Features and Benefits
- Completely Manages All Timekeeping Functions
- Real-Time Clock Counts Seconds, Minutes, Hours, Date of the Month, Month, Day of the Week, and Year with Leap-Year Compensation Valid Up to 2100
- 31 x 8 Battery-Backed General-Purpose RAM
- Simple Serial Port Interfaces to Most Microcontrollers
- Simple 3-Wire Interface
- TTL-Compatible (VCC = 5V)
- Single-Byte or Multiple-Byte (Burst Mode) Data Transfer for Read or Write of Clock or RAM Data
- Low Power Operation Extends Battery Backup Run Time
- 2.0V to 5.5V Full Operation
- Uses Less Than 300nA at 2.0V
- 8-Pin DIP and 8-Pin SO Minimizes Required Space
- Optional Industrial Temperature Range: -40°C to +85°C Supports Operation in a Wide Range of Applications
- Underwriters Laboratories® (UL) Recognized
The DS1302 trickle-charge timekeeping chip contains a real-time clock/calendar and 31 bytes of static RAM. It communicates with a microprocessor via a simple serial interface. The real-time clock/calendar provides seconds, minutes, hours, day, date, month, and year information. 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 24-hour or 12-hour format with an AM/PM indicator.
Interfacing the DS1302 with a microprocessor is simplified by using synchronous serial communication. Only three wires are required to communicate with the clock/RAM: CE, I/O (data line), and SCLK (serial clock). Data can be transferred to and from the clock/RAM 1 byte at a time or in a burst of up to 31 bytes. The DS1302 is designed to operate on very low power and retain data and clock information on less than 1µW.
The DS1302 is the successor to the DS1202. In addition to the basic timekeeping functions of the DS1202, the DS1302 has the additional features of dual power pins for primary and backup power supplies, programmable trickle charger for VCC1, and seven additional bytes of scratchpad memory.
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Documentation & Resources
DS1302 Reliability Data1/12/2023
Oscillator Design Considerations for Low-Current Applications1/26/2011
Selecting a Backup Source for Real-Time Clocks5/26/2006
Estimating Super Capacitor Backup Time on Trickle-Charger Real-Time Clocks5/24/2005
Interfacing a DS1302 With an 8051-Type Microcontroller2/21/2005
Using the DS32kHz with Maxim Real-Time Clocks2/15/2002
Design Considerations for Maxim Real-Time Clocks2/15/2002
Replacing the DS1202 with the DS13022/7/2002
Crystal Considerations with Maxim Real-Time Clocks (RTCs)3/29/2001
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
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