DS1216D DS1216D SmartWatch/RAM 256K/1M FEATURES PIN ASSIGNMENT * Converts standard 8K x 8, 32K x 8, 128K x 8, and 512K x 8 CMOS static RAMs into nonvolatile memory 1 32 2 31 3 30 VCC 4 29 WE 5 28 6 27 7 26 8 25 9 24 10 23 * Lithium energy source is electrically disconnected to 11 22 retain freshness until power is applied for the first time 12 21 DQ0 13 20 14 19 15 18 GND 16 17 * Embedded lithium energy cell maintains watch information and retains RAM data * Watch function is transparent to RAM operation * Keeps track of hundredths of seconds, seconds, minutes, hours, days, date of the month, months, and years * Month and year determine the number of days in each month; leap year compensation valid up to 2100 * Proven gas-tight socket contacts * Full +10% operating range * Operating temperature range 0C to 70C * Accuracy is better than 1 min./month @ 25C VCC OE CE 32-PIN INTELLIGENT SOCKET PIN DESCRIPTION All pins pass through except 22, 30 and 32. - RESET Pin 1 RST Pin 13 DQ0 - Data Input/Output 0 Pin 16 GND - Ground Pin 22 CE - Conditioned Chip Enable Pin 24 OE - Output Enable - Write Enable Pin 29 WE Pin 30 VCC - Switched VCC for 28-pin RAM Pin 32 VCC - Switched VCC for 32-pin RAM DESCRIPTION The DS1216D SmartWatch/RAM 256K/1M is a 32-pin, 600 MIL wide DIP socket with a built-in CMOS watch function, a nonvolatile RAM controller circuit, and an embedded lithium energy source. It accepts either an 8K x 8, 32K x 8, 128K x 8, or 512K x 8 JEDEC bytewide CMOS static RAM. When the socket is mated with a CMOS SRAM, it provides a complete solution to prob- Copyright 1995 by Dallas Semiconductor Corporation. All Rights Reserved. For important information regarding patents and other intellectual property rights, please refer to Dallas Semiconductor data books. lems associated with memory volatility and uses a common energy source to maintain time and date. A key feature of the SmartWatch is that the watch function remains transparent to the RAM. See the DS1216B SmartWatch/RAM 16/64K data sheet for technical details. 080697 1/1