JSM1302Z

The JSM1302Z slow-charge real-time clock chip integrates an RTC/calendar and 31 bytes of non-volatile static RAM. It communicates with a microprocessor through a simple serial interface. The RTC/calendar tracks seconds, minutes, hours, date, day, month, and year. The date at the end of the month is automatically adjusted for months with fewer than 31 days, with leap year correction supported. The clock operates in either 24-hour format or 12-hour format with AM/PM indication. The 31 bytes of RAM can be used to temporarily store critical data. Synchronous serial communication simplifies the interface between the JSM1302Z and a microprocessor. Only 3 lines are required to communicate with the clock/RAM: (1) RST (Reset), (2) I/O (Data Line), and (3) SCLK (Serial Clock). Data can be transferred in single-byte format, one byte at a time, or in multi-byte burst mode of up to 31 bytes. The JSM1302Z operates at extremely low power consumption, retaining data and clock information at less than 1uW.

Applications

• Multi-rate energy meter
• IC card water meter
• IC card gas meter
• Fax machine
• Portable instruments
• Mobile phone

Key features

• Counts seconds, minutes, hours, days, weeks, months, and years with leap year compensation
• 31-byte non-volatile static RAM for high-speed data scratchpad
• Wide operating voltage range: 2.0V ~ 5.5V
• Current consumption less than 300nA at 2.5V
• Single-byte or multi-byte data transfer for clock or RAM data read/write
• Simple 3-wire interface for MCU communication
• TTL compatible (VCC = 5V)
• Optional industrial temperature range: -40°C to +85°C
• Package options: DIP8 and SOP8