GREENMICRO DS1302Z137

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. End-of-month date is automatically adjusted for months with fewer than 31 days, including corrections for leap years. The clock operates in either 24-hour or 12-hour format with an AM/PM indicator. The interface between the DS1302 and a microprocessor is simplified by using synchronous serial communication. Only three wires 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 to or from the clock/RAM one byte at a time or in burst mode of up to 31 bytes. The DS1302 is designed for extremely low-power operation, maintaining data and clock information at less than 1μW. The chip is available in a standard SOP8 package.

• Real-time clock (RTC) counts seconds, minutes, hours, day of month, month, day of week, and year with leap-year compensation valid through 2100
• 31-byte battery-backed NV RAM for data storage
• Serial I/O for minimal pin count
• 2.0V to 5.5V full-range operating voltage
• Power consumption below 300nA at 2.0V
• Burst mode for reading/writing consecutive addresses in clock/RAM
• Simple 3-wire interface
• TTL compatible (Vcc = 5V)
• Optional temperature range: 0°C to +70°C

• Clock ICs
• Mobile phones
• Portable instruments