Real time clock module
Product Number (Please contact us)
RTC-72421 : Q42724212xxxx00
RTC-72423 : Q42724232xxxx00
4-bit REAL TIME CLOCK MODULE
RTC-72421
RTC-72423
Built-in crystal unit allows adjustment-free efficient operation.
24 h /12 h changeable and leap year automatically adjustable
(Gregorian calendar).
Actual size
RTC-72421
RTC-72423
Block diagram
RTC-72421/72423
OSC
Counter
D3
RESET STOP
HOLD BUSY
D2
D1
D0
Gate
Gate
bit
bit
bit
bit
24/12
bit
30 sec ADJ
bit
S1
S10
D10
MI1 MI10
H1
Y1
H10
Y10
W
W R
RD
S1 to
CF
A3
A2
D1
MO1 MO10
Decoder
A1
Latch
A0
CS0
Output
Selector
ALE
CS1
STD.P
64 Hz
1
1
Second carry
Minute carry
CD
CE
CF
1
Hour carry
Terminal connection/External dimensions
(Unit:mm)
RTC-72421 (DIP 18-pin)
RTC-72423 (SOP 24-pin)
No.
Pin
terminal
STD.P
/CS0
ALE
A0
A1
A2
A3
/RD
GND
No.
Pin
terminal
VDD
(VDD)
(VDD)
CS1
C0
D1
D2
D3
/WR
No.
Pin
terminal
No.
Pin
terminal
16.3 Max.
23.1 Max.
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
#24
#13
1
2
3
4
5
6
7
8
9
STD.P
/CS0
N.C.
ALE
A0
N.C.
A1
N.C.
A2
24
23
22
21
20
19
18
17
16
15
14
13
VDD
(VDD)
(VDD)
N.C.
CS1
D0
N.C.
N.C.
D1
#18
#10
RTC72421 A
RTC762423
EPSON 1234A
EPSON 1234A
#1
#9
#1
#12
10
11
12
A3
/RD
GND
D2
D3
/WR
7.62
0.2
Min.
4.2
0.2
2.8 Max.
0.1 Min.
Max.
1.52
0.46
3.3
Min.
0 - 10
1.0
0.35
1.27
2.54
0.25
0 -15
Metal may be exposed on the top or bottom of this product. This will not affect any quality, reliability or electrical spec.
Specifications (characteristics)
*Refer to application manual for details.
Absolute Max. rating
DC characteristics
Item
Supply voltage
Symbol
VDD
Condition
Ta=+25 C
Min.
-0.3
Max.
+7.0
Unit
V
Item
Symbol
IDD1
Condition
Min.
2.2
Typ.
1
Max. Unit Applicable terminal
10
CS1= 0 V
VDD=5 V
Current consumption
Exclude input/
output current
A
Input voltage
VI/O
GND-0.3
VDD+0.3
IDD2
VDD=2 V
0.9
5
Ta=+25 C
RTC-72421
RTC-72423
-55
-55
+85
HIGH input voltage (1)
LOW input voltage (1)
LOW output voltage (1)
VIH1
VIL1
Storage
temperature *
All inputs other than
V
TSTG
C
CS1
+125
0.8
0.4
VOL1
VOH
IOL=2.5 mA
*Stored as bare product after unpacking
D0 to D3
HIGH output voltage
IOH=-400 µA
2.4
V
Operating range
LOW output voltage (2)
OFF leak current
VOL2
IOL=2.5 mA
V1=VDD/0 V
0.4
Item
Power voltage
Symbol
VDD
Condition
Min.
4.5
Max.
5.5
Unit
V
STD.P
IOFFLK
10/-10
A
Input other than
D0 to D3
D0 to D3, STD.P
Clock voltage
VCLK
TOPR
2.0
5.5
10
20
Input frequency
1 MHz
Input capacity
C1
pF
RTC-72421
RTC-72423
-10
-40
+70
+85
Operating
temperature
C
HIGH input voltage (2)
LOW input voltage (2)
VIH2
VIL2
4/5 VDD
VDD=2.0 V to 5.5 V
V1=VDD/0 V
V
CS1
1/5 VDD
1/-1
Stored as bare produc after unpacking
Input other than
D0 to D3
Input leak current (1)
Input leak current (2)
ILK1
ILK2
A
Frequency characteristics
10/-10
D0 to D3
Item
Symbol
Condition
Range
10
50
20
50
Unit
72421A
72421B
72423A
72423B
Frequency
precision
Ta=+25 °C
VDD=5.0 V
f /f
10-6
Frequency
temperature
characteristics
Frequency voltage
characteristics
+10 / -120
-10 C to +70 C (+25 C)
-40 C to +85 C(+25 C)
Ta=+25 C,VDD=2.0 V to 5.5 V 5.0 Max. 10-6/V
TOP
+10 / -220
f/V
fa
Ta=+25 C,VDD=5.0 V,First year 5.0 Max. 10-6/year
Aging