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Low-Current, SPI-Compatible Real-Time Clock

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

Product Details

Key Features

Parametric specs for Timekeeping & Real-Time Clocks
Interface SPI
VSUPPLY (V) 2.0 to 5.5
Date/ Time Format (hh = sec/100) YYYY-MM-DD/ HH:MM:SS
Time Keeping Current (nA) (typ) 350
CL (pF) 12.5
Memory Type SRAM
Memory Size (Bytes) 31
Time of Day Alarms 1
Package/Pins TDFN/8
Budgetary
Price (See Notes)
1.56
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Simplified Block Diagram

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Parameters

Parametric specs for Timekeeping & Real-Time Clocks
Interface SPI
VSUPPLY (V) 2.0 to 5.5
Date/ Time Format (hh = sec/100) YYYY-MM-DD/ HH:MM:SS
Time Keeping Current (nA) (typ) 350
CL (pF) 12.5
Memory Type SRAM
Memory Size (Bytes) 31
Time of Day Alarms 1
Package/Pins TDFN/8
Budgetary
Price (See Notes)
1.56

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

Applications/Uses

  • Battery-Powered Products
  • Fax Machines
  • Intelligent Instruments
  • Point-of-Sale Equipment
  • Portable Instruments

Description

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.

Simplified Block Diagram

DS1346, DS1347: Typical Operating Circuit DS1346, DS1347: Typical Operating Circuit Zoom icon

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .