MT48LC64M8A2P-75:C [MICROSS]
Synchronous DRAM, 64MX8, 5.4ns, CMOS, PDSO54, 0.400 INCH, LEAD FREE, PLASTIC, TSOP2-54;型号: | MT48LC64M8A2P-75:C |
厂家: | MICROSS COMPONENTS |
描述: | Synchronous DRAM, 64MX8, 5.4ns, CMOS, PDSO54, 0.400 INCH, LEAD FREE, PLASTIC, TSOP2-54 时钟 动态存储器 光电二极管 内存集成电路 |
文件: | 总77页 (文件大小:3584K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
512Mb: x4, x8, x16 SDRAM
Features
SDR SDRAM
MT48LC128M4A2 – 32 Meg x 4 x 4 banks
MT48LC64M8A2 – 16 Meg x 8 x 4 banks
MT48LC32M16A2 – 8 Meg x 16 x 4 banks
Options
Marking
Features
• PC100- and PC133-compliant
• Fully synchronous; all signals registered on positive
edge of system clock
• Internal, pipelined operation; column address can
be changed every clock cycle
• Internal banks for hiding row access/precharge
• Programmable burst lengths: 1, 2, 4, 8, or full page
• Auto precharge, includes concurrent auto precharge
and auto refresh modes
• Self refresh mode
• Auto refresh
• Configurations
– 128 Meg x 4 (32 Meg x 4 x 4 banks)
– 64 Meg x 8 (16 Meg x 8 x 4 banks)
– 32 Meg x 16 (8 Meg x 16 x 4 banks)
• Write recovery (tWR)
128M4
64M8
32M16
–
tWR = 2 CLK1
A2
• Plastic package – OCPL2
– 54-pin TSOP II (400 mil) (standard)
– 54-pin TSOP II (400 mil) Pb-free
• Timing – cycle time
TG
P
– 7.5ns @ CL = 3 (PC133)
– 7.5ns @ CL = 2 (PC133)
• Self refresh
– Standard
– Low power
• Operating temperature range
– Commercial (0˚C to +70˚C)
– Industrial (–40˚C to +85˚C)
• Revision
-75
-7E3
– 64ms, 8192-cycle refresh (commercial and
industrial)
• LVTTL-compatible inputs and outputs
• Single 3.3V ±0.3V power supply
None
L4
None
IT
:C
1. See technical note TN-48-05 on
Micron's Web site.
Notes:
2. Off-center parting line.
3. Available on x4 and x8 only.
4. Contact Micron for availability.
Table 1: Key Timing Parameters
CL = CAS (READ) latency
Access Time
CL = 2
Clock
Speed Grade
Frequency
143 MHz
133 MHz
133 MHz
100 MHz
CL = 3
5.4ns
5.4ns
–
Setup Time
1.5ns
Hold Time
0.8ns
-7E
-75
-7E
-75
–
–
1.5ns
0.8ns
5.4ns
6ns
1.5ns
0.8ns
–
1.5ns
0.8ns
PDF: 09005aef809bf8f3
512Mb_sdr.pdf - Rev. Q 12/12 EN
Micron Technology, Inc. reserves the right to change products or specifications without notice.
1
© 2000 Micron Technology, Inc. All rights reserved.
Products and specifications discussed herein are subject to change by Micron without notice.
512Mb: x4, x8, x16 SDRAM
Features
Table 2: Address Table
32 Meg
Parameter
32 Meg x 4
32 Meg x 4 x 4 banks
8K
32 Meg x 8
x 16
8 Meg x 16 x 4 banks
8K
Configuration
Refresh count
Row addressing
Bank addressing
16 Meg x 8 x 4 banks
8K
8K A[12:0]
8K A[12:0]
8K A[12:0]
4 BA[1:0]
4 BA[1:0]
4 BA[1:0]
Column
4K A[9:0], A11, A12
2K A[9:0], A11
1K A[9:0]
addressing
Table 3: 512Mb SDR Part Numbering
Part Numbers
MT48LC128M4A2P
MT48LC128M4A2TG
MT48LC64M8A2P
MT48LC64M8A2TG
MT48LC32M16A2P
MT48LC32M16A2TG
Architecture
Package
128 Meg x 4
128 Meg x 4
64 Meg x 8
64 Meg x 8
32 Meg x 16
32 Meg x 16
54-pin TSOP II
54-pin TSOP II
54-pin TSOP II
54-pin TSOP II
54-pin TSOP II
54-pin TSOP II
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512Mb: x4, x8, x16 SDRAM
Features
Contents
General Description ......................................................................................................................................... 6
Functional Block Diagrams ............................................................................................................................... 7
Pin and Ball Assignments and Descriptions ..................................................................................................... 10
Package Dimensions ....................................................................................................................................... 12
Temperature and Thermal Impedance ............................................................................................................ 13
Electrical Specifications .................................................................................................................................. 15
Electrical Specifications – IDD Parameters ........................................................................................................ 17
Electrical Specifications – AC Operating Conditions ......................................................................................... 18
Functional Description ................................................................................................................................... 21
Commands .................................................................................................................................................... 22
COMMAND INHIBIT .................................................................................................................................. 22
NO OPERATION (NOP) ............................................................................................................................... 23
LOAD MODE REGISTER (LMR) ................................................................................................................... 23
ACTIVE ...................................................................................................................................................... 23
READ ......................................................................................................................................................... 24
WRITE ....................................................................................................................................................... 25
PRECHARGE .............................................................................................................................................. 26
BURST TERMINATE ................................................................................................................................... 26
REFRESH ................................................................................................................................................... 27
AUTO REFRESH ..................................................................................................................................... 27
SELF REFRESH ....................................................................................................................................... 27
Truth Tables ................................................................................................................................................... 28
Initialization .................................................................................................................................................. 33
Mode Register ................................................................................................................................................ 35
Burst Length .............................................................................................................................................. 37
Burst Type .................................................................................................................................................. 37
CAS Latency ............................................................................................................................................... 39
Operating Mode ......................................................................................................................................... 39
Write Burst Mode ....................................................................................................................................... 39
Bank/Row Activation ...................................................................................................................................... 40
READ Operation ............................................................................................................................................. 41
WRITE Operation ........................................................................................................................................... 50
Burst Read/Single Write .............................................................................................................................. 57
PRECHARGE Operation .................................................................................................................................. 58
Auto Precharge ........................................................................................................................................... 58
AUTO REFRESH Operation ............................................................................................................................. 70
SELF REFRESH Operation ............................................................................................................................... 72
Power-Down .................................................................................................................................................. 74
Clock Suspend ............................................................................................................................................... 75
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512Mb: x4, x8, x16 SDRAM
Features
List of Figures
Figure 1: 128 Meg x 4 Functional Block Diagram ............................................................................................... 7
Figure 2: 64 Meg x 8 Functional Block Diagram ................................................................................................. 8
Figure 3: 32 Meg x 16 Functional Block Diagram ............................................................................................... 9
Figure 4: 54-Pin TSOP (Top View) .................................................................................................................. 10
Figure 5: 54-Pin Plastic TSOP (400 mil) – Package Codes TG/P ......................................................................... 12
Figure 6: Example: Temperature Test Point Location, 54-Pin TSOP (Top View) ................................................. 14
Figure 7: ACTIVE Command .......................................................................................................................... 23
Figure 8: READ Command ............................................................................................................................. 24
Figure 9: WRITE Command ........................................................................................................................... 25
Figure 10: PRECHARGE Command ................................................................................................................ 26
Figure 11: Initialize and Load Mode Register .................................................................................................. 34
Figure 12: Mode Register Definition ............................................................................................................... 36
Figure 13: CAS Latency .................................................................................................................................. 39
t
Figure 14: Example: Meeting tRCD (MIN) When 2 < RCD (MIN)/tCK < 3 .......................................................... 40
Figure 15: Consecutive READ Bursts .............................................................................................................. 42
Figure 16: Random READ Accesses ................................................................................................................ 43
Figure 17: READ-to-WRITE ............................................................................................................................ 44
Figure 18: READ-to-WRITE With Extra Clock Cycle ......................................................................................... 45
Figure 19: READ-to-PRECHARGE .................................................................................................................. 45
Figure 20: Terminating a READ Burst ............................................................................................................. 46
Figure 21: Alternating Bank Read Accesses ..................................................................................................... 47
Figure 22: READ Continuous Page Burst ......................................................................................................... 48
Figure 23: READ – DQM Operation ................................................................................................................ 49
Figure 24: WRITE Burst ................................................................................................................................. 50
Figure 25: WRITE-to-WRITE .......................................................................................................................... 51
Figure 26: Random WRITE Cycles .................................................................................................................. 52
Figure 27: WRITE-to-READ ............................................................................................................................ 52
Figure 28: WRITE-to-PRECHARGE ................................................................................................................. 53
Figure 29: Terminating a WRITE Burst ............................................................................................................ 54
Figure 30: Alternating Bank Write Accesses ..................................................................................................... 55
Figure 31: WRITE – Continuous Page Burst ..................................................................................................... 56
Figure 32: WRITE – DQM Operation ............................................................................................................... 57
Figure 33: READ With Auto Precharge Interrupted by a READ ......................................................................... 59
Figure 34: READ With Auto Precharge Interrupted by a WRITE ........................................................................ 60
Figure 35: READ With Auto Precharge ............................................................................................................ 61
Figure 36: READ Without Auto Precharge ....................................................................................................... 62
Figure 37: Single READ With Auto Precharge .................................................................................................. 63
Figure 38: Single READ Without Auto Precharge ............................................................................................. 64
Figure 39: WRITE With Auto Precharge Interrupted by a READ ........................................................................ 65
Figure 40: WRITE With Auto Precharge Interrupted by a WRITE ...................................................................... 65
Figure 41: WRITE With Auto Precharge ........................................................................................................... 66
Figure 42: WRITE Without Auto Precharge ..................................................................................................... 67
Figure 43: Single WRITE With Auto Precharge ................................................................................................. 68
Figure 44: Single WRITE Without Auto Precharge ............................................................................................ 69
Figure 45: Auto Refresh Mode ........................................................................................................................ 71
Figure 46: Self Refresh Mode .......................................................................................................................... 73
Figure 47: Power-Down Mode ........................................................................................................................ 74
Figure 48: Clock Suspend During WRITE Burst ............................................................................................... 75
Figure 49: Clock Suspend During READ Burst ................................................................................................. 76
Figure 50: Clock Suspend Mode ..................................................................................................................... 77
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512Mb: x4, x8, x16 SDRAM
Features
List of Tables
Table 1: Key Timing Parameters ....................................................................................................................... 1
Table 2: Address Table ..................................................................................................................................... 2
Table 3: 512Mb SDR Part Numbering ............................................................................................................... 2
Table 4: Pin and Ball Descriptions .................................................................................................................. 11
Table 5: Temperature Limits .......................................................................................................................... 13
Table 6: Thermal Impedance Simulated Values ............................................................................................... 14
Table 7: Absolute Maximum Ratings .............................................................................................................. 15
Table 8: DC Electrical Characteristics and Operating Conditions ..................................................................... 15
Table 9: Capacitance ..................................................................................................................................... 16
Table 10: IDD Specifications and Conditions (-7E, -75) ..................................................................................... 17
Table 11: Electrical Characteristics and Recommended AC Operating Conditions (-7E, -75) ............................. 18
Table 12: AC Functional Characteristics (-7E, -75) ........................................................................................... 19
Table 13: Truth Table – Commands and DQM Operation ................................................................................. 22
Table 14: Truth Table – Current State Bank n, Command to Bank n .................................................................. 28
Table 15: Truth Table – Current State Bank n, Command to Bank m ................................................................. 30
Table 16: Truth Table – CKE ........................................................................................................................... 32
Table 17: Burst Definition Table ..................................................................................................................... 38
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512Mb: x4, x8, x16 SDRAM
General Description
General Description
The 512Mb SDRAM is a high-speed CMOS, dynamic random-access memory contain-
ing 536,870,912 bits. It is internally configured as a quad-bank DRAM with a synchro-
nous interface (all signals are registered on the positive edge of the clock signal, CLK).
Each of the x4’s 134,217,728-bit banks is organized as 8192 rows by 4096 columns by 4
bits. Each of the x8’s 134,217,728-bit banks is organized as 8192 rows by 2048 columns
by 8 bits. Each of the x16’s 134,217,728-bit banks is organized as 8192 rows by 1024 col-
umns by 16 bits.
Read and write accesses to the SDRAM are burst-oriented; accesses start at a selected
location and continue for a programmed number of locations in a programmed se-
quence. Accesses begin with the registration of an ACTIVE command, which is then fol-
lowed by a READ or WRITE command. The address bits registered coincident with the
ACTIVE command are used to select the bank and row to be accessed (BA[1:0] select the
bank; A[12:0] select the row). The address bits registered coincident with the READ or
WRITE command are used to select the starting column location for the burst access.
The SDRAM provides for programmable read or write burst lengths (BL) of 1, 2, 4, or 8
locations, or the full page, with a burst terminate option. An auto precharge function
may be enabled to provide a self-timed row precharge that is initiated at the end of the
burst sequence.
The 512Mb SDRAM uses an internal pipelined architecture to achieve high-speed oper-
ation. This architecture is compatible with the 2n rule of prefetch architectures, but it
also allows the column address to be changed on every clock cycle to achieve a high-
speed, fully random access. Precharging one bank while accessing one of the other
three banks will hide the PRECHARGE cycles and provide seamless, high-speed, ran-
dom-access operation.
The 512Mb SDRAM is designed to operate in 3.3V memory systems. An auto refresh
mode is provided, along with a power-saving, power-down mode. All inputs and out-
puts are LVTTL-compatible.
SDRAMs offer substantial advances in DRAM operating performance, including the
ability to synchronously burst data at a high data rate with automatic column-address
generation, the ability to interleave between internal banks to hide precharge time, and
the capability to randomly change column addresses on each clock cycle during a burst
access.
