Real time clock module
4-bit REAL TIME CLOCK MODULE
RTC-72421/72423
•
•
•
•
•
•
Built-in crystal unit allows adjustment-free efficient operation.
ALE input terminal available for 8048, 8051, and 8085 series.
12/24 h clock switchover function and automatic leap year setting.
Interrupt masking.
30 second adjustment function.
Low current consumption and features a backup function.
Actual size
Specifications (characteristics)
Absolute Max. rating
Symbol
Item
V
DD
Power source voltage
V
I/O
Input and output voltage
Storage temperature
T
STG
Condition
Ta=+25 °C
Ta=+25 °C
RTC-72421
RTC-72423
RTC-72421
Soldering condition
T
SOL
RTC-72423
Specifications
-0.3 to 7.0
GND -0.3 to V
DD
+0.3
-55 to +85
-55 to +125
Under +260 °C within 10 s
(lead part) (package should
be less than +150 °C)
Terminal connection
Unit
V
°C
RTC-72421
18 17 16 15 14 13 12 11 10
Twice at under +260
°
C within 10
s or under +230
°
C within 3 min.
1
2
3
4
5
6
7
8
9
Operating range
Item
Operating voltage
Operating temperature
Data holding voltage
CSI data holding time
Operation restoring time
Symbol
V
DD
T
OPR
V
DH
t
CDR
t
R
Refer to the data
holding timing
RTC-72421
RTC-72423
Condition
Specifications
4.5 to 5.5
-10 to 70
-40 to 85
2.0 to 5.5
2.0 Min.
Unit
V
°C
V
µs
RTC-72423
24 23 22 21 20 19 18 17 16 15 14 13
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
72421
STD. P
CS
0
ALE
A
0
A
1
A
2
A
3
RD
GND
WR
D
3
D
2
D
1
D
0
CS
1
(V
DD
)
(V
DD
)
V
DD
1 2 3 4 5 6 7 8 9 10 11 12
(V
DD
) and V
DD
are to have the same level of voltage
.
Do not connect it to any external terminals.
NC is not connected internally.
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
72423
STD. P
CS
0
NC
ALE
A
0
NC
A
1
NC
A
2
A
3
RD
GND
WR
D
3
D
2
D
1
NC
NC
D
0
CS
1
NC
(V
DD
)
(V
DD
)
V
DD
Frequency characteristics and current consumption
characteristics
Item
Symbol
Condition
72421 A
Frequency tolerance
∆f/fo
Specifications
±10
±50
±20
±50
+10/-120
±5 Max.
±10 Max.
10 Max.
5 Max.
Unit
External dimensions
RTC-72421
23.1 Max.
(Unit: mm)
Ta=+25 °C
72421 B
V
DD
=5 V
72423 A
72423
Aging
Shock resistance
Current consumption
fa
S.R.
I
DD1
I
DD2
V
DD
=5 V, Ta=+25 °C,
first year
Three drops on a
hard board from 750 mm
or 29400 m/s
2
x 0.3 ms x
1/2 sine wave x 3 directions
x 10
-6
/year
x 10
-6
4.2
0.2 Min.
Frequency temperature
characteristics
(+25 °C reference temperature)
-10 °C to +70 °C
6.3
x 10
-6
RTC72421 A
EPSON 5053C
7.62
0.25
90° to
105°
2.54
0.65 Max.
CS
1
=0 V V
DD
=5 V
Exclude input/
output current
V
DD
=2 V
µA
DC characteristics
Item
“H” input voltage
“L” input voltage
(1)
(1)
Symbol Condition
V
IH1
V
IL1
I
LK1
I
LK2
V
OL1
V
OH
V
OL2
I
OFFLK
C
1
(2)
(2)
V
IH2
V
IL2
—
Min. Typ. Max.
2.2
—
0.8
±1
—
—
RTC-72423
Unit
V
µA
Applicable
terminal
All inputs
other than
CS
1
Input other
than D
0
to D
3
16.3 Max.
Input leak current (1)
Input leak current (2)
“L” output voltage (1)
“H” output voltage
“L” output voltage (2)
Off leak current
Input capacity
“H” input voltage
20
—
1.27
0.35
2.8 Max.
77
“L” input voltage
V
DD
=2 to 5.5 V
4/5 V
DD
—
—
1/5 V
DD
V
CS
1
0.3
D
0
to D
3
0.2
frequency 1 MHz
Input
10
pF
Input other
than D
0
to D
3
2.5
I
OL
=2.5 mA
I
OH
=-400 µA
I
OL
=2.5 mA
V
1
=V
DD
/0 V
0.4
2.4
—
0.4
—
10
µA
V
D
0
to D
3
STD.P
0° to
10°
0.05 Min.
7.9
±10
12.2 Max.
V
1
=V
DD
/0 V
RTC72423 A
EPSON 6150
3.3 Min.
1.0
EPSON [ EPSON COMPANY ]
