DS1302 Trickle-Charge Timekeeping Chip BENEFITS AND FEATURES PIN CONFIGURATIONS Completely Manages All Timekeeping Functions o Real-Time Clock Counts Seconds, TOP VIEW Minutes, Hours, Date of the Month, Month, V V 1 8 CC1 CC2 Day of the Week, and Year with Leap-Year SCLK X1 2 7 Compensation Valid Up to 2100 I/O X2 3 6 o 31 x 8 Battery-Backed General-Purpose GND CE 4 5 RAM Simple Serial Port Interfaces to Most DIP (300 mils) Microcontrollers o Simple 3-Wire Interface o TTL-Compatible (V = 5V) CC V 1 8 V CC2 CC1 o Single-Byte or Multiple-Byte (Burst Mode) X1 2 7 SCLK Data Transfer for Read or Write of Clock or X2 3 6 I/O RAM Data GND 4 5 CE Low Power Operation Extends Battery Backup Run Time SO (208 mils/150 mils) o 2.0V to 5.5V Full Operation o Uses Less Than 300nA at 2.0V 8-Pin DIP and 8-Pin SO Minimizes Required Space Optional Industrial Temperature Range: -40C to +85C Supports Operation in a Wide Range of Applications Underwriters Laboratories (UL) Recognized ORDERING INFORMATION PART TEMP RANGE PIN-PACKAGE TOP MARK* DS1302+ 0C to +70C 8 PDIP (300 mils) DS1302 DS1302N+ -40C to +85C 8 PDIP (300 mils) DS1302 DS1302S+ 0C to +70C 8 SO (208 mils) DS1302S DS1302SN+ -40C to +85C 8 SO (208 mils) DS1302S DS1302Z+ 0C to +70C 8 SO (150 mils) DS1302Z DS1302ZN+ -40C to +85C 8 SO (150 mils) DS1302ZN +Denotes a lead-free/RoHS-compliant package. *An N anywhere on the top mark indicates an industrial temperature grade device. A + anywhere on the top mark indicates a lead-free device. UL is a registered trademark of Underwriters Laboratories, Inc. 1 of 13 REV: 3/15 DS1302 DS1302 DS1302 Trickle-Charge Timekeeping Chip DETAILED DESCRIPTION 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 1 W. 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 , and seven additional bytes of scratchpad memory. trickle charger for V CC1 OPERATION Figure 1 shows the main elements of the serial timekeeper: shift register, control logic, oscillator, real-time clock, and RAM. TYPICAL OPERATING CIRCUIT V CC X1 X2 CE V CC V CC2 CPU DS1302 I/O SCLK V CC1 GND 2 of 13