HT1307BRMZ

The HT1307 is a low-power, 512-bit static CMOS RAM organized as 64 words × 8 bits. It incorporates a built-in 32,768 Hz oscillator controlled by an external crystal, with the first 8 bytes of RAM dedicated to clock/calendar functions configured in BCD format. Address and data are transferred serially through a bidirectional two-wire bus. The built-in address register automatically increments after each write or read data byte. This clock IC features an integrated power-fail detection circuit that detects power failures and automatically switches to battery backup during such events. The energy required to maintain RAM and clock operation can be supplied by a small lithium coin cell battery. With a 50mAh, 3V lithium battery, typical data retention exceeds 10 years.

Key features

• 5V ±10% supply voltage
• Seconds, minutes, hours, day-of-week, date, month, year, and century counters
• Year 2000 compliant
• Software clock calibration
• Automatic power-fail detection and switchover circuit
• I²C bus compatible
• 56-byte general-purpose RAM
• 450nA ultra-low battery supply current
• 300μA low operating current
• -40 to 125℃ operating temperature range
• Automatic leap year compensation
• Special software-programmable output