3-wire interface RTC with 31Byte NVRAM

The PT7C4302 serial real-time clock is a lowpowerclock/calendar with a programmable square-waveoutput and 31 bytes of nonvolatile RAM. Using external 32.768kHz quartz crystalReal-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 209931-byte, nonvolatile (NV) RAM for data storageTime keeping voltage: 1.5V to 5.5VUses less than 300nA at 2.0VSimple 3-wire interfaceSerial I/O for minimum pin countBurst mode for reading/writing successive addresses in clock/RAMTTL-compatible (VCC = 5V)Optional industrial temperature range: -40°C to +85°CBattery backupTrickle charger on chip for rechargeable energy source backup