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512Mb: x4, x8, x16 SDRAM
Functional Block Diagrams
Functional Block Diagrams
Figure 1: 128 Meg x 4 Functional Block Diagram
CKE
CLK
CONTROL
LOGIC
CS#
WE#
BANK3
CAS#
RAS#
BANK2
BANK1
REFRESH
COUNTER
13
MODE REGISTER
12
BANK0
ROW-
ADDRESS
LATCH
&
ROW-
ADDRESS
MUX
13
BANK0
MEMORY
ARRAY
1
1
8192
DQM
13
(8192 x 4096 x 4)
DECODER
DATA
SENSE AMPLIFIERS
OUTPUT
REGISTER
4
16384
I/O GATING
2
4
DQ[3:0]
DQM MASK LOGIC
READ DATA LATCH
WRITE DRIVERS
BANK
CONTROL
LOGIC
A[12:0]
BA[1:0]
ADDRESS
REGISTER
15
DATA
INPUT
REGISTER
2
4
4096
(x4)
COLUMN
DECODER
COLUMN-
ADDRESS
COUNTER/
LATCH
12
12
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512Mb: x4, x8, x16 SDRAM
Functional Block Diagrams
Figure 2: 64 Meg x 8 Functional Block Diagram
CKE
CLK
CONTROL
LOGIC
CS#
WE#
BANK3
CAS#
RAS#
BANK2
BANK1
REFRESH
COUNTER
13
MODE REGISTER
12
BANK0
ROW-
ADDRESS
LATCH
&
ROW-
ADDRESS
MUX
13
BANK0
MEMORY
ARRAY
1
1
8192
DQM
13
(8192 x 2048 x 8)
DECODER
DATA
OUTPUT
REGISTER
SENSE AMPLIFIERS
16384
8
I/O GATING
2
8
DQ[7:0]
DQM MASK LOGIC
READ DATA LATCH
WRITE DRIVERS
BANK
CONTROL
LOGIC
A[12:0]
BA[1:0]
ADDRESS
REGISTER
15
DATA
INPUT
REGISTER
2
8
2048
(x8)
COLUMN
DECODER
COLUMN-
ADDRESS
COUNTER/
LATCH
11
11
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512Mb: x4, x8, x16 SDRAM
Functional Block Diagrams
Figure 3: 32 Meg x 16 Functional Block Diagram
CKE
CLK
CONTROL
LOGIC
CS#
WE#
BANK3
CAS#
RAS#
BANK2
BANK1
REFRESH
COUNTER
13
MODE REGISTER
12
BANK0
ROW-
ADDRESS
LATCH
&
ROW-
ADDRESS
MUX
13
BANK0
MEMORY
ARRAY
2
2
8192
DQML,
DQMH
13
(8192 x 1024 x 16)
DECODER
DATA
OUTPUT
REGISTER
SENSE AMPLIFIERS
16384
16
I/O GATING
2
16
DQ[15:0]
DQM MASK LOGIC
READ DATA LATCH
WRITE DRIVERS
BANK
CONTROL
LOGIC
A[12:0]
BA[1:0]
ADDRESS
REGISTER
15
DATA
INPUT
REGISTER
2
16
1024
(x16)
COLUMN
DECODER
COLUMN-
ADDRESS
COUNTER/
LATCH
10
10
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512Mb: x4, x8, x16 SDRAM
Pin and Ball Assignments and Descriptions
Pin and Ball Assignments and Descriptions
Figure 4: 54-Pin TSOP (Top View)
x4
x8
x16
x16
x8
x4
-
NC
-
DQ0
-
NC
DQ1
-
NC
DQ2
-
NC
DQ3
-
VDD
DQ0
VDDQ
DQ1
DQ2
VSSQ
DQ3
DQ4
VDDQ
DQ5
DQ6
VSSQ
DQ7
VDD
VSS
DQ15 DQ7
VSSQ
DQ14 NC
DQ13 DQ6
VDDQ
DQ12 NC
DQ11 DQ5
VSSQ
-
-
NC
-
NC
DQ3
-
NC
NC
-
NC
DQ2
-
NC
-
1
2
3
4
5
6
7
8
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
-
NC
DQ0
-
NC
NC
-
NC
DQ1
-
NC
-
NC
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
9
DQ10 NC
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
DQ9
VDDQ
DQ8
VSS
DQ4
-
NC
-
-
NC
-
NC DQML
NC
-
-
-
-
-
-
-
-
-
-
-
-
-
WE#
CAS#
RAS#
CS#
BA0
BA1
A10
A0
A1
A2
A3
VDD
DQMH DQM DQM
CLK
CKE
A12
A11
A9
A8
A7
A6
A5
A4
VSS
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
1. The # symbol indicates that the signal is active LOW. A dash (-) indicates that the x8 and
x4 pin function is the same as the x16 pin function.
Notes:
2. Package may or may not be assembled with a location notch.
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512Mb: x4, x8, x16 SDRAM
Pin and Ball Assignments and Descriptions
Table 4: Pin and Ball Descriptions
Symbol
Type Description
CLK
Input Clock: CLK is driven by the system clock. All SDRAM input signals are sampled on the positive
edge of CLK. CLK also increments the internal burst counter and controls the output registers.
CKE
Input Clock enable: CKE activates (HIGH) and deactivates (LOW) the CLK signal. Deactivating the
clock provides precharge power-down and SELF REFRESH operation (all banks idle), active
power-down (row active in any bank), or CLOCK SUSPEND operation (burst/access in pro-
gress). CKE is synchronous except after the device enters power-down and self refresh modes,
where CKE becomes asynchronous until after exiting the same mode. The input buffers, in-
cluding CLK, are disabled during power-down and self refresh modes, providing low standby
power. CKE may be tied HIGH.
CS#
Input Chip select: CS# enables (registered LOW) and disables (registered HIGH) the command decod-
er. All commands are masked when CS# is registered HIGH, but READ/WRITE bursts already in
progress will continue, and DQM operation will retain its DQ mask capability while CS# is
HIGH. CS# provides for external bank selection on systems with multiple banks. CS# is consid-
ered part of the command code.
CAS#, RAS#,
WE#
Input Command inputs: RAS#, CAS#, and WE# (along with CS#) define the command being entered.
x4, x8:
DQM
Input Input/output mask: DQM is an input mask signal for write accesses and an output enable sig-
nal for read accesses. Input data is masked when DQM is sampled HIGH during a WRITE cycle.
The output buffers are placed in a High-Z state (two-clock latency) when DQM is sampled
HIGH during a READ cycle. On the x4 and x8, DQML (pin 15) is a NC and DQMH is DQM. On
the x16, DQML corresponds to DQ[7:0], and DQMH corresponds to DQ[15:8]. DQML and
DQMH are considered same state when referenced as DQM.
x16:
DQML, DQMH
LDQM, UDQM
(54-ball)
BA[1:0]
Input Bank address input(s): BA[1:0] define to which bank the ACTIVE, READ, WRITE, or PRECHARGE
command is being applied.
A[12:0]
Input Address inputs: A[12:0] are sampled during the ACTIVE command (row address A[12:0]) and
READ or WRITE command (column address A[9:0], A11, and A12 for x4; A[9:0] and A11 for x8;
A[9:0] for x16; with A10 defining auto precharge) to select one location out of the memory
array in the respective bank. A10 is sampled during a PRECHARGE command to determine if
all banks are to be precharged (A10 HIGH) or bank selected by A10 (LOW). The address inputs
also provide the op-code during a LOAD MODE REGISTER command.
x16:
DQ[15:0]
I/O
I/O
I/O
Data input/output: Data bus for x16 (pins 4, 7, 10, 13, 15, 42, 45, 48, and 51 are NC for x8; and
pins 2, 4, 7, 8, 10, 13, 15, 42, 45, 47, 48, 51, and 53 are NC for x4).
x8:
DQ[7:0]
Data input/output: Data bus for x8 (pins 2, 8, 47, 53 are NC for x4).
x4:
Data input/output: Data bus for x4.
DQ[3:0]
VDDQ
VSSQ
VDD
VSS
Supply DQ power: DQ power to the die for improved noise immunity.
Supply DQ ground: DQ ground to the die for improved noise immunity.
Supply Power supply: +3.3V ±0.3V.
Supply Ground.
NC
–
These should be left unconnected.
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512Mb: x4, x8, x16 SDRAM
Package Dimensions
Package Dimensions
Figure 5: 54-Pin Plastic TSOP (400 mil) – Package Codes TG/P
0.10
1.2 MAX
0.375 ±0.075 TYP
Pin #1 ID
0.80 TYP
(for reference only)
22.22 ±0.08
2X R 0.75
2X R 1.00
2X 0.71
Plated lead finish: 90% Sn, 10% Pb or 100% Sn
Plastic package material: Epoxy novolac
Package width and length do not include
mold protrusion. Allowable protrusion is
0.25 per side.
2X 0.10
2.80
Gage plane
0.25
10.16 ±0.08
+0.10
-0.05
11.76 ±0.20
0.10
See Detail A
+0.03
-0.02
0.15
0.50 ±0.10
0.80
Detail A
1. All dimensions are in millimeters.
Notes:
2. Package width and length do not include mold protrusion; allowable mold protrusion is
0.25mm per side.
3. 2X means the notch is present in two locations (both ends of the device).
4. Package may or may not be assembled with a location notch.
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512Mb: x4, x8, x16 SDRAM
Temperature and Thermal Impedance
Temperature and Thermal Impedance
It is imperative that the SDRAM device’s temperature specifications, shown in Table 6
(page 14), be maintained to ensure the junction temperature is in the proper operat-
ing range to meet data sheet specifications. An important step in maintaining the prop-
er junction temperature is using the device’s thermal impedances correctly. The ther-
mal impedances are listed in Table 6 (page 14) for the applicable die revision and
packages being made available. These thermal impedance values vary according to the
density, package, and particular design used for each device.
Incorrectly using thermal impedances can produce significant errors. Read Micron
technical note TN-00-08, “Thermal Applications” prior to using the thermal impedan-
ces listed in Table 6 (page 14). To ensure the compatibility of current and future de-
signs, contact Micron Applications Engineering to confirm thermal impedance values.
The SDRAM device’s safe junction temperature range can be maintained when the TC
specification is not exceeded. In applications where the device’s ambient temperature
is too high, use of forced air and/or heat sinks may be required to satisfy the case tem-
perature specifications.
Table 5: Temperature Limits
Parameter
Symbol
Min
0
Max
80
Unit
Notes
Operating case temperature
Commercial
Industrial
TC
°C
1, 2, 3, 4
–40
0
90
Junction temperature
Ambient temperature
Commercial
Industrial
TJ
TA
85
°C
°C
°C
3
–40
0
95
Commercial
Industrial
70
3, 5
–40
–
85
Peak reflow temperature
Notes:
TPEAK
260
1. MAX operating case temperature, TC, is measured in the center of the package on the
top side of the device, as shown in Figure 6 (page 14).
2. Device functionality is not guaranteed if the device exceeds maximum TC during opera-
tion.
3. All temperature specifications must be satisfied.
4. The case temperature should be measured by gluing a thermocouple to the top-center
of the component. This should be done with a 1mm bead of conductive epoxy, as de-
fined by the JEDEC EIA/JESD51 standards. Take care to ensure that the thermocouple
bead is touching the case.
5. Operating ambient temperature surrounding the package.
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Temperature and Thermal Impedance
Table 6: Thermal Impedance Simulated Values
Θ JA (°C/W)
Airflow =
Θ JA (°C/W)
Airflow =
Θ JA (°C/W)
Airflow =
2m/s
Die
Revision
Package
Substrate
2-layer
0m/s
1m/s
Θ JB (°C/W) Θ JC (°C/W)
D
54-pin TSOP
62.6
39.2
48.4
32.3
44.2
30.6
19.2
19.3
6.7
4-layer
1. For designs expected to last beyond the die revision listed, contact Micron Applications
Engineering to confirm thermal impedance values.
Notes:
2. Thermal resistance data is sampled from multiple lots, and the values should be viewed
as typical.
3. These are estimates; actual results may vary.
Figure 6: Example: Temperature Test Point Location, 54-Pin TSOP (Top View)
22.22mm
11.11mm
Test point
10.16mm
5.08mm
1. Package may or may not be assembled with a location notch.
Note:
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Electrical Specifications
Electrical Specifications
Stresses greater than those listed may cause permanent damage to the device. This is a
stress rating only, and functional operation of the device at these or any other condi-
tions above those indicated in the operational sections of this specification is not im-
plied. Exposure to absolute maximum rating conditions for extended periods may affect
reliability.
Table 7: Absolute Maximum Ratings
Voltage/Temperature
Symbol
VDD/VDDQ
VIN
Min Max Unit
Notes
Voltage on VDD/VDDQ supply relative to VSS
Voltage on inputs, NC, or I/O balls relative to VSS
Storage temperature (plastic)
Power dissipation
–1
–1
+4.6
+4.6
V
1
TSTG
–55 +155
°C
W
–
–
1
1. VDD and VDDQ must be within 300mV of each other at all times. VDDQ must not exceed
VDD
Note:
.
Table 8: DC Electrical Characteristics and Operating Conditions
Notes 1–3 apply to all parameters and conditions; VDD/VDDQ = +3.3V ±0.3V
Parameter/Condition
Symbol
VDD, VDDQ
VIH
Min
3
Max
Unit Notes
Supply voltage
3.6
V
Input high voltage: Logic 1; All inputs
Input low voltage: Logic 0; All inputs
Output high voltage: IOUT = –4mA
Output low voltage: IOUT = 4mA
Input leakage current:
2
VDD + 0.3
V
V
4
4
VIL
–0.3
2.4
–
+0.8
–
VOH
V
VOL
0.4
5
V
IL
–5
μA
Any input 0V ≤ VIN ≤ VDD (All other balls not under test = 0V)
Output leakage current: DQ are disabled; 0V ≤ VOUT ≤ VDDQ
IOZ
TA
TA
–5
0
–5
μA
˚C
Operating temperature:
Commercial
Industrial
+70
+85
–40
˚C
1. All voltages referenced to VSS.
Notes:
2. The minimum specifications are used only to indicate cycle time at which proper opera-
tion over the full temperature range is ensured; (0°C ≤ TA ≤ +70°C (commercial), –40°C ≤
TA ≤ +85°C (industrial), and –40°C ≤ TA ≤ +105°C (automotive)).
3. An initial pause of 100μs is required after power-up, followed by two AUTO REFRESH
commands, before proper device operation is ensured. (VDD and VDDQ must be powered
up simultaneously. VSS and VSSQ must be at same potential.) The two AUTO REFRESH
command wake-ups should be repeated any time the tREF refresh requirement is excee-
ded.
4. VIH overshoot: VIH,max = VDDQ + 2V for a pulse width ≤ 3ns, and the pulse width cannot
be greater than one-third of the cycle rate. VIL undershoot: VIL,min = –2V for a pulse
width ≤3ns.
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Electrical Specifications
Table 9: Capacitance
Note 1 applies to all parameters and conditions
Package
Parameter
Symbol
CL1
Min
2.5
Max
3.5
Unit
pF
Notes
TSOP "TG" package
Input capacitance: CLK
2
3
Input capacitance: All other input-only
balls
CL2
2.5
3.8
pF
Input/output capacitance: DQ
CL0
4
6
pF
4
1. This parameter is sampled. VDD, VDDQ = +3.3V; f = 1 MHz, TA = 25°C; pin under test
biased at 1.4V.
