DS1501/DS1511
Y2K-Compliant Watchdog
Real-Time Clocks
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
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 (W) or +5V (Y) 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 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 (DS1501)
Battery Voltage-Level Indicator Flags
Available as Chip (DS1501) or Stand-Alone
Encapsulated DIP Module with Embedded
Battery and Crystal (DS1511)
Underwriters Laboratories (UL) Recognized
PIN-PACKAGE
28 TSOP
28 TSOP
28 TSOP
28 TSOP
TOP MARK*
DS1501WE
DS1501WEN
DS1501WEN
DS1501WE
APPLICATIONS
Remote Systems
Battery-Backed Systems
Telecom Switches
Office Equipment
Consumer Electronics
Pin Configurations and Typical Operating Circuit appear at
end of data sheet.
ORDERING INFORMATION
PART
DS1501WE+
DS1501WEN+
DS1501WEN+T&R
DS1501WE+T&R
VOLTAGE (V)
3.3
3.3
3.3
3.3
TEMP RANGE
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
+Denotes
a lead(Pb)-free/RoHS-compliant package.
*A
“+” anywhere on the top mark denotes a lead(Pb)-free device. An N or IND denotes an industrial temperature device.
T&R = Tape and reel.
Ordering Information 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.maximintegrated.com/errata.
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19-6820; Rev 10/13
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
DS1501………………………………………………………….………………………………….-40°C to +85°C (Note 1)
DS1511……………………………………………………………….………………………………………...0°C to +70°C
Storage Temperature Range
DS1501…………………...………………………………………………………………………………...-55°C to +125°C
DS1511………………………………………………………………….…………………………………....-40°C to +70°C
Lead Temperature (soldering, 10 seconds)…..………...………………………………………...……..…………..+260°C
Note:
EDIP is hand or wave-soldered only. (Note 2)
Soldering Temperature (reflow, SO or TSOP)…….………….….......................................................................+260°C
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
(DS1511: V
CC
= 3.3V or 5V ±10%, T
A
= 0°C to +70°C; DS1501: V
CC
= 3.3V or 5V ±10%, T
A
= -40°C to +85°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
5V (Y)
4.5
5.0
5.5
Power Supply Voltage (Note 3)
V
CC
V
3.3V (W)
3.0
3.3
3.6
Y
2.2
V
CC
+ 0.3
Logic 1 Voltage All Inputs (Note 3)
V
IH
V
W
2.0
V
CC
+ 0.3
Pullup Voltage,
IRQ, PWR,
and
V
PU
5.5
V
RST
Outputs (Note 3)
Y
-0.3
+0.8
Logic 0 Voltage All Inputs (Note 3)
V
IL
V
W
-0.3
+0.6
Battery Voltage (Note 3)
V
BAT
2.5
3.0
3.7
V
Auxiliary Battery Voltage (Note 3)
V
BAUX
Y
W
2.5
2.5
3.0
3.0
5.3
3.7
V
DC ELECTRICAL CHARACTERISTICS
(DS1511: V
CC
= 3.3V or 5V ±10%, T
A
= 0°C to +70°C; DS1501: V
CC
= 3.3V or 5V ±10%, T
A
= -40°C to +85°C.)
PARAMETER
SYMBOL CONDITIONS
MIN
TYP
MAX
UNITS
Y
15
Active Supply Current (Note 4)
I
CC
mA
W
10
Y
5
TTL Standby Current (CE = V
IH
)
I
CC1
mA
W
4
CMOS Standby Current
Y
5
I
CC2
mA
(CE
=
V
CC
- 0.2V)
W
4
Input Leakage Current (Any Input)
Output Leakage Current (Any Output)
Output Logic 1 Voltage
(I
OUT
= -1.0mA)
Output Logic 0 Voltage (I
OUT
= 2.1mA,
DQ0–7; I
OUT
= 5.0mA,
IRQ,
I
OUT
=
7.0mA,
PWR
and
RST)
Battery Low, Flag Trip Point (Note 2)
Power-Fail Voltage (Note 2)
I
IL
I
OL
V
OH
V
OL1
V
OL2
V
BLF
V
PF
(Note 3)
(Note 3)
(Notes 3, 5)
Y
W
Y
W
2.0
1.9
4.20
2.75
4.50
2.97
-1
-1
2.4
0.4
0.4
+1
+1
µA
µA
V
V
V
V
V
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DS1501/DS1511 Y2KC Watchdog Real-Time Clocks
PARAMETER
Battery Switchover Voltage (Notes 3, 6)
Battery Leakage Current
SYMBOL
V
SO
I
LKG
CONDITIONS
MIN
TYP
V
BAT,
V
BAUX,
or V
PF
MAX
UNITS
V
100
nA
DC ELECTRICAL CHARACTERISTICS
(DS1511: V
CC
= 0V; T
A
= 0°C to +70°C; DS1501: V
CC
= 0V, T
A
= -40°C to +85°C.)
