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

  • 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

Complies with EU RoHS directive.


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 )

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


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)

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).

Page Top