M48T39Y Datasheet, PDF (1/4 Pages) STMicroelectronics – 256 Kb 32K x8 TIMEKEEPER SRAM

M48T39Y
256 Kb (32K x8) TIMEKEEPER^® SRAM
PRELIMINARY DATA
s INTEGRATED ULTRA LOW POWER SRAM,
REAL TIME CLOCK, POWER-FAIL CONTROL
CIRCUIT, BATTERY and CRYSTAL
s BCD CODED YEAR, MONTH, DAY, DATE,
HOURS, MINUTES and SECONDS
s AUTOMATIC POWER-FAIL CHIP DESELECT
and WRITE PROTECTION
s WRITE PROTECT VOLTAGE
(V_PFD = Power-fail Deselect Voltage):
– M48T39Y: 4.20V ≤ V_PFD ≤ 4.50V
s PROGRAMMABLE INTERRUPTS and
SQUARE WAVE OUTPUT
s WATCHDOG TIMER RESTARTS on
OUT-OF-CONTROL PROCESSOR
s CLOCK ACCURACY IS BETTER THAN
±1 MINUTE per MONTH at 25°C
s 10 YEARS of DATA RETENTION and CLOCK
OPERATION in the ABSENCE of POWER
s SELF-CONTAINED BATTERY and CRYSTAL
in DIP PACKAGE
s PROGRAMMABLE ALARM OUTPUT ACTIVE
in the BATTERY BACK-UP MODE
s PIN and FUNCTION COMPATIBLE with
DS1386
DESCRIPTION
The M48T39Y TIMEKEEPER^® RAM is a non-vol-
atile 262,144 bit static RAM and real time clock or-
ganized 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 inte-
grated battery back-up memory and real time
clock solution.
32
1
PMDIP32 (PM)
Module
Figure 1. Logic Diagram
VCC
15
A0-A14
8
DQ0-DQ7
W
M48Z129Y
INTA
E
INTB
G
SQW
VSS
AI02311
January 1998
1/4
This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice.