18Mb: 1 MEG x 18, 512K x 32/36
FLOW-THROUGH ZBT SRAM
18Mb ZBT
®
SRAM
Features
• High frequency and 100 percent bus utilization
• Single 3.3V ±5 percent or 2.5V ±5 percent power
supply
• Separate 3.3V ±5 percent or 2.5V ±5 percent isolated
output buffer supply (V
DD
Q)
• Advanced control logic for minimum control signal
interface
• Individual byte write controls may be tied LOW
• Single R/W# (read/write) control pin/ball
• CKE# pin/ball to enable clock and suspend
operations
• Three chip enables for simple depth expansion
• Clock-controlled and registered addresses, data
I/Os, and control signals
• Internally self-timed, fully coherent write
• Internally self-timed, registered outputs to
eliminate the need to control OE#
• SNOOZE MODE for reduced-power standby
• Common data inputs and data outputs
• Linear or Interleaved Burst Modes
• Burst feature (optional)
• Pin and ball/function compatibility with 2Mb, 4Mb,
and 8Mb ZBT SRAM
MT55L1MY18F, MT55V1MV18F,
MT55L512Y32F, MT55V512V32F,
MT55L512Y36F, MT55V512V36F
3.3V V
DD
, 3.3V or 2.5V I/O; 2.5V V
DD
, 2.5V I/O
Figure 1: 100-Pin TQFP
JEDEC-Standard MS-026 BHA (LQFP)
Figure 2: 165-Ball FBGA
JEDEC-Standard MS-216 (Var. CAB-1)
Options
• Timing (Access/Cycle/MHz)
6.5ns/8.8ns/113 MHz
7.5ns/10ns/100 MHz
8.5ns/11ns/90 MHz
• Configurations
3.3V V
DD
, 3.3V or 2.5V I/O
1 Meg x 18
512K x 32
512K x 36
2.5V V
DD
, 2.5V I/O
1 Meg x 18
512K x 32
512K x 36
• Packages
100-pin TQFP
165-ball, 13mm x 15mm FBGA
• Operating Temperature Range
Commercial (0ºC
£
T
A
£
+70ºC)
Industrial (-40ºC
£
T
A
£
+85ºC)
NOTE:
TQFP
Marking
-8.8
-10
-11
Part Number Example:
MT55L1MY18F
MT55L512Y32F
MT55L512Y36F
MT55V1MV18F
MT55V512V32F
MT55V512V36F
T
F
1
None
IT
2
MT55L512Y36FT-11
General Description
The Micron
®
Zero Bus Turnaround
™
(ZBT
®
) SRAM
family employs high-speed, low-power CMOS designs
using an advanced CMOS process.
Micron’s 18Mb ZBT SRAMs integrate a 1 Meg x 18,
512K x 32, or 512K x 36 SRAM core with advanced syn-
chronous peripheral circuitry and a 2-bit burst
counter. These SRAMs are optimized for 100 percent
bus utilization, eliminating any turnaround cycles for
READ to WRITE, or WRITE to READ, transitions. All
synchronous inputs pass through registers controlled
by a positive-edge-triggered single clock input (CLK).
The synchronous inputs include all addresses, all data
inputs, chip enable (CE#), two additional chip enables
1
©2003 Micron Technology, Inc.
1. A Part Marking Guide for the FBGA devices can be found on
Micron’s Web site—http://www.micron.com/numberguide.
2. Contact Factory for availability of Industrual Temperature
devices.
18Mb: 1 Meg x 18, 512K x 32/36 Flow-through ZBT SRAM
MT55L1MY18F_16_D.fm – Rev. D, Pub. 2/03
PRODUCTS AND SPECIFICATIONS DISCUSSED HEREIN ARE SUBJECT TO CHANGE BY MICRON WITHOUT NOTICE.
