![](http://datasheet.mmic.net.cn/390000/MT55L64L32F1_datasheet_16823617/MT55L64L32F1_5.png)
5
2Mb: 128K x 18, 64K x 32/36 3.3V I/O, Flow-Through ZBT SRAM
MT55L128L18F1_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, FLOW-THROUGH ZBT SRAM
PIN DESCRIPTIONS
TQFP (x18)
37
36
32-35, 44-49,
80-82, 99, 100
TQFP (x32/x36)
37
36
32-35, 44-49,
81, 82, 99, 100
SYMBOL
SA0
SA1
SA
TYPE
Input
DESCRIPTION
Synchronous Address Inputs: These inputs are registered
and must meet the setup and hold times around the rising
edge of CLK. Pins 50, 83, and 84 are reserved as address
bits for the higher-density 4Mb, 8Mb, and 16Mb ZBT
SRAMs, respectively. SA0 and SA1 are the two least
significant bits (LSB) of the address field and set the
internal burst counter if burst is desired.
Synchronous Byte Write Enables: These active LOW inputs
allow individual bytes to be written when a WRITE cycle is
active and must meet the setup and hold times around
the rising edge of CLK.
BYTE WRITEs need to be asserted
on the same cycle as the address.
BWa# controls DQa pins;
BWb# controls DQb pins; BWc# controls DQc pins; BWd#
controls DQd pins.
Clock: This signal registers the address, data, chip enables,
byte write enables and burst control inputs on its rising
edge. All synchronous inputs must meet setup and hold
times around the clock
’
s rising edge.
Synchronous Chip Enable: This active LOW input is used to
enable the device and is sampled only when a new
external address is loaded (ADV/LD# LOW).
Synchronous Chip Enable: This active LOW input is used to
enable the device and is sampled only when a new
external address is loaded (ADV/LD# LOW). This input can
be used for memory depth expansion.
Synchronous Chip Enable: This active HIGH input is used to
enable the device and is sampled only when a new
external address is loaded (ADV/LD# LOW). This input can
be used for memory depth expansion.
Output Enable: This
active LOW, asynchronous input
enables the data I/O output drivers. G# is the JEDEC-
standard term for OE#.
Synchronous Address Advance/Load: When HIGH, this
input is used to advance the internal burst counter,
controlling burst access after the external address is
loaded. When ADV/LD# is HIGH, R/W# is ignored. A LOW
on ADV/LD# clocks a new address at the CLK rising edge.
Synchronous Clock Enable: This active LOW input permits
CLK to propagate throughout the device. When CKE# is
HIGH, the device ignores the CLK input and effectively
internally extends the previous CLK cycle. This input must
meet setup and hold times around the rising edge of CLK.
Snooze Enable: This active HIGH, asynchronous input
causes the device to enter a low-power standby mode in
which all data in the memory array is retained. When ZZ is
active, all other inputs are ignored.
93
94
–
–
93
94
95
96
BWa#
BWb#
BWc#
BWd#
Input
89
89
CLK
Input
98
98
CE#
Input
92
92
CE2#
Input
97
97
CE2
Input
86
86
OE#
(G#)
Input
85
85
ADV/LD#
Input
87
87
CKE#
Input
64
64
ZZ
Input