DS1216D - Dallas Semiconductor - Datasheet.Directory

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DS1216D

SmartWatch/RAM 256K/1M

DS1216D

080697 1/1

FEATURES

•Converts standard 8K x 8, 32K x 8, 128K x 8, and

512K x 8 CMOS static RAMs into nonvolatile memory

•Embedded lithium energy cell maintains watch infor-

mation and retains RAM data

•W atch function is transparent to RAM operation

•Keeps track of hundredths of seconds, seconds, min-

utes, 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

•Lithium energy source is electrically disconnected to

retain freshness until power is applied for the first time

•Proven gas–tight socket contacts

•Full +10% operating range

•Operating temperature range 0°C to 70°C

•Accuracy is better than ±1 min./month @ 25°C

PIN ASSIGNMENT

DQ0 13

GND 16

32–PIN INTELLIGENT SOCKET

32 VCC

30 VCC

29 WE

24 OE

22 CE

PIN DESCRIPTION

All pins pass through except 22, 30 and 32.

Pin 1 RST – RESET

Pin 13 DQ0 – Data Input/Output 0

Pin 16 GND – Ground

Pin 22 CE – Conditioned Chip Enable

Pin 24 OE – Output Enable

Pin 29 WE – Write Enable

Pin 30 VCC – Switched VCC for 28–pin RAM

Pin 32 VCC – Switched VCC for 32–pin RAM

DESCRIPTION

The DS1216D SmartW atch/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-

lems associated with memory volatility and uses a com-

mon energy source to maintain time and date. A key

feature of the SmartW atch is that the watch function re-

mains transparent to the RAM.

See the DS1216B SmartWatch/RAM 16/64K data sheet

for technical details.