Notes:
2. PC100 specifies a maximum of 4pF.
3. PC100 specifies a maximum of 5pF.
4. PC100 specifies a maximum of 6.5pF.
5. PC133 specifies a minimum of 2.5pF.
6. PC133 specifies a minimum of 2.5pF.
7. PC133 specifies a minimum of 3.0pF.
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Electrical Specifications – IDD Parameters
Electrical Specifications – IDD Parameters
Table 10: IDD Specifications and Conditions (-7E, -75)
Notes 1–5 apply to all parameters and conditions; VDD/VDDQ = +3.3V ±0.3V
Max
Parameter/Condition
Symbol
-7E
-75
Unit
Notes
Operating current: Active mode; Burst = 2; READ or WRITE; tRC = tRC
(MIN)
IDD1
120
110
mA
6, 9, 10,
13
Standby current: Power-down mode; All banks idle; CKE = LOW
IDD2
IDD3
3.5
45
3.5
45
mA
mA
13
Standby current: Active mode; CKE = HIGH; CS# = HIGH; All banks active
after tRCD met; No accesses in progress
6, 8, 10,
13
Operating current: Burst mode; Page burst; READ or WRITE; All banks ac-
tive
IDD4
125
115
mA
6, 9, 10,
13
Auto refresh current: CKE = HIGH; CS# = HIGH
tRFC = tRFC (MIN)
tRFC = 7.813μs
Standard
IDD5
IDD6
IDD7
IDD7
255
6
255
6
mA 6, 8, 9, 10,
13, 14
mA
Self refresh current: CKE ≤ 0.2V
6
6
mA
Low power (L)
3
3
mA
7
1. All voltages referenced to VSS.
Notes:
2. The minimum specifications are used only to indicate cycle time at which proper opera-
tion over the full temperature range is ensured; (0°C ≤ TA ≤ +70°C (commercial), –40°C ≤
TA ≤ +85°C (industrial), and –40°C ≤ TA ≤ +105°C (automotive)).
3. An initial pause of 100μs is required after power-up, followed by two AUTO REFRESH
commands, before proper device operation is ensured. (VDD and VDDQ must be powered
up simultaneously. VSS and VSSQ must be at same potential.) The two AUTO REFRESH
command wake-ups should be repeated any time the tREF refresh requirement is excee-
ded.
4. AC operating and IDD test conditions have VIL = 0V and VIH = 3.0V using a measurement
reference level of 1.5V. If the input transition time is longer than 1ns, then the timing is
measured from VIL, max and VIH,min and no longer from the 1.5V midpoint. CLK should
always be 1.5V referenced to crossover. Refer to Micron technical note TN-48-09.
5. IDD specifications are tested after the device is properly initialized.
6. IDD is dependent on output loading and cycle rates. Specified values are obtained with
minimum cycle time and the outputs open.
7. Enables on-chip refresh and address counters.
8. Other input signals are allowed to transition no more than once every two clocks and
are otherwise at valid VIH or VIL levels.
9. The IDD current will increase or decrease proportionally according to the amount of fre-
quency alteration for the test condition.
10. Address transitions average one transition every two clocks.
11. PC100 specifies a maximum of 4pF.
12. PC100 specifies a maximum of 5pF.
13. For -75, CL = 3 and tCK = 7.5ns; for -7E, CL = 2 and tCK = 7.5ns.
14. CKE is HIGH during REFRESH command period tRFC (MIN) else CKE is LOW. The IDD6 limit
is actually a nominal value and does not result in a fail value.
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Electrical Specifications – AC Operating Conditions
Electrical Specifications – AC Operating Conditions
Table 11: Electrical Characteristics and Recommended AC Operating Conditions (-7E, -75)
Notes 1, 2, 4, 5, 7, and 20 apply to all parameters and conditions
-7E
-75
Parameter
Symbol
tAC(3)
tAC(2)
tAH
Min
–
Max
5.4
5.4
–
Min
–
Max
5.4
6
Unit
Notes
Access time from CLK (positive edge)
CL = 3
CL = 2
ns
18
–
–
Address hold time
Address setup time
CLK high-level width
CLK low-level width
Clock cycle time
0.8
1.5
2.5
2.5
7
0.8
1.5
2.5
2.5
7.5
10
0.8
1.5
0.8
1.5
0.8
1.5
–
–
ns
ns
ns
ns
ns
tAS
tCH
tCL
tCK(3)
tCK(2)
tCKH
tCKS
tCMH
tCMS
tDH
–
–
–
–
–
–
CL = 3
CL = 2
–
–
14
21
7.5
0.8
1.5
0.8
1.5
0.8
1.5
–
–
–
CKE hold time
–
–
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ms
ns
ns
tCK
ns
ns
CKE setup time
–
–
CS#, RAS#, CAS#, WE#, DQM hold time
CS#, RAS#, CAS#, WE#, DQM setup time
Data-in hold time
–
–
–
–
–
–
Data-in setup time
tDS
–
–
Data-out High-Z time
CL = 3
CL = 2
tHZ(3)
tHZ(2)
tLZ
5.4
5.4
–
5.4
6
6
–
–
Data-out Low-Z time
1
1
–
Data-out hold time (load)
Data-out hold time (no load)
ACTIVE-to-PRECHARGE command
ACTIVE-to-ACTIVE command period
ACTIVE-to-READ or WRITE delay
Refresh period (8192 rows)
AUTO REFRESH period
tOH
2.7
1.8
37
60
15
–
–
2.7
1.8
44
66
20
–
–
tOHn
tRAS
tRC
tRCD
tREF
tRFC
tRP
tRRD
tT
tWR
–
–
19
23
120,000
120,000
–
–
–
–
64
–
64
–
66
15
14
0.3
66
20
15
0.3
PRECHARGE command period
ACTIVE bank a to ACTIVE bank b command
Transition time
–
–
–
–
1.2
–
1.2
–
3
WRITE recovery time
1 CLK +
7ns
1 CLK +
7.5ns
15
14
67
–
–
15
75
–
–
16
12
Exit SELF REFRESH-to-ACTIVE command
tXSR
ns
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Electrical Specifications – AC Operating Conditions
Table 12: AC Functional Characteristics (-7E, -75)
Notes 1–5 and note 7 apply to all parameters and conditions
Parameter
Symbol
tBDL
tCCD
tCDL
tCKED
tDAL
-7E
1
-75
1
Unit
tCK
tCK
tCK
tCK
tCK
tCK
tCK
tCK
tCK
tCK
tCK
tCK
tCK
tCK
tCK
Notes
11
Last data-in to burst STOP command
READ/WRITE command to READ/WRITE command
Last data-in to new READ/WRITE command
CKE to clock disable or power-down entry mode
Data-in to ACTIVE command
1
1
11
1
1
11
1
1
8
4
5
9, 13
10, 13
11
Data-in to PRECHARGE command
tDPL
2
2
DQM to input data delay
tDQD
tDQM
tDQZ
tDWD
tMRD
tPED
tRDL
tROH(3)
tROH(2)
0
0
DQM to data mask during WRITEs
0
0
11
DQM to data High-Z during READs
2
2
11
WRITE command to input data delay
0
0
11
LOAD MODE REGISTER command to ACTIVE or REFRESH command
CKE to clock enable or power-down exit setup mode
Last data-in to PRECHARGE command
2
2
17
1
1
8
2
2
10, 13
11
Data-out High-Z from PRECHARGE command
CL = 3
CL = 2
3
3
2
2
11
1. The minimum specifications are used only to indicate cycle time at which proper opera-
tion over the full temperature range (0˚C ≤ TA ≤ +70˚C commercial temperature, -40˚C ≤
TA ≤ +85˚C industrial temperature, and -40˚C ≤ TA ≤ +105˚C automotive temperature) is
ensured.
Notes:
2. An initial pause of 100μs is required after power-up, followed by two AUTO REFRESH
commands, before proper device operation is ensured. (VDD and VDDQ must be powered
up simultaneously. VSS and VSSQ must be at same potential.) The two AUTO REFRESH
command wake-ups should be repeated any time the tREF refresh requirement is excee-
ded.
3. AC characteristics assume tT = 1ns.
4. In addition to meeting the transition rate specification, the clock and CKE must transit
between VIH and VIL (or between VIL and VIH) in a monotonic manner.
5. Outputs measured at 1.5V with equivalent load:
Q
50pF
6. tHZ defines the time at which the output achieves the open circuit condition; it is not a
reference to VOH or VOL. The last valid data element will meet tOH before going High-Z.
7. AC operating and IDD test conditions have VIL = 0V and VIH = 3.0V using a measurement
reference level of 1.5V. If the input transition time is longer than 1ns, then the timing is
measured from VIL,max and VIH,min and no longer from the 1.5V midpoint. CLK should al-
ways be 1.5V referenced to crossover. Refer to Micron technical note TN-48-09.
8. Timing is specified by tCKS. Clock(s) specified as a reference only at minimum cycle rate.
9. Timing is specified by tWR plus tRP. Clock(s) specified as a reference only at minimum cy-
cle rate.
10. Timing is specified by tWR.
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Electrical Specifications – AC Operating Conditions
11. Required clocks are specified by JEDEC functionality and are not dependent on any tim-
ing parameter.
12. CLK must be toggled a minimum of two times during this period.
13. Based on tCK = 7.5ns for -75 and -7E, 6ns for -6A.
14. The clock frequency must remain constant (stable clock is defined as a signal cycling
within timing constraints specified for the clock pin) during access or precharge states
(READ, WRITE, including tWR, and PRECHARGE commands). CKE may be used to reduce
the data rate.
15. Auto precharge mode only. The precharge timing budget (tRP) begins at 7ns for -7E and
7.5ns for -75 after the first clock delay and after the last WRITE is executed.
16. Precharge mode only.
17. JEDEC and PC100 specify three clocks.
18. tAC for -75/-7E at CL = 3 with no load is 4.6ns and is guaranteed by design.
19. Parameter guaranteed by design.
20. PC100 specifies a maximum of 6.5pF.
21. For operating frequencies ≤ 45 MHz, tCKS = 3.0ns.
22. Auto precharge mode only. The precharge timing budget (tRP) begins 6ns for -6A after
the first clock delay, after the last WRITE is executed. May not exceed limit set for pre-
charge mode.
23. DRAM devices should be evenly addressed when being accessed. Disproportionate ac-
cesses to a particular row address may result in reduction of the product lifetime.
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Functional Description
Functional Description
In general, 512Mb SDRAM devices (32 Meg x 4 x 4 banks, 16 Meg x 8 x 4 banks, and 16
Meg x 16 x 4 banks) are quad-bank DRAM that operate at 3.3V and include a synchro-
nous interface. All signals are registered on the positive edge of the clock signal, CLK.
Each of the x8’s 134,217,728-bit banks is organized as 8192 rows by 4096 columns by 4
bits. Each of the x8’s 134,217,728-bit banks is organized as 8192 rows by 2048 columns
by 8 bits. Each of the x16’s 134,217,728-bit banks is organized as 8192 rows by 1024 col-
umns by 16 bits.
Read and write accesses to the SDRAM are burst-oriented; accesses start at a selected
location and continue for a programmed number of locations in a programmed se-
quence. Accesses begin with the registration of an ACTIVE command, followed by a
READ or WRITE command. The address bits registered coincident with the ACTIVE
command are used to select the bank and row to be accessed (BA0 and BA1 select the
bank, A[12:0] select the row). The address bits (x4: A[9:0], A11, A12; x8: A[9:0], A11; x16:
A[9:0]) registered coincident with the READ or WRITE command are used to select the
starting column location for the burst access.
Prior to normal operation, the SDRAM must be initialized. The following sections pro-
vide detailed information covering device initialization, register definition, command
descriptions, and device operation.
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Commands
Commands
The following table provides a quick reference of available commands, followed by a
written description of each command. Additional Truth Tables (Table 14 (page 28), Ta-
ble 15 (page 30), and Table 16 (page 32)) provide current state/next state informa-
tion.
Table 13: Truth Table – Commands and DQM Operation
Note 1 applies to all parameters and conditions
Name (Function)
CS# RAS# CAS# WE# DQM ADDR
DQ Notes
COMMAND INHIBIT (NOP)
H
L
X
H
L
X
H
H
L
X
H
H
H
L
X
X
X
X
X
NO OPERATION (NOP)
X
ACTIVE (select bank and activate row)
READ (select bank and column, and start READ burst)
WRITE (select bank and column, and start WRITE burst)
BURST TERMINATE
L
X
Bank/row
Bank/col
X
X
2
3
L
H
H
H
L
L/H
L/H
X
L
L
Bank/col Valid
3
L
H
H
L
L
X
Active
X
4
PRECHARGE (Deactivate row in bank or banks)
AUTO REFRESH or SELF REFRESH (enter self refresh mode)
LOAD MODE REGISTER
L
L
X
Code
5
L
L
H
L
X
X
X
6, 7
8
L
L
L
X
Op-code
X
Write enable/output enable
X
X
X
X
X
X
X
X
L
X
X
Active
High-Z
9
Write inhibit/output High-Z
H
9
1. CKE is HIGH for all commands shown except SELF REFRESH.
Notes:
2. A[0:n] provide row address (where An is the most significant address bit), BA0 and BA1
determine which bank is made active.
3. A[0:i] provide column address (where i = the most significant column address for a given
device configuration). A10 HIGH enables the auto precharge feature (nonpersistent),
while A10 LOW disables the auto precharge feature. BA0 and BA1 determine which
bank is being read from or written to.
4. The purpose of the BURST TERMINATE command is to stop a data burst, thus the com-
mand could coincide with data on the bus. However, the DQ column reads a “Don’t
Care” state to illustrate that the BURST TERMINATE command can occur when there is
no data present.
5. A10 LOW: BA0, BA1 determine the bank being precharged. A10 HIGH: all banks pre-
charged and BA0, BA1 are “Don’t Care.”
6. This command is AUTO REFRESH if CKE is HIGH, SELF REFRESH if CKE is LOW.
7. Internal refresh counter controls row addressing; all inputs and I/Os are “Don’t Care” ex-
cept for CKE.
8. A[11:0] define the op-code written to the mode register.
9. Activates or deactivates the DQ during WRITEs (zero-clock delay) and READs (two-clock
delay).
COMMAND INHIBIT
The COMMAND INHIBIT function prevents new commands from being executed by
the device, regardless of whether the CLK signal is enabled. The device is effectively de-
selected. Operations already in progress are not affected.
