STK16C88-3 Simtek, STK16C88-3 Datasheet - Page 7

• Manufacturer Part Number: STK16C88-3
• Description: CMOS Nonvolatile Static RAM
• Manufacturer: Simtek

The AutoStorePlus™ STK16C88-3 is a fast 32K x 8
SRAM that does not lose its data on power-down.
The data is preserved in integral QuantumTrap™
Nonvolatile Elements while power is unavailable.
The nonvolatility of the STK16C88-3 does not
require
AutoStorePlus™ on power-down and automatic
RECALL on power-up guarantee data integrity with-
out the use of batteries.
NOISE CONSIDERATIONS
Note that the STK16C88-3 is a high-speed memory
and so must have a high-frequency bypass capaci-
tor of approximately 0.1μF connected between V
and V
possible. As with all high-speed
careful routing of power, ground and signals will
help prevent noise problems.
SRAM READ
The STK16C88-3 performs a
E and G are low and W is high. The address speci-
fied on pins A
data bytes will be accessed. When the
ated by an address transition, the outputs will be
valid after a delay of t
READ
at t
The data outputs will repeatedly respond to address
changes within the t
for transitions on any control input pins, and will
remain valid until another address change or until E
or G is brought high.
SRAM WRITE
A
low. The address inputs must be stable prior to
entering the
until either E or W goes high at the end of the cycle.
The data on the common I/O pins DQ
ten into the memory if it is valid t
of a W controlled
E controlled
It is recommended that G be kept high during the
entire
the common I/O lines. If G is left low, internal circuitry
will turn off the output buffers t
March 2006
WRITE
ELQV
SS
is initiated by E or G, the outputs will be valid
WRITE
or at t
, using leads and traces that are as short as
cycle is performed whenever E and W are
any
WRITE
GLQV
WRITE
cycle to avoid data bus contention on
0-14
system
, whichever is later (
WRITE
determines which of the 32,768
.
AVQV
cycle and must remain stable
AVQV
access time without the need
or t
intervention
DVEH
(
READ
WLQZ
READ
before the end of an
DVWH
CMOS
after W goes low.
cycle #1). If the
cycle whenever
READ
DEVICE OPERATION
before the end
0-7
or
READ
ICs, normal
will be writ-
cycle #2).
support:
is initi-
CC
7
AutoStorePlus™ OPERATION
The STK16C88-3’s automatic
down is completely transparent to the system. The
AutoStore™ initiation takes less than 500ns when
power is lost (V
depends only on its internal capacitor for
completion. If the power supply drops faster than
20μs/volt before Vccx reaches Vswitch, then a 2.2
ohm resistor should be inserted between Vccx and
the system supply to avoid a momentary excess of
current between Vccx and Vcap.
In order to prevent unneeded
automatic
one
most recent
initiated
whether or not a
POWER-UP RECALL
During power up, or after any low-power condition
(V
latched. When V
voltage of V
be initiated and will take t
If the STK16C88-3 is in a
power-up
To help avoid this situation, a 10kΩ resistor should
be connected either between W and system V
between E and system V
SOFTWARE NONVOLATILE STORE
The STK16C88-3 software
by executing sequential
cific address locations. During the
erase of the previous nonvolatile data is first per-
formed, followed by a program of the nonvolatile
elements. The program operation copies the
data into nonvolatile memory. Once a
is initiated, further input and output are disabled until
the cycle is completed.
Because a sequence of
addresses is used for
tant that no other
vene in the sequence or the sequence will be
aborted and no
CC
WRITE
< V
Document Control # ML0019 rev 0.2
STORE
RESET
RECALL
STORE
SWITCH
operation has taken place since the
), an internal
STORE
STORE
CC
cycles are performed regardless of
WRITE
CC
, a
s will be ignored unless at least
, the
< V
READ
once again exceeds the sense
RECALL
SWITCH
or
SRAM
STORE
or
operation has taken place.
CC
READ
RESTORE
RECALL
or
RECALL
WRITE
.
) at which point the part
RECALL
STORE
WRITE
cycle will automatically
READ
data will be corrupted.
initiation, it is impor-
cycles from six spe-
to complete.
STORE
STORE
state at the end of
STK16C88-3
will take place.
s from specific
cycle. Software-
STORE
cycle is initiated
accesses inter-
request will be
STORE
operations,
on power-
cycle an
STORE
SRAM
cycle
CC
or