Real time clock module
Epson Toyocom
Product Number (Please contact us)
RTC-72421 : Q42724211xxxx00
RTC-72423 : Q42724231xxxx00
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
RT C-7 2421 /724 23
OS C
D3
D2
D1
D0
R ESET S TOP
bi t
bit
30 s ec AD J
bit
S1
Gat e
S 10
Count er
H OLD
bit
BU SY
bit
Gat e
24/12
bi t
WR
RD
MI1
M I10
H1
H 10
W
A3
A2
A1
A0
C S0
ALE
C S1
Latc h
De coder
S1 t o
CF
D1
D 10
M O 1 MO 10
Y1
Y10
O u tp u t
S e le c to r
CD
CE
64 Hz
1 Sec ond carry
C F 1 M inut e c arry
1 H our c arry
S TD . P
Terminal connection/External dimensions
RTC-72 421 (DIP 18 -pin)
No .
2 3.1 Ma x.
#18
#10
(Unit:mm)
R TC -72423 (SOP 24-pin)
6.3
#1
#9
#1
#12
7 .62
0. 2 4. 2
Min. Max.
3.3
Min.
0. 25
0
°
-15
°
0.35
7.9
EPSON
1234A
RTC 62423
72423
EPSON 1 234A
12. 2 Max.
RTC7 2421 A
1
2
3
4
5
6
7
8
9
Pin
te rmina l
STD.P
/CS
0
AL E
A
0
A
1
A
2
A
3
/RD
GND
No .
18
17
16
15
14
13
12
11
10
Pin
te rmina l
V
DD
(V
D D
)
(V
D D
)
CS
1
C
0
D
1
D
2
D
3
/W R
16.3 Max.
#24
#1 3
No .
1
2
3
4
5
6
7
8
9
10
11
12
0.2
Pin
te rmina l
STD.P
/CS
0
N.C.
AL E
A
0
N.C.
A1
N.C.
A
2
A
3
/RD
GND
No .
24
23
22
21
20
19
18
17
16
15
14
13
Pin
te rmina l
V
D D
(V
D D
)
(V
D D
)
N.C.
CS
1
D
0
N.C.
N.C.
D
1
D
2
D
3
/WR
1.52
0.46
2.54
2.8 Max.
0.1 Min.
1. 27
1. 0
0
°
- 10
°
Metal may be expo sed o n the top or bottom of th is pro duct. T his w ill not affect any qu ality, re liability o r electrical spec.
Specifications (characteristics)
Absolute Max. rating
Item
Symbol
Supply voltage
V
DD
Input voltage
Storage
temperature
*
V
I/O
T
STG
Condition
T
a
=+25
°C
T
a
=+25
°C
RTC-72421
RTC-72423
Min.
-0.3
GND-0.3
-55
-55
Ma x.
+7.0
V
DD
+0.3
+85
+125
Unit
V
°C
*Refer
to application manual for details.
DC characteristics
Item
Current consumption
HIGH input voltage (1)
LOW input voltage (1)
LOW output voltage (1)
HIGH output voltage
Symbol
I
DD1
I
DD2
V
IH1
V
IL1
V
OL1
V
OH
V
OL2
I
OFFLK
C
1
V
IH2
V
IL2
I
LK1
I
LK2
Condition
CS
1
= 0 V
V
DD
=5 V
Exclude input/
output current V
DD
=2 V
-
I
OL
=2.5 mA
I
OH
=-400 µA
I
OL
=2.5 mA
V
1
=V
DD
/0 V
Input frequency
1 MH z
V
DD
=2.0 V to 5.5 V
V
1
=V
DD
/0 V
-
10
20
4/5 V
DD
-
-
-
-
1/5 V
DD
1/-1
10/-10
Min.
-
2.2
-
-
2.4
-
Typ.
1
0.9
Ma x.
10
5
-
0.8
0.4
-
0.4
10/-10
Unit Applicable terminal
-
µA
-
V
All inputs other than
CS
1
D
0
to D
3
STD.P
Input other than
D
0
to D
3
D
0
to D
3
, STD.P
CS
1
Input other than
D
0
to D
3
D
0
to D
3
*Stored
as bare product after unpacking
Operating range
Item
Power voltage
Clock voltage
Operating
temperature
Symbol
V
DD
V
CLK
T
OPR
Condition
-
-
RTC-72421
RTC-72423
Min.
4.5
2.0
-10
-40
Ma x.
5.5
5.5
+70
+85
Unit
V
V
µA
pF
V
µA
LOW output voltage (2)
OFF leak current
Input capacity
°C
Stored as bare produc after unpacking
HIGH input voltage (2)
LOW input voltage (2)
Input leak current (1)
Frequency characteristics
Item
Frequency
precision
Frequency
temperature
characteristics
Frequency voltage
characteristics
Symbol
∆f
/f
TOP
f/V
fa
Condition
72421A
72421B
T
a
=+25 °C
V
DD
=5.0 V
72423A
72423
-10
°C
to +70
°C
(+25
°C)
-40
°C
to +85
°C(+25 °C)
Range
±10
±50
±20
±50
+10 / -120
+10 / -220
Unit
Input leak current (2)
×10
-6
T
a
=+25
°C,V
DD
=2.0 V to 5.5 V
±5.0
Max.
×10
-6
/V
T
a
=+25
°C,V
DD
=5.0 V,First year
±5.0
Max.
×10
-6
/year
Aging
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