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Commands
NO OPERATION (NOP)
The NO OPERATION (NOP) command is used to perform a NOP to the selected device
(CS# is LOW). This prevents unwanted commands from being registered during idle or
wait states. Operations already in progress are not affected.
LOAD MODE REGISTER (LMR)
The mode registers are loaded via inputs A[n:0] (where An is the most significant ad-
dress term), BA0, and BA1(see Mode Register (page 35)). The LOAD MODE REGISTER
command can only be issued when all banks are idle and a subsequent executable com-
mand cannot be issued until tMRD is met.
ACTIVE
The ACTIVE command is used to activate a row in a particular bank for a subsequent
access. The value on the BA0, BA1 inputs selects the bank, and the address provided se-
lects the row. This row remains active for accesses until a PRECHARGE command is is-
sued to that bank. A PRECHARGE command must be issued before opening a different
row in the same bank.
Figure 7: ACTIVE Command
CLK
CKE HIGH
CS#
RAS#
CAS#
WE#
Row address
Bank address
Address
BA0, BA1
Don’t Care
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Commands
READ
The READ command is used to initiate a burst read access to an active row. The values
on the BA0 and BA1 inputs select the bank; the address provided selects the starting col-
umn location. The value on input A10 determines whether auto precharge is used. If au-
to precharge is selected, the row being accessed is precharged at the end of the READ
burst; if auto precharge is not selected, the row remains open for subsequent accesses.
Read data appears on the DQ subject to the logic level on the DQM inputs two clocks
earlier. If a given DQM signal was registered HIGH, the corresponding DQ will be High-
Z two clocks later; if the DQM signal was registered LOW, the DQ will provide valid data.
Figure 8: READ Command
CLK
CKE
HIGH
CS#
RAS#
CAS#
WE#
Column address
EN AP
Address
1
A10
DIS AP
BA0, BA1
Bank address
Don’t Care
1. EN AP = enable auto precharge, DIS AP = disable auto precharge.
Note:
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Commands
WRITE
The WRITE command is used to initiate a burst write access to an active row. The values
on the BA0 and BA1 inputs select the bank; the address provided selects the starting col-
umn location. The value on input A10 determines whether auto precharge is used. If au-
to precharge is selected, the row being accessed is precharged at the end of the write
burst; if auto precharge is not selected, the row remains open for subsequent accesses.
Input data appearing on the DQ is written to the memory array, subject to the DQM in-
put logic level appearing coincident with the data. If a given DQM signal is registered
LOW, the corresponding data is written to memory; if the DQM signal is registered
HIGH, the corresponding data inputs are ignored and a WRITE is not executed to that
byte/column location.
Figure 9: WRITE Command
CLK
CKE HIGH
CS#
RAS#
CAS#
WE#
Column address
EN AP
Address
1
A10
DIS AP
Bank address
BA0, BA1
Valid address
1. EN AP = enable auto precharge, DIS AP = disable auto precharge.
Don’t Care
Note:
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Commands
PRECHARGE
The PRECHARGE command is used to deactivate the open row in a particular bank or
the open row in all banks. The bank(s) will be available for a subsequent row access a
specified time (tRP) after the PRECHARGE command is issued. Input A10 determines
whether one or all banks are to be precharged, and in the case where only one bank is
precharged, inputs BA0 and BA1 select the bank. Otherwise BA0 and BA1 are treated as
“Don’t Care.” After a bank has been precharged, it is in the idle state and must be acti-
vated prior to any READ or WRITE commands are issued to that bank.
Figure 10: PRECHARGE Command
CLK
CKE HIGH
CS#
RAS#
CAS#
WE#
Address
A10
All banks
Bank selected
Bank address
BA0, BA1
Valid address
Don’t Care
BURST TERMINATE
The BURST TERMINATE command is used to truncate either fixed-length or continu-
ous page bursts. The most recently registered READ or WRITE command prior to the
BURST TERMINATE command is truncated.
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Commands
REFRESH
AUTO REFRESH
AUTO REFRESH is used during normal operation of the SDRAM and is analogous to
CAS#-BEFORE-RAS# (CBR) refresh in conventional DRAMs. This command is nonper-
sistent, so it must be issued each time a refresh is required. All active banks must be pre-
charged prior to issuing an AUTO REFRESH command. The AUTO REFRESH command
should not be issued until the minimum tRP has been met after the PRECHARGE com-
mand, as shown in Bank/Row Activation (page 40).
The addressing is generated by the internal refresh controller. This makes the address
bits a “Don’t Care” during an AUTO REFRESH command. Regardless of device width,
the 512Mb SDRAM requires 8192 AUTO REFRESH cycles every 64ms (commercial and
industrial). Providing a distributed AUTO REFRESH command every 7.813μs (commer-
cial and industrial) will meet the refresh requirement and ensure that each row is re-
freshed. Alternatively, 8192 AUTO REFRESH commands can be issued in a burst at the
minimum cycle rate (tRFC), once every 64ms (commercial and industrial).
SELF REFRESH
The SELF REFRESH command can be used to retain data in the SDRAM, even if the rest
of the system is powered-down. When in the self refresh mode, the SDRAM retains data
without external clocking.
The SELF REFRESH command is initiated like an AUTO REFRESH command except
CKE is disabled (LOW). After the SELF REFRESH command is registered, all the inputs
to the SDRAM become a “Don’t Care” with the exception of CKE, which must remain
LOW.
After self refresh mode is engaged, the SDRAM provides its own internal clocking, caus-
ing it to perform its own AUTO REFRESH cycles. The SDRAM must remain in self re-
fresh mode for a minimum period equal to tRAS and may remain in self refresh mode
for an indefinite period beyond that.
The procedure for exiting self refresh requires a sequence of commands. First, CLK
must be stable (stable clock is defined as a signal cycling within timing constraints
specified for the clock pin) prior to CKE going back HIGH. After CKE is HIGH, the
SDRAM must have NOP commands issued (a minimum of two clocks) for tXSR because
time is required for the completion of any internal refresh in progress.
Upon exiting the self refresh mode, AUTO REFRESH commands must be issued at the
specified intervals, as both SELF REFRESH and AUTO REFRESH utilize the row refresh
counter.
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Truth Tables
Truth Tables
Table 14: Truth Table – Current State Bank n, Command to Bank n
Notes 1–6 apply to all parameters and conditions
Current State
CS# RAS# CAS# WE# Command/Action
Notes
Any
H
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
X
H
L
X
H
H
L
X
H
H
H
L
COMMAND INHIBIT (NOP/continue previous operation)
NO OPERATION (NOP/continue previous operation)
ACTIVE (select and activate row)
Idle
L
AUTO REFRESH
7
7
L
L
LOAD MODE REGISTER
L
H
L
L
PRECHARGE
8
Row active
H
H
L
H
L
READ (select column and start READ burst)
WRITE (select column and start WRITE burst)
PRECHARGE (deactivate row in bank or banks)
READ (select column and start new READ burst)
WRITE (select column and start WRITE burst)
PRECHARGE (truncate READ burst, start PRECHARGE)
BURST TERMINATE
9
L
9
H
L
L
10
9
Read
H
H
L
H
L
(auto precharge disabled)
L
9
H
H
L
L
10
11
9
H
H
H
L
L
Write
H
L
READ (select column and start READ burst)
WRITE (select column and start new WRITE burst)
PRECHARGE (truncate WRITE burst, start PRECHARGE)
BURST TERMINATE
(auto precharge disabled)
L
9
H
H
L
10
11
H
L
1. This table applies when CKEn-1 was HIGH and CKEn is HIGH (see Table 16 (page 32))
and after tXSR has been met (if the previous state was self refresh).
Notes:
2. This table is bank-specific, except where noted (for example, the current state is for a
specific bank and the commands shown can be issued to that bank when in that state).
Exceptions are covered below.
3. Current state definitions:
Idle: The bank has been precharged, and tRP has been met.
Row active: A row in the bank has been activated, and tRCD has been met. No data
bursts/accesses and no register accesses are in progress.
Read: A READ burst has been initiated, with auto precharge disabled, and has not yet
terminated or been terminated.
Write: A WRITE burst has been initiated, with auto precharge disabled, and has not yet
terminated or been terminated.
4. The following states must not be interrupted by a command issued to the same bank.
COMMAND INHIBIT or NOP commands, or supported commands to the other bank
should be issued on any clock edge occurring during these states. Supported commands
to any other bank are determined by the bank’s current state and the conditions descri-
bed in this and the following table.
Precharging: Starts with registration of a PRECHARGE command and ends when tRP is
met. After tRP is met, the bank will be in the idle state.
Row activating: Starts with registration of an ACTIVE command and ends when tRCD is
met. After tRCD is met, the bank will be in the row active state.
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Truth Tables
Read with auto precharge enabled: Starts with registration of a READ command
with auto precharge enabled and ends when tRP has been met. After tRP is met, the
bank will be in the idle state.
Write with auto precharge enabled: Starts with registration of a WRITE command
with auto precharge enabled and ends when tRP has been met. After tRP is met, the
bank will be in the idle state.
5. The following states must not be interrupted by any executable command; COMMAND
INHIBIT or NOP commands must be applied on each positive clock edge during these
states.
Refreshing: Starts with registration of an AUTO REFRESH command and ends when
tRFC is met. After tRFC is met, the device will be in the all banks idle state.
Accessing mode register: Starts with registration of a LOAD MODE REGISTER com-
mand and ends when tMRD has been met. After tMRD is met, the device will be in the
all banks idle state.
Precharging all: Starts with registration of a PRECHARGE ALL command and ends
when tRP is met. After tRP is met, all banks will be in the idle state.
6. All states and sequences not shown are illegal or reserved.
7. Not bank specific; requires that all banks are idle.
8. Does not affect the state of the bank and acts as a NOP to that bank.
9. READs or WRITEs listed in the Command/Action column include READs or WRITEs with
auto precharge enabled and READs or WRITEs with auto precharge disabled.
10. May or may not be bank specific; if all banks need to be precharged, each must be in a
valid state for precharging.
11. Not bank-specific; BURST TERMINATE affects the most recent READ or WRITE burst, re-
gardless of bank.
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Truth Tables
Table 15: Truth Table – Current State Bank n, Command to Bank m
Notes 1–6 apply to all parameters and conditions
Current State
CS# RAS# CAS# WE# Command/Action
Notes
Any
H
L
X
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
X
H
X
L
X
H
X
H
L
X
H
X
H
H
L
COMMAND INHIBIT (NOP/continue previous operation)
NO OPERATION (NOP/continue previous operation)
Any command otherwise supported for bank m
ACTIVE (select and activate row)
READ (select column and start READ burst)
WRITE (select column and start WRITE burst)
PRECHARGE
Idle
Row activating, active, or
precharging
H
H
L
7
7
L
H
H
L
L
Read
L
H
H
L
ACTIVE (select and activate row)
READ (select column and start new READ burst)
WRITE (select column and start WRITE burst)
PRECHARGE
(auto precharge disabled)
H
H
L
7, 10
7, 11
9
L
H
H
L
L
Write
L
H
H
L
ACTIVE (select and activate row)
READ (select column and start READ burst)
WRITE (select column and start new WRITE burst)
PRECHARGE
(auto precharge disabled)
H
H
L
7, 12
7, 13
9
L
H
H
L
L
Read
L
H
H
L
ACTIVE (select and activate row)
READ (select column and start new READ burst)
WRITE (select column and start WRITE burst)
PRECHARGE
(with auto precharge)
H
H
L
7, 8, 14
7, 8, 15
9
L
H
H
L
L
Write
(with auto precharge)
L
H
H
L
ACTIVE (select and activate row)
READ (select column and start READ burst)
WRITE (select column and start new WRITE burst)
PRECHARGE
H
H
L
7, 8, 16
7, 8, 17
9
L
H
L
1. This table applies when CKEn-1 was HIGH and CKEn is HIGH (Table 16 (page 32)), and
after tXSR has been met (if the previous state was self refresh).
Notes:
2. This table describes alternate bank operation, except where noted; for example, the cur-
rent state is for bank n and the commands shown can be issued to bank m, assuming
that bank m is in such a state that the given command is supported. Exceptions are cov-
ered below.
3. Current state definitions:
Idle: The bank has been precharged, and tRP has been met.
Row active: A row in the bank has been activated, and tRCD has been met. No data
bursts/accesses and no register accesses are in progress.
Read: A READ burst has been initiated, with auto precharge disabled, and has not yet
terminated or been terminated.
Write: A WRITE burst has been initiated, with auto precharge disabled, and has not yet
terminated or been terminated.
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Truth Tables
Read with auto precharge enabled: Starts with registration of a READ command
with auto precharge enabled and ends when tRP has been met. After tRP is met, the
bank will be in the idle state.
Write with auto precharge enabled: Starts with registration of a WRITE command
with auto precharge enabled and ends when tRP has been met. After tRP is met, the
bank will be in the idle state.
4. AUTO REFRESH, SELF REFRESH, and LOAD MODE REGISTER commands can only be is-
sued when all banks are idle.
5. A BURST TERMINATE command cannot be issued to another bank; it applies to the bank
represented by the current state only.
6. All states and sequences not shown are illegal or reserved.
7. READs or WRITEs to bank m listed in the Command/Action column include READs or
WRITEs with auto precharge enabled and READs or WRITEs with auto precharge disa-
bled.
8. Concurrent auto precharge: Bank n will initiate the auto precharge command when its
burst has been interrupted by bank m burst.
9. The burst in bank n continues as initiated.
10. For a READ without auto precharge interrupted by a READ (with or without auto pre-
charge), the READ to bank m will interrupt the READ on bank n, CAS latency (CL) later.
11. For a READ without auto precharge interrupted by a WRITE (with or without auto pre-
charge), the WRITE to bank m will interrupt the READ on bank n when registered. DQM
should be used one clock prior to the WRITE command to prevent bus contention.
12. For a WRITE without auto precharge interrupted by a READ (with or without auto pre-
charge), the READ to bank m will interrupt the WRITE on bank n when registered, with
the data-out appearing CL later. The last valid WRITE to bank n will be data-in regis-
tered one clock prior to the READ to bank m.
13. For a WRITE without auto precharge interrupted by a WRITE (with or without auto pre-
charge), the WRITE to bank m will interrupt the WRITE on bank n when registered. The
last valid WRITE to bank n will be data-in registered one clock prior to the READ to bank
m.
14. For a READ with auto precharge interrupted by a READ (with or without auto pre-
charge), the READ to bank m will interrupt the READ on bank n, CL later. The PRE-
CHARGE to bank n will begin when the READ to bank m is registered.
