DS1687-3 Maxim Integrated Products, DS1687-3 Datasheet - Page 6
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DS1687-3
Manufacturer Part Number
DS1687-3
Description
IC RTC 3V 64-BIT Y2K 24-EDIP
Manufacturer
Maxim Integrated Products
Type
Clock/Calendar/NVSRAM/Y2Kr
Datasheet
1.DS1685S-5.pdf
(34 pages)
Specifications of DS1687-3
Memory Size
242B
Time Format
HH:MM:SS (12/24 hr)
Date Format
YY-MM-DD-dd
Interface
Parallel
Voltage - Supply
2.7 V ~ 3.7 V
Operating Temperature
0°C ~ 70°C
Mounting Type
Through Hole
Package / Case
24-DIP (600 mil) Module
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
DS1687-3
Manufacturer:
DALLAS
Quantity:
20 000
Company:
Part Number:
DS1687-3+
Manufacturer:
Maxim
Quantity:
14
Company:
Part Number:
DS1687-3+
Manufacturer:
ELHA
Quantity:
6 000
Company:
Part Number:
DS1687-3IND
Manufacturer:
MAXIM
Quantity:
2 450
Company:
Part Number:
DS1687-3IND+
Manufacturer:
LT
Quantity:
665
Figure 1. Block Diagram
OSCILLATOR CIRCUIT
The DS1685 uses an external 32.768kHz crystal. The oscillator circuit does not require any external resistors or
capacitors to operate. Table 1 specifies several crystal parameters for the external crystal, and Figure 2 shows a
functional schematic of the oscillator circuit. The oscillator is controlled by an enable bit in the control register.
Oscillator startup times are highly dependent upon crystal characteristics, PC board leakage, and layout. High ESR
and excessive capacitive loads are the major contributors to long startup times. A circuit using a crystal with the
recommended characteristics and proper layout usually starts within one second.
AD0 - AD7
DS1687 only
DS1687 only
V
GND
V
ALE
BAUX
V
W R
R D
C S
BAT
CC
X1
X2
Interface
Control
Power
OSC
BUS
DS1685/DS1687
Clock/Calender
Update Logic
Divide
by 8
6 of 34
Divide by
64
16:1 M ux
Extended RAM Addr/
64-Bit Serial Num ber
Calendar and Alarm
Clock/Calendar and
Registers A, B,C,D
User Ram
114 Bytes
Extended Control/
Status Registers
Century Counter
Alarm Registers
RTC Address -2
RTC Address -3
Buffered Clock/
Data Registers
Date Alarm
DS1685/DS1687 3V/5V Real-Time Clocks
Registers
Select
Generator
Generator
Square
W ave
Divide by
IRQ
Logic
Clear
RAM
64
R L C R
User RAM
128 Bytes
Extended
SQW
IR Q
P W R
K S