HT1302BRMZ

The HT1302B trickle-charge timekeeping chip integrates 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 of week, date, month, and year information. End-of-month dates are automatically adjusted for months with fewer than 31 days, including leap year correction. The clock operates in either 24-hour or 12-hour format with an AM/PM indicator. The interface between the HT1302B and a microprocessor is simplified through synchronous serial communication. Only three lines are required to communicate with the clock/RAM: CE, I/O (data line), and 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 HT1302B is designed to operate at extremely low power consumption, retaining data and clock information at less than 1μW. Additional features of the HT1302B include dual power supply pins for primary and backup power, a programmable trickle charger for VCC1, and seven additional scratchpad memory bytes.

Key features

• Real-time clock counts seconds, minutes, hours, date, month, day of week, and year with leap year compensation valid through 2100
• 31×8 battery-backed general-purpose RAM
• Serial I/O for minimal pin count
• Full operation from 2.0V to 5.5V
• Less than 300nA power consumption at 2.0V
• Single-byte or multi-byte (burst mode) data transfer for reading or writing clock or RAM data
• 8-pin DIP or optional 8-pin SO surface mount package
• Simple 3-wire interface
• TTL compatible (VCC = 5V)
• Optional industrial temperature range: -40°C to +85°C
• UL® recognized