PARAMETER
Battery Current, BB32 = 0,
EOSC
= 0
Battery Current, BB32 = 0,
EOSC
= 1
V
BAUX
Current BB32 = 1, SQW Open
SYMBOL
I
BAT1
I
BAT2
I
BAUX
CONDITIONS
(Note 7)
(Note 7)
(Note 7)
MIN
TYP
0.27
0.01
2
MAX
1.0
0.1
UNITS
µA
µA
µA
CRYSTAL SPECIFICATIONS*
PARAMETER
Nominal Frequency
Series Resistance
Load Capacitance
SYMBOL
f
O
ESR
C
L
CONDITIONS
MIN
TYP
32.768
6/12.5
MAX
45
UNITS
kHz
kΩ
pF
*The crystal, traces, and crystal input pins should be isolated from RF generating signals.
Refer to
Application Note 58: Crystal Considerations
for Dallas Real-Time Clocks
for additional specifications.
AC OPERATING CHARACTERISTICS
(DS1511: V
CC
= 5V ±10%, T
A
= 0°C to +70°C; DS1501: V
CC
= 5V ±10%, T
A
= -40°C to +85°C.)
PARAMETER
Read Cycle Time
Address Access Time
CE
to DQ Low-Z
CE
Access Time
CE
Data-Off Time
OE
to DQ Low-Z (0°C to +85°C)
OE
to DQ Low-Z (-40°C to 0°C)
OE
Access Time
OE
Data-Off Time
Output Hold from Address
Write Cycle Time
Address Setup Time
WE
Pulse Width
CE
Pulse Width
Data Setup Time
Data Hold Time
Address Hold Time
WE
Data-Off Time
Write Recovery Time
Pulse Width,
OE, WE,
or
CE
High
Pulse Width,
OE, WE,
or
CE
Low
SYMBOL
t
RC
t
AA
t
CEL
t
CEA
t
CEZ
t
OEL
t
OEL
t
OEA
t
OEZ
t
OH
t
WC
t
AS
t
WEW
t
CEW
t
DS
t
DH
t
AH
t
WEZ
t
WR
PW
HIGH
PW
LOW
CONDITIONS
MIN
70
5
70
25
5
2
35
25
5
70
0
50
55
30
5
0
(Note 8)
15
20
70
25
TYP
MAX
70
(Note 8)
(Note 8)
(Note 8)
(Note 8)
(Note 8)
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
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DS1501/DS1511 Y2KC Watchdog Real-Time Clocks
AC OPERATING CHARACTERISTICS
(DS1511:
V
CC
= 3.3V ±10%,
T
A
= 0°C to +70°C; DS1501:
V
CC
= 3.3V ±10%,
T
A
= -40°C to +85°C.)
PARAMETER
Read Cycle Time
Address Access Time
CE
to DQ Low-Z
CE
Access Time
CE
Data Off Time
OE
to DQ Low-Z (0°C to +85°C)
OE
to DQ Low-Z (-40°C to 0°C)
OE
Access Time
OE
Data-Off Time
Output Hold from Address
Write Cycle Time
Address Setup Time
WE
Pulse Width
CE
Pulse Width
Data Setup Time
Data Hold Time
Address Hold Time
WE
Data-Off Time
Write Recovery Time
Pulse Width,
OE, WE,
or
CE
High
Pulse Width,
OE, WE,
or
CE
Low
SYMBOL
t
RC
t
AA
t
CEL
t
CEA
t
CEZ
t
OEL
t
OEL
t
OEA
t
OEZ
t
OH
t
WC
t
AS
t
WEW
t
CEW
t
DS
t
DH
t
AH
t
WEZ
t
WR
PW
HIGH
PW
LOW
CONDITIONS
MIN
120
5
120
40
5
2
100
35
5
120
0
100
110
80
5
5
(Note 8)
15
40
100
40
TYP
MAX
120
(Note 8)
(Note 8)
(Note 8)
(Note 8)
(Note 8)
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Figure 1. Read Cycle Timing
t
RC
A0–A4
t
AA
CE
t
CEA
t
CEZ
t
OH
t
CEL
OE
t
OEA
t
OEZ
t
OEL
DQ0-DQ7
VALID
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DS1501/DS1511 Y2KC Watchdog Real-Time Clocks
Figure 2. Write Cycle Timing, Write-Enable Controlled
t
WC
A0–A4
VALID
VALID
t
AS
t
AH
CE
t
AS
t
WEW
t
WR
WE
t
WEZ
t
DS
t
DH
DQ0–DQ7
DATA OUTPUT
DATA INPUT
DATA INPUT
Figure 3. Write Cycle Timing, Chip-Enable Controlled
t
WC
A0-A4
VALID
VALID
t
AS
t
CEW
t
AH
CE
t
AS
t
WR
WE
t
DS
t
DH
DQ0-DQ7
DATA INPUT
DATA INPUT
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