DS1347:Low-Current, SPI-Compatible Real-Time Clock

Save Board Space with TDFN Package and Ability to Drive Surface-Mount Crystals

The DS1347 SPI-compatible real-time clock (RTC) contains a real-time clock/calendar and 31 x 8 bits of static random-access memory (SRAM). The real-time clock/calendar provides seconds, minutes, hours, day, date, month, year, and century information. A time/date programmable polled ALARM is included in the device. The end-of-the-month date is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24hr or 12hr format with an active-low AM/PM indicator. The device operates with a supply voltage of +2V to +5.5V, are available in the ultra-small 8-pin TDFN package, and work over the -40°C to +85°C industrial temperature range.

Key Features
  • Completely Manages All Timekeeping Functions
    • RTC Counts Seconds, Minutes, Hours, Day of Week, Date of Month, Month, Year, and Century
    • Leap-Year Compensation
    • 31 x 8-Bit SRAM for Scratchpad Data Storage
    • Programmable Time/Date Polled ALARM Function
    • Uses Standard 32.768kHz Watch Crystal
  • Low-Power Operation Extends Battery Life
    • Low Timekeeping Current (400nA at 2V)
    • +2V to +5.5V Wide Operating Voltage Range
  • Standard Serial Port Interfaces with Most Microcontrollers
    • SPI (Mode 1 or 3) Interface: 4MHz at 5V, 1MHz at 2V
    • Single-Byte or Multiple-Byte (Burst Mode) Data Transfer for Read or Write of Clock Registers or SRAM
  • 3mm x 3mm x 0.8mm, 8-Pin TDFN Package Minimizes Required Space
    • No External Crystal Bias Resistors or Capacitors Required
DS1346, DS1347: Typical Operating Circuit
DS1346, DS1347: Typical Operating Circuit
Applications/Uses
  • Battery-Powered Products
  • Fax Machines
  • Intelligent Instruments
  • Point-of-Sale Equipment
  • Portable Instruments
DataSheet
titleDownload file
DS1347 Data SheetDS1347.pdf
Parametrics
Part NumberInterfaceVSUPPLY
(V)
Time Keeping Current
(nA)
CL
(pF)
Memory TypeMemory Size
(Bytes)
Time of Day AlarmsFunctionsPackage/PinsBudgetary
Price
typSee Notes
DS1347SPI2.0 to 5.535012.5SRAM311RTCTDFN-EP/8$1.40 @1k
Quality and Environmental Data
Related Products
  • DS1343:Low-Current SPI/3-Wire RTCs
  • DS1344:Low-Current SPI/3-Wire RTCs
  • DS1305:Serial Alarm Real-Time Clock
  • DS1306:Serial Alarm Real-Time Clock
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
DS1347T+ActiveTDFN-EP,;8 pin;9.6 mm²-40°C to +85°CLead Free
DS1347T+T&RActiveTDFN-EP,;8 pin;9.6 mm²-40°C to +85°CLead Free
DS1347.pdf DS1347
DS1347.pdf DS1347
DS1347.pdf DS1347
Tips for Writing Bulletproof Real-Time Clock Control Code DS3234
State Machine Logic in Binary-Coded Decimal (BCD)-Formatted Real-Time Clocks DS3234
Interfacing an SPI RTC with a Motorola DSP DS3234
Interfacing an SPI-Interface RTC with a PIC Microcontroller DS3234
Design Considerations for Maxim Real-Time Clocks DS3234
Interfacing SPI Real-Time Clocks (RTCs) with a Microcontroller DS3234
Crystal Considerations with Maxim Real-Time Clocks (RTCs) DS3234
DS1347.pdf DS1347
DS1347.pdf DS1347