15. For a READ with auto precharge interrupted by a WRITE (with or without auto pre-
charge), the WRITE to bank m will interrupt the READ on bank n when registered. DQM
should be used two clocks prior to the WRITE command to prevent bus contention. The
PRECHARGE to bank n will begin when the WRITE to bank m is registered.
16. For a WRITE with auto precharge interrupted by a READ (with or without auto pre-
charge), the READ to bank m will interrupt the WRITE on bank n when registered, with
the data-out appearing CL later. The PRECHARGE to bank n will begin after tWR is met,
where tWR begins when the READ to bank m is registered. The last valid WRITE bank n
will be data-in registered one clock prior to the READ to bank m.
17. For a WRITE with auto precharge interrupted by a WRITE (with or without auto pre-
charge), the WRITE to bank m will interrupt the WRITE on bank n when registered. The
PRECHARGE to bank n will begin after tWR is met, where tWR begins when the WRITE
to bank m is registered. The last valid WRITE to bank n will be data registered one clock
to the WRITE to bank m.
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Truth Tables
Table 16: Truth Table – CKE
Notes 1–4 apply to all parameters and conditions
Current State
Power-down
Self refresh
CKEn-1
CKEn
Commandn
Actionn
Notes
L
L
X
Maintain power-down
Maintain self refresh
Maintain clock suspend
Exit power-down
X
Clock suspend
Power-down
Self refresh
X
L
H
L
COMMAND INHIBIT or NOP
COMMAND INHIBIT or NOP
X
5
6
7
Exit self refresh
Clock suspend
All banks idle
All banks idle
Reading or writing
Exit clock suspend
Power-down entry
Self refresh entry
Clock suspend entry
H
COMMAND INHIBIT or NOP
AUTO REFRESH
VALID
H
H
See Table 15 (page 30).
1. CKEn is the logic state of CKE at clock edge n; CKEn-1 was the state of CKE at the previ-
ous clock edge.
Notes:
2. Current state is the state of the SDRAM immediately prior to clock edge n.
3. COMMANDn is the command registered at clock edge n, and ACTIONn is a result of
COMMANDn.
4. All states and sequences not shown are illegal or reserved.
5. Exiting power-down at clock edge n will put the device in the all banks idle state in time
for clock edge n + 1 (provided that tCKS is met).
6. Exiting self refresh at clock edge n will put the device in the all banks idle state after
tXSR is met. COMMAND INHIBIT or NOP commands should be issued on any clock edges
occurring during the tXSR period. A minimum of two NOP commands must be provided
during the tXSR period.
7. After exiting clock suspend at clock edge n, the device will resume operation and recog-
nize the next command at clock edge n + 1.
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Initialization
Initialization
SDRAM must be powered up and initialized in a predefined manner. Operational proce-
dures other than those specified may result in undefined operation. After power is ap-
plied to VDD and VDDQ (simultaneously) and the clock is stable (stable clock is defined
as a signal cycling within timing constraints specified for the clock pin), the SDRAM re-
quires a 100μs delay prior to issuing any command other than a COMMAND INHIBIT or
NOP. Starting at some point during this 100μs period and continuing at least through
the end of this period, COMMAND INHIBIT or NOP commands must be applied.
After the 100μs delay has been satisfied with at least one COMMAND INHIBIT or NOP
command having been applied, a PRECHARGE command should be applied. All banks
must then be precharged, thereby placing the device in the all banks idle state.
Once in the idle state, at least two AUTO REFRESH cycles must be performed. After the
AUTO REFRESH cycles are complete, the SDRAM is ready for mode register program-
ming. Because the mode register will power up in an unknown state, it must be loaded
prior to applying any operational command. If desired, the two AUTO REFRESH com-
mands can be issued after the LMR command.
The recommended power-up sequence for SDRAM:
1. Simultaneously apply power to VDD and VDDQ
.
2. Assert and hold CKE at a LVTTL logic LOW since all inputs and outputs are LVTTL-
compatible.
3. Provide stable CLOCK signal. Stable clock is defined as a signal cycling within tim-
ing constraints specified for the clock pin.
4. Wait at least 100μs prior to issuing any command other than a COMMAND INHIB-
IT or NOP.
5. Starting at some point during this 100μs period, bring CKE HIGH. Continuing at
least through the end of this period, 1 or more COMMAND INHIBIT or NOP com-
mands must be applied.
6. Perform a PRECHARGE ALL command.
7. Wait at least tRP time; during this time NOPs or DESELECT commands must be
given. All banks will complete their precharge, thereby placing the device in the all
banks idle state.
8. Issue an AUTO REFRESH command.
9. Wait at least tRFC time, during which only NOPs or COMMAND INHIBIT com-
mands are allowed.
10. Issue an AUTO REFRESH command.
11. Wait at least tRFC time, during which only NOPs or COMMAND INHIBIT com-
mands are allowed.
12. The SDRAM is now ready for mode register programming. Because the mode reg-
ister will power up in an unknown state, it should be loaded with desired bit values
prior to applying any operational command. Using the LMR command, program
the mode register. The mode register is programmed via the MODE REGISTER SET
command with BA1 = 0, BA0 = 0 and retains the stored information until it is pro-
grammed again or the device loses power. Not programming the mode register
upon initialization will result in default settings which may not be desired. Out-
puts are guaranteed High-Z after the LMR command is issued. Outputs should be
High-Z already before the LMR command is issued.
13. Wait at least tMRD time, during which only NOP or DESELECT commands are al-
lowed.
At this point the DRAM is ready for any valid command.
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Initialization
Note:
More than two AUTO REFRESH commands can be issued in the sequence. After steps 9
and 10 are complete, repeat them until the desired number of AUTO REFRESH + tRFC
loops is achieved.
Figure 11: Initialize and Load Mode Register
T0
T1
Tn + 1
t
To + 1
CL
Tp + 1
Tp + 2
Tp + 3
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
t
t
CK
CK
((
))
CH
t
t
CKS CKH
((
))
((
))
( (
) )
( (
) )
( (
) )
( (
) )
CKE
t
t
CMS CMH
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
AUTO
REFRESH
AUTO
REFRESH
LOAD MODE
REGISTER
2
2
2
2
COMMAND
NOP
PRECHARGE
NOP
NOP
NOP
ACTIVE
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
DQM/DQML,
DQMU
t
t
t
5
AS AH
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
A[9:0],
A[12:11]
CODE
ROW
ROW
BANK
t
AS AH
CODE
( (
) )
( (
) )
( (
) )
( (
) )
ALL BANKS
( (
) )
( (
) )
( (
) )
( (
) )
A10
SINGLE BANK
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
ALL
BANKS
BA[1:0]
DQ
High-Z
((
))
((
))
T = 100µs
MIN
t
t
t
t
RP
RFC
RFC
MRD
Power-up:
1,3,4
Program Mode Register
AUTO REFRESH
AUTO REFRESH
V
and
Precharge
all banks
DD
CLK stable
DON’T CARE
UNDEFINED
1. The mode register may be loaded prior to the AUTO REFRESH cycles if desired.
2. If CS is HIGH at clock HIGH time, all commands applied are NOP.
3. JEDEC and PC100 specify three clocks.
Notes:
4. Outputs are guaranteed High-Z after command is issued.
5. A12 should be a LOW at tP + 1.
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Mode Register
Mode Register
The mode register defines the specific mode of operation, including burst length (BL),
burst type, CAS latency (CL), operating mode, and write burst mode. The mode register
is programmed via the LOAD MODE REGISTER command and retains the stored infor-
mation until it is programmed again or the device loses power.
Mode register bits M[2:0] specify the BL; M3 specifies the type of burst; M[6:4] specify
the CL; M7 and M8 specify the operating mode; M9 specifies the write burst mode; and
M10–Mn should be set to zero to ensure compatibility with future revisions. Mn + 1 and
Mn + 2 should be set to zero to select the mode register.
The mode registers must be loaded when all banks are idle, and the controller must wait
tMRD before initiating the subsequent operation. Violating either of these requirements
will result in unspecified operation.
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Mode Register
Figure 12: Mode Register Definition
A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
Address Bus
Mode Register (Mx)
Burst Length
11 10
3
1
0
12
8
6
5
2
9
4
7
Op Mode
WB
CASLatency
BT
Burst Length
Reserved
Program
BA1, BA0 = “0, 0”
to ensure compatibility
with future devices.
M2 M1 M0
M3 = 0
M3 = 1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
1
1
2
2
Write Burst Mode
M9
0
4
4
Programmed Burst Length
Single Location Access
8
8
1
Reserved
Reserved
Reserved
Full Page
Reserved
Reserved
Reserved
Reserved
M8
M7
0
M6-M0
Defined
–
Operating Mode
0
–
Standard Operation
–
All other states reserved
Burst Type
M3
0
Sequential
Interleaved
1
CAS Latency
Reserved
1
M6 M5 M4
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
2
3
Reserved
Reserved
Reserved
Reserved
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Mode Register
Burst Length
Read and write accesses to the device are burst oriented, and the burst length (BL) is
programmable. The burst length determines the maximum number of column loca-
tions that can be accessed for a given READ or WRITE command. Burst lengths of 1, 2,
4, 8, or continuous locations are available for both the sequential and the interleaved
burst types, and a continuous page burst is available for the sequential type. The con-
tinuous page burst is used in conjunction with the BURST TERMINATE command to
generate arbitrary burst lengths.
Reserved states should not be used, as unknown operation or incompatibility with fu-
ture versions may result.
When a READ or WRITE command is issued, a block of columns equal to the burst
length is effectively selected. All accesses for that burst take place within this block,
meaning that the burst wraps within the block when a boundary is reached. The block
is uniquely selected by A[8:1] when BL = 2, A[8:2] when BL = 4, and A[8:3] when BL = 8.
The remaining (least significant) address bit(s) is (are) used to select the starting loca-
tion within the block. Continuous page bursts wrap within the page when the boundary
is reached.
Burst Type
Accesses within a given burst can be programmed to be either sequential or interleaved;
this is referred to as the burst type and is selected via bit M3.
The ordering of accesses within a burst is determined by the burst length, the burst
type, and the starting column address.
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Mode Register
Table 17: Burst Definition Table
Order of Accesses Within a Burst
Burst Length
Starting Column Address
Type = Sequential
Type = Interleaved
2
A0
0
0-1
1-0
0-1
1-0
1
4
8
A1
0
A0
0
0-1-2-3
1-2-3-0
2-3-0-1
3-0-1-2
0-1-2-3
1-0-3-2
2-3-0-1
3-2-1-0
0
1
1
0
1
1
A2
0
A1
0
A0
0
0-1-2-3-4-5-6-7
1-2-3-4-5-6-7-0
2-3-4-5-6-7-0-1
3-4-5-6-7-0-1-2
4-5-6-7-0-1-2-3
5-6-7-0-1-2-3-4
6-7-0-1-2-3-4-5
7-0-1-2-3-4-5-6
0-1-2-3-4-5-6-7
1-0-3-2-5-4-7-6
2-3-0-1-6-7-4-5
3-2-1-0-7-6-5-4
4-5-6-7-0-1-2-3
5-4-7-6-1-0-3-2
6-7-4-5-2-3-0-1
7-6-5-4-3-2-1-0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Continuous
n = A0–An/9/8 (location 0–y)
Cn, Cn + 1, Cn + 2, Cn + 3...Cn - 1,
Cn...
Not supported
1. For full-page accesses: y = 2048 (x4); y = 1024 (x8); y = 512 (x16).
Notes:
2. For BL = 2, A1–A9, A11 (x4); A1–A9 (x8); or A1–A8 (x16) select the block-of-two burst; A0
selects the starting column within the block.
3. For BL = 4, A2–A9, A11 (x4); A2–A9 (x8); or A2–A8 (x16) select the block-of-four burst;
A0–A1 select the starting column within the block.
4. For BL = 8, A3–A9, A11 (x4); A3–A9 (x8); or A3–A8 (x16) select the block-of-eight burst;
A0–A2 select the starting column within the block.
5. For a full-page burst, the full row is selected and A0–A9, A11 (x4); A0–A9 (x8); or A0–A8
(x16) select the starting column.
6. Whenever a boundary of the block is reached within a given sequence above, the fol-
lowing access wraps within the block.
7. For BL = 1, A0–A9, A11 (x4); A0–A9 (x8); or A0–A8 (x16) select the unique column to be
accessed, and mode register bit M3 is ignored.
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Mode Register
CAS Latency
The CAS latency (CL) is the delay, in clock cycles, between the registration of a READ
command and the availability of the output data. The latency can be set to two or three
clocks.
If a READ command is registered at clock edge n, and the latency is m clocks, the data
will be available by clock edge n + m. The DQ start driving as a result of the clock edge
one cycle earlier (n + m - 1), and provided that the relevant access times are met, the
data is valid by clock edge n + m. For example, assuming that the clock cycle time is
such that all relevant access times are met, if a READ command is registered at T0 and
the latency is programmed to two clocks, the DQ start driving after T1 and the data is
valid by T2.
Reserved states should not be used as unknown operation or incompatibility with fu-
ture versions may result.
Figure 13: CAS Latency
T0
T1
T2
T3
CLK
Command
READ
NOP
NOP
t
t
OH
LZ
D
DQ
OUT
t
AC
CL = 2
T0
T1
T2
T3
T4
CLK
Command
READ
NOP
NOP
NOP
t
t
OH
LZ
D
DQ
OUT
t
AC
CL = 3
Don’t Care
Undefined
Operating Mode
Write Burst Mode
The normal operating mode is selected by setting M7 and M8 to zero; the other combi-
nations of values for M7 and M8 are reserved for future use. Reserved states should not
be used because unknown operation or incompatibility with future versions may result.
When M9 = 0, the burst length programmed via M[2:0] applies to both READ and
WRITE bursts; when M9 = 1, the programmed burst length applies to READ bursts, but
write accesses are single-location (nonburst) accesses.
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Bank/Row Activation
Bank/Row Activation
Before any READ or WRITE commands can be issued to a bank within the SDRAM, a
row in that bank must be opened. This is accomplished via the ACTIVE command,
which selects both the bank and the row to be activated.
After a row is opened with the ACTIVE command, a READ or WRITE command can be
issued to that row, subject to the tRCD specification. tRCD (MIN) should be divided by
the clock period and rounded up to the next whole number to determine the earliest
clock edge after the ACTIVE command on which a READ or WRITE command can be
entered. For example, a tRCD specification of 20ns with a 125 MHz clock (8ns period)
results in 2.5 clocks, rounded to 3. This is reflected in Figure 14 (page 40), which covers
any case where 2 < tRCD (MIN)/tCK ≤ 3. (The same procedure is used to convert other
specification limits from time units to clock cycles.)
