ISSI IS42S16400

ISSI
®
IS42S16400
1 Meg Bits x 16 Bits x 4 Banks (64-MBIT)
SYNCHRONOUS DYNAMIC RAM
FEATURES
• Clock frequency: 166, 133, 100 MHz
• Fully synchronous; all signals referenced to a
positive clock edge
• Internal bank for hiding row access/precharge
FINAL PRODUCTION
MAY 2001
OVERVIEW
ISSI's 64Mb Synchronous DRAM IS42S16400 is organized
as 1,048,576 bits x 16-bit x 4-bank for improved
performance. The synchronous DRAMs achieve high-speed
data transfer using pipeline architecture. All inputs and
outputs signals refer to the rising edge of the clock input.
• Single 3.3V power supply
• LVTTL interface
PIN CONFIGURATIONS
• Programmable burst length
– (1, 2, 4, 8, full page)
54-Pin TSOP (Type II)
VCC
1
54
GND
I/O0
2
53
I/O15
VCCQ
3
52
GNDQ
I/O1
4
51
I/O14
I/O2
5
50
I/O13
GNDQ
6
49
VCCQ
I/O3
7
48
I/O12
I/O4
8
47
I/O11
VCCQ
9
46
GNDQ
I/O5
10
45
I/O10
I/O6
11
44
I/O9
GNDQ
12
43
VCCQ
I/O7
13
42
I/O8
VCC
14
41
GND
LDQM
15
40
NC
WE
16
39
UDQM
CAS
17
38
CLK
• Byte controlled by LDQM and UDQM
RAS
18
37
CKE
CS
19
36
NC
• Industrial temperature availability
BA0
20
35
A11
BA1
21
34
A9
A10
22
33
A8
A0
23
32
A7
A1
24
31
A6
A2
25
30
A5
A3
26
29
A4
VCC
27
28
GND
• Programmable burst sequence:
Sequential/Interleave
• Self refresh modes
• 4096 refresh cycles every 64 ms
• Random column address every clock cycle
• Programmable CAS latency (2, 3 clocks)
• Burst read/write and burst read/single write
operations capability
• Burst termination by burst stop and precharge
command
• Package: 400-mil 54-pin TSOP II
PIN DESCRIPTIONS
A0-A11
Address Input
WE
Write Enable
BA0, BA1
Bank Select Address
LDQM
Lower Bye, Input/Output Mask
I/O0 to I/O15
Data I/O
UDQM
Upper Bye, Input/Output Mask
CLK
System Clock Input
Vcc
Power
CKE
Clock Enable
GND
Ground
CS
Chip Select
Vcc Q
Power Supply for I/O Pin
RAS
Row Address Strobe Command
GNDQ
Ground for I/O Pin
CAS
Column Address Strobe Command
NC
No Connection
This document contains TARGET SPECIFICATION data. ISSI reserves the right to make changes to its products at any time without notice in order to improve design and supply the best
possible product. We assume no responsibility for any errors which may appear in this publication. © Copyright 2001, Integrated Silicon Solution, Inc.
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
1
ISSI
IS42S16400
®
GENERAL DESCRIPTION
The 64Mb SDRAM is a high speed CMOS, dynamic
random-access memory designed to operate in 3.3V
memory systems containing 67,108,864 bits. Internally
configured as a quad-bank DRAM with a synchronous
interface. Each 16,777,216-bit bank is organized as 4,096
rows by 256 columns by 16 bits.
The 64Mb SDRAM includes an AUTO REFRESH MODE,
and a power-saving, power-down mode. All signals are
registered on the positive edge of the clock signal, CLK.
All inputs and outputs are LVTTL compatible.
The 64Mb SDRAM has 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
burst access.
A self-timed row precharge initiated at the end of the burst
sequence is available with the AUTO PRECHARGE
function enabled. Precharge one bank while accessing one
of the other three banks will hide the precharge cycles and
provide seamless, high-speed, random-access operation.
SDRAM read and write accesses are burst oriented starting
at a selected location and continuing for a programmed
number of locations in a programmed sequence. The
registration of an ACTIVE command begins accesses,
followed by a READ or WRITE command. The ACTIVE
command in conjunction with address bits registered are
used to select the bank and row to be accessed (BA0, BA1
select the bank; A0-A11 select the row). The READ or
WRITE commands in conjunction with address bits registered are used to select the starting column location for
the burst access.
Programmable READ or WRITE burst lengths consist of
1, 2, 4 and 8 locations or full page, with a burst terminate
option.
FUNCTIONAL BLOCK DIAGRAM
DQM
DATA IN
BUFFER
COMMAND
DECODER
&
CLOCK
GENERATOR
16
MODE
REGISTER
11
I/O 0-15
SELF
Vcc/VccQ
DATA OUT
BUFFER
REFRESH
A10
CONTROLLER
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
BA0
BA1
16
REFRESH
CONTROLLER
GND/GNDQ
16
16
11
MULTIPLEXER
REFRESH
COUNTER
ROW
ADDRESS
LATCH
11
11
COLUMN
ADDRESS LATCH
ROW
ADDRESS
BUFFER
ROW DECODER
CLK
CKE
CS
RAS
CAS
WE
A11
4096
4096
4096
4096
MEMORY CELL
ARRAY
BANK 0
SENSE AMP I/O GATE
256K
(x 16)
BANK CONTROL LOGIC
8
BURST COUNTER
COLUMN
ADDRESS BUFFER
2
COLUMN DECODER
8
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
PIN FUNCTIONS
Symbol
Pin No.
Type
Function (In Detail)
A0-A11
23 to 26
29 to 34
22, 35
Input Pin
Address Inputs: A0-A11 are sampled during the ACTIVE
command (row-address A0-A11) and READ/WRITE command (A0-A7
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
BA0, BA1 (LOW). The address inputs also provide the op-code during a LOAD
MODE REGISTER command.
BA0, BA1
20, 21
Input Pin
Bank Select Address: BA0 and BA1 defines which bank the ACTIVE, READ,
WRITE or PRECHARGE command is being applied.
CAS
17
Input Pin
CAS, in conjunction with the RAS and WE, forms the device command. See the
"Command Truth Table" for details on device commands.
CKE
37
Input Pin
The CKE input determines whether the CLK input is enabled. The next rising edge
of the CLK signal will be valid when is CKE HIGH and invalid when LOW. When
CKE is LOW, the device will be in either power-down mode, clock suspend mode,
or self refresh mode. CKE is an asynchronous input.
CLK
38
Input Pin
CLK is the master clock input for this device. Except for CKE, all inputs to this
device are acquired in synchronization with the rising edge of this pin.
