DS1284/DS1286
Watchdog Timekeepers
www.maxim-ic.com
GENERAL DESCRIPTION
FEATURES
The DS1284/DS1286 watchdog timekeepers are ꢀ Keeps Track of Hundredths of Seconds,
self-contained real-time clocks, alarms, watchdog
timers, and interval timers in a 28-pin JEDEC DIP
and encapsulated DIP package. The DS1286
Seconds, Minutes, Hours, Days, Date of the
Month, Months, and Years; Valid Leap Year
Compensation Up to 2100
contains an embedded lithium energy source and a ꢀ Watchdog Timer Restarts an Out-of-Control
quartz crystal, which eliminates the need for any
external circuitry. The DS1284 requires an external ꢀ Alarm Function Schedules Real-Time-Related
quartz crystal and a VBAT source, which could be a Activities
Processor
lithium battery. Data contained within 64 8-bit ꢀ Embedded Lithium Energy Cell Maintains
registers can be read or written in the same manner
as byte-wide static RAM. Data is maintained in the
Time, Watchdog, User RAM, and Alarm
Information
watchdog timekeeper by intelligent control circuitry ꢀ Programmable Interrupts and Square-Wave
that detects the status of VCC and write protects
memory when VCC is out of tolerance. The lithium ꢀ All Registers are Individually Addressable via
energy source can maintain data and real time for the Address and Data Bus
over 10 years in the absence of VCC. Watchdog ꢀ Accuracy is Better than ±1 Minute/Month at
timekeeper information includes hundredths of +25°C (EDIP)
seconds, seconds, minutes, hours, day, date, month, ꢀ Greater than 10 Years of Timekeeping in the
Outputs Maintain JEDEC Footprint
and year. The date at the end of the month is
Absence of VCC
automatically adjusted for months with fewer than ꢀ 50 Bytes of User NV RAM
31 days, including correction for leap year. The ꢀ Underwriters Laboratory (UL) Recognized
DS1284/DS1286 operate in either 24-hour or 12- ꢀ -40°C to +85°C Industrial Temperature Range
hour format with an AM/PM indicator. The devices
provide alarm windows and interval timing between
0.01 seconds and 99.99 seconds. The real-time
alarm provides for preset times of up to one week.
Option
Pin Configurations appear at end of data sheet.
ORDERING INFORMATION
PART
TEMP RANGE
0°C to +70°C
-40°C to +85°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
VOLTAGE (V)
PIN-PACKAGE
28 DIP (600 mils)
28 DIP (600 mils)
28 PLCC
TOP MARK*
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
DS1284
DS1284
DS1284N
DS1284 N
DS1284Q
DS1284Q
DS1284Q
DS1284Q
DS1284QN
DS1284QN
DS1284QN
DS1284QN
DS1286
DS1284Q
DS1284Q+
28 PLCC
DS1284Q/T&R
DS1284Q+T&R
DS1284QN
DS1284QN+
DS1284QN/T&R
DS1284QN+T&R
DS1286
28 PLCC/Tape and Reel
28 PLCC/Tape and Reel
28 PLCC
28 PLCC
28 PLCC/Tape and Reel
28 PLCC/Tape and Reel
28 EDIP (720 mils)
28 EDIP (720 mils)
28 EDIP (720 mils)
DS1286I
DS1286 IND
DS1286 IND
DS1286I+
+ Denotes a lead-free/RoHS-compliant package.
* A “+” anywhere on the top mark indicates a lead-free package.
1 of 18
REV: 032406
DALLAS [ DALLAS SEMICONDUCTOR ]
