M48T201V datasheet(5/35 Pages) STMICROELECTRONICS

5 / 35 page

M48T201Y, M48T201V

Description

5/35

Description

The M48T201Y/V are self-contained devices that include a real time clock (RTC),

programmable alarms, a watchdog timer, and a square wave output which provides control

of up to 512K x 8 of external low-power static RAM. Access to all RTC functions and the

external RAM is the same as conventional bytewide SRAM. The 16 TIMEKEEPER®

registers offer year, month, date, day, hour, minute, second, calibration, alarm, century,

watchdog, and square wave output data. Externally attached static RAMs are controlled by

the M48T201Y/V via the GCON and ECON signals.

The 44-pin, 330mil SOIC provides sockets with gold plated contacts at both ends for direct

connection to a separate SNAPHAT® housing containing the battery and crystal. The

unique design allows the SNAPHAT battery package to be mounted on top of the SOIC

package after the completion of the surface mount process.

Insertion of the SNAPHAT housing after reflow prevents potential battery damage due to the

high temperatures required for device surface-mounting. The SNAPHAT housing is keyed to

prevent reverse insertion. The SOIC and battery packages are shipped separately in plastic

anti-static tubes or in Tape & Reel form. For the 44-lead SOIC, the battery/crystal package

(e.g., SNAPHAT) part number is “M4Txx-BR12SH” (see Table 19 on page 33).

Caution:

Do not place the SNAPHAT battery/crystal top in conductive foam as this will drain the

lithium button-cell battery.

Figure 1.

Logic diagram

AI02240

A0-A18

WDI

DQ0-DQ7

VCC

M48T201Y

M48T201V

VSS

ECON

GCON

RSTIN2

RSTIN1

RST

IRQ/FT

VOUT

SQW

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