RX-8025NB (High-Stability I2C-Bus Interface Real Time Clock Module)


Complies with EU RoHS directive.

  • Built-in 32.768kHz crystal unit
    Frequency adjusted for high accuracy
    (±5×10-6 / Ta=+25°C)
  • Interface Type
    I2C-Bus Interface (400kHz)
  • Operating voltage range
    1.70V to 5.5V
  • Wide voltage for timekeeping
    1.15V to 5.5V
  • Various detection Functions
    Ex. Oscillation stop detection function
  • Low backup current
    0.48µA / 3V(Typ.)
  • 32.768kHz frequency output function
    C-MOS output with OE pin
  • The various functions include full calendar,Dual alarm, Periodic interruption
  • *The I2C-Bus is a trademark of NXP Semiconductors

Block diagram

Block diagram


  • Features built-in 32.768kHz crystal unit
    • Frequency adjusted for high accuracy.
      (±5×10-6 / Ta=+25°C)
      (Equivalent to 13 seconds of monthly deviation)
  • The various detection function
    • Power supply voltage monitoring function
      (with selectable detection threshold)
    • Stop detection function
    • Power-on reset detection function
  • Alarm function and Periodic interrupt function
    • The periodic interrupt outputs
    • Dual Alarm function.
      (Date of the week , Hour , minute)
      (Month, Day, Hour, Minute )

Pin function

Signal Name Input/Output Function
SCL Input Serial clock input pin
SDA Bi-directional Data input and output pin
FOUT Output 32.768kHz clock output pin with the output control function. (C-MOS)
H 0 0 32.768kHz
0 1 32.768kHz
1 0 32.768kHz
1 1 OFF(LOW)
FOE Input
/ INTA Output Interrupt output A pin (N-ch open drain)
/ INTB Output Interrupt output B pin (N-ch open drain)
TEST - *Used by the manufacture for testing.
(Do not connect externally.)
VDD - Connected to a positive power supply.
GND - Connected to a ground.

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 - 1.7 3.0 5.5 V
Clock voltage VCLK - 1.15 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
AA: 5±5  *1)
AC: 0±5  *2)
Oscillation start-up time tSTA Ta=+25°C
1 Max. s
Frequency voltage characteristics f/V Ta=+25°C
VDD=2.0V to 5.5V
±1 Max. ×10-6

*1) 2) Equivalent to 13 seconds of monthly deviation (excluding offset).

Current consumption characteristics

Ta=-40°C to +85°C

Item Symbol Conditions Min. Typ. Max. Unit
Current Consumption lBK fSCL=0Hz
FOUT;output OFF(LOW)
VDD=5V - 0.60 1.80 µA
VDD=3V - 0.48 1.20
l32k fSCL=0Hz
FOUT;output ON
VDD=5.5V - 3.0 6.5 µA

Power supply detection voltage

Ta=-30°C to +70°C

Item Symbol Condition Min. Typ. Max. Unit
High-voltage mode VDETH VDD pin 1.90 2.10 2.30 V
Low-voltage mode VDETL VDD pin 1.15 1.30 1.45 V
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