CS
19
Input Pin
The CS input determines whether command input is enabled within the device.
Command input is enabled when CS is LOW, and disabled with CS is HIGH. The
device remains in the previous state when CS is HIGH.
I/O0 to
I/O15
2, 4, 5, 7, 8, 10,
11,13, 42, 44, 45,
47, 48, 50, 51, 53
I/O Pin
LDQM,
UDQM
15, 39
Input Pin
LDQM and UDQM control the lower and upper bytes of the I/O buffers. In read
mode, LDQM and UDQM control the output buffer. When LDQM or UDQM is
LOW, the corresponding buffer byte is enabled, and when HIGH, disabled. The
outputs go to the HIGH impedance state when LDQM/UDQM is HIGH. This
function corresponds to OE in conventional DRAMs. In write mode, LDQM and
UDQM control the input buffer. When LDQM or UDQM is LOW, the corresponding
buffer byte is enabled, and data can be written to the device. When LDQM or
UDQM is HIGH, input data is masked and cannot be written to the device.
RAS
18
Input Pin
RAS, in conjunction with CAS and WE, forms the device command. See the
"Command Truth Table" item for details on device commands.
WE
16
Input Pin
WE, in conjunction with RAS and CAS, forms the device command. See the
"Command Truth Table" item for details on device commands.
VCCQ
3, 9, 43, 49
Power Supply Pin
VCCQ is the output buffer power supply.
VCC
1, 14, 27
Power Supply Pin
VCC is the device internal power supply.
GND Q
6, 12, 46, 52
Power Supply Pin
GNDQ is the output buffer ground.
GND
28, 41, 54
Power Supply Pin
GND is the device internal ground.
I/O0 to I/O15 are I/O pins. I/O through these pins can be controlled in byte units
using the LDQM and UDQM pins.
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
3
ISSI
IS42S16400
®
FUNCTION (In Detail)
READ
A0-A11 are address inputs sampled during the ACTIVE
(row-address A0-A11) and READ/WRITE command (A0-A7
with A10 defining auto PRECHARGE). A10 is sampled during
a PRECHARGE command to determine if all banks are to
be PRECHARGED (A10 HIGH) or bank selected by BA0,
BA1 (LOW). The address inputs also provide the op-code
during a LOAD MODE REGISTER command.
Bank Select Address (BA0 and BA1) defines which bank the
ACTIVE, READ, WRITE or PRECHARGE command is
being applied.
CAS, in conjunction with the RAS and WE, forms the
device command. See the “Command Truth Table” for
details on device commands.
The CKE input determines whether the CLK input is
enabled. The next rising edge of the CLK signal will be
valid when is CKE HIGH and invalid when LOW. When
CKE is LOW, the device will be in either power-down
mode, CLOCK SUSPEND mode, or SELF-REFRESH
mode. CKE is an asynchronous input.
CLK is the master clock input for this device. Except for
CKE, all inputs to this device are acquired in synchronization with the rising edge of this pin.
The CS input determines whether command input is
enabled within the device. Command input is enabled
when CS is LOW, and disabled with CS is HIGH. The
device remains in the previous state when CS is HIGH. I/
O0 to I/O15 are I/O pins. I/O through these pins can be
controlled in byte units using the LDQM and UDQM pins.
The READ command selects the bank from BA0, BA1
inputs and starts a burst read access to an active row.
Inputs A0-A7 provides the starting column location. When
A10 is HIGH, this command functions as an AUTO
PRECHARGE command. When the auto precharge is
selected, the row being accessed will be precharged at
the end of the READ burst. The row will remain open for
subsequent accesses when AUTO PRECHARGE is not
selected. DQ’s read data is subject to the logic level on
the DQM inputs two clocks earlier. When a given DQM
signal was registered HIGH, the corresponding DQ’s will
be High-Z two clocks later. DQ’s will provide valid data
when the DQM signal was registered LOW.
LDQM and UDQM control the lower and upper bytes of the
I/O buffers. In read mode, LDQM and UDQM control the
output buffer. When LDQM or UDQM is LOW, the corresponding buffer byte is enabled, and when HIGH, disabled. The outputs go to the HIGH Impedance State when
LDQM/UDQM is HIGH. This function corresponds to OE
in conventional DRAMs. In write mode, LDQM and UDQM
control the input buffer. When LDQM or UDQM is LOW,
the corresponding buffer byte is enabled, and data can be
written to the device. When LDQM or UDQM is HIGH,
input data is masked and cannot be written to the device.
RAS, in conjunction with CAS and WE , forms the device
command. See the “Command Truth Table” item for
details on device commands.
WE , in conjunction with RAS and CAS , forms the device
command. See the “Command Truth Table” item for
details on device commands.
VCCQ is the output buffer power supply.
VCC is the device internal power supply.
GNDQ is the output buffer ground.
GND is the device internal ground.
4
WRITE
A burst write access to an active row is initiated with the
WRITE command. BA0, BA1 inputs selects the bank, and
the starting column location is provided by inputs A0-A7.
Whether or not AUTO-PRECHARGE is used is determined by A10.
The row being accessed will be precharged at the end of
the WRITE burst, if AUTO PRECHARGE is selected. If
AUTO PRECHARGE is not selected, the row will remain
open for subsequent accesses.
A memory array is written with corresponding input data
on DQ’s and DQM input logic level appearing at the same
time. Data will be written to memory when DQM signal is
LOW. When DQM is HIGH, the corresponding data inputs
will be ignored, and a WRITE will not be executed to that
byte/column location.
PRECHARGE
The PRECHARGE command is used to deactivate the
open row in a particular bank or the open row in all banks.
BA0, BA1 can be used to select which bank is precharged
or they are treated as “Don’t Care”. A10 determined
whether one or all banks are precharged. After executing
this command, the next command for the selected banks(s)
is executed after passage of the period tRP, which is the
period required for bank precharging. Once 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
The AUTO PRECHARGE function ensures that the
precharge is initiated at the earliest valid stage within a
burst. This function allows for individual-bank precharge
without requiring an explicit command. A10 to enables the
AUTO PRECHARGE function in conjunction with a specific READ or WRITE command. For each individual
READ or WRITE command, auto precharge is either
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
enabled or disabled. AUTO PRECHARGE does not apply
except in full-page burst mode. Upon completion of the
READ or WRITE burst, a precharge of the bank/row that
is addressed is automatically performed.
AUTO REFRESH COMMAND
This command executes the AUTO REFRESH operation.
The row address and bank to be refreshed are automatically
generated during this operation. The stipulated period (tRC)
is required for a single refresh operation, and no other
commands can be executed during this period. This command is executed at least 4096 times every 64ms. During
an AUTO REFRESH command, address bits are “Don’t
Care”. This command corresponds to CBR Auto-refresh.