A subsequent ACTIVE command to a different row in the same bank can only be issued
after the previous active row has been precharged. The minimum time interval between
successive ACTIVE commands to the same bank is defined by tRC.
A subsequent ACTIVE command to another bank can be issued while the first bank is
being accessed, which results in a reduction of total row-access overhead. The mini-
mum time interval between successive ACTIVE commands to different banks is defined
by tRRD.
Figure 14: Example: Meeting tRCD (MIN) When 2 < tRCD (MIN)/tCK < 3
T0
T1
T2
T3
CLK
t
t
t
CK
CK
CK
READ or
WRITE
Command
ACTIVE
NOP
NOP
t
RCD(MIN)
Don’t Care
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READ Operation
READ Operation
READ bursts are initiated with a READ command, as shown in Figure 8 (page 24). The
starting column and bank addresses are provided with the READ command, and auto
precharge is either enabled or disabled for that burst access. If auto precharge is ena-
bled, the row being accessed is precharged at the completion of the burst. In the follow-
ing figures, auto precharge is disabled.
During READ bursts, the valid data-out element from the starting column address is
available following the CAS latency after the READ command. Each subsequent data-
out element will be valid by the next positive clock edge. Figure 16 (page 43) shows
general timing for each possible CAS latency setting.
Upon completion of a burst, assuming no other commands have been initiated, the DQ
signals will go to High-Z. A continuous page burst continues until terminated. At the
end of the page, it wraps to column 0 and continues.
Data from any READ burst can be truncated with a subsequent READ command, and
data from a fixed-length READ burst can be followed immediately by data from a READ
command. In either case, a continuous flow of data can be maintained. The first data
element from the new burst either follows the last element of a completed burst or the
last desired data element of a longer burst that is being truncated. The new READ com-
mand should be issued x cycles before the clock edge at which the last desired data ele-
ment is valid, where x = CL - 1. This is shown in Figure 16 (page 43) for CL2 and CL3.
SDRAM devices use a pipelined architecture and therefore do not require the 2n rule as-
sociated with a prefetch architecture. A READ command can be initiated on any clock
cycle following a READ command. Full-speed random read accesses can be performed
to the same bank, or each subsequent READ can be performed to a different bank.
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READ Operation
Figure 15: Consecutive READ Bursts
T0
T1
T2
T3
T4
T5
T6
CLK
READ
NOP
NOP
NOP
READ
NOP
NOP
Command
X = 1 cycle
Bank,
Col n
Bank,
Col b
Address
DQ
DOUT
n
DOUT
n + 1
DOUT
n + 2
DOUT
n + 3
DOUT
b
CL = 2
T0
T1
T2
T3
T4
T5
T6
T7
CLK
READ
NOP
NOP
NOP
READ
NOP
NOP
NOP
Command
X = 2 cycles
Bank,
Col n
Bank,
Col b
Address
DQ
DOUT
DOUT
DOUT
DOUT
DOUT
CL = 3
Transitioning data
Don’t Care
1. Each READ command can be issued to any bank. DQM is LOW.
Note:
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READ Operation
Figure 16: Random READ Accesses
T0
T1
T2
T3
T4
T5
CLK
Command
Address
DQ
READ
READ
READ
READ
NOP
NOP
Bank,
Col n
Bank,
Col a
Bank,
Col x
Bank,
Col m
DOUT
DOUT
DOUT
DOUT
CL = 2
T0
T1
T2
T3
T4
T5
T6
CLK
READ
READ
READ
READ
NOP
NOP
NOP
Command
Address
DQ
Bank,
Col n
Bank,
Col a
Bank,
Col x
Bank,
Col m
DOUT
DOUT
DOUT
DOUT
CL = 3
Transitioning data
Don’t Care
1. Each READ command can be issued to any bank. DQM is LOW.
Note:
Data from any READ burst can be truncated with a subsequent WRITE command, and
data from a fixed-length READ burst can be followed immediately by data from a
WRITE command (subject to bus turnaround limitations). The WRITE burst can be ini-
tiated on the clock edge immediately following the last (or last desired) data element
from the READ burst, provided that I/O contention can be avoided. In a given system
design, there is a possibility that the device driving the input data will go Low-Z before
the DQ go High-Z. In this case, at least a single-cycle delay should occur between the
last read data and the WRITE command.
The DQM input is used to avoid I/O contention, as shown in Figure 17 (page 44) and
Figure 18 (page 45). The DQM signal must be asserted (HIGH) at least two clocks prior
to the WRITE command (DQM latency is two clocks for output buffers) to suppress da-
ta-out from the READ. After the WRITE command is registered, the DQ will go to High-Z
(or remain High-Z), regardless of the state of the DQM signal, provided the DQM was
active on the clock just prior to the WRITE command that truncated the READ com-
mand. If not, the second WRITE will be an invalid WRITE. For example, if DQM was
LOW during T4, then the WRITEs at T5 and T7 would be valid, and the WRITE at T6
would be invalid.
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READ Operation
The DQM signal must be de-asserted prior to the WRITE command (DQM latency is
zero clocks for input buffers) to ensure that the written data is not masked. Figure 17
(page 44) shows where, due to the clock cycle frequency, bus contention is avoided
without having to add a NOP cycle, while Figure 18 (page 45) shows the case where an
additional NOP cycle is required.
A fixed-length READ burst may be followed by or truncated with a PRECHARGE com-
mand to the same bank, provided that auto precharge was not activated. The PRE-
CHARGE command should be issued x cycles before the clock edge at which the last de-
sired data element is valid, where x = CL - 1. This is shown in Figure 19 (page 45) for
each possible CL; data element n + 3 is either the last of a burst of four or the last de-
sired data element of a longer burst. Following the PRECHARGE command, a subse-
quent command to the same bank cannot be issued until tRP is met. Note that part of
the row precharge time is hidden during the access of the last data element(s).
In the case of a fixed-length burst being executed to completion, a PRECHARGE com-
mand issued at the optimum time (as described above) provides the same operation
that would result from the same fixed-length burst with auto precharge. The disadvant-
age of the PRECHARGE command is that it requires that the command and address
buses be available at the appropriate time to issue the command. The advantage of the
PRECHARGE command is that it can be used to truncate fixed-length or continuous
page bursts.
Figure 17: READ-to-WRITE
T0
T1
T2
T3
T4
CLK
DQM
READ
NOP
NOP
NOP
Command
Address
WRITE
Bank,
Col n
Bank,
Col b
t
CK
t
HZ
DOUT
DIN
DQ
t
DS
Transitioning data
Don’t Care
1. CL = 3. The READ command can be issued to any bank, and the WRITE command can be
to any bank. If a burst of one is used, DQM is not required.
Note:
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READ Operation
Figure 18: READ-to-WRITE With Extra Clock Cycle
T0
T1
T2
T3
T4
T5
CLK
DQM
READ
NOP
NOP
NOP
NOP
WRITE
Command
Address
Bank,
Col n
Bank,
Col b
t
HZ
D
D
OUT
IN
DQ
t
DS
Transitioning data
Don’t Care
1. CL = 3. The READ command can be issued to any bank, and the WRITE command can be
to any bank.
Note:
Figure 19: READ-to-PRECHARGE
T0
T1
T2
T3
T4
T5
T6
T7
CLK
t
RP
READ
NOP
NOP
NOP
NOP
NOP
ACTIVE
PRECHARGE
Command
Address
DQ
X = 1 cycle
Bank
a or all)
Bank
Col
a
n
,
Bank
a,
(
Row
DOUT
DOUT
DOUT
DOUT
CL = 2
T0
T1
T2
T3
T4
T5
T6
T7
CLK
t
RP
READ
NOP
NOP
NOP
PRECHARGE
Bank
NOP
X = 2 cycles
NOP
ACTIVE
Command
Address
DQ
Bank
Col
a,
Bank
a,
(a or all)
Row
DOUT
DOUT
DOUT
DOUT
CL = 3
Transitioning data
Don’t Care
1. DQM is LOW.
Note:
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READ Operation
Continuous-page READ bursts can be truncated with a BURST TERMINATE command
and fixed-length READ bursts can be truncated with a BURST TERMINATE command,
provided that auto precharge was not activated. The BURST TERMINATE command
should be issued x cycles before the clock edge at which the last desired data element is
valid, where x = CL - 1. This is shown in Figure 20 (page 46) for each possible CAS la-
tency; data element n + 3 is the last desired data element of a longer burst.
Figure 20: Terminating a READ Burst
T0
T1
T2
T3
T4
T5
T6
CLK
BURST
READ
NOP
NOP
NOP
NOP
NOP
Command
Address
DQ
TERMINATE
X = 1 cycle
Bank,
Col n
DOUT
DOUT
DOUT
DOUT
CL = 2
T0
T1
T2
T3
T4
T5
T6
T7
CLK
Command
Address
DQ
BURST
READ
NOP
NOP
NOP
NOP
X = 2 cycles
NOP
NOP
TERMINATE
Bank,
Col n
DOUT
DOUT
DOUT
DOUT
CL = 3
Transitioning data
Don’t Care
1. DQM is LOW.
Note:
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READ Operation
Figure 21: Alternating Bank Read Accesses
T0
T1
T2
T3
T4
T5
T6
T7
T8
t
CK
t
CL
CLK
CKE
t
CH
t
t
CKS
CKH
t
t
CMS
CMH
Command
DQM
ACTIVE
NOP
READ
t
NOP
ACTIVE
NOP
READ
NOP
ACTIVE
t
CMS
CMH
t
AS
t
AH
Row
Row
Row
Row
Column m
Column b1
Address
t
t
AH
AS
Enable auto precharge
Enable auto precharge
Row
Row
A10
t
AS
t
AH
Bank 0
Bank 0
Bank 3
Bank 3
BA0, BA1
Bank 0
t
AC
t
t
t
t
AC
OH
AC
OH
AC
OH
AC
OH
t
t
t
t
t
t
OH
AC
D
D
D
D
D
OUT
DQ
OUT
OUT
OUT
OUT
t
LZ
t
t
t
t
t
t
RP - bank 0
CL - bank 0
RCD - bank 0
Undefined
RCD - bank 0
RAS - bank 0
RC - bank 0
RRD
t
CL - bank 3
Don’t Care
RCD - bank 3
1. For this example, BL = 4 and CL = 2.
Note:
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READ Operation
Figure 22: READ Continuous Page Burst
T0
T1
T2
T3
T4
T5
T6
Tn + 1
Tn + 2
Tn + 3
Tn + 4
( (
) )
( (
) )
t
t
CK
CL
CLK
t
CH
t
t
CKS CKH
( (
) )
CKE
( (
) )
t
t
CMS
CMH
( (
) )
( (
) )
Command
ACTIVE
NOP
READ
t
NOP
NOP
NOP
NOP
NOP
BURST TERM
NOP
NOP
t
CMS
CMH
( (
) )
DQM
( (
) )
t
t
AH
AS
( (
) )
( (
) )
Address
Row
Column m
t
t
AH
AS
( (
) )
( (
) )
Row
A10
t
t
AH
AS
( (
) )
( (
) )
BA0, BA1
Bank
Bank
t
AC
t
t
t
t
t
AC
AC
AC
AC
AC
( (
) )
t
t
t
t
t
t
OH
OH
OH
OH
OH
OH
( (
) )
( (
) )
D
D
D
D
D
OUT
D
OUT
OUT
OUT
OUT
DQ
OUT
t
LZ
t
HZ
t
All locations within same row
Full page completed
RCD
CAS latency
Don’t Care
Undefined
Full-page burst does not self-terminate.
Can use BURST TERMINATE command.
1. For this example, CL = 2.
Note:
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READ Operation
Figure 23: READ – DQM Operation
T0
T1
T2
T3
T4
T5
T6
T7
T8
t
t
CL
CK
CLK
t
CH
t
t
CKS
CKH
CKE
t
t
CMS
CMH
Command
ACTIVE
NOP
READ
NOP
NOP
NOP
NOP
NOP
NOP
t
t
CMH
CMS
DQM
t
AS
t
AH
Row
Column m
Address
t
t
AS
AH
Enable auto precharge
Row
A10
Disable auto precharge
Bank
t
AS
t
AH
BA0, BA1
Bank
t
AC
t
t
t
t
t
AC
OH
DOUT
t
AC
OH
OH
DQ
DOUT
DOUT
t
t
LZ
LZ
t
HZ
HZ
t
RCD
CL = 2
Don’t Care
Undefined
1. For this example, BL = 4 and CL = 2.
Note:
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WRITE Operation
WRITE Operation
WRITE bursts are initiated with a WRITE command, as shown in Figure 9 (page 25). The
starting column and bank addresses are provided with the WRITE command and auto
precharge is either enabled or disabled for that access. If auto precharge is enabled, the
row being accessed is precharged at the completion of the burst. For the generic WRITE
commands used in the following figures, auto precharge is disabled.
During WRITE bursts, the first valid data-in element is registered coincident with the
WRITE command. Subsequent data elements are registered on each successive positive
clock edge. Upon completion of a fixed-length burst, assuming no other commands
have been initiated, the DQ will remain at High-Z and any additional input data will be
ignored (see Figure 24 (page 50)). A continuous page burst continues until terminated;
at the end of the page, it wraps to column 0 and continues.
Data for any WRITE burst can be truncated with a subsequent WRITE command, and
data for a fixed-length WRITE burst can be followed immediately by data for a WRITE
command. The new WRITE command can be issued on any clock following the previ-
ous WRITE command, and the data provided coincident with the new command ap-
plies to the new command (see Figure 25 (page 51)). Data n + 1 is either the last of a
burst of two or the last desired data element of a longer burst.
SDRAM devices use a pipelined architecture and therefore do not require the 2n rule as-
sociated with a prefetch architecture. A WRITE command can be initiated on any clock
cycle following a previous WRITE command. Full-speed random write accesses within a
page can be performed to the same bank, as shown in Figure 26 (page 52), or each
subsequent WRITE can be performed to a different bank.
Figure 24: WRITE Burst
T0
T1
T2
T3
CLK
WRITE
NOP
NOP
NOP
Command
Address
DQ
Bank,
Col n
DIN
DIN
Transitioning data
1. BL = 2. DQM is LOW.
Don’t Care
Note:
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WRITE Operation
Figure 25: WRITE-to-WRITE
T0
T1
T2
CLK
WRITE
NOP
WRITE
Command
Address
DQ
Bank,
Col n
Bank,
Col b
DIN
DIN
DIN
Transitioning data
Don’t Care
1. DQM is LOW. Each WRITE command may be issued to any bank.
Note:
Data for any WRITE burst can be truncated with a subsequent READ command, and
data for a fixed-length WRITE burst can be followed immediately by a READ command.
