DS1558
Watchdog Clock with NV RAM Control
www.maxim-ic.com
FEATURES
PIN CONFIGURATION
CꢀIntegrated Real-Time Clock (RTC), Power-
Fail Control Circuit, and NV RAM Controller
CꢀClock Registers are Accessed Identically to
the Static RAM; These Registers are Resident
in the 16 Top RAM Locations
TOP VIEW
1
N.C.
36
35
34
33
32
31
30
29
28
27
26
25
A15
VBAT1
WE
2
A18
A16
A14
A12
A7
3
CꢀCentury Register
4
IRQ/FT
A13
A8
CꢀGreater than 10 Years of Timekeeping and
Data Retention in the Absence of Power with
Small Lithium Coin Cell(s) and Low-Leakage
SRAM
5
6
DS1558
7
A6
A9
8
A5
A11
9
A4
OE
10
11
12
A3
A10
CE
A2
CꢀPrecision Power-On Reset
A1
OER
CꢀProgrammable Watchdog Timer and RTC
Alarm
CꢀBCD-Coded Year, Month, Date, Day, Hours,
Minutes, and Seconds with Automatic Leap-
Year Compensation Valid Up to the Year
2100
TQFP
For package information, go to :
www.maxim-ic.com/DallasPackInfo
CꢀBattery Voltage-Level Indicator Flag
CꢀPower-Fail Write Protection Allows for M10%
V
CC Power-Supply Tolerance
CꢀUnderwriters Laboratory (UL) Recognized
ORDERING INFORMATION
VOLTAGE
PART
TEMP RANGE
PIN-PACKAGE
TOP MARK*
(V)
3.3
3.3
3.3
3.3
5.0
5.0
5.0
5.0
DS1558W
-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
-40°C to +85°C
-40°C to +85°C
48 TQFP (7 x 7 x 1mm)
48 TQFP (7 x 7 x 1mm)
48 TQFP (7 x 7 x 1mm)
48 TQFP (7 x 7 x 1mm)
48 TQFP (7 x 7 x 1mm)
48 TQFP (7 x 7 x 1mm)
48 TQFP (7 x 7 x 1mm)
48 TQFP (7 x 7 x 1mm)
DS1558D
DS1558D
DS1558D
DS1558D
DS1558B
DS1558B
DS1558B
DS1558B
DS1558W+
DS1558W-TRL
DS1558W+TRL
DS1558Y
DS1558Y+
DS1558Y-TRL
DS1558Y+TRL
+ Denotes a lead-free/RoHS-compliant device.
* A “+” anywhere on the top mark indicates a lead-free device.
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: 071305