SELF REFRESH
During the SELF REFRESH operation, the row address to
be refreshed, the bank, and the refresh interval are
generated automatically internally. SELF REFRESH can
be used to retain data in the SDRAM without external
clocking, even if the rest of the system is powered down.
The SELF REFRESH operation is started by dropping the
CKE pin from HIGH to LOW. During the SELF REFRESH
operation all other inputs to the SDRAM become “Don’t
Care”.The device must remain in self refresh mode for a
minimum period equal to tRAS or may remain in self refresh
mode for an indefinite period beyond that.The SELFREFRESH operation continues as long as the CKE pin
remains LOW and there is no need for external control of
any other pins.The next command cannot be executed
until the device internal recovery period (tRC) has elapsed.
Once CKE goes HIGH, the NOP command must be
issued (minimum of two clocks) to provide time for the
completion of any internal refresh in progress. After the
self-refresh, since it is impossible to determine the address of the last row to be refreshed, an AUTO-REFRESH
should immediately be performed for all addresses.
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
®
BURST TERMINATE
The BURST TERMINATE command forcibly terminates
the burst read and write operations by truncating either
fixed-length or full-page bursts and the most recently
registered READ or WRITE command prior to the BURST
TERMINATE.
COMMAND INHIBIT
COMMAND INHIBIT prevents new commands from being
executed. Operations in progress are not affected, apart
from whether the CLK signal is enabled
NO OPERATION
When CS is low, the NOP command prevents unwanted
commands from being registered during idle or wait
states.
LOAD MODE REGISTER
During the LOAD MODE REGSITER command the mode
register is loaded from A0-A11. This command can only
be issued when all banks are idle.
ACTIVE COMMAND
When the ACTIVE COMMAND is activated, BA0, BA1
inputs selects a bank to be accessed, and the address
inputs on A0-A11 selects the row. Until a PRECHARGE
command is issued to the bank, the row remains open for
accesses.
5
ISSI
IS42S16400
®
TRUTH TABLE – COMMANDS AND DQM OPERATION(1)
FUNCTION
COMMAND INHIBIT (NOP)
NO OPERATION (NOP)
ACTIVE (Select bank and activate row)
(3)
(4)
READ (Select bank/column, start READ burst)
(4)
WRITE (Select bank/column, start WRITE burst)
BURST TERMINATE
(5)
PRECHARGE (Deactivate row in bank or banks)
AUTO REFRESH or SELF REFRESH
(Enter self refresh mode)
(2)
LOAD MODE REGISTER
(8)
Write Enable/Output Enable
(8)
Write Inhibit/Output High-Z
(6,7)
CS
RAS
CAS
WE
DQM
ADDR
DQs
H
X
X
X
X
X
X
L
H
H
H
X
X
X
L
L
H
H
X
Bank/Row
X
(8)
Bank/Col
X
L
H
L
H
L/H
L
H
L
L
L/H(8)
Bank/Col
Valid
L
H
H
L
X
X
Active
L
L
H
L
X
Code
X
L
L
L
H
X
X
X
L
L
L
L
X
Op-Code
X
—
—
—
—
L
—
Active
—
—
—
—
H
—
High-Z
NOTES:
1. CKE is HIGH for all commands except SELF REFRESH.
2. A0-A11 define the op-code written to the mode register.
3. A0-A11 provide row address, and BA0, BA1 determine which bank is made active.
4. A0-A7 (x16) provide column address; A10 HIGH enables the auto precharge feature (nonpersistent), while A10 LOW disables
auto precharge; BA0, BA1 determine which bank is being read from or written to.
5. A10 LOW: BA0, BA1 determine the bank being precharged. A10 HIGH: All banks precharged and BA0, BA1 are “Don’t Care.”
6. 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” except for CKE.
8. Activates or deactivates the DQs during WRITEs (zero-clock delay) and READs (two-clock delay).
6
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
TRUTH TABLE – CKE (1-4)
CURRENT STATE
COMMANDn
ACTIONn
CKEn-1
CKEn
Power-Down
X
Maintain Power-Down
L
L
Self Refresh
X
Maintain Self Refresh
L
L
X
Maintain Clock Suspend
L
L
COMMAND INHIBIT or NOP
Exit Power-Down
L
H
COMMAND INHIBIT or NOP
Exit Self Refresh
L
H
X
Exit Clock Suspend
L
H
All Banks Idle
COMMAND INHIBIT or NOP
Power-Down Entry
H
L
All Banks Idle
AUTO REFRESH
Self Refresh Entry
H
L
Reading or Writing
VALID
Clock Suspend Entry
H
L
H
H
Clock Suspend
(5)
Power-Down
(6)
Self Refresh
Clock Suspend
(7)
See TRUTH TABLE – CURRENT STATE BANK n, COMMAND TO BANK n
NOTES:
1. CKEn is the logic state of CKE at clock edge n; CKEn-1 was the state of CKE at the previous clock edge.
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 ACTONn 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 all banks idle state once tXSR is met. COMMAND INHIBIT or NOP commands
should be issued on clock edges occurring during the tXSR period. A minimum of two NOP commands must be sent during tXSR period.
7. After exiting clock suspend at clock edge n, the device will resume operation and recognize the next command at clock edge n+1.
TRUTH TABLE – CURRENT STATE BANK n, COMMAND TO BANK n (1-6)
CS RAS CAS WE
CURRENT STATE
COMMAND (ACTION)
Any
COMMAND INHIBIT (NOP/Continue previous operation)
H
X
X
X
NO OPERATION (NOP/Continue previous operation)
L
H
H
H
ACTIVE (Select and activate row)
L
L
H
H
AUTO REFRESH(7)
L
L
L
H
LOAD MODE REGISTER(7)
L
L
L
L
L
L
H
L
L
H
L
H
L
H
L
L
L
L
H
L
L
H
L
H
Idle
PRECHARGE
Row Active
(11)
(10)
READ (Select column and start READ burst)
WRITE (Select column and start WRITE burst)(10)
(8)
PRECHARGE (Deactivate row in bank or banks)
(10)
Read
READ (Select column and start new READ burst)
(Auto
(10)
WRITE (Select column and start WRITE burst)
L
H
L
L
Precharge
PRECHARGE (Truncate READ burst, start PRECHARGE)(8)
L
L
H
L
L
H
H
L
L
H
L
H
L
H
L
L
Disabled)
Write
(9)
BURST TERMINATE
(10)
READ (Select column and start READ burst)
(10)
(Auto
WRITE (Select column and start new WRITE burst)
Precharge
PRECHARGE (Truncate WRITE burst, start PRECHARGE)(8)
L
L
H
L
Disabled)
BURST TERMINATE(9)
L
H
H
L
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
7
IS42S16400
ISSI
®
NOTE:
1. This table applies when CKE n-1 was HIGH and CKE n is HIGH (see Truth Table - CKE) and after tXSR has been met (if the
previous state was SELF REFRESH).
