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DS1553WP-120+

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20
1 of 20
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
.
GENERAL DESCRIPTION
The DS1553 is a full-function, year-2000-
compliant (Y2KC) real-time clock/calendar (RTC)
with an RTC alarm, watchdog timer, power-on
reset, battery monitor, and 8k x 8 nonvolatile static
RAM. User access to all registers within the
DS1553 is accomplished with a byte-wide
interface as shown in Figure 1. The RTC registers
contain century, year, month, date, day, hours,
minutes, and seconds data in 24-hour BCD format.
Corrections for day of month and leap year are
made automatically.
Pin Configurations appear at end of data sheet.
FEATURES
Integrated NV SRAM, RTC, Crystal, Power-Fail
Control Circuit, and Lithium Energy Source
Clock Registers are Accessed Identically to the
Static RAM; These Registers are Resident in the
16 Top RAM Locations
Totally Nonvolatile with Over 10 Years of
Operation in the Absence of Power
Precision Power-On Reset
Programmable Watchdog Timer and RTC Alarm
BCD-Coded Year, Month, Date, Day, Hours,
Minutes, and Seconds with Automatic Leap Year
Compensation Valid Up to the Year 2100
Battery Voltage Level Indicator Flag
Power-Fail Write Protection Allows for 10%
V
CC
Power-Supply Tolerance
Lithium Energy Source is Electrically
Disconnected to Retain Freshness Until Power is
Applied for the First Time
ORDERING INFORMATION
PART VOLTAGE (V) TEMP RANGE PIN-PACKAGE TOP MARK**
DS1553-85+ 5.0 0°C to +70°C 28 EDIP (0.740) DS1553+85
DS1553-100+ 5.0 0°C to +70°C 28 EDIP (0.740) DS1553+100
DS1553W-120+ 3.3 0°C to +70°C 28 EDIP (0.740) DS1553W+120
DS1553W-150+ 3.3 0°C to +70°C 28 EDIP (0.740) DS1553W+150
DS1553P-85+ 5.0 0°C to +70°C 34 PowerCap* DS1553P+85
DS1553P-100+ 5.0 0°C to +70°C 34 PowerCap* DS1553P+100
DS1553WP-120+ 3.3 0°C to +70°C 34 PowerCap* DS1553WP+120
DS1553WP-150+ 3.3 0°C to +70°C 34 PowerCap* DS1553WP+150
DS9034PCX+ 3 0°C to +70°C — DS9034PCX
+Denotes a lead(Pb)-free/RoHS-compliant package.
*
PowerCap required, must be ordered separately
**A “+” symbol anywhere on the top mark indicates a lead(Pb)-free package.
DS1553
64kB, Nonvolatile, Year-2000-Compliant
Timekeeping RAM
www.maxim-ic.com
19-5480
;
Rev 8/10
DS1553 64kB, Nonvolatile, Year-2000-Compliant Timekeeping RAM
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PIN DESCRIPTION
PIN
EDIP PowerCap
NAME FUNCTION
1 2
RST
Active-Low Power-On Reset Output (Open Drain)
2 30 A12
3 25 A7
4 24 A6
5 23 A5
6 22 A4
7 21 A3
8 20 A2
9 19 A1
10 18 A0
21 28 A10
23 29 A11
24 27 A9
25 26 A8
Address Inputs
11 16 DQ0
12 15 DQ1
13 14 DQ2
15 13 DQ3
16 12 DQ4
17 11 DQ5
18 10 DQ6
19 9 DQ7
Data Input/Outputs
20 8
CE
Active-Low Chip Enable
22 7
OE
Active-Low Output Enable
26 1 IRQ/FT Active-Low Interrupt/Frequency Test Output (Open Drain)
27 6
WE
Active-Low Write Enable
28 5 V
CC
Power-Supply Input
17 GND Ground
— 2, 3, 31–34 N.C No Connection
DS1553 64kB, Nonvolatile, Year-2000-Compliant Timekeeping RAM
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DETAILED DESCRIPTION
The RTC registers in the DS1553 are double-buffered into an internal and external set. The user has direct
access to the external set. Clock/calendar updates to the external set of registers can be disabled and
enabled to allow the user to access static data. Assuming the internal oscillator is turned on, the internal
set of registers is continuously updated. This occurs regardless of external registers settings to guarantee
that accurate RTC information is always maintained.
The DS1553 has interrupt ( IRQ /FT) and reset ( RST ) outputs that can be used to control CPU activity.
The IRQ /FT interrupt output can be used to generate an external interrupt when the RTC register values
match user-programmed alarm values. The interrupt is always available while the device is powered from
the system supply, and it can be programmed to occur when in the battery-backed state to serve as a
system wakeup. Either the IRQ /FT or RST outputs can also be used as a CPU watchdog timer. CPU
activity is monitored and an interrupt or reset output is activated if the correct activity is not detected
within programmed limits. The DS1553 power-on reset can be used to detect a system power-down or
failure and can hold the CPU in a safe reset state until normal power returns and stabilizes. The RST
output is used for this function.
The DS1553 also contains its own power-fail circuitry, which automatically deselects the device when the
V
CC
supply enters an out-of-tolerance condition. This feature provides a high degree of data security
during unpredictable system operation brought on by low V
CC
levels.
PACKAGES
The DS1553 is available in a 28-pin DIP and a 34-pin PowerCap module. The 28-pin DIP module
integrates the crystal, lithium energy source, and silicon in one package. The 34-pin PowerCap module
board is designed with contacts for connection to a separate PowerCap (DS9034PCX) that contains the
crystal and battery. This design allows the PowerCap to be mounted on top of the DS1553P after
completion of the surface-mount process. Mounting the PowerCap after the surface-mount process
prevents damage to the crystal and battery due to the high temperatures required for solder reflow. The
PowerCap is keyed to prevent reverse insertion. The PowerCap module board and PowerCap are ordered
separately and shipped in separate containers. The part number for the PowerCap is DS9034PCX.
Figure 1. Block Diagram
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20

DS1553WP-120+

Mfr. #:
Buy DS1553WP-120+
Manufacturer:
Description:
Real Time Clock 64kB NV RAM Timekeepe
Lifecycle:
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