Real Time Clock Integrates EEPROM And Crystal

To reduce board space and increase reliability, the M41T56C64 serial real-time clock (RTC) integrates EEPROM and an embedded crystal in a single, 18-pin SOIC package. The RTC section provides year, month, and day data along with hours, minutes, and seconds. Drawing 450 nA typical, the IC can accurately keep time for more than ten years on a 48-mAh lithium coin cell. The EEPROM section provides 8,192 bytes of memory with more than 1 million erase/write cycles per byte. The RTC and EEPROM are accessed via a two-wire I2C bus. The pre-calibrated, 32-kHz crystal specifies an accuracy of ±5ppm. Other features include eight bytes of BCD registers for clock/calendar functions and 56 bytes of NVRAM. When power is removed, the device automatically switches to its backup battery input and goes into a low-current mode to maximize battery life. Price for the M41T56C64 is $1.35 each in high volume. STMICROELECTRONICS, Lexington, MA. (888) 787-3550.