DS1685/DS1687
3V/5V Real-Time Clocks
www.maxim-ic.com
FEATURES
Incorporates Industry-Standard DS1287 PC Clock
plus Enhanced Features Such as: Y2K Compliant
+3V or +5V Operation
64-Bit Silicon Serial Number
Power-Control Circuitry Supports System
Power-On from Date/Time Alarm or Key
Closure
32kHz Output for Power Management
Crystal-Select Bit Allows RTC to Operate with
6pF or 12.5pF Crystal
SMI Recovery Stack
242 Bytes Battery-Backed NV RAM
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
Underwriters Laboratory (UL) Recognized
APPLICATIONS
Embedded Systems
Utility Meters
Security Systems
Network Hubs, Bridges, and Routers
PIN CONFIGURATIONS
TOP VIEW
PWR
X1
X2
AD0
AD1
AD2
AD3
AD4
AD5
AD6
AD7
GND
1
2
24
23
V
CC
X2
X1
PWR
N.C.
V
CC
SQW
PWR
1
2
3
4
5
6
7
8
9
10
11
12
24
V
CC
SQW
V
BAUX
RCLR
N.C.
IRQ
KS
RD
N.C.
WR
ALE
CS
DS1685/
3
DS1685S/
22
4
DS1685E
21
5
6
7
8
9
10
11
12
20
19
18
17
16
15
14
13
V
BAUX
RCLR
V
BAT
IRQ
KS
RD
GND
WR
ALE
CS
AD0
AD1
AD2
AD3
AD4
AD5
N.C.
5
6
7
8
9
V
BAUX
SQW
N.C.
N.C.
RCLR
V
BAT
IRQ
KS
RD
GND
WR
AD0
AD1
AD2
AD3
AD4
AD5
AD6
AD7
GND
DS1687
23
22
21
20
19
18
17
16
15
14
13
4
3
2
1
28
27
26
25
24
23
22
21
20
19
DS1685Q
10
11
12
13 14
15 16
17
18
DIP (0.600″)/
SO (0.300″)/
TSSOP (0.173″)
AD6
N.C.
AD7
GND
CS
ALE
N.C.
PLCC
EDIP (0.740″)
1 of 39
REV: 112105
DALLAS [ DALLAS SEMICONDUCTOR ]
