m48t128y STMicroelectronics, m48t128y Datasheet - Page 10

• Manufacturer Part Number: m48t128y
• Description: 5.0 Or 3.3v, 1 Mbit 128 Kb X 8 Timekeeper Sram
• Manufacturer: STMicroelectronics

M48T128Y, M48T128V*
Data Retention Mode
With valid V
as a conventional BYTEWIDE™ static RAM.
Should the supply voltage decay, the RAM will au-
tomatically power-fail deselect, write protecting it-
self when V
(min) window. All outputs become high imped-
ance, and all inputs are treated as “Don't care.”
Note: A power failure during a WRITE cycle may
corrupt data at the currently addressed location,
but does not jeopardize the rest of the RAM's con-
tent. At voltages below V
assured the memory will be in a write protected
state, provided the V
The M48T128Y/V may respond to transient noise
10/22
CC
CC
applied, the M48T128Y/V operates
falls within the V
CC
fall time is not less than t
PFD
(min), the user can be
PFD
(max), V
PFD
F
.
spikes on V
during the time the device is sampling V
fore, decoupling of the power supply lines is rec-
ommended.
When V
switches power to the internal battery, preserving
data and powering the clock. The internal energy
source will maintain data in the M48T128Y/V for
an accumulated period of at least 10 years at room
temperature. As system power rises above V
the battery is disconnected, and the power supply
is switched to external V
t
REC
after V
CC
CC
CC
drops below V
that reach into the deselect window
reaches V
CC
PFD
. Deselect continues for
SO
(max).
, the control circuit
CC
. There-
SO
,