
95
Real time clock module
96
Real time clock module
4-bit REAL TIME CLOCK MODULE
RTC-72421 / 72423
Product number (please refer to page 5)
Q 4 2 7 2 4 2 1 x x x x x 0 0
Q 4 2 7 2 4 2 3 x x x x x 0 0
Built-in crystal unit allows adjustment-free efficient operation.
12/24 h clock switchover function and automatic leap year setting.
Interrupt masking.
Available for lead (Pb) - free soldering.
Available for lead (Pb) - free terminal.
Specifications (characteristics)
Absolute Max. rating
Item
Symbol
Condition
Min.
Max.
Unit
Supply voltage
VDD
Ta = +25 °C
-0.3
7.0
V
Input and output voltage
VI/O
Ta = +25 °C
GND -0.3 VDD +0.3
Storage temperature
TSTG
RTC-72421
-55
+85
°C
RTC-72423
-55
+125
Stored as bare product after unpacking
Operating range
Item
Symbol
Condition
Min.
Max.
Unit
Power voltage
VDD
4.5
5.5
V
Supply voltage
VCLK
2.0
5.5
V
Operating temperature
TOPR
RTC-72421
-10
70
°C
RTC-72423
-40
85
No condensation
Frequency characteristics
Item
Symbol
Condition
Range
Unit
Frequency tolerance
Δf/f
Ta = +25 °C,
VDD = 5 V
72421 A
±10
x 10-6
72421 B
±50
72423 A
±20
72423
±50
Frequency temperature
characteristics
Top
-10 °C to +70 °C
(Reference at +25 °C)
+10 / -120
-40 °C to +85 °C
(Reference at +25 °C)
+10 / -220
Frequency voltage
f/V
Ta = +25 °C
VDD = 2.0 V to 5.5V
±5 Max. x 10-6 / V
Aging
fa
VDD = 5 V, Ta = +25 °C, first year ±5 Max. x 10-6 / year
DC characteristics
Item
Symbol
Condition
Min. Typ. Max. Unit
Applicable
terminal
Current consumption
IDD1 CS1 = 0 V
Exclude input/
output current
VDD = 5 V
–
1
10
A
–
IDD2
VDD = 2 V
0.9
5
“H” input voltage (1) VIH1
–
2.2
–
V
All inputs
other than
CS1
“L” input voltage (1) VIL1
–
0.8
Input leak current (1) ILK1
V1 = VDD / 0 V
±1
A
Input other
than D0 to D3
Input leak current (2) ILK2
±10
D0 to D3
“L” output voltage (1) VOL1
IOL = 2.5 mA
0.4
V
“H” output voltage
VOH
IOH = -400 A
2.4
–
“L” output voltage (2) VOL2
IOL = 2.5 mA
–
0.4
STD.P
Off leak current
IOFFLK
V1 = VDD/0 V
10
A
Input capacity
C1
Input
frequency 1 MHz
10
–
pF
Input other
than D0 to D3
20
D0 to D3
“H” input voltage (2) VIH2
VDD = 2 V to 5.5 V
4/5 VDD
–
V
CS1
“L” input voltage (2) VIL2
–
1/5 VDD
Terminal connection
#1
#18
#9
#10
#1
#24
#12
#13
No.
1
2
3
4
5
6
7
8
9
Pin terminal
STD. P
CS0
ALE
A0
A1
A2
A3
RD
GND
No.
18
17
16
15
14
13
12
11
10
Pin terminal
VDD
(VDD)
CS1
D0
D1
D2
D3
WR
No.
1
2
3
4
5
6
7
8
9
10
11
12
Pin terminal
STD. P
CS0
NC
ALE
A0
NC
A1
NC
A2
A3
RD
GND
No.
24
23
22
21
20
19
18
17
16
15
14
13
Pin terminal
VDD
(VDD)
NC
CS1
D0
NC
D1
D2
D3
WR
External dimensions
(Unit: mm)
23.1 Max.
3.3
0.2
Min.
6.3
4.2
0.1 Min.
2.8 Max.
7.62
0.25
16.3 Max.
7.9
12.2
Max.
0.2
1.0
90
° to 105°
0
° to 10°
1.27
0.35
2.54
0.65 Max.
(DIP 18-pin)
(SOP 24-pin)
The details are mentioned in the application manual.
Actual size
RTC-72423
RTC-72421