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
RTC-72421/72423
OS C
Counter
D3
R ESET S TOP
H OLD BU SY
D2
D1
D0
Gate
Gate
bit
bit
bit
bit
24/12
bi t
30 sec AD J
bit
S1
S 10
D 10
MI1 M I10
H 1
Y1
H 10
Y10
W
W R
R D
S1 to
CF
A3
A2
D1
M O1 MO10
Decoder
A1
Latch
A0
C S0
O utput
Selec tor
ALE
C S1
STD.P
64 Hz
1 Second carry
1 M inute carry
C F
1 H our carry
C D
CE
Terminal connection/External dimensions
(Unit:mm)
RTC-72421 (DIP 18-pin)
RTC-72423 (SOP 24-pin)
No.
Pin
te rmina l
No.
Pin
te rmina l
DD
V
No.
Pin
te rmina l
STD.P
No.
Pin
te rmina l
DD
V
16.3 Max.
23.1 Max.
#24
#1 3
#18
#10
1
2
3
4
5
6
7
8
9
STD.P
18
17
16
15
14
13
12
11
10
1
2
3
4
5
6
7
8
9
24
23
22
21
20
19
18
17
16
15
14
13
0
DD
/CS
(V
)
)
0
DD
/CS
(V
(V
)
)
ALE
(VDD
DD
RTC72421 A
N.C.
0
1
A
CS
C0
ALE
N.C.
RTC762423
A1
2
0
1
EPSON 1234A
A
CS
0
D
1
A
A
D
D
N.C.
A1
EPSON 1234A
#1
#9
3
2
N.C.
N.C.
D1
/RD
GND
D3
N.C.
A2
/W R
#1
#12
3
2
10
11
12
A
D
D
3
/RD
GND
7.62
/WR
0.2
Min.
4.2
0.2
2.8 Max.
0.1 Min.
Max.
1.52
0.46
3.3
Min.
° °
- 10
0
1.0
0.35
1.27
2.54
0.25
°
°
-15
0
Metal may be expo sed o n the top or bottom of th is pro duct. This will not affect any qu ality, re liability o r electrical spec.
Specifications (characteristics)
*Refer to application manual for details.
Absolute Max. rating
DC characteristics
Item
Symbol
Condition
=+25 °C
=+25 °C
Min.
-0.3
Ma x.
+7.0
Unit
Item
Symbol
Condition
1= 0 V
Min.
Typ.
1
Ma x. Unit Applicable terminal
10
CS
Supply voltage
VDD
T
a
I
DD1
DD2
IH1
IL1
OL1
OH
OL2
OFFLK
V
DD=5 V
V
Current consumption
Exclude input/
output current
µA
Input voltage
VI/O
Ta
GND-0.3
V
DD+0.3
I
V
DD=2 V
0.9
5
RTC-72421
RTC-72423
-55
-55
+85
HIGH input voltage (1)
LOW input voltage (1)
LOW output voltage (1)
V
2.2
Storage
temperature *
All inputs other than
V
TSTG
°C
CS1
+125
V
0.8
0.4
V
I
OL=2.5 mA
OH=-400 µA
OL=2.5 mA
=VDD/0 V
*Stored as bare product after unpacking
D0 to D3
HIGH output voltage
V
I
2.4
V
Operating range
Item
Power voltage
LOW output voltage (2)
OFF leak current
V
I
0.4
Symbol
VDD
Condition
Min.
4.5
Ma x.
5.5
Unit
V
STD.P
I
V1
10/-10 µA
Input other than
Clock voltage
VCLK
2.0
5.5
10
20
Input frequency
1 MHz
Input capacity
C
1
pF
D
0
to D
3
RTC-72421
RTC-72423
-10
-40
+70
+85
D
0
to D , STD.P
3
Operating
temperature
TOPR
°C
HIGH input voltage (2)
LOW input voltage (2)
V
IH2
IL2
LK1
LK2
4/5 VDD
V
DD=2.0 V to 5.5 V
V
CS
1
V
1/5 VDD
Stored as bare produc after unpacking
Input other than
Input leak current (1)
Input leak current (2)
I
1/-1
µA
Frequency characteristics
D
D
0
0
to D
to D
3
3
V1=VDD/0 V
I
10/-10
Item
Symbol
Condition
Range
Unit
72421A
72421B
72423A
72423
±10
±50
±20
±50
Frequency
precision
T
V
a
=+25 °C
∆f /f
DD=5.0 V
×10-6
Frequency
temperature
characteristics
Frequency voltage
characteristics
-10 °C to +70 °C (+25 °C)
+10 / -120
+10 / -220
TOP
-40 °C to +85 °C(+25 °C)
f/V
fa
T
a
=+25 °C,VDD=2.0 V to 5.5 V ±5.0 Max. ×10-6/V
Ta
=+25 °C,VDD=5.0 V,First year ±5.0 Max. ×10-6/year
Aging
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