2. This table is bank-specific, except where noted; i.e., the current state is for a specific bank and the commands shown are those
allowed to be issued to that bank when in that state. Exceptions are covered in the notes 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
allowable commands to the other bank should be issued on any clock edge occurring during these states. Allowable commands to
the other bank are determined by its current state and CURRENT STATE BANK n truth tables.
Precharging: Starts with registration of a PRECHARGE command and ends when tRP is met. Once 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. Once tRCD is met, the bank will
be in the row active state.
Read w/Auto
Precharge Enabled: Starts with registration of a READ command with auto precharge enabled and ends when tRP has been met.
Once tRP is met, the bank will be in the idle state.
Write w/Auto
Precharge Enabled: Starts with registration of a WRITE command with auto precharge enabled and ends when tRP has been met.
Once 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 tRC is met. Once tRC is met, the
SDRAM will be in the all banks idle state.
Accessing Mode
Register: Starts with registration of a LOAD MODE REGISTER command and ends when tMRD has been met. Once
tMRD is met, the SDRAM will be in the all banks idle state.
Precharging All: Starts with registration of a PRECHARGE ALL command and ends when tRP is met. Once 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. May or may not be bank-specific; if all banks are to be precharged, all must be in a valid state for precharging.
9. Not bank-specific; BURST TERMINATE affects the most recent READ or WRITE burst, regardless of bank.
10. 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.
11. Does not affect the state of the bank and acts as a NOP to that bank.
8
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
TRUTH TABLE – CURRENT STATE BANK n, COMMAND TO BANK m (1-6)
CS RAS CAS WE
CURRENT STATE
COMMAND (ACTION)
Any
COMMAND INHIBIT (NOP/Continue previous operation)
H
X
X
X
NO OPERATION (NOP/Continue previous operation)
L
H
H
H
Idle
Any Command Otherwise Allowed to Bank m
X
X
X
X
Row
ACTIVE (Select and activate row)
L
L
H
H
Activating,
READ (Select column and start READ burst)(7)
L
H
L
H
(7)
Active, or
WRITE (Select column and start WRITE burst)
L
H
L
L
Precharging
PRECHARGE
L
L
H
L
Read
ACTIVE (Select and activate row)
L
L
H
H
(Auto
READ (Select column and start new READ burst)(7,10)
L
H
L
H
L
H
L
L
L
L
H
L
L
L
H
H
L
H
L
H
L
H
L
L
L
L
H
L
L
L
H
H
L
H
L
H
L
H
L
L
L
L
H
L
L
L
H
H
L
H
L
H
L
H
L
L
L
L
H
L
Precharge
(7,11)
WRITE (Select column and start WRITE burst)
(9)
Disabled)
PRECHARGE
Write
ACTIVE (Select and activate row)
(Auto
READ (Select column and start READ burst)(7,12)
Precharge
WRITE (Select column and start new WRITE burst)
(7,13)
(9)
Disabled)
PRECHARGE
Read
ACTIVE (Select and activate row)
(With Auto
READ (Select column and start new READ burst)(7,8,14)
Precharge)
(7,8,15)
WRITE (Select column and start WRITE burst)
PRECHARGE
(9)
Write
ACTIVE (Select and activate row)
(With Auto
READ (Select column and start READ burst)(7,8,16)
Precharge)
WRITE (Select column and start new WRITE burst)
PRECHARGE
(9)
(7,8,17)
NOTE:
1. This table applies when CKE n-1 was HIGH and CKE n is HIGH (Truth Table - CKE) and after tXSR has been met (if the previous
state was self refresh).
2. This table describes alternate bank operation, except where noted; i.e., the current state is for bank n and the commands shown
are those allowed to be issued to bank m (assuming that bank m is in such a state that the given command is allowable). Exceptions are
covered in the notes 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.
Read w/Auto
Precharge Enabled: Starts with registration of a READ command with auto precharge enabled, and ends when tRP has been met.
Once tRP is met, the bank will be in the idle state.
Write w/Auto
Precharge Enabled: Starts with registration of a WRITE command with auto precharge enabled, and ends when tRP has been
met. Once tRP is met, the bank will be in the idle state.
4. AUTO REFRESH, SELF REFRESH and LOAD MODE REGISTER commands may only be issued 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.
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
9
IS42S16400
ISSI
®
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 disabled.
8. CONCURRENT AUTO PRECHARGE: Bank n will initiate the AUTO PRECHARGE command when its burst has been interrupted by bank m’s burst.
9. Burst in bank n continues as initiated.
10. For a READ without auto precharge interrupted by a READ (with or without auto precharge), the READ to bank m will interrupt the
READ on bank n, CAS latency later (Consecutive READ Bursts).
11. For a READ without auto precharge interrupted by a WRITE (with or without auto precharge), the WRITE to bank m will interrupt
the READ on bank n when registered (READ to WRITE). 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 precharge), the READ to bank m will interrupt
the WRITE on bank n when registered (WRITE to READ), with the data-out appearing CAS latency later. The last valid WRITE to
bank n will be data-in registered one clock prior to the READ to bank m.
13. For a WRITE without auto precharge interrupted by a WRITE (with or without auto precharge), the WRITE to bank m will interrupt
the WRITE on bank n when registered (WRITE to WRITE). 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 precharge), the READ to bank m will interrupt the
READ on bank n, CAS latency later. The PRECHARGE to bank n will begin when the READ to bank m is registered (Fig CAP 1).
15. For a READ with auto precharge interrupted by a WRITE (with or without auto precharge), 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 (Fig CAP 2).
16. For a WRITE with auto precharge interrupted by a READ (with or without auto precharge), the READ to bank m will interrupt the
WRITE on bank n when registered, with the data-out appearing CAS latency 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 to bank n will be data-in registered
one clock prior to the READ to bank m (Fig CAP 3).
17. For a WRITE with auto precharge interrupted by a WRITE (with or without auto precharge), 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 t WR begins when the WRITE
to bank m is registered. The last valid WRITE to bank n will be data registered one clock prior to the WRITE to bank m (Fig CAP 4).
10
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
ABSOLUTE MAXIMUM RATINGS(1)
Symbol
Parameters
VCC MAX
VCCQ MAX
VIN
VOUT
PD MAX
I CS
TOPR
Maximum Supply Voltage
Maximum Supply Voltage for Output Buffer
Input Voltage
Output Voltage
Allowable Power Dissipation
Output Shorted Current
Operating Temperature
Com.
