RX-4574LC (Small size, low profile model package Serial-Interface Real Time Clock

  • Built in frequency adjusted 32.768 kHz crystal unit.
  • Interface Type
    3-wire serial interface
  • Operating voltage range
    1.6V to 5.5V
  • Wide Timekeeper voltage range
    1.3V to 5.5V
  • Low backup current
    0.35µA / 3V(Typ.)
  • 32.768kHz frequency output function
    C-MOS output With Control Pin
  • The various functions include full calendar, alarm, timer.

Complies with EU RoHS directive.


Block diagram

Block diagram


  • 32.768kHz frequency output function
    • FOUT pin output (C-MOS output), CL=30pF
    • Output frequency is selectable from 1/30Hz to 32.768kHz
      (32 Values)
  • Timer function
    • Timer function which can be set up between 1/4096second and 255minutes.
    • It is recorded automatically to TF-bit at the time of event
      occurrence, and it's possible to output with /TIRQ pin output
      (open-drain output).
    • Selectable one time mode or repeat mode.
  • Alarm function
    • Alarm function can be set to any combination of day of week, hour, or minute.
    • It is recorded automatically to AF-bit at the time of event
      occurrence, and it's possible to output with /AIRQ pin output
      (open-drain output).
  • Functions are compatible with RTC-4574SA/JE/NB.

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
1Max. s
Ta=-40°C to +85°C
3Max. s

* Equivalent to ±1 minute of monthly deviation

Current consumption characteristics

*Ta=-40°C to +85°C

Item Symbol Conditions Min. Typ. Max. Unit

FOUT ;output OFF(Hi-z)
VDD=5V - 0.45 0.9 µA
VDD=3V - 0.35 0.7
l32k CE0=GND

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


Pin function

Signal Name Input/Output Function
CE0 Input The chip enabled input pin 0. (Built-in pull-down resistance)
When both CE0 and CE1 pins are at the "H" level , access to this
Real time clock module becomes possible.
CE1 Input The chip enabled input pin 1. When the CE1 pin is at the HIGH level, the FOUT pin is in the output state.
CLK Input The shift clock input pin for serial data transfer.
DATA Bi-directional The data input / output pin for serial data transfer.
FOUT Output This pin outputs the reference clock signal at 32.768kHz (C-MOS output).
High impedance at the time of output off.
FCON Input The input pin for the FOUT output control.
/ AIRQ Output The open drain output pin for alarm and time update interrupts.
/ TIRQ Output The open drain output pin for timer interrupt.
VDD - Connected to a positive power supply.
GND - Connected to a ground.

Terminal connection / External dimensions

Terminal connection External dimensions

(Unit: mm)

Stop using the glue
Any glue must never use it after soldering LC-package to a circuit board.
This product has glass on the back side of a package.
When glue invasions between circuit board side and glass side, then glass cracks by thermal expansion of glue.
In this case a crystal oscillation stops.Consider glue abolition or glue do not touch to LC-package

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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