18Mb: 1 MEG x 18, 512K x 32/36
FLOW-THROUGH ZBT SRAM
for easy depth expansion (CE2, CE2#), cycle start input
(ADV/LD#), synchronous clock enable (CKE#), byte
write enables (BWa#, BWb#, BWc#, and BWd#), and
read/write (R/W#).
Asynchronous inputs include the output enable
(OE#, which may be tied LOW for control signal mini-
mization), clock (CLK) and snooze enable (ZZ, which
may be tied LOW if unused). There is also a burst mode
pin/ball (MODE) that selects between interleaved and
linear burst modes. MODE may be tied HIGH, LOW or
left unconnected if burst is unused. The data out (Q) is
enabled by OE#. WRITE cycles can be from one to four
bytes wide as controlled by the write control inputs.
All READ, WRITE, and DESELECT cycles are initi-
ated by the ADV/LD# input. Subsequent burst
addresses can be internally generated as controlled by
the burst advance pin/ball (ADV/LD#). Use of burst
mode is optional. It is allowable to give an address for
each individual READ and WRITE cycle. BURST cycles
wrap around after the fourth access from a base
address.
To allow for continuous, 100 percent use of the data
bus, the flow-through ZBT SRAM uses a LATE WRITE
cycle. For example, if a WRITE cycle begins in clock
cycle one, the address is present on rising edge one.
BYTE WRITEs need to be asserted on the same cycle as
the address. The write data associated with the address
is required one cycle later, or on the rising edge of
clock cycle two.
Address and write control are registered on-chip to
simplify WRITE cycles. This allows self-timed WRITE
cycles. Individual byte enables allow individual bytes
to be written. During a BYTE WRITE cycle, BWa# con-
trols DQa pins/balls; BWb# controls DQb pins/balls;
BWc# controls DQc pins/balls; and BWd# controls
DQd pins/balls. Cycle types can only be defined when
an address is loaded, i.e., when ADV/LD# is LOW. Par-
ity/ECC bits are only available on the x 18 and x36 ver-
sions.
The device is ideally suited for systems requiring
high bandwidth and zero bus turnaround delays.
Please refer to Micron’s Web site (www.micron.com/
sramds)
for the latest data sheet.
Dual Voltage I/O
The 3.3V V
DD
device is tested for 3.3V and 2.5V I/O
function. The 2.5V V
DD
device is tested for only 2.5V
I/O function.
18Mb: 1 Meg x 18, 512K x 32/36 Flow-through ZBT SRAM
MT55L1MY18F_16_D.fm – Rev. D, Pub. 2/03
2
Micron Technology, Inc., reserves the right to change products or specifications without notice.
©2003 Micron Technology, Inc.
18Mb: 1 MEG x 18, 512K x 32/36
FLOW-THROUGH ZBT SRAM
Figure 3: Functional Block Diagram
1 Meg x 18
20
SA0, SA1, SA
MODE
CLK
CKE#
K
CE
ADV/LD#
K
WRITE ADDRESS
REGISTER
ADDRESS
REGISTER
20
SA1
D1
SA0
D0
18
Q1 SA1'
SA0'
Q0
20
20
O
U
T
P
U
T
B
U
F
F
E
R
S
E
20
BURST
LOGIC
ADV/LD#
BWa#
BWb#
R/W#
WRITE REGISTRY
AND DATA COHERENCY
CONTROL LOGIC
18
1 Meg x 9 x 2
WRITE
DRIVERS
18
MEMORY
ARRAY
18
S
E
N
S
E
A
M
P
S
D
A
T
A
18
S
T
E
E
R
I
N
G
18
18
DQs
DQPa
DQPb
18
OE#
CE#
CE2
CE2#
INPUT
REGISTER E
READ LOGIC
Figure 4: Functional Block Diagram
512K x 32/36
19
SA0, SA1, SA
MODE
CLK
CKE#
K
CE
ADV/LD#
K
WRITE ADDRESS
REGISTER
ADDRESS
REGISTER
19
SA1
D1
SA0
D0
17
Q1 SA1'
SA0'
Q0
19
19
O
U
T
P
U
T
B
U
F
F
E
R
S
E
19
BURST
LOGIC
ADV/LD#
BWa#
BWb#
BWc#
BWd#
R/W#
WRITE REGISTRY
AND DATA COHERENCY
CONTROL LOGIC
36
512K x 8 x 4
(x32)
WRITE
DRIVERS
36
512K x 9 x 4
36
(x36)
S
E
N
S
E
A
M
P
S
D
A
T
A
36
MEMORY
ARRAY
S
T
E
E
R
I
N
G
36
36
DQs
DQPa
DQPb
DQPc
DQPd
36
OE#
CE#
CE2
CE2#
INPUT
E
REGISTER
READ LOGIC
NOTE:
Functional block diagrams illustrate simplified device operation. See truth tables, pin/ball descriptions, and tim-
ing diagrams for detailed information.