Ind.
Storage Temperature
TSTG
Rating
Unit
–1.0 to +4.6
–1.0 to +4.6
–1.0 to +4.6
–1.0 to +4.6
1
50
0 to +70
–40 to +85
–55 to +150
V
V
V
V
W
mA
°C
°C
DC RECOMMENDED OPERATING CONDITIONS(2) (At TA = 0 to +70°C)
Symbol
VCC, VCCQ
VIH
VIL
Parameter
Min.
Typ.
Max.
Unit
Supply Voltage
Input High Voltage
Input Low Voltage
3.0
2.0
-0.3
3.3
—
—
3.6
VCC + 0.3
+0.8
V
V
V
CAPACITANCE CHARACTERISTICS(1,2) (At TA = 0 to +25°C, Vcc = VccQ = 3.3 ± 0.3V, f = 1 MHz)
Symbol
Parameter
CIN1
CIN2
CI/O
Input Capacitance: A0-A11, BA0, BA1
Input Capacitance: (CLK, CKE, CS, RAS, CAS, WE, LDQM, UDQM)
Data Input/Output Capacitance: I/O0-I/O15
Typ.
Max.
Unit
—
—
—
4
4
5
pF
pF
pF
Notes:
1. Stress greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent damage to the device. This is a
stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational
sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
reliability.
2. All voltages are referenced to GND.
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
11
ISSI
IS42S16400
®
DC ELECTRICAL CHARACTERISTICS (Recommended Operation Conditions unless otherwise noted.)
Symbol
IIL
Parameter
Input Leakage Current
IOL
VOH
VOL
ICC1
Output Leakage Current
Output High Voltage Level
Output Low Voltage Level
Operating Current(1,2)
ICC2P
Precharge Standby Current
ICC2PS
(In Power-Down Mode)
ICC2N
ICC2NS
Precharge Standby Current
(In Non Power-Down Mode)
ICC3P
Active Standby Current
ICC3PS
(In Power-Down Mode)
ICC3N
ICC3NS
Active Standby Current
(In Non Power-Down Mode)
ICC4
Operating Current
(In Burst Mode)(1)
ICC5
Auto-Refresh Current
ICC6
Self-Refresh Current
Test Condition
0V ≤ VIN ≤ VCC, with pins other than
the tested pin at 0V
Output is disabled, 0V ≤ VOUT ≤ VCC
IOUT = –2 mA
IOUT = +2 mA
One Bank Operation,
CAS latency = 3
Burst Length=1
Com.
tRC ≥ tRC (min.)
Ind.
IOUT = 0mA
Com.
Ind.
CKE ≤ VIL (MAX)
tCK = tCK (MIN) Com.
Ind.
tCK = ∞
Com.
Ind.
CKE ≥ VIH (MIN)
tCK = tCK (MIN)
tCK = ∞
Com.
Ind.
CKE ≤ VIL (MAX)
tCK = tCK (MIN) Com.
Ind.
Ind.
tCK = ∞
Com.
Ind.
CKE ≥ VIH (MIN)
tCK = tCK (MIN)
tCK = ∞
Com.
Ind.
tCK = tCK (MIN)
CAS latency = 3
IOUT = 0mA
Com.
Ind.
Com.
Ind.
CAS latency = 2
Com.
Ind.
Com.
Ind.
tRC = tRC (MIN)
CAS latency = 3
Com.
Ind.
Com.
Ind.
CAS latency = 2
Com.
Ind.
Com.
Ind.
CKE ≤ 0.2V
Speed
-6
-7
-7
-10
-10
—
—
—
—
—
—
—
—
—
—
—
—
—
—
-6
-7
-7
-10
-10
-6
-7
-7
-10
-10
-6
-7
-7
-10
-10
-6
-7
-7
-10
-10
—
Min.
–5
Max.
5
Unit
µA
–5
2.4
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
5
—
0.4
140
125
145
110
125
3
4
2
3
30
10
15
3
7
3
5
40
20
25
130
100
120
80
100
130
100
120
80
100
150
130
150
110
130
130
100
120
80
100
1
µA
V
V
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
Notes:
1. These are the values at the minimum cycle time. Since the currents are transient, these values decrease as the cycle time
increases. Also note that a bypass capacitor of at least 0.01 µF should be inserted between Vcc and GND for each memory chip
to suppress power supply voltage noise (voltage drops) due to these transient currents.
2. Icc1 and Icc4 depend on the output load. The maximum values for Icc1 and Icc4 are obtained with the output open state.
12
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
AC ELECTRICAL CHARACTERISTICS (1,2,3)
-6
Symbol
Parameter
tCK3
tCK2
Clock Cycle Time
tAC3
tAC2
Access Time From CLK(4)
tCHI
-7
-10
Min.
Max
Min.
Max.
Min.
Max.
CAS Latency = 3
CAS Latency = 2
6
8
—
—
7
10
—
—
10
10
—
—
ns
ns
CAS Latency = 3
CAS Latency = 2
—
—
5.5
6
—
—
6
6
—
—
7
9
ns
ns
CLK HIGH Level Width
2
—
2.5
—
3.5
—
ns
tCL
CLK LOW Level Width
2
—
2.5
—
3.5
—
ns
tOH3
tOH2
Output Data Hold Time
2.5
2.5
—
—
2.5
2.5
—
—
2.5
2.5
—
—
ns
ns
tLZ
Output LOW Impedance Time
0
—
0
—
0
—
ns
—
—
5.5
6
—
—
6
6
—
—
7
9
ns
ns
CAS Latency = 3
CAS Latency = 2
(5)
CAS Latency = 3
CAS Latency = 2
Units
tHZ3
tHZ2
Output HIGH Impedance Time
tDS
Input Data Setup Time
1.5
—
1.5
—
2.0
—
ns
tDH
Input Data Hold Time
0.8
—
0.8
—
1
—
ns
tAS
Address Setup Time
1.5
—
1.5
—
2.0
—
ns
tAH
Address Hold Time
0.8
—
0.8
—
1
—
ns
tCKS
CKE Setup Time
1.5
—
1.5
—
2.0
—
ns
tCKH
CKE Hold Time
0.8
—
0.8
—
1
—
ns
tCKA
CKE to CLK Recovery Delay Time
1CLK+3
—
1CLK+3
—
1CLK+3
—
ns
tCS
Command Setup Time (CS, RAS, CAS, WE, DQM)
1.5
—
1.5
—
2.0
—
ns
tCH
Command Hold Time (CS, RAS, CAS, WE, DQM)
0.8
—
0.8
—
1
—
ns
tRC
Command Period (REF to REF / ACT to ACT)
60
—
63
—
70
—
ns
tRAS
Command Period (ACT to PRE)
35
120,000
37
120,000
44
120,000
ns
tRP
Command Period (PRE to ACT)
15
—
15
—
18
—
ns
tRCD
Active Command To Read / Write Command Delay Time
15
—
15
—
18
—
ns
tRRD
Command Period (ACT [0] to ACT[1])
14
—
14
—
15
—
ns
tDPL3
Input Data To Precharge
Command Delay time
CAS Latency = 3
2CLK
—
2CLK
—
2CLK
—
ns
tDPL2
CAS Latency = 2
2CLK
—
2CLK
—
2CLK
—
ns
tDAL3
Input Data To Active / Refresh CAS Latency = 3
Command Delay time (During Auto-Precharge)
CAS Latency = 2
2CLK+tRP
—
2CLK+tRP
—
2CLK+tRP
—
ns
2CLK+tRP
—
2CLK+tRP
—
2CLK+tRP
—
ns
1
10
1
10
1
10
ns
—
64
—
64
—
64
ms
tDAL2
tT
tREF
Transition Time
Refresh Cycle Time (4096)
Notes:
1. When power is first applied, memory operation should be started 100 µs after Vcc and VccQ reach their stipulated voltages. Also
note that the power-on sequence must be executed before starting memory operation.
