m48t129v STMicroelectronics, m48t129v Datasheet - Page 4

• Manufacturer Part Number: m48t129v
• Description: 5.0 Or 3.3v, 1 Mbit 128 Kbit X 8 Timekeeper Sram
• Manufacturer: STMicroelectronics

M48T129Y, M48T129V
DESCRIPTION
The M48T129Y/V TIMEKEEPER
128 Kb x 8 non-volatile static RAM and real-time
clock with programmable alarms and a watchdog
timer. The special DIP package provides a fully in-
tegrated battery back-up memory and real-time
clock solution. The M48T129Y/V directly replaces
industry standard 128 Kb x 8 SRAM. It also pro-
vides the non-volatility of Flash without any re-
quirement for special WRITE timing or limitations
on the number of WRITEs that can be performed.
For surface-mount environments ST provides an
equivalent SMT solution consisting of a 44-pin,
330mil
(M48T201V/Y) and a 32-pin, (TSOP, 8 x 20mm)
1Mb LPSRAM.
The 44-pin, 330mil SOIC provides sockets with
gold plated contacts at both ends for direct con-
Figure 2. Logic Diagram
4/30
A0-A16
W
SOIC
G
E
17
TIMEKEEPER
M48T129Y
M48T129V
V CC
V SS
8
SUPERVISOR
®
RAM is a
DQ0-DQ7
RST
IRQ/FT
AI02260
nection to a separate SNAPHAT
taining the battery.
The unique design allows the SNAPHAT battery
package to be mounted on top of the SOIC pack-
age after the completion of the surface-mount pro-
cess. 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 pre-
vent reverse insertion.
The SNAPHAT battery package is shipped sepa-
rately in plastic anti-static tubes or in Tape & Reel
form. The part number is “M4Txx-BR12SH1” (see
Table 18., page
The 32-pin, 600mil DIP Hybrid houses a controller
chip, SRAM, quartz crystal, and a long life lithium
button cell in a single package.
Table 1. Signal Names
DQ0-DQ7
A0-A16
IRQ/FT
RST
V
V
W
G
E
CC
SS
28).
Address Inputs
Data Inputs / Outputs
Chip Enable Input
Output Enable Input
WRITE Enable Input
Reset Output (open drain)
Interrupt / Frequency Test
Output (open drain)
Supply Voltage
Ground
®
housing con-