Actual size
Real time clock module
www.eea.epson.com
Block diagram
Terminal connection/External dimensions
(Unit:mm)
Specifications (characteristics)
Absolute Max. rating DC characteristics
Item
Symbol
Condition
Min.
Max.
Unit
Item
Symbol
Condition
Min.
Typ.
Max.
Unit
Applicable terminal
Supply voltage
VDD
Ta=+25 C
-0.3
+7.0
V
Current consumption
IDD1
CS1= 0 V
Exclude input/
output current
VDD=5 V
-
1
10
A
-
Input voltage
VI/O
Ta=+25 C
GND-0.3
VDD+0.3
IDD2
VDD=2 V
0.9
5
-
Storage
temperature *
TSTG
RTC-72421
-55
+85
C
HIGH input voltage (1)
VIH1
-
2.2
-
-
V
All inputs other than
CS1
RTC-72423
-55
+125
LOW input voltage (1)
VIL1
-
0.8
*Stored as bare product after unpacking
LOW output voltage (1)
VOL1
IOL=2.5 mA
-
0.4
V
D0 to D3
Operating range
HIGH output voltage
VOH
IOH=-400 µA
2.4
-
Item
Symbol
Condition
Min.
Max.
Unit
LOW output voltage (2)
VOL2
IOL=2.5 mA
-
0.4
STD.P
Power voltage
VDD
-
4.5
5.5
V
OFF leak current
IOFFLK
V1=VDD/0 V
10/-10
A
Clock voltage
VCLK
-
2.0
5.5
Input capacity
C1
Input frequency
1 MHz
10
-
pF
Input other than
D0 to D3
Operating
temperature
TOPR
RTC-72421
-10
+70
C
20
D0 to D3, STD.P
RTC-72423
-40
+85
HIGH input voltage (2)
VIH2
VDD=2.0 V to 5.5 V
4/5 VDD
-
V
CS1
Stored as bare produc after unpacking
LOW input voltage (2)
VIL2
-
1/5 VDD
Frequency characteristics
Input leak current (1)
ILK1
V1=VDD/0 V
-
1/-1
A
Input other than
D0 to D3
Item
Symbol
Condition
Range
Unit
Input leak current (2)
ILK2
10/-10
D0 to D3
Frequency
precision
f /f
Ta=+25 °C
VDD=5.0 V
72421A
10
10-6
72421B
50
72423A
20
72423B
50
Frequency
temperature
characteristics
TOP
-10 C to +70 C (+25 C)
+10 / -120
-40 C to +85 C(+25 C)
+10 / -220
Frequency voltage
characteristics
f/V
Ta=+25 C,VDD=2.0 V to 5.5 V
5.0 Max.
10-6/V
Aging
fa
Ta=+25 C,VDD=5.0 V,First year
5.0 Max.
10-6/year
OSC
RESET
bit
STOP
bit
30 sec ADJ
bit
Counter
HOLD
bit
BUSY
bit
D3
D2
D1
D0
WR
RD
A3
A2
A1
A0
CS0
ALE
CS1
S1
S10
MI1
MI10
H1
H10
W
D1
D10
MO1
MO10
Y1
Y10
64 Hz
1 Second carry
1 Minute carry
1 Hour carry
S1 to
CF
CD
CE
CF
Gate
Gate
Latch
Decoder
24/12
bit
RTC-72421/72423
STD.P
Output
Selector
RTC-72421
RTC-72423
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).
Metal may be exposed on the top or bottom of this product. This will not affect any quality, reliability or electrical spec.
RTC-72421 (DIP 18-pin)
7.62
0 -15
0.25
0.46
4.2
Max.
3.3
Min.
0.2
Min.
2.54
1.52
23.1 Max.
6.3
#1
#18
#10
#9
RTC72421 A
EPSON 1234A
No.
Pin
terminal
No.
Pin
terminal
1
STD.P
18
VDD
2
/CS0
17
(VDD)
3
ALE
16
(VDD)
4
A0
15
CS1
5
A1
14
C0
6
A2
13
D1
7
A3
12
D2
8
/RD
11
D3
9
GND
10
/WR
RTC-72423 (SOP 24-pin)
1.0
0.2
0 - 10
0.2
0 - 10
1.27
0.35
2.8 Max.
0.1 Min.
2.8 Max.
0.1 Min.
#12
#1
16.3 Max.
#24
#13
7.9
12.2 Max.
RTC62423
EPSON 1234A
#12
#1
16.3 Max.
#24
#13
7.9
12.2 Max.
RTC72423
EPSON 1234A
No.
Pin
terminal
No.
Pin
terminal
1
STD.P
24
VDD
2
/CS0
23
(VDD)
3
N.C.
22
(VDD)
4
ALE
21
N.C.
5
A0
20
CS1
6
N.C.
19
D0
7
A1
18
N.C.
8
N.C.
17
N.C.
9
A2
16
D1
10
A3
15
D2
11
/RD
14
D3
12
GND
13
/WR
Product Number (Please contact us)
RTC-72421 : Q42724212xxxx00
RTC-72423 : Q42724232xxxx00