2. Measured with tT = 1 ns.
3. The reference level is 1.4 V when measuring input signal timing. Rise and fall times are measured between VIH (min.) and VIL
(max.).
4. Access time is measured at 1.4V with the load shown in the figure below.
5. The time tHZ (max.) is defined as the time required for the output voltage to transition by ± 200 mV from VOH (min.) or VOL (max.)
when the output is in the high impedance state.
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
13
ISSI
IS42S16400
®
OPERATING FREQUENCY / LATENCY RELATIONSHIPS
SYMBOL
PARAMETER
-6
-7
-10.
UNITS
—
Clock Cycle Time
6
7
10
ns
—
Operating Frequency
166
133
100
MHz
t CCD
READ/WRITE command to READ/WRITE command
1
1
1
cycle
t CKED
CKE to clock disable or power-down entry mode
1
1
1
cycle
t PED
CKE to clock enable or power-down exit setup mode
1
1
1
cycle
t DQD
DQM to input data delay
0
0
0
cycle
tDQM
DQM to data mask during WRITEs
0
0
0
cycle
tDQZ
DQM to data high-impedance during READs
2
2
2
cycle
t DWD
WRITE command to input data delay
0
0
0
cycle
t DAL
Data-in to ACTIVE command
5
5
4
cycle
t DPL
Data-in to PRECHARGE command
2
2
2
cycle
t BDL
Last data-in to burst STOP command
1
1
1
cycle
t CDL
Last data-in to new READ/WRITE command
1
1
1
cycle
t RDL
Last data-in to PRECHARGE command
2
2
2
cycle
t MRD
LOAD MODE REGISTER command
to ACTIVE or REFRESH command
2
2
2
cycle
Data-out to high-impedance from
CL = 3
3
3
3
PRECHARGE command
CL = 2
2
2
2
t ROH
cycle
AC TEST CONDITIONS (Input/Output Reference Level: 1.4V)
Input Load
Output Load
tCK
tCHI
tCL
2.0V
CLK 1.4V
50 Ω
0.8V
tCS
I/O
tCH
+1.4V
2.0V
50 pF
INPUT 1.4V
0.8V
tAC
tOH
OUTPUT
14
1.4V
1.4V
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
FUNCTIONAL DESCRIPTION
Initialization
The 64Mb SDRAMs (1 Meg x 16 x 4 banks) are quad-bank
DRAMs which operate at 3.3V and include a synchronous
interface (all signals are registered on the positive edge of
the clock signal, CLK). Each of the 16,777,216-bit banks
is organized as 4,096 rows by 256 columns 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
sequence. Accesses begin with the registration of an
ACTIVE command which is then 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, A0-A11
select the row). The address bits (A0-A7) 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 provide detailed information covering
device initialization, register definition, command
descriptions and device operation.
SDRAMs must be powered up and initialized in a
predefined manner.
The 64M SDRAM is initialized after the power is applied
to VCC and VCCQ (simultaneously) and the clock is stable.
A 100µs delay is required prior to issuing any command
other than a COMMAND INHIBIT or a NOP. The COMMAND
INHIBIT or NOP may be applied during the 100us period
and continue should at least through the end of the period.
With at least one COMMAND INHIBIT or NOP command
having been applied, a PRECHARGE command should be
applied once the 100µs delay has been satisfied. All
banks must be precharged. This will leave all banks in an
idle idle state where two AUTO REFRESH cycles must be
performed. After the AUTO REFRESH cycles are complete,
the SRDRAM is then ready for mode register programming.
The mode register should be loaded prior to applying any
operational command because it will power up in an
unknown state.
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
15
ISSI
IS42S16400
®
until it is programmed again or the device loses power.
Mode register bits M0-M2 specify the burst length, M3
specifies the type of burst (sequential or interleaved), M4- M6
specify the CAS latency, M7 and M8 specify the operating
mode, M9 specifies the WRITE burst mode, and M10 and
M11 are reserved for future use.
The mode register must be loaded when all banks are idle,
and the controller must wait the specified time before
initiating the subsequent operation. Violating either of
these requirements will result in unspecified operation.
REGISTER DEFINITION
Mode Register
The mode register is used to define the specific mode of
operation of the SDRAM. This definition includes the
selection of a burst length, a burst type, a CAS\ latency,
an operating mode and a write burst mode, as shown in
MODE REGISTER DEFINITION.
The mode register is programmed via the LOAD MODE
REGISTER command and will retain the stored information
MODE REGISTER DEFINITION
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
Address Bus
Mode Register (Mx)
(1)
Burst Length
Reserved
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
2
4
8
Reserved
Reserved
Reserved
Full Page
1
2
4
8
Reserved
Reserved
Reserved
Reserved
Burst Type
M3
Type
0
1
Sequential
Interleaved
Latency Mode
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
CAS Latency
Reserved
Reserved
2
3
Reserved
Reserved
Reserved
Reserved
Operating Mode
M8 M7
M6-M0
Mode
0 0
— —
Defined
—
Standard Operation
All Other States Reserved
Write Burst Mode
M9
0
1
16
Mode
Programmed Burst Length
Single Location Access
1. To ensure compatibility with future devices,
should program M11, M10 = "0, 0"
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
Burst Length
Read and write accesses to the SDRAM are burst oriented, with the burst length being programmable, as
shown in MODE REGISTER DEFINITION. The burst
length determines the maximum number of column locations that can be accessed for a given READ or WRITE
command. Burst lengths of 1, 2, 4 or 8 locations are
available for both the sequential and the interleaved burst
types, and a full-page burst is available for the sequential
type. The full-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 future 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 will wrap within the block if a
boundary is reached. The block is uniquely selected by
A1-A7 (x16) when the burst length is set to two; by A2-A7
(x16) when the burst length is set to four; and by A3-A7
(x16) when the burst length is set to eight. The remaining
(least significant) address bit(s) is (are) used to select the
starting location within the block. Full-page bursts wrap
within the page if the boundary is reached.
