DESCRIPTION

The DS1643 is a 8K x 8 nonvolatile static RAM with a full function Real Time Clock (RTC) which are both accessible in a byte-wide format. The nonvolatile timekeeping RAM is functionally equivalent to any JEDEC standard 8K x 8 SRAM. The device can also be easily substituted in ROM, EPROM and EEPROM sockets providing read/write nonvolatility and the addition of the real time clock function.

FEATURES

Integrated NV SRAM, real time clock, crystal, power-fail control circuit and lithium energy source

Clock registers are accessed identically to the static RAM. These registers are resident in the eight top RAM locations.

Totally nonvolatile with over 10 years of operation in the absence of power

Access times of 70 ns and 100 ns

BCD coded year, month, date, day, hours, minutes, and seconds with leap year compensation valid up to 2100

Power-fail write protection allows for ±10% VCC power supply tolerance

Lithium energy source is electrically disconnected to retain freshness until power is applied for the first time

DS1643 only (DIP Module)

–  Standard JEDEC byte-wide 8K x 8 RAM pinout DS1643P only (PowerCap Module Board)

–  Surface mountable package for direct connection to PowerCap containing battery and crystal

–  Replaceable battery (PowerCap)

–  Power-fail output

–  Pin-for-pin compatible with other densities of DS164XP Timekeeping RAM