DS1688 Maxim Integrated Products, DS1688 Datasheet
DS1688
Manufacturer Part Number
DS1688
Description
IC RTC W/NV RAM CTRL 28-DIP
Manufacturer
Maxim Integrated Products
Type
Clock/Calendar/Serializedr
Datasheet
1.DS1688S.pdf
(3 pages)
Specifications of DS1688
Memory Size
114B
Time Format
HH:MM:SS (12/24 hr)
Date Format
YY-MM-DD
Interface
Parallel
Voltage - Supply
2.7 V ~ 3.3 V, 4.5 V ~ 5.5 V
Operating Temperature
0°C ~ 70°C
Mounting Type
Through Hole
Package / Case
28-DIP (0.600", 15.24mm)
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
DS1688S
Manufacturer:
DALLAS
Quantity:
10
Part Number:
DS1688S
Manufacturer:
DS
Quantity:
20 000
www.maxim-ic.com
GENERAL DESCRIPTION
The DS1688/DS1691 are real-time clocks
(RTCs) designed as successors to the industry
standard
DS1585 PC real-time clocks. These devices
provide the industry standard DS1285 clock
function with the new feature of either +3.0V or
+5.0V operation and automatic backup and write
protection to an external SRAM. The DS1688
also incorporates a number of enhanced features
including a silicon serial number, power-on/off
control circuitry, 114 bytes of user NV SRAM,
power-on elapsed timer, and power-cycle
counter.
PIN CONFIGURATIONS
ORDERING INFORMATION
+ Denotes a lead(Pb)-free/RoHS-compliant device.
+ A “+” anywhere on the top mark denotes a lead(Pb)-free/RoHS-compliant device.
DS1688S
DS1688S+
DS1691
TOP VIEW
PART
DS1285,
DS1385,
TEMP RANGE
0C to +70C
0C to +70C
0C to +70C
DS1485,
and
VOLTAGE (V)
3V/5V Serialized Real-Time Clocks
1 of 3
3 to 5
3 to 5
3 to 5
FEATURES
Incorporates Industry Standard DS1287 PC
Clock Plus Enhanced Features:
+3V or +5V Operation
64-Bit Silicon Serial Number
64-Bit Customer Specific ROM or
Power Control Circuitry Supports System
Automatic Battery Backup and Write
Crystal Select Bit Allows RTC to Operate
114 Bytes User NV RAM
Auxiliary Battery Input
RAM Clear Input
Century Register
32kHz Output for Power Management
32-Bit V
32-Bit V
16-Bit Power-Cycle Counter
Compatible with Existing BIOS for
Available as IC (DS1688) or Stand-Alone
Timekeeping Algorithm Includes Leap
Additional Serial Number Available
Power-On from Date/Time Alarm or Key
Closure
Protection to External SRAM
with 6Pf or 12.5Pf Crystal
Counter
Counter
Original DS1287 Functions
Module with Embedded Battery and
Crystal (DS1691)
Year Compensation Valid Up to 2100
PIN-PACKAGE
28 SO (0.330)
28 SO (0.330)
28 EDIP (0.740)
CC
BAT
with NV RAM Control
Powered Elapsed Time
Powered Elapsed Time
DS1688/DS1691
REV: 112205
TOP MARK*
DS1688S
DS1688S
DS1691
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DS1688 Summary of contents
Page 1
... V Counter 32-Bit V Counter 16-Bit Power-Cycle Counter Compatible with Existing BIOS for Original DS1287 Functions Available as IC (DS1688) or Stand-Alone Module with Embedded Battery and Crystal (DS1691) Timekeeping Algorithm Includes Leap Year Compensation Valid Up to 2100 VOLTAGE ( ...
Page 2
... The DS1688 is a clock/calendar chip with the features described above. An external crystal and battery are the only components required to maintain time-of-day and memory status in the absence of power. The DS1691 incorporates the DS1688 chip, a 32.768kHz crystal, and a lithium battery in a complete, self- contained timekeeping module. The entire unit is fully tested at Dallas Semiconductor such that a ...
Page 3
... The square wave is output on this pin if either SQWE = 1 or E32K = 1. RAM Power-Supply Output +3V or +5V Main Supply Active-Low RAM Chip Enable Out Active-Low RAM Chip Enable In No Connection DOCUMENT NO. 21-0251 21-0044 21-0241 © 2005 Maxim Integrated Products DS1688/DS1691 , after a power-up REC ...