
13
2Mb: 128K x 18, 64K x 32/36 3.3V I/O, Pipelined ZBT SRAM
MT55L128L18P1_2.p65
–
Rev. 8/00
Micron Technology, Inc., reserves the right to change products or specifications without notice.
2000, Micron Technology, Inc.
2Mb: 128K x 18, 64K x 32/36
3.3V I/O, PIPELINED ZBT SRAM
TRUTH TABLE
(Notes 5-10)
OPERATION
ADDRESS CE# CE2# CE2
USED
None
H
None
X
None
X
None
X
External
L
ZZ
ADV/ R/W#
LD#
L
L
L
H
L
BWx
OE# CKE#
CLK
DQ
NOTES
DESELECT CYCLE
DESELECT CYCLE
DESELECT CYCLE
CONTINUE DESELECT CYCLE
READ CYCLE
(Begin Burst)
READ CYCLE
(Continue Burst)
NOP/DUMMY READ
(Begin Burst)
DUMMY READ
(Continue Burst)
WRITE CYCLE
(Begin Burst)
WRITE CYCLE
(Continue Burst)
NOP/WRITE ABORT
(Begin Burst)
WRITE ABORT
(Continue Burst)
IGNORE CLOCK EDGE
(Stall)
SNOOZE MODE
X
H
X
X
L
X
X
L
X
H
L
L
L
L
L
X
X
X
X
H
X
X
X
X
X
X
X
X
X
L
L
L
L
L
L
L
H High-Z
L
H High-Z
L
H High-Z
L
H High-Z
L
H
1
Q
Next
X
X
X
L
H
X
X
L
L
L
H
Q
1, 11
External
L
L
H
L
L
H
X
H
L
L
H High-Z
2
Next
X
X
X
L
H
X
X
H
L
L
H High-Z
1, 2,
11
3
External
L
L
H
L
L
L
L
X
L
L
H
D
Next
X
X
X
L
H
X
L
X
L
L
H
D
1, 3,
11
2, 3
None
L
L
H
L
L
L
H
X
L
L
H High-Z
Next
X
X
X
L
H
X
H
X
L
L
H High-Z
1, 2,
3, 11
4
Current
X
X
X
L
X
X
X
X
H
L
H
–
None
X
X
X
H
X
X
X
X
X
X
High-Z
NOTE:
1. CONTINUE BURST cycles, whether READ or WRITE, use the same control inputs. The type of cycle performed (READ or
WRITE) is chosen in the initial BEGIN BURST cycle. A CONTINUE DESELECT cycle can only be entered if a DESELECT cycle
is executed first.
2. DUMMY READ and WRITE ABORT cycles can be considered NOPs because the device performs no external operation.
A WRITE ABORT means a WRITE command is given, but no operation is performed.
3. OE# may be wired LOW to minimize the number of control signals to the SRAM. The device will automatically turn off
the output drivers during a WRITE cycle. OE# may be used when the bus turn-on and turn-off times do not meet an
application
’
s requirements.
4. If an IGNORE CLOCK EDGE command occurs during a READ operation, the DQ bus will remain active (Low-Z). If it
occurs during a WRITE cycle, the bus will remain in High-Z. No WRITE operations will be performed during the IGNORE
CLOCK EDGE cycle.
5. X means
“
Don
’
t Care.
”
H means logic HIGH. L means logic LOW. BWx = H means all byte write signals (BWa#, BWb#,
BWc# and BWd#) are HIGH. BWx = L means one or more byte write signals are LOW.
6. BWa# enables WRITEs to Byte
“
a
”
(DQa pins); BWb# enables WRITEs to Byte
“
b
”
(DQb pins); BWc# enables WRITEs to
Byte
“
c
”
(DQc pins); BWd# enables WRITEs to Byte
“
d
”
(DQd pins).
7. All inputs except OE# and ZZ must meet setup and hold times around the rising edge (LOW to HIGH) of CLK.
8. Wait states are inserted by setting CKE# HIGH.
9. This device contains circuitry that will ensure that the outputs will be in High-Z during power-up.
10. The device incorporates a 2-bit burst counter. Address wraps to the initial address every fourth burst cycle.
11. The address counter is incremented for all CONTINUE BURST cycles.