SGS Thomson Microelectronics M48T39Y Datasheet

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PRELIMINARY DATA

January 1998

This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice.

M48T39Y

256 Kb (32K x8) TIMEKEEPER® SRAM

■ INTEGRATED ULTRA LOW POWER SRAM,

REAL TIME CLOCK, POWER-FAIL CONTROL
CIRCUIT, BATTERY and CRYSTAL

■ BCD CODED YEAR, MONTH, DAY, DATE,

HOURS, MINUTES and SECONDS

■ AUTOMATIC POWER-FAIL CHIP DESELECT

and WRITE PROTECTION

■ WRITE PROTECT VOLTAGE

(V

PFD

= Power-fail Deselect Voltage):

– M48T39Y: 4.20V ≤ V

PFD

≤ 4.50V

■ PROGRAMMABLE INTERRUPTS and

SQUARE WAVE OUTPUT

■ WATCHDOG TIMER RESTARTS on

OUT-OF-CONTROL PROCESSOR

■ CLOCK ACCURACY IS BETTER THAN

±1 MINUTE per MONTH at 25°C

■ 10 YEARS of DATA RETENTION and CLOCK

OPERATION in the ABSENCE of POWER

■ SELF-CON TAINED BATTERY and CRYSTA L

in DIP PACKAGE

■ PROG R AMMABLE ALARM OUTPUT ACTIVE

in the BATTERY BACK-UP MODE

■ PIN and FUNCTION COMPATIBLE with

DS1386

DESCRIPTION

The M48T39Y TIMEKEEPER

®

RAM is a non-vol­atile 262,144 bit static RAM and real time clock or­ganized as 32,768 words by 8 bits. System
integration features include Programmable
Alarms, Watchdog Timer and Interval Timer. The
special 32-pin DIP package provides a highly inte­grated battery back-up memory and real time
clock soluti o n.

Figure 1. Logic Diagram

AI02311

15

A0-A14

W

DQ0-DQ7

V

CC

M48Z129Y

G

V

SS

8

E

INTA

INTB
SQW

32

1

PMDIP32 (PM)

Module

M48T39Y

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Figure 2. DIP C on ne ctions

A1
A0

DQ0

A7

A4
A3
A2

A6
A5

A13

A10

A8
A9

DQ7

SQW

A11
G

E

DQ5DQ1

DQ2

DQ3V

SS

DQ4

DQ6

INTB

INTA V

CC

AI02312

10

1
2

5
6
7
8
9

11
12
13
14
15
16

30
29

26
25
24
23
22
21
20
19
18
17

A12

A14

W

V

CC

3
4

28
27

32
31

M48T39Y

Table 1. Signal Names

A0-A14 Address Inputs

DQ0-DQ7 Data Inputs / Outputs
E

Chip Enable Input

G

Output Enable Input

W

Write Enable Input

INTA

Interrupt Output A (Open Drain)

INTB

Interrupt Output B (Open Drain)
SQW Square Wave Output

V

CC

Supply Voltage

V

SS

Ground

Table 2. Ordering Information Scheme

For a list of available options (Speed, Pac kage, etc...) or for furthe r information on any aspect of this de­vice, please contact the ST Sales Office nearest to you.

Example: M48T39Y -100 PM 1

Device Type

M48T

Supply Voltage and Write Protect Voltage

39Y = V

CC

= 4.5V to 5.5V; V

PFD

= 4.2V to 4.5V

Speed

-100 = 100ns

-150 = 150ns

Package

PM = PMDIP32

Temperature Range

1 = 0 to 70 °C