bq4830Y

The bq4830Y RTC Module is a nonvolatile 262,144-bit SRAM organized as 32,768 words by 8 bits with an integral accessible real-time clock.


The bq4830Y combines an internal lithium battery, quartz crystal, clock and power-fail chip, and a full CMOS SRAM in a plastic 28-pin DIP module. The RTC Module directly replaces industry-standard SRAMs and also fits into many EPROM and EEPROM sockets without any requirement for special write timing or limitations on the numberofwritecycles.


Registers for the real-time clock and clock calibration of bq4830Y are located in registers 7FF8h7FFFh of the memory array.


The clock registers of bq4830Y are dual-port read/write SRAM locations that are updated once per second by a clock control circuit from the internal clock counters. The dual-port regis-ters allow clock updates to occur without interrupting normal access totherestoftheSRAMarray.


The bq4830Y also contains a power fail-detect circuit. The circuit deselects the device whenever V_CC falls below tolerance,providing a high degree of data security. The battery is electrically isolated when shipped from the factory to provide maximum battery capacity. The battery remains disconnected until the first applicationofV_CC.