeeping
    1.3V to 5.5V
  • Low backup current
    220nA / 3V(Typ.)
  • 32.768kHz frequency output function
    C-MOS output With Control Pin
  • Built in user RAM
    128bit (8bit x 16, SRAM)
  • The various functions include full calendar, alarm, timer,etc.
    (Long-running timer : 65535 hours)

Complies with EU RoHS directive.


Block diagram

Block diagram


  • 32.768kHz frequency output function
    • FOE pin enable output on/off control.
    • Output frequency can be selected as 32.768kHz, 1024Hz, 1Hz.
  • Timer function
    • Timer function can be set up between 1/4096second and 65535hours.
    • Timing period are 1h, 1min, 64Hz, 4096Hz.
    • It is recorded automatically to TF-bit at the time of
      event occurs, and possible to output with /IRQ pin output.
  • Alarm function
    • Alarm function can be set to day of week, day, hour, or minute.
    • It is recorded automatically to AF-bit at the time of
      event occurs, and possible to output with /IRQ pin output.
  • User RAM
    • 128bit (8bit x 16,SRAM)

Specifications *Refer to application manual for details.

Recommend Operating Conditions

Item Symbol Condition Min. Typ. Max. Unit
Power voltage VDD - 1.6 3.0 5.5 V
Clock voltage VCLK - 1.3 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
Oscillation start up time tSTA Ta=+25°C
1 Max. s

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

Current consumption characteristics

Item Symbol Conditions Min. Typ. Max. Unit
- 200 400 nA
VDD =3.0V
Ta= -40°C to +85°C
- - 550 nA


Terminal connection / External dimensions

Terminal connection External dimensions
(Unit: mm)

The metal case inside of the molding compound may be exposed on the top or bottom of this product.
This purely cosmetic and does not have any effect on quality, reliability or electrical specs.

Footprint (Recommended)


(Unit: mm)

To maintain stable operation, provide a 0.1uF by-pass capacitor
at a location as near as possible to the power source terminal of the crystal product (between Vcc - GND).

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