Description The PT7C4302 serial real-time clock is a low power clock/calendar with a programmable square-wavenoutput and 31 bytes of nonvolatile RAM.

FEATUREs
• Using external 32.768kHz quartz crystal
• Real-time clock (RTC) counts seconds, minutes hours, date of the month, month, day of the week, and year with leap-year compensation valid up to 2099
• 31-byte, nonvolatile (NV) RAM for data storage
• 2.0V to 5.5V full operation
• Uses less than 300nA at 2.0V
• Simple 3-wire interface
• Serial I/O for minimum pin count
• Burst mode for reading/writing successive addresses in clock/RAM
• TTL-compatible (VCC = 5V)
• Optional industrial temperature range: -40°C to +85°C
• Battery backup
• Trickle charger on chip for rechargeable energy source backup