18Mb: 1 Meg x 18, 512K x 32/36 Flow-through ZBT SRAM
MT55L1MY18F_16_D.fm – Rev. D, Pub. 2/03
3
Micron Technology, Inc., reserves the right to change products or specifications without notice.
©2003 Micron Technology, Inc.
18Mb: 1 MEG x 18, 512K x 32/36
FLOW-THROUGH ZBT SRAM
Figure 5: Pin Layout (Top View)
100-Pin TQFP
SA
NC
NC
V
DD
Q
V
SS
NC
DQPa
DQa
DQa
V
SS
V
DD
Q
DQa
DQa
V
SS
V
SS
2
V
DD
ZZ
DQa
DQa
V
DD
Q
V
SS
DQa
DQa
NC
NC
V
SS
V
DD
Q
NC
NC
NC
SA
SA
SA
SA
ADV/LD#
OE# (G#)
CKE#
R/W#
CLK
V
SS
V
DD
CE2#
BWa#
BWb#
NC
NC
CE2
CE#
SA
SA
80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51
50
81
49
82
48
83
47
84
46
85
45
86
44
87
43
88
42
89
41
90
40
91
39
92
38
93
37
94
36
95
35
96
34
97
33
98
32
99
31
100
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
x18
SA
SA
SA
SA
SA
SA
SA
DNU
4
DNU
4
V
DD
V
SS
DNU
DNU
SA0
SA1
SA
SA
SA
SA
MODE
(LBO#)
SA
SA
SA
SA
ADV/LD#
OE# (G#)
CKE#
R/W#
CLK
V
SS
V
DD
CE2#
BWa#
BWb#
BWc#
BWd#
CE2
CE#
SA
SA
80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51
50
81
49
82
48
83
47
84
46
85
45
86
44
87
43
88
42
89
41
90
40
91
39
92
38
93
37
94
36
95
35
96
34
97
33
98
32
99
31
100
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
NF/DQPb
1
DQb
DQb
V
DD
Q
V
SS
DQb
DQb
DQb
DQb
V
SS
V
DD
Q
DQb
DQb
V
SS
V
SS
2
V
DD
ZZ
DQa
DQa
V
DD
Q
V
SS
DQa
DQa
DQa
DQa
V
SS
V
DD
Q
DQa
DQa
NF/DQPa
1
NC
NC
NC
V
DD
Q
V
SS
NC
NC
DQb
DQb
V
SS
V
DD
Q
DQb
DQb
V
SS
2
V
DD
V
DD
3
V
SS
DQb
DQb
V
DD
Q
V
SS
DQb
DQb
DQPb
NC
V
SS
V
DD
Q
NC
NC
NC
x32/x36
SA
SA
SA
SA
SA
SA
SA
DNU
4
DNU
4
V
DD
V
SS
DNU
DNU
SA0
SA1
SA
SA
SA
SA
MODE
(LBO#)
NOTE:
1. No Function (NF) is used on the x32 version. Parity (DQPx) is used on the x36 version.
2. Pins 14 and 66 do not have to be connected directly to V
SS
if the input voltage is
£
V
IL
.
