as7c251mntf18a Alliance Memory, Inc, as7c251mntf18a Datasheet - Page 5
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as7c251mntf18a
Manufacturer Part Number
as7c251mntf18a
Description
2.5v Flowthrough Synchronous Sram With
Manufacturer
Alliance Memory, Inc
Datasheet
1.AS7C251MNTF18A.pdf
(18 pages)
Signal descriptions
Snooze Mode
SNOOZE MODE is a low current, power-down mode in which the device is deselected and current is reduced to I
SNOOZE MODE is dictated by the length of time the ZZ is in a High state.
The ZZ pin is an asynchronous, active high input that causes the device to enter SNOOZE MODE.
When the ZZ pin becomes a logic High, I
is disabled and all outputs go to High-Z. Any operation pending when entering SNOOZE MODE is not guaranteed to successfully complete.
Therefore, SNOOZE MODE (READ or WRITE) must not be initiated until valid pending operations are completed. Similarly, when exiting
SNOOZE MODE during t
CLK
CEN
A, A0, A1
DQ[a,b]
CE0, CE1,
CE2
ADV/LD
R/W
BW[a,b]
OE
LBO
ZZ
NC
12/23/04, v 1.1
Signal
I/O Properties
I/O
I
I
I
I
I
I
I
I
I
I
-
CLOCK
ASYNC
ASYNC
STATIC
PUS
SYNC
SYNC
SYNC
SYNC
SYNC
SYNC
SYNC
-
, only a DESELECT or READ cycle should be given while the SRAM is transitioning out of SNOOZE MODE.
Clock. All inputs except OE, LBO, and ZZ are synchronous to this clock.
Clock enable. When de-asserted high, the clock input signal is masked.
Address. Sampled when all chip enables are active and ADV/LD is asserted.
Data. Driven as output when the chip is enabled and OE is active.
Synchronous chip enables. Sampled at the rising edge of CLK, when ADV/LD is asserted.
Are ignored when ADV/LD is high.
Advance or Load. When sampled high, the internal burst address counter will increment in
the order defined by the LBO input value. When low, a new address is loaded.
A high during LOAD initiates a READ operation. A low during LOAD initiates a WRITE
operation. Is ignored when ADV/LD is high.
Byte write enables. Used to control write on individual bytes. Sampled along with WRITE
command and BURST WRITE.
Asynchronous output enable. I/O pins are not driven when OE is inactive.
Snooze. Places device in low power mode; data is retained. Connect to GND if unused.
No connect
Selects Burst mode. When tied to V
driven Low, device follows linear Burst order. This signal is internally pulled High.
SB2
is guaranteed after the time t
Alliance Semiconductor
DD
ZZI
®
or left floating, device follows interleaved Burst order. When
is met. After entering SNOOZE MODE, all inputs except ZZ
Description
AS7C251MNTF18A
SB2
. The duration of
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