M48T201V datasheet(4/33 Pages) STMICROELECTRONICS

4 / 33 page

M48T201Y, M48T201V

4/33

DESCRIPTION

The M48T201Y/V are self-contained devices that

include a real time clock (RTC), programmable

alarms, a watchdog timer, and a square wave out-

put which provides control of up to 512K x 8 of ex-

ternal low-power static RAM. Access to all RTC

functions and the external RAM is the same as

conventional bytewide SRAM. The 16 TIME-

KEEPER® registers offer year, month, date, day,

hour, minute, second, calibration, alarm, century,

watchdog, and square wave output data. External-

ly 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 con-

nection to a separate SNAPHAT® housing con-

taining 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-mount-

ing. 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

“M4Txx-BR12SH”

(see

Table

19., page 31).

Caution: Do not place the SNAPHAT battery/crys-

tal top in conductive foam as this will drain the lith-

ium button-cell battery.

Figure 2. Logic Diagram

Table 1. Signal Names

AI02240

A0-A18

WDI

DQ0-DQ7

VCC

M48T201Y

M48T201V

VSS

ECON

GCON

RSTIN2

RSTIN1

RST

IRQ/FT

VOUT

SQW

A0-A18

Address Inputs

DQ0-DQ7

Data Inputs / Outputs

RSTIN1

Reset 1 Input

RSTIN2

Reset 2 Input

RST

Reset Output (Open Drain)

WDI

Watchdog Input

Chip Enable Input

Output Enable Input

WRITE Enable Input

ECON

RAM Chip Enable Output

GCON

RAM Enable Output

IRQ/FT

Interrupt / Frequency Test Output

(Open Drain)

SQW

Square Wave Output

VOUT

Supply Voltage Output

VCC

Supply Voltage

VSS

Ground

Not Connected Internally

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