After the READ command is registered, data input is ignored and WRITEs will not be
executed (see Figure 27 (page 52)). Data n + 1 is either the last of a burst of two or the
last desired data element of a longer burst.
Data for a fixed-length WRITE burst can be followed by or truncated with a PRE-
CHARGE command to the same bank, provided that auto precharge was not activated.
A continuous-page WRITE burst can be truncated with a PRECHARGE command to the
same bank. The PRECHARGE command should be issued tWR after the clock edge at
which the last desired input data element is registered. The auto precharge mode re-
quires a tWR of at least one clock with time to complete, regardless of frequency.
In addition, when truncating a WRITE burst at high clock frequencies (tCK < 15ns), the
DQM signal must be used to mask input data for the clock edge prior to and the clock
edge coincident with the PRECHARGE command (see Figure 28 (page 53)). Data n + 1
is either the last of a burst of two or the last desired data element of a longer burst. Fol-
lowing the PRECHARGE command, a subsequent command to the same bank cannot
be issued until tRP is met.
In the case of a fixed-length burst being executed to completion, a PRECHARGE com-
mand issued at the optimum time (as described above) provides the same operation
that would result from the same fixed-length burst with auto precharge. The disadvant-
age of the PRECHARGE command is that it requires that the command and address
buses be available at the appropriate time to issue the command. The advantage of the
PRECHARGE command is that it can be used to truncate fixed-length bursts or continu-
ous page bursts.
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WRITE Operation
Figure 26: Random WRITE Cycles
T0
T1
T2
T3
CLK
WRITE
WRITE
WRITE
WRITE
Command
Address
DQ
Bank,
Col n
Bank,
Col a
Bank,
Col x
Bank,
Col m
D
D
D
D
IN
IN
IN
IN
Transitioning data
Don’t Care
1. Each WRITE command can be issued to any bank. DQM is LOW.
Note:
Figure 27: WRITE-to-READ
T0
T1
T2
T3
T4
T5
CLK
WRITE
NOP
READ
NOP
NOP
NOP
Command
Address
DQ
Bank,
Col n
Bank,
Col b
DIN
DIN
DOUT
DOUT
Don’t Care
Transitioning data
1. The WRITE command can be issued to any bank, and the READ command can be to any
bank. DQM is LOW. CL = 2 for illustration.
Note:
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WRITE Operation
Figure 28: WRITE-to-PRECHARGE
T0
T1
T2
T3
T4
T5
T6
CLK
t
t
WR @ CK ≥ 15ns
DQM
t
RP
NOP
NOP
NOP
WRITE
NOP
PRECHARGE
ACTIVE
Command
Address
Bank
(a or all)
Bank a,
Col n
Bank a,
Row
t
WR
D
D
IN
IN
DQ
t
t
WR @ CK < 15ns
DQM
t
RP
NOP
NOP
WRITE
NOP
NOP
PRECHARGE
ACTIVE
Command
Address
Bank
(a or all)
Bank a,
Col n
Bank a,
Row
t
WR
D
D
IN
IN
DQ
Transitioning data
Don’t Care
1. In this example DQM could remain LOW if the WRITE burst is a fixed length of two.
Note:
Fixed-length WRITE bursts can be truncated with the BURST TERMINATE command.
When truncating a WRITE burst, the input data applied coincident with the BURST
TERMINATE command is ignored. The last data written (provided that DQM is LOW at
that time) will be the input data applied one clock previous to the BURST TERMINATE
command. This is shown in Figure 29 (page 54), where data n is the last desired data
element of a longer burst.
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WRITE Operation
Figure 29: Terminating a WRITE Burst
T0
T1
T2
CLK
BURST
TERMINATE
NEXT
COMMAND
WRITE
Command
Address
DQ
Bank,
Col n
Address
Data
DIN
Transitioning data
1. DQM is LOW.
Don’t Care
Note:
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WRITE Operation
Figure 30: Alternating Bank Write Accesses
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
t
t
CL
CK
CLK
CKE
t
CH
t
t
CKS
CKH
t
t
CMS
CMH
Command
DQM
ACTIVE
NOP
WRITE
NOP
ACTIVE
NOP
WRITE
NOP
NOP
ACTIVE
t
t
CMS
CMH
t
t
AH
AS
Row
Row
Row
Row
Row
Column m
Column b
Address
t
t
AH
AS
Enable auto precharge
Enable auto precharge
Row
A10
t
t
AH
AS
BA0, BA1
Bank 0
Bank 0
Bank 1
t
Bank 1
Bank 0
t
t
DS
t
t
t
t
t
t
t
t
DS
t
t
t
t
t
DS DH
DS
DS
DS
DS
DS
DH
DIN
WR - bank 0
DH
DH
DH
DH
DH
DH
DIN
DIN
DIN
DIN
DIN
DIN
RP - bank 0
DIN
DQ
t
t
RCD - bank 0
t
t
RCD - bank 0
t
t
t
RAS - bank 0
RC - bank 0
RRD
t
WR - bank 1
t
RCD - bank 1
Don’t Care
1. For this example, BL = 4.
Note:
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WRITE Operation
Figure 31: WRITE – Continuous Page Burst
T0
T1
T2
T3
T4
T5
Tn + 1
Tn + 2
Tn + 3
( (
) )
( (
) )
t
t
CK
CL
CLK
t
CH
t
t
CKS
CKH
( (
) )
CKE
( (
) )
t
t
CMS
CMH
( (
) )
( (
) )
Command
ACTIVE
NOP
WRITE
t
NOP
NOP
NOP
NOP
BURST TERM
NOP
t
CMH
CMS
( (
) )
( (
) )
DQM
t
AS
t
AH
( (
) )
( (
) )
Column
m
Address
Row
t
AS
t
AH
( (
) )
( (
) )
Row
A10
t
AS
t
AH
( (
) )
( (
) )
BA0, BA1
Bank
Bank
t
t
t
t
t
t
t
t
t
t
DS
DH
DS
DH
DS
DH
DS
DH
DS
DH
( (
) )
( (
) )
DIN
DIN
DIN
DIN
DIN
DQ
t
RCD
Full-page burst
All locations within same row
does not self-terminate.
Use BURST TERMINATE
command to stop.
1, 2
Full page completed
Don’t Care
1. tWR must be satisfied prior to issuing a PRECHARGE command.
2. Page left open; no tRP.
Notes:
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WRITE Operation
Figure 32: WRITE – DQM Operation
T0
T1
T2
T3
T4
T5
T6
T7
t
t
CL
CK
CLK
CKE
t
CH
t
t
CKS
CKH
t
t
CMS
CMH
Command
DQM
ACTIVE
NOP
WRITE
t
NOP
NOP
NOP
NOP
NOP
t
CMS CMH
t
t
t
t
AH
AS
Address
Row
t
Column m
AS
AH
Enable auto precharge
Row
t
A10
Disable auto precharge
Bank
AS
AH
BA0, BA1
Bank
t
t
t
t
t
t
DS
DH
DIN
DS
DH
DS
DH
DIN
DIN
DQ
t
Don’t Care
RCD
1. For this example, BL = 4.
Note:
Burst Read/Single Write
The burst read/single write mode is entered by programming the write burst mode bit
(M9) in the mode register to a 1. In this mode, all WRITE commands result in the access
of a single column location (burst of one), regardless of the programmed burst length.
READ commands access columns according to the programmed burst length and se-
quence, just as in the normal mode of operation (M9 = 0).
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PRECHARGE Operation
PRECHARGE Operation
The PRECHARGE command (see Figure 10 (page 26)) is used to deactivate the open row
in a particular bank or the open row in all banks. The bank(s) will be available for a sub-
sequent row access some specified time (tRP) after the PRECHARGE command is is-
sued. Input A10 determines whether one or all banks are to be precharged, and in the
case where only one bank is to be precharged (A10 = LOW), inputs BA0 and BA1 select
the bank. When all banks are to be precharged (A10 = HIGH), inputs BA0 and BA1 are
treated as “Don’t Care.” After a bank has been precharged, it is in the idle state and
must be activated prior to any READ or WRITE commands being issued to that bank.
Auto Precharge
Auto precharge is a feature that performs the same individual-bank PRECHARGE func-
tion described previously, without requiring an explicit command. This is accomplished
by using A10 to enable auto precharge in conjunction with a specific READ or WRITE
command. A precharge of the bank/row that is addressed with the READ or WRITE
command is automatically performed upon completion of the READ or WRITE burst,
except in the continuous page burst mode where auto precharge does not apply. In the
specific case of write burst mode set to single location access with burst length set to
continuous, the burst length setting is the overriding setting and auto precharge does
not apply. Auto precharge is nonpersistent in that it is either enabled or disabled for
each individual READ or WRITE command.
Auto precharge ensures that the precharge is initiated at the earliest valid stage within a
burst. Another command cannot be issued to the same bank until the precharge time
(tRP) is completed. This is determined as if an explicit PRECHARGE command was is-
sued at the earliest possible time, as described for each burst type in the Burst Type
(page 37) section.
Micron SDRAM supports concurrent auto precharge; cases of concurrent auto pre-
charge for READs and WRITEs are defined below.
READ with auto precharge interrupted by a READ (with or without auto precharge)
A READ to bank m will interrupt a READ on bank n following the programmed CAS la-
tency. The precharge to bank n begins when the READ to bank m is registered (see Fig-
ure 33 (page 59)).
READ with auto precharge interrupted by a WRITE (with or without auto precharge)
A WRITE to bank m will interrupt a READ on bank n when registered. DQM should be
used two clocks prior to the WRITE command to prevent bus contention. The pre-
charge to bank n begins when the WRITE to bank m is registered (see Figure 34
(page 60)).
WRITE with auto precharge interrupted by a READ (with or without auto precharge)
A READ to bank m will interrupt a WRITE on bank n when registered, with the data-out
appearing CL later. The precharge to bank n will begin after tWR is met, where tWR be-
gins when the READ to bank m is registered. The last valid WRITE to bank n will be da-
ta-in registered one clock prior to the READ to bank m (see Figure 39 (page 65)).
WRITE with auto precharge interrupted by a WRITE (with or without auto precharge)
A WRITE to bank m will interrupt a WRITE on bank n when registered. The precharge to
bank n will begin after tWR is met, where tWR begins when the WRITE to bank m is reg-
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PRECHARGE Operation
istered. The last valid data WRITE to bank n will be data registered one clock prior to a
WRITE to bank m (see Figure 40 (page 65)).
Figure 33: READ With Auto Precharge Interrupted by a READ
T0
T1
T2
T3
T4
T5
T6
T7
CLK
READ - AP
Bank n
READ - AP
Bank m
NOP
NOP
NOP
NOP
NOP
NOP
Command
Bank n
Page active
READ with burst of 4
Interrupt burst, precharge
Idle
t
t
RP - bank m
RP - bank n
Internal
states
Precharge
Page active
READ with burst of 4
Bank m
Bank n,
Col a
Bank m,
Col d
Address
DQ
D
D
D
D
OUT
OUT
OUT
OUT
CL = 3 (bank n)
CL = 3 (bank m)
Don’t Care
1. DQM is LOW.
Note:
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PRECHARGE Operation
Figure 34: READ With Auto Precharge Interrupted by a WRITE
T0
T1
T2
T3
T4
T5
T6
T7
CLK
READ - AP
Bank n
WRITE - AP
Bank m
NOP
NOP
NOP
NOP
NOP
NOP
Command
Bank n
Page
active
READ with burst of 4
Page active
Interrupt burst, precharge
t
Idle
Internal
States
t
RP - bank
n
WR - bankm
Write-back
WRITE with burst of 4
Bank m
Address
Bank n,
Col a
Bank m,
Col d
1
DQM
D
D
D
D
D
IN
OUT
IN
IN
IN
DQ
CL = 3 (bank n)
Transitioning data
Don’t Care
1. DQM is HIGH at T2 to prevent DOUTa + 1 from contending with DINd at T4.
Note:
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PRECHARGE Operation
Figure 35: READ With Auto Precharge
T0
T1
T2
T3
T4
T5
T6
T7
T8
t
t
CL
CK
CLK
t
CH
t
t
CKS
CKH
CKE
t
t
CMS
CMH
Command
ACTIVE
NOP
READ
NOP
NOP
NOP
NOP
NOP
ACTIVE
t
t
CMH
CMS
DQM
t
t
AH
AS
Row
Row
Column m
Address
t
t
AH
AS
Enable auto precharge
Row
Row
A10
t
t
AH
AS
BA0, BA1
Bank
Bank
Bank
t
t
t
AC
AC
AC
OH
t
AC
t
t
t
t
OH
OH
OH
DOUT
DOUT
DOUT
DQ
DOUT m
t
m + 1
m + 2
m + 3
LZ
t
HZ
t
t
RCD
CL = 2
RP
t
RAS
t
RC
Don’t Care
Undefined
1. For this example, BL = 4 and CL = 2.
Note:
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PRECHARGE Operation
Figure 36: READ Without Auto Precharge
T0
T1
T2
T3
T4
T5
T6
T7
T8
t
t
CL
CK
CLK
t
CH
t
t
CKS
CKH
CKE
t
t
CMS
CMH
Command
ACTIVE
NOP
READ
NOP
NOP
NOP
PRECHARGE
NOP
ACTIVE
t
t
CMS CMH
DQM
t
AS
t
AH
Row
Row
Column m
Address
t
AS
t
AH
All banks
Row
Row
A10
Single bank
Disable auto precharge
Bank
t
t
AS
AH
BA0, BA1
Bank(s)
t
Bank
Bank
t
t
AC
AC
AC
t
t
OH
t
OH
t
OH
t
OH
AC
DOUT
DOUT
DOUT
DOUT
DQ
t
LZ
t
HZ
t
t
RCD
CL = 2
RP
t
RAS
t
RC
Don’t Care
Undefined
1. For this example, BL = 4, CL = 2, and the READ burst is followed by a manual PRE-
CHARGE.
