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Real-Time Clock IC - RTC 
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DS1347
Low-Current, SPI-Compatible Real-Time Clock
Save Board Space with TDFN Package and Ability to Drive Surface-Mount Crystals
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Key Features
Applications/Uses
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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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.
Technical Docs
Support & Training
Search our knowledge base for answers to your technical questions.
Filtered SearchOur dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .
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