DS1251/DS1251P

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ORDERING INFORMATION

DS1251YP–XXXY (5V)

- IND Industrial

- 70

70ns access

blank 32-Pin DIP Module

P

34-Pin PowerCap Module board*

DS1251WP-XXXY (3.3V)

- IND Industrial

- 120

120ns access

blank 32-Pin DIP Module

P

34-Pin PowerCap Module board*

*DS9034PCX (PowerCap) Required:

(Must be ordered separately.)

PIN DESCRIPTION

- Address Inputs

CE

- Chip Enable

OE

- Output Enable

WE

- Write Enable

- Power Supply Input

GND

- Ground

- Data In/Data Out

NC

- No Connection

X1, X2

- Crystal Connection

- Battery Connection

RST

- Reset

DESCRIPTION

The DS1251 4096k NV SRAM with Phantom Clock is a fully static nonvolatile RAM (organized as 512k

words by 8 bits) with a built-in real-time clock. The DS1251Y has a self-contained lithium energy source

condition occurs, the lithium energy source is automatically switched on and write protection is

unconditionally enabled to prevent garbled data in both the memory and real-time clock.

The phantom clock provides timekeeping information including hundredths of seconds, seconds, minutes,

hours, days, dates, months, and years. The date at the end of the month is automatically adjusted for

months with fewer than 31 days, including correction for leap years. The phantom clock operates in either

24-hour or 12-hour format with an AM/PM indicator.

PACKAGES

The DS1251 is available in two packages: 32-pin DIP and 34-pin PowerCap module. The 32-pin DIP

style module integrates the crystal, lithium energy source, and silicon in one package. The 34-pin

PowerCap module board is designed with contacts for connection to a separate PowerCap (DS9034PCX)

that contains the crystal and battery. This design allows the PowerCap to be mounted on top of the

DS1251P after the completion of the surface mount process. Mounting the PowerCap after the surface

mount process prevents damage to the crystal and battery because of the high temperatures required for

solder reflow. The PowerCap is keyed to prevent reverse insertion. The PowerCap Module Board and

PowerCap are ordered separately and shipped in separate containers.