Burst Type
Accesses within a given burst may 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, as shown in BURST DEFINITION table.
BURST DEFINITION
Burst
Starting Column
Length
Address
Order of Accesses Within a Burst
Type = Sequential
Type = Interleaved
0
0-1
0-1
1
1-0
1-0
A0
2
A1
A0
0
0
0-1-2-3
0-1-2-3
0
1
1-2-3-0
1-0-3-2
1
0
2-3-0-1
2-3-0-1
1
1
3-0-1-2
3-2-1-0
A2
A1
A0
0
0
0
0-1-2-3-4-5-6-7
0-1-2-3-4-5-6-7
0
0
1
1-2-3-4-5-6-7-0
1-0-3-2-5-4-7-6
0
1
0
2-3-4-5-6-7-0-1
2-3-0-1-6-7-4-5
0
1
1
3-4-5-6-7-0-1-2
3-2-1-0-7-6-5-4
1
0
0
4-5-6-7-0-1-2-3
4-5-6-7-0-1-2-3
1
0
1
5-6-7-0-1-2-3-4
5-4-7-6-1-0-3-2
1
1
0
6-7-0-1-2-3-4-5
6-7-4-5-2-3-0-1
1
1
1
7-0-1-2-3-4-5-6
7-6-5-4-3-2-1-0
Cn, Cn + 1, Cn + 2
Cn + 3, Cn + 4...
…Cn - 1,
Cn…
Not Supported
4
8
Full
Page
(y)
n = A0-A7
(location 0-y)
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
17
ISSI
IS42S16400
®
reserved for future use and/or test modes. The programmed
burst length applies to both READ and WRITE bursts.
Test modes and reserved states should not be used
because unknown operation or incompatibility with future
versions may result.
CAS Latency
The CAS latency is the delay, in clock cycles, between the
registration of a READ command and the availability of the first
piece of 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 DQs will 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 will be 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 DQs will start
driving after T1 and the data will be valid by T2, as shown
in CAS Latency diagrams. The Allowable Operating
Frequency table indicates the operating frequencies at
which each CAS latency setting can be used.
Reserved states should not be used as unknown operation
or incompatibility with future versions may result.
Write Burst Mode
When M9 = 0, the burst length programmed via M0-M2
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.
CAS Latency
Allowable Operating Frequency (MHz)
Operating Mode
The normal operating mode is selected by setting M7 and M8
to zero; the other combinations of values for M7 and M8 are
Speed
CAS Latency = 2
CAS Latency = 3
6
—
166
7
—
133
10
100
—
CAS Latency
T0
T1
T2
T3
READ
NOP
NOP
CLK
COMMAND
tAC
DOUT
DQ
tOH
tLZ
CAS Latency - 2
T0
T1
T2
T3
T4
READ
NOP
NOP
NOP
CLK
COMMAND
tAC
DOUT
DQ
tLZ
tOH
CAS Latency - 3
DON'T CARE
UNDEFINED
18
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
OPERATION
®
Activating Specific Row Within Specific Bank
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
(see Activating Specific Row Within Specific Bank).
After opening a row (issuing an ACTIVE command), a READ
or WRITE command may be issued to that row, subject to
the tRCD specification. Minimum tRCD 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 the following example, 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 “closed” (precharged). The minimum time
interval between successive ACTIVE commands to the
same bank is defined by tRC.
CLK
CKE
HIGH - Z
CS
RAS
CAS
WE
A0-A11
ROW ADDRESS
BA0, BA1
BANK ADDRESS
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
minimum time interval between successive ACTIVE commands to different banks is defined by tRRD.
Example: Meeting tRCD (MIN) when 2 < [tRCD (min)/tCK] ≤ 3
T0
T1
T2
ACTIVE
NOP
NOP
T3
T4
CLK
COMMAND
READ or
WRITE
tRCD
DON'T CARE
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
19
ISSI
IS42S16400
READS
READ bursts are initiated with a READ command, as
shown in the READ COMMAND diagram.
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
enabled, the row being accessed is precharged at the
completion of the burst. For the generic READ commands
used in the following illustrations, auto precharge is disabled.
During READ bursts, the valid data-out element from the
starting column address will be available following the
CAS latency after the READ command. Each subsequent
data-out element will be valid by the next positive clock
edge. The CAS Latency diagram shows general timing
for each possible CAS latency setting.
Upon completion of a burst, assuming no other commands
have been initiated, the DQs will go High-Z. A full-page
burst will continue until terminated. (At the end of the page,
it will wrap to column 0 and continue.)
Data from any READ burst may be truncated with a
subsequent READ command, and data from a fixed-length
READ burst may be immediately followed 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 follows either the last element of a completed burst or
the last desired data element of a longer burst which is
being truncated.
The new READ command should be issued x cycles
before the clock edge at which the last desired data
element is valid, where x equals the CAS latency minus
one. This is shown in Consecutive READ Bursts for CAS
latencies of two and three; data element n + 3 is either the
last of a burst of four or the last desired of a longer burst.
The 64Mb SDRAM uses a pipelined architecture and
therefore does not require the 2n rule associated with a
prefetch architecture. A READ command can be initiated
on any clock cycle following a previous READ command.
Full-speed random read accesses can be performed to the
same bank, as shown in Random READ Accesses, or each
subsequent READ may be performed to a different bank.
Data from any READ burst may be truncated with a
subsequent WRITE command, and data from a fixed-length
READ burst may be immediately followed by data from a
WRITE command (subject to bus turnaround limitations).
The WRITE burst may be initiated 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 may be
a possibility that the device driving the input data will go
Low-Z before the SDRAM DQs go High-Z. In this case, at
least a single-cycle delay should occur between the last
read data and the WRITE command.