Note:
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PRECHARGE Operation
Figure 37: Single READ With Auto Precharge
T0
T1
T2
T3
T4
T5
T6
T7
t
t
CL
CK
CLK
t
CH
t
t
CKS
CKH
CKE
t
t
CMS
CMH
Command
ACTIVE
NOP
READ
NOP
NOP
NOP
NOP
ACTIVE
t
t
CMS CMH
DQM
t
AS
t
AH
Row
Column m
Row
Address
t
AS
t
AH
Enable auto precharge
Row
Row
A10
t
AS
t
AH
BA0, BA1
Bank
Bank
Bank
t
t
OH
AC
DOUT
DQ
t
LZ
t
t
RCD
CL = 2
RP
t
RAS
t
RC
Don’t Care
Undefined
1. For this example, BL = 1 and CL = 2.
Note:
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PRECHARGE Operation
Figure 38: Single READ Without Auto Precharge
T0
T1
T2
T3
T4
T5
T6
T7
T8
t
t
CL
CK
CLK
t
CH
t
t
CKS
CKH
CKE
t
t
CMS
CMH
Command
ACTIVE
NOP
READ
NOP
NOP
PRECHARGE
NOP
ACTIVE
NOP
t
t
CMS CMH
DQM
t
t
AS
AH
Row
Column m
Row
Address
t
t
AS
AH
All banks
Row
Row
A10
Single bank
Bank(s)
Disable auto precharge
Bank
t
t
AS
AH
BA0, BA1
Bank
Bank
t
AC
t
OH
DOUT
DQ
t
LZ
t
HZ
t
t
RCD
CL = 2
RP
Don’t Care
Undefined
t
RAS
t
RC
1. For this example, BL = 1, CL = 2, and the READ burst is followed by a manual PRE-
CHARGE.
Note:
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PRECHARGE Operation
Figure 39: WRITE With Auto Precharge Interrupted by a READ
T0
T1
T2
T3
T4
T5
T6
T7
CLK
WRITE - AP
Bank n
READ - AP
Bank m
NOP
NOP
NOP
NOP
NOP
NOP
Command
Bank n
Interrupt burst, write-back Precharge
t
Page active
WRITE with burst of 4
Internal
States
RP - bank n
t
WR - bank n
t
RP - bank m
Page active
READ with burst of 4
Bank m
Bank n,
Col a
Bank m,
Col d
Address
DQ
DIN
DIN
DOUT
DOUT
CL = 3 (bank m)
Don’t Care
1. DQM is LOW.
Note:
Figure 40: WRITE With Auto Precharge Interrupted by a WRITE
T0
T1
T2
T3
T4
T5
T6
T7
CLK
WRITE - AP
Bank n
WRITE - AP
Bank m
NOP
NOP
NOP
NOP
NOP
NOP
Command
Bank n
Page active
WRITE with burst of 4
Interrupt burst, write-back Precharge
t
RP - bank n
t
Internal
States
WR - bank n
t
WR - bank m
Write-back
Page active
WRITE with burst of 4
Bank m
Bank n,
Col a
Bank m,
Col d
Address
DQ
DIN
DIN
DIN
DIN
DIN
DIN
DIN
Don’t Care
1. DQM is LOW.
Note:
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PRECHARGE Operation
Figure 41: WRITE With Auto Precharge
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
t
t
CL
CK
CLK
CKE
t
CH
t
t
CKS
CKH
t
t
CMS
CMH
Command
DQM
ACTIVE
NOP
WRITE
NOP
NOP
NOP
NOP
NOP
NOP
ACTIVE
t
t
CMS
CMH
t
t
t
t
AH
AS
Address
Row
Row
Bank
Row
Column m
t
AS
AH
Enable auto precharge
Row
A10
t
AS
AH
BA0, BA1
Bank
Bank
t
t
t
t
t
t
t
t
DH
DS
DH
DS
DH
DS
DH
DS
DIN
DIN
DIN
DIN
DQ
t
t
RP
t
RCD
WR
t
RAS
t
RC
Don’t Care
1. For this example, BL = 4.
Note:
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PRECHARGE Operation
Figure 42: WRITE Without Auto Precharge
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
t
t
CL
CK
CLK
CKE
t
CH
t
t
CKS
CKH
t
t
CMS
CMH
Command
DQM
ACTIVE
NOP
WRITE
NOP
NOP
NOP
NOP
PRECHARGE
NOP
ACTIVE
t
t
CMS
CMH
t
t
t
t
AH
AS
Address
Row
Column m
Row
Row
Bank
t
AS
AH
All banks
Row
A10
Disable auto precharge
Bank
Single bank
Bank
t
AS
Bank
AH
BA0, BA1
t
t
t
t
t
t
t
t
DS DH
DS DH
DS DH
DS
DH
DIN
DIN
DIN
DIN
DQ
t
t
RP
t
RCD
WR
t
RAS
t
RC
Don’t Care
1. For this example, BL = 4 and the WRITE burst is followed by a manual PRECHARGE.
Note:
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PRECHARGE Operation
Figure 43: Single WRITE With Auto Precharge
T0
T1
T2
T3
T4
T5
T6
T7
T8
t
t
CL
CK
CLK
CKE
t
CH
t
t
CKS
CKH
t
t
CMS
CMH
Command
ACTIVE
NOP
WRITE
NOP
NOP
NOP
NOP
ACTIVE
NOP
t
t
CMS
CMH
DQM
t
t
t
t
AH
AS
Address
Row
Row
Row
Bank
Column m
t
AS
AH
Enable auto precharge
Row
A10
t
AS
Bank
AH
Bank
BA0, BA1
t
t
DS
DH
DIN
DQ
t
t
RP
t
RCD
WR
t
RAS
t
RC
Don’t Care
1. For this example, BL = 1.
Note:
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PRECHARGE Operation
Figure 44: Single WRITE Without Auto Precharge
T0
T1
T2
T3
T4
T5
T6
T7
T8
t
CK
t
CL
CLK
t
CH
t
t
CKS
CKH
CKE
t
t
CMS
CMH
Command
ACTIVE
NOP
WRITE
NOP
NOP
PRECHARGE
NOP
ACTIVE
NOP
t
t
CMS CMH
DQM
t
t
AS
AH
Row
Column m
Address
t
t
AS
AH
All banks
Row
Row
A10
Single bank
Bank
Disable auto precharge
Bank
t
t
AH
AS
BA0, BA1
Bank
Bank
t
t
DS DH
DIN
DQ
t
t
t
RCD
WR
RP
t
RAS
t
RC
Don’t Care
1. For this example, BL = 1 and the WRITE burst is followed by a manual PRECHARGE.
Note:
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AUTO REFRESH Operation
AUTO REFRESH Operation
The AUTO REFRESH command is used during normal operation of the device to refresh
the contents of the array. This command is nonpersistent, so it must be issued each
time a refresh is required. All active banks must be precharged prior to issuing an AUTO
REFRESH command. The AUTO REFRESH command should not be issued until the
minimum tRP is met following the PRECHARGE command. Addressing is generated by
the internal refresh controller. This makes the address bits “Don’t Care” during an AU-
TO REFRESH command.
After the AUTO REFRESH command is initiated, it must not be interrupted by any exe-
cutable command until tRFC has been met. During tRFC time, COMMAND INHIBIT or
NOP commands must be issued on each positive edge of the clock. The SDRAM re-
quires that every row be refreshed each tREF period. Providing a distributed AUTO RE-
FRESH command—calculated by dividing the refresh period (tREF) by the number of
rows to be refreshed—meets the timing requirement and ensures that each row is re-
freshed. Alternatively, to satisfy the refresh requirement a burst refresh can be employed
after every tREF period by issuing consecutive AUTO REFRESH commands for the num-
ber of rows to be refreshed at the minimum cycle rate (tRFC).
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AUTO REFRESH Operation
Figure 45: Auto Refresh Mode
T0
T1
T2
Tn + 1
CL
To + 1
( (
) )
( (
) )
t
CLK
CKE
t
t
( (
( (
CK
CH
) )
) )
( (
) )
( (
) )
t
t
CKS
CKH
t
t
CMS
CMH
( (
) )
( (
) )
AUTO
REFRESH
AUTO
REFRESH
Command
DQM
PRECHARGE
NOP
NOP
NOP
NOP
NOP
ACTIVE
( (
( (
) )
) )
( (
) )
( (
) )
( (
( (
) )
) )
( (
) )
( (
) )
( (
) )
( (
) )
Row
Row
Address
A10
( (
) )
( (
) )
( (
) )
( (
) )
All banks
Single bank
t
t
AH
AS
( (
) )
( (
) )
BA0, BA1
DQ
Bank(s)
Bank
( (
( (
) )
) )
High-Z
( (
) )
( (
) )
t
t
t
RFC
RP
RFC
Precharge all
active banks
Don’t Care
1. Back-to-back AUTO REFRESH commands are not required.
Note:
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SELF REFRESH Operation
SELF REFRESH Operation
The self refresh mode can be used to retain data in the device, even when the rest of the
system is powered down. When in self refresh mode, the device retains data without ex-
ternal clocking. The SELF REFRESH command is initiated like an AUTO REFRESH com-
mand, except CKE is disabled (LOW). After the SELF REFRESH command is registered,
all the inputs to the device become “Don’t Care” with the exception of CKE, which must
remain LOW.
After self refresh mode is engaged, the device provides its own internal clocking, ena-
bling it to perform its own AUTO REFRESH cycles. The device must remain in self re-
fresh mode for a minimum period equal to tRAS and remains in self refresh mode for an
indefinite period beyond that.
The procedure for exiting self refresh requires a sequence of commands. First, CLK
must be stable prior to CKE going back HIGH. (Stable clock is defined as a signal cycling
within timing constraints specified for the clock ball.) After CKE is HIGH, the device
must have NOP commands issued for a minimum of two clocks for tXSR because time is
required for the completion of any internal refresh in progress.
Upon exiting the self refresh mode, AUTO REFRESH commands must be issued accord-
ing to the distributed refresh rate (tREF/refresh row count) as both SELF REFRESH and
AUTO REFRESH utilize the row refresh counter.
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SELF REFRESH Operation
Figure 46: Self Refresh Mode
T0
T1
T2
Tn + 1
To + 1
To + 2
( (
) )
( (
) )
t
CL
CLK
CKE
t
( (
) )
( (
) )
t
CK
CH
t
CKS
( (
) )
( (
) )
( (
) )
t
t
CKS
CKH
t
t
CMS
CMH
( (
) )
( (
) )
( (
) )
( (
) )
AUTO
REFRESH
AUTO
REFRESH
Command
DQM
PRECHARGE
NOP
NOP
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
( (
) )
Address
A10
All banks
( (
) )
( (
) )
( (
) )
( (
) )
Single bank
t
t
AH
AS
( (
) )
( (
) )
( (
) )
( (
) )
Bank(s)
BA0, BA1
DQ
High-Z
( (
) )
( (
) )
t
t
RP
XSR
Precharge all
active banks
Enter self refresh mode
Exit self refresh mode
(Restart refresh time base)
CLK stable prior to exiting
self refresh mode
Don’t Care
1. Each AUTO REFRESH command performs a REFRESH cycle. Back-to-back commands are
not required.
Note:
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Power-Down
Power-Down
Power-down occurs if CKE is registered LOW coincident with a NOP or COMMAND IN-
HIBIT when no accesses are in progress. If power-down occurs when all banks are idle,
this mode is referred to as precharge power-down; if power-down occurs when there is a
row active in any bank, this mode is referred to as active power-down. Entering power-
down deactivates the input and output buffers, excluding CKE, for maximum power
savings while in standby. The device cannot remain in the power-down state longer
than the refresh period (64ms) because no REFRESH operations are performed in this
mode.
The power-down state is exited by registering a NOP or COMMAND INHIBIT with CKE
HIGH at the desired clock edge (meeting tCKS).
Figure 47: Power-Down Mode
T0
T1
T2
Tn + 1
Tn + 2
( (
) )
( (
) )
t
t
CK
CL
CLK
CKE
t
CH
t
t
CKS
CKS
( (
) )
t
t
CKS
CKH
t
t
CMS CMH
PRECHARGE
( (
) )
( (
) )
Command
DQM
NOP
NOP
NOP
ACTIVE
( (
) )
( (
) )
( (
) )
( (
) )
Address
A10
Row
Row
All banks
( (
) )
( (
) )
Single bank
t
t
AH
AS
( (
) )
( (
) )
BA0, BA1
DQ
Bank(s)
Bank
High-Z
( (
) )
Input buffers gated off
while in power-down mode
Two clock cycles
All banks idle
Precharge all
active banks
All banks idle, enter
power-down mode
Exit power-down mode
Don’t Care
1. Violating refresh requirements during power-down may result in a loss of data.
Note:
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Clock Suspend
Clock Suspend
The clock suspend mode occurs when a column access/burst is in progress and CKE is
registered LOW. In the clock suspend mode, the internal clock is deactivated, freezing
the synchronous logic.
For each positive clock edge on which CKE is sampled LOW, the next internal positive
clock edge is suspended. Any command or data present on the input balls when an in-
ternal clock edge is suspended will be ignored; any data present on the DQ balls re-
mains driven; and burst counters are not incremented, as long as the clock is suspen-
ded.
Exit clock suspend mode by registering CKE HIGH; the internal clock and related opera-
tion will resume on the subsequent positive clock edge.
Figure 48: Clock Suspend During WRITE Burst
T0
T1
T2
T3
T4
T5
CLK
CKE
Internal
clock
NOP
WRITE
NOP
NOP
Command
Address
DIN
Bank,
Col n
D
D
D
IN
IN
IN
Don’t Care
1. For this example, BL = 4 or greater, and DQM is LOW.
Note:
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Clock Suspend
Figure 49: Clock Suspend During READ Burst
T0
T1
T2
T3
T4
T5
T6
CLK
CKE
Internal
clock
READ
NOP
NOP
NOP
NOP
NOP
Command
Address
DQ
Bank,
Col n
DOUT
DOUT
DOUT
DOUT
Don’t Care
1. For this example, CL = 2, BL = 4 or greater, and DQM is LOW.
Note:
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Clock Suspend
Figure 50: Clock Suspend Mode
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
t
t
CL
CK
CLK
CKE
t
CH
t
t
CKS CKH
t
t
CKS CKH
t
t
CMS
CMH
Command
DQM
READ
NOP
NOP
NOP
NOP
NOP
WRITE
NOP
t
t
CMS
CMH
t
t
AH
AS
Column e
Column m
Address
t
t
AH
AS
A10
t
t
AS
AH
BA0, BA1
Bank
Bank
t
AC
t
t
t
t
t
DH
OH
HZ
DS
AC
D
D
D
D
DQ
OUT
OUT
IN
IN
t
LZ
Don’t Care
Undefined
1. For this example, BL = 2, CL = 3, and auto precharge is disabled.
Note:
8000 S. Federal Way, P.O. Box 6, Boise, ID 83707-0006, Tel: 208-368-3900
www.micron.com/productsupport Customer Comment Line: 800-932-4992
Micron and the Micron logo are trademarks of Micron Technology, Inc.
All other trademarks are the property of their respective owners.
This data sheet contains minimum and maximum limits specified over the power supply and temperature range set forth herein.
Although considered final, these specifications are subject to change, as further product development and data characterization some-
times occur.
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