DS1501/DS1511
Y2K-Compliant Watchdog
Real-Time Clocks
www.maxim-ic.com
GENERAL DESCRIPTION
FEATURES
The DS1501/DS1511 are full-function, year 2000compliant 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.
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APPLICATIONS
Remote Systems
Battery-Backed Systems
Telecom Switches
Office Equipment
Consumer Electronics
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ORDERING INFORMATION
PART
TEMP RANGE
PIN-PACKAGE
DS1501YN
-40°C to +85°C
28 DIP (600 mil)
DS1501YEN
-40°C to +85°C
28 TSOP
DS1501YSN
-40°C to +85°C
28 SO (330 mil)
DS1501WN
-40°C to +85°C
28 DIP (600 mil)
DS1501WEN
-40°C to +85°C
28 TSOP
DS1501WSN
-40°C to +85°C
28 SO (330 mil)
DS1511Y
0°C to +70°C
28 Module (720 mil)
DS1511W
0°C to +70°C
28 Module (720 mil)
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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 PowerOn 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
PIN CONFIGURATION
TOP VIEW
PWR
X1
X2
RST
IRQ
A4
A3
A2
A1
A0
DQ0
DQ1
DQ2
GND
Selector Guide appears at end of data sheet.
Typical Operating Circuits appears at end of data sheet.
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
VCC
WE
VBAUX
VBAT
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: www.maxim-ic.com/errata.
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REV: 031704
DS1501/DS1511 Y2KC Watchdog Real-Time Clocks
ABSOLUTE MAXIMUM RATINGS
Voltage Range on Any Pin Relative to Ground……………………………………………………..……....-0.5V to +6.0V
Operating Temperature Range (Module)…………………………………………………………..………....0°C to +70°C
Operating Temperature Range, DS1501………………………………………………..-40°C to +85°C (Note 1)
Operating Temperature Range, DS1511……………………………………………………………….……..0°C to +70°C
Storage Temperature Range, DS1501…………………...…………………………………....-55°C to +125°C
Storage Temperature Range, DS1511………………………………………………………………….…..-40°C to +70°C
Soldering Temperature (DIP, Module)….………………….+260°C Lead Temperature for 10 seconds (max) (Note 2)
Soldering Temperature (SO, TSOP)…….……………..See IPC/JEDEC J-STD-020A for Surface-Mount Devices
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only,
and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is
not implied. Exposure to the absolute maximum rating conditions for extended periods may affect device reliability.
RECOMMENDED DC OPERATING CONDITIONS
(VCC = 3.3V or 5V ±10%, TA = 0°C to +70°C; VCC = 3.3V or 5V ±10%, TA = -40°C to +85°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
5V (Y)
4.5
5.0
Power Supply Voltage (Note 3)
VCC
3.3V (W)
3.0
3.3
Y
2.2
Logic 1 Voltage All Inputs (Note 3)
VIH
W
2.0
Pullup Voltage, IRQ, PWR, and
VPU
RST Outputs (Note 3)
Y
-0.3
Logic 0 Voltage All Inputs (Note 3)
VIL
W
-0.3
Battery Voltage (Note 3)
VBAT
Auxiliary Battery Voltage (Note 3)
VBAUX
Y
W
MAX
5.5
3.6
VCC + 0.3
VCC + 0.3
UNITS
5.5
V
+0.8
+0.6
V
V
V
2.5
3.0
3.7
V
2.5
2.5
3.0
3.0
5.3
3.7
V
DC ELECTRICAL CHARACTERISTICS
(VCC = 3.3V or 5V ±10%, TA = 0°C to +70°C; VCC = 3.3V or 5V ±10%, TA = -40°C to +85°C.)
PARAMETER
SYMBOL CONDITIONS
MIN
TYP
Y
Active Supply Current (Note 4)
ICC
W
Y
ICC1
TTL Standby Current (CE = VIH)
W
CMOS Standby Current
Y
ICC2
(CE = VCC - 0.2V)
W
MAX
15
10
5
4
5
4
UNITS
mA
mA
mA
Input Leakage Current (Any Input)
IIL
-1
+1
mA
Output Leakage Current (Any Output)
Output Logic 1 Voltage
(IOUT = -1.0mA)
Output Logic 0 Voltage (IOUT = 2.1mA,
DQ0–7; IOUT = 5.0mA, IRQ, IOUT =
7.0mA, PWR and RST)
IOL
-1
+1
mA
VOH
(Note 3)
VOL1
(Note 3)
0.4
V
VOL2
(Notes 3, 5)
0.4
V
Battery Low, Flag Trip Point (Note 2)
VBLF
Power-Fail Voltage (Note 2)
VPF
Battery Switchover Voltage (Notes 3, 6)
VSO
Battery Leakage Current
ILKG
Y
W
Y
W
2.4
V
2.0
1.9
4.20
2.75
V
4.50
2.97
VBAT,
VBAUX,
or VPF
V
100
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V
nA