19-5801; Rev 1; 12/11
Low-Current SPI/3-Wire RTCs
General Description
Features
SꢀLow_Timekeeping_Current_of_250nA_(typ)
The DS1343/DS1344 low-current real-time clocks (RTCs)
are timekeeping devices that provide an extremely low
standby current, permitting longer life from a backup
supply source. The devices also support high-ESR
crystals, broadening the pool of usable crystals for the
devices. The clock/calendar provides seconds, minutes,
hours, day, date, month, and year information. The date
at the end of the month is automatically adjusted for
months with fewer than 31 days, including corrections
for leap year. The clock operates in either 24-hour or
12-hour format with an AM/PM indicator.
SꢀCompatible_with_Crystal_ESR_Up_to_100kI
SꢀVersions_Available_to_Support_Either_6pF_or_
12.5pF_Crystals
SꢀRTC_Counts_Seconds,_Minutes,_Hours,_Day,_Date,_
Month,_and_Year_with_Leap_Year_Compensation_
Valid_Through_2099
SꢀPower-Fail_and_Switch_Circuitry
SꢀThree_Operating_Voltages
ꢀ 1.8V_ 5ꢁ
Address and data are transferred serially through an
SPI or 3-wire interface. Two programmable time-of-day
alarms are provided. Each alarm can generate an inter-
rupt on a combination of seconds, minutes, hours, and
day. Don’t-care states can be inserted into one or more
fields if it is desired for them to be ignored for the alarm
condition. The time-of-day alarms can be programmed
to assert two different interrupt outputs, or they can be
combined to assert one common interrupt output. Both
interrupt outputs operate when the device is powered by
ꢀ 3.0V 10ꢁ
ꢀ 3.3V_ 10ꢁ
SꢀTrickle-Charge_Capability
SꢀMaintain_Time_Down_to_1.15V_(typ)
SꢀSupport_Motorola_SPI_Modes_1_and_3,_or_Standard_
3-Wire_Interface
SꢀBurst_Mode_for_Reading/Writing_Successive_
Addresses_in_Clock/RAM
Sꢀ96-Byte_Battery-Backed_NV_RAM_for_Data_Storage
either V
or V
.
CC
BAT
SꢀTwo_Time-of-Day_Alarms_with_Two_Interrupt_
The devices are available in a lead-free/RoHS-compliant,
20-pin TSSOP or 14-pin TDFN package, and support a
-40°C to +85°C extended industrial temperature range.
Outputs
SꢀIndustrial_Temperature_Range
Sꢀ20-Pin_TSSOP_or_14-Pin_TDFN_Package
SꢀUnderwriters_Laboratories_(UL)_Recognized
Applications
Medical
Handheld Devices
Telematics
Typical Operating Circuit
Embedded Timestamping
V
CC
R
PU
V
CC
INT
RST
INT0
PF
X1
INT1
CE
SCLK
SDI
μP
DS1343
DS1344
X2
Ordering Information appears at end of data sheet.
3-WIRE
PORT
V
SDO
BAT
SERMODE GND
NOTE: SHOWN IN 3-WIRE I/O CONFIGURATION.
_ꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀ _Maxim Integrated Products_ _ 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.