RTC-72421 (4-bit Real Time Clock Module)

  • Built-in crystal unit allows adjustment-free
    efficient operation.
  • 24h /12h changeable and leap year automatically adjustable
    (Gregorian calendar).


  • 7242series does not have complete compatibility
    ability for the "old product RTC-6242 series"
  • When replace to 7242series from 6242 series, confirm
    the technical information of RTC7242 latest manual by all means.

Complies with EU RoHS directive.


Block diagram

Block diagram

Specifications *Refer to application manual for details.

Absolute Max. rating

Item Symbol Condition Min. Max. Unit
Supply voltage VDD Ta=+25°C -0.3 +7.0 V
Input voltage VI/O Ta=+25°C GND-0.3 VDD+0.3
Storage temperature * TSTG - -55 +85 °C

* Stored as bare product after unpacking

Operating range

Item Symbol Condition Min. Max. Unit
Power voltage VDD - 4.5 5.5 V
Clock voltage VCLK - 2.0 5.5
Operating temperature TOPR - -10 +70 °C

* Stored as bare product after unpacking

Frequency characteristics

Item Symbol Condition Range Unit
Frequency precision Δf/f Ta=+25°C
72421A ±10 ×10-6
72421B ±50
TOP -10°C to +70°C (+25°C) +10 / -120
-40°C to +85°C(+25°C) +10 / -220
Frequency voltage
f/V Ta=+25°C,VDD=2.0V to 5.5V ±5.0 Max. ×10-6/V
Aging fa Ta=+25°C,VDD=5.0V,First year ±5.0 Max. ×10-6/year

DC characteristics

Item Symbol Condition Min. Typ. Max. Unit Applicable terminal
Current consumption IDD1 CS1= 0V
Exclude input/
output current
VDD=5V - 1 10 µA -
IDD2 VDD=2V 0.9 5 -
HIGH input voltage (1) VIH1 - 2.2 - - V All inputs other than CS1
LOW input voltage (1) VIL1 - 0.8
LOW output voltage (1) VOL1 IOL=2.5mA - 0.4 V D0 to D3
HIGH output voltage VOH IOH=-400µA 2.4 -
LOW output voltage (2) VOL2 IOL=2.5mA - 0.4 STD.P
OFF leak current IOFFLK V1=VDD/0V 10/-10 µA
Input capacity C1 Input frequency 1MHz 10 - pF Input other than D0 to D3
20 D0 to D3, STD.P
HIGH input voltage (2) VIH2 VDD=2.0V to 5.5V 4/5VDD - V CS1
LOW input voltage (2) VIL2 - 1/5VDD
Input leak current (1) ILK1 V1=VDD/0V - 1/-1 µA Input other than D0 to D3
Input leak current (2) ILK2 10/-10 D0 to D3


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.

Page Top