DS1501/DS1511
Y2K-Compliant Watchdog
Real-Time Clocks
www.maxim-ic.com
GENERAL DESCRIPTION
The DS1501/DS1511 are full-function, year 2000-
compliant real-time clock/calendars (RTCs) with an
RTC alarm, watchdog timer, power-on reset, battery
monitors, 256 bytes NV SRAM, and a 32.768kHz
output. User access to all registers within the
DS1501/DS1511 is accomplished with a byte-wide
interface, as shown in Figure 8. The RTC registers
contain century, year, month, date, day, hours,
minutes, and seconds data in 24-hour binary-coded
decimal (BCD) format. Corrections for day of month
and leap year are made automatically.
FEATURES
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BCD-Coded Century, Year, Month, Date, Day,
Hours, Minutes, and Seconds with Automatic
Leap-Year Compensation Valid Up to the Year
2100
Programmable Watchdog Timer and RTC Alarm
Century Register; Y2K-Compliant RTC
+3.3 or +5V Operation
Precision Power-On Reset
Power-Control Circuitry Support System Power-
On from Date/Day/Time Alarm or Key
Closure/Modem-Detect Signal
256 Bytes Battery-Backed NV SRAM
Auxiliary Battery Input
Accuracy of DS1511 Better than ±1
Minute/Month at +25°C
Day-of-Week/Date Alarm Register
Crystal Select Bit Allow RTC to Operate with 6pF
or 12.6pF Crystal
Battery Voltage-Level Indicator Flags
Available as Chip (DS1501) or Stand-Alone
Module with Embedded Battery and Crystal
(DS1511)
UL Recognized
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APPLICATIONS
Remote Systems
Battery-Backed Systems
Telecom Switches
Office Equipment
Consumer Electronics
ORDERING INFORMATION
PART
DS1501YN
DS1501YEN
DS1501YSN
DS1501WN
DS1501WEN
DS1501WSN
DS1511Y
DS1511W
TEMP RANGE
-40°C to +85°C
-40°C to +85°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
0°C to +70°C
PIN-PACKAGE
28 DIP (600 mil)
28 TSOP
28 SO (330 mil)
28 DIP (600 mil)
28 TSOP
28 SO (330 mil)
28 Module (720 mil)
28 Module (720 mil)
PIN CONFIGURATION
TOP VIEW
Selector Guide appears at end of data sheet.
Typical Operating Circuits appears at end of data sheet.
PWR
X1
X2
RST
IRQ
A4
A3
A2
A1
A0
DQ0
DQ1
DQ2
GND
1
28
2
27
3
26
4
25
Dallas
5
Semiconductor
24
6
DS1501
23
22
7
21
8
20
9
19
10
18
11
17
12
16
13
15
14
V
CC
WE
V
BAUX
V
BAT
KS
SQW
OE
GND
CE
DQ7
DQ6
DQ5
DQ4
DQ3
DIP, SO
Pin Configurations are continued at end of data sheet.
Note:
Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device
may be simultaneously available through various sales channels. For information about device errata, click here:
1 of 20
REV: 031704
DALLAS [ DALLAS SEMICONDUCTOR ]