3. Pin 16 does not have to be connected directly to V
DD
if the input voltage is
³
V
IH
.
4. Pins 43 and 42 are reserved for address expansion; 36Mb and 72Mb, respectively.
18Mb: 1 Meg x 18, 512K x 32/36 Flow-through ZBT SRAM
MT55L1MY18F_16_D.fm – Rev. D, Pub. 2/03
NF/DQPc
1
DQc
DQc
V
DD
Q
V
SS
DQc
DQc
DQc
DQc
V
SS
V
DD
Q
DQc
DQc
V
SS
2
V
DD
V
DD
3
V
SS
DQd
DQd
V
DD
Q
V
SS
DQd
DQd
DQd
DQd
V
SS
V
DD
Q
DQd
DQd
NF/DQPd
1
4
Micron Technology, Inc., reserves the right to change products or specifications without notice.
©2003 Micron Technology, Inc.
18Mb: 1 MEG x 18, 512K x 32/36
FLOW-THROUGH ZBT SRAM
Table 1:
SYMBOL
ADV/LD#
TQFP Pin Descriptions
TYPE
Input
DESCRIPTION
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 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. BWs need to be asserted on the same cycle as the address. BWs are
associated with addresses and apply to subsequent data. BWa# controls DQa pins; BWb#
controls DQb pins; BWc# controls DQc pins; BWd# controls DQd pins.
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.
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.
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.
Mode: This input selects the burst sequence. A LOW on this pin selects linear burst. NC or
HIGH on this pin selects interleaved burst. Do not alter input state while device is operating.
LBO# is the JEDEC-standard term for MODE.
Output Enable: This active LOW, asynchronous input enables the data I/O output drivers. G#
is the JEDEC-standard term for OE#.
Read/Write: This input determines the cycle type when ADV/LD# is LOW and is the only
means for determining READs and WRITEs. READ cycles may not be converted into WRITEs
(and vice versa) other than by loading a new address. A LOW on this pin permits BYTE WRITE
operations and must meet the setup and hold times around the rising edge of CLK. Full bus-
width WRITEs occur if all byte write enables are LOW.
Synchronous Address Inputs: These inputs are registered and must meet the setup and hold
times around the rising edge of CLK. SA0 and SA1 are the two least significant bits (LSB) of
the address field and set the internal burst counter if burst is desired.
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. This pin has an internal pull-down and can be left unconnected.
SRAM Data I/Os: Byte “a” is associated with DQa pins; byte “b” is associated with DQb pins;
byte “c” is associated with DQc pins; byte “d” is associated with DQd pins. Input data must
meet setup and hold times around the rising edge CLK.
No Function/Parity Data I/Os: On the x32 version, these are No Function (NF). On the x18
version, byte “a” parity is DQPa; byte “b” parity is DQPb. On the x36 version, byte “a” parity
is DQPa; byte “b” parity is DQPb; byte “c” parity is DQPc; byte “d” parity is DQPd.
Power Supply: See DC Electrical Characteristics and Operating Conditions for range.
Isolated Output Buffer Supply: See DC Electrical Characteristics and Operating Conditions for
range.
Ground: GND.
Micron Technology, Inc., reserves the right to change products or specifications without notice.
©2003 Micron Technology, Inc.
BWa#
BWb#
BWc#
BWd#
CE#
CE2#
Input
Input
Input
CE2
Input
CKE#
Input
CLK
Input
MODE (LBO#)
Input
OE# (G#)
R/W#
Input
Input
SA0
SA1
SA
ZZ
Input
Input
DQa
DQb
DQc
DQd
NF/DQPa
NF/DQPb
NF/DQPc
NF/DQPd
V
DD
V
DD
Q
V
SS
Input/
Output
NF
I/O
Supply
Supply
Supply
18Mb: 1 Meg x 18, 512K x 32/36 Flow-through ZBT SRAM
MT55L1MY18F_16_D.fm – Rev. D, Pub. 2/03
5
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