DS1685/DS1687
3V/5V Real-Time Clocks
FEATURES
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Incorporates Industry-Standard DS1287 PC
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Auxiliary Battery Input
RAM Clear Input
Century Register
Date Alarm Register
Compatible with Existing BIOS for Original
DS1287 Functions
Available as Chip (DS1685) or Stand-Alone
Encapsulated DIP (EDIP) with Embedded
Battery and Crystal (DS1687)
Timekeeping Algorithm Includes Leap-Year
Compensation Valid Through 2099
Clock plus Enhanced Features Such as Y2K
Compliant
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+3V or +5V Operation
64-Bit Silicon Serial Number
Power-Control Circuitry Supports System
Power-On from Date/Time Alarm or Key
Closure
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32kHz Output for Power Management
Crystal-Select Bit Allows RTC to Operate with
6pF or 12.5pF Crystal
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SMI Recovery Stack
242 Bytes Battery-Backed NV RAM
Underwriters Laboratory (UL) Recognized
APPLICATIONS
Embedded Systems
Utility Meters
Security Systems
Network Hubs, Bridges, and Routers
PIN CONFIGURATIONS
TOP VIEW
VCC
1
2
PWR
X1
24
23
VCC
1
2
PWR
N.C.
N.C.
AD0
24
23
SQW
VBAUX
SQW
VBAUX
DS1685/
DS1685S/
DS1685E
DS1687
X2
3
4
5
22
21
20
3
4
5
22
21
20
AD0
RCLR
VBAT
IRQ
KS
RCLR
N.C.
IRQ
KS
4
3
2
1
28 27 26
5
25
RCLR
AD0
AD1
AD2
AD3
AD4
AD5
N.C.
AD1
AD2
AD3
AD4
AD5
AD6
AD7
GND
6
24
23
VBAT
AD1
AD2
AD3
AD4
AD5
AD6
AD7
GND
DS1685Q
7
IRQ
KS
6
19
18
17
16
15
6
22
21
20
19
8
19
18
17
16
15
9
RD
7
7
10
11
GND
WR
RD
8
RD
8
12 13 14 15 16 17 18
9
GND
9
N.C.
10
11
12
WR
10
11
12
WR
PLCC
ALE
14
13
ALE
14
13
CS
CS
PDIP (0.600″)/
SO (0.300″)/
TSSOP (0.173″)
EDIP (0.740″)
19-5215; Rev 10/12
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