20
®
READ COMMAND
CLK
CKE
HIGH-Z
CS
RAS
CAS
WE
A0-A7
COLUMN ADDRESS
A8, A9, A11
AUTO PRECHARGE
A10
NO PRECHARGE
BA0, BA1
BANK ADDRESS
The DQM input is used to avoid I/O contention, as shown
in Figures RW1 and RW2. 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 data-out from the READ. Once the WRITE
command is registered, the DQs will go 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 command. If
not, the second WRITE will be an invalid WRITE. For
example, if DQM was LOW during T4 in Figure RW2, then
the WRITEs at T5 and T7 would be valid, while the WRITE
at T6 would be invalid.
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 RW1
shows the case where the clock frequency allows for bus
contention to be avoided without adding a NOP cycle, and
Figure RW2 shows the case where the additional NOP is
needed.
A fixed-length READ burst may be followed by, or truncated
with, a PRECHARGE command to the same bank (provided
that auto precharge was not activated), and a full-page burst
may be truncated with a PRECHARGE command to the
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
same bank. The PRECHARGE command should be issued
x cycles before the clock edge at which the last desired
data element is valid, where x equals the CAS latency
minus one. This is shown in the READ to PRECHARGE
diagram for each possible CAS latency; data element n +
3 is either the last of a burst of four or the last desired of a
longer burst. Following the PRECHARGE command, a
subsequent 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 command 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 disadvantage 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 full-page bursts.
Full-page READ bursts can be truncated with the BURST
TERMINATE command, and fixed-length READ bursts
may 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 equals the CAS latency minus
one. This is shown in the READ Burst Termination
diagram for each possible CAS latency; data element n +
3 is the last desired data element of a longer burst.
CAS Latency
T0
T1
T2
T3
READ
NOP
NOP
CLK
COMMAND
tAC
DOUT
DQ
tOH
tLZ
CAS Latency - 2
T0
T1
T2
T3
T4
READ
NOP
NOP
NOP
CLK
COMMAND
tAC
DOUT
DQ
tLZ
tOH
CAS Latency - 3
DON'T CARE
UNDEFINED
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
21
ISSI
IS42S16400
®
Consecutive READ Bursts
T0
T1
T2
T3
T4
T5
T6
READ
NOP
NOP
NOP
READ
NOP
NOP
DOUT n+3
DOUT b
CLK
COMMAND
x =1 cycle
BANK,
COL n
ADDRESS
BANK,
COL b
DQ
DOUT n
DOUT n+1
DOUT n+2
CAS Latency - 2
DON'T CARE
T0
T1
T2
T3
T4
T5
T6
T7
READ
NOP
NOP
NOP
READ
NOP
NOP
NOP
DOUT n+3
DOUT b
CLK
COMMAND
x = 2 cycles
ADDRESS
BANK,
COL n
BANK,
COL b
DQ
DOUT n
DOUT n+1
DOUT n+2
CAS Latency - 3
DON'T CARE
22
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
Random READ Accesses
T0
T1
T2
T3
T4
T5
COMMAND
READ
READ
READ
READ
NOP
NOP
ADDRESS
BANK,
COL n
BANK,
COL b
BANK,
COL m
BANK,
COL x
CLK
DQ
DOUT n
DOUT b
DOUT m
DOUT x
CAS Latency - 2
DON'T CARE
T0
T1
T2
T3
T4
T5
T6
COMMAND
READ
READ
READ
READ
NOP
NOP
NOP
ADDRESS
BANK,
COL n
BANK,
COL b
BANK,
COL m
BANK,
COL x
CLK
DQ
DOUT n
DOUT b
DOUT m
DOUT x
CAS Latency - 3
DON'T CARE
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
23
ISSI
IS42S16400
®
RW1 - READ to WRITE
T0
T1
T2
T3
COMMAND
READ
NOP
NOP
NOP
ADDRESS
BANK,
COL n
T4
CLK
DQM
WRITE
BANK,
COL b
tHZ
DOUT n
DQ
DIN b
tDS
DON'T CARE
RW2 - READ to WRITE With Extra Clock Cycle
T0
T1
T2
T3
T4
T5
COMMAND
READ
NOP
NOP
NOP
NOP
WRITE
ADDRESS
BANK,
COL n
CLK
DQM
DQ
BANK,
COL b
tHZ
DOUT n
DIN b
tDS
DON'T CARE
24
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
READ to PRECHARGE
T0
T1
T2
T3
T4
T5
T6
T7
CLK
tRP
COMMAND
READ
NOP
NOP
NOP
NOP
PRECHARGE
NOP
ACTIVE
x = 1 cycle
ADDRESS
BANK a,
COL n
BANK
(a or all)
DQ
DOUT n
DOUT n+1
BANK a,
ROW
DOUT n+2
DOUT n+3
CAS Latency - 2
DON'T CARE
T0
T1
T2
T3
T4
T5
T6
T7
CLK
tRP
COMMAND
READ
NOP
NOP
NOP
NOP
PRECHARGE
NOP
ACTIVE
x = 2 cycles
ADDRESS
BANK,
COL n
BANK,
COL b
DQ
DOUT n
DOUT n+1
BANK a,
ROW
DOUT n+2
DOUT n+3
CAS Latency - 3
DON'T CARE
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
25
ISSI
IS42S16400
®
READ Burst Termination
T0
T1
T2
T3
T4
READ
NOP
NOP
NOP
T5
T6
NOP
NOP
CLK
COMMAND
BURST
TERMINATE
x = 1 cycle
BANK a,
COL n
ADDRESS
DQ
DOUT n
DOUT n+1
DOUT n+2
DOUT n+3
CAS Latency - 2
DON'T CARE
T0
T1
T2
T3
READ
NOP
NOP
NOP
T4
T5
T6
T7
NOP
NOP
NOP
CLK
COMMAND
BURST
TERMINATE
x = 2 cycles
ADDRESS
BANK,
COL n
DQ
DOUT n
DOUT n+1
DOUT n+2
DOUT n+3
CAS Latency - 3
DON'T CARE
26
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
WRITEs
WRITE bursts are initiated with a WRITE command, as
shown in WRITE Command diagram.
WRITE Command
CLK
CKE
HIGH - Z
CS
RAS
CAS
WE
A0-A7
COLUMN ADDRESS
A8, A9, A11
AUTO PRECHARGE
A10
NO PRECHARGE
BA0, BA1
BANK ADDRESS
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 illustrations, auto precharge is disabled.
During WRITE bursts, the first valid data-in element will be
registered coincident with the WRITE command. Subsequent
data elements will be registered on each successive
positive clock edge. Upon completion of a fixed-length
burst, assuming no other commands have been initiated,
the DQs will remain High-Z and any additional input data will
be ignored (see WRITE Burst). A full-page burst will
continue until terminated. (At the end of the page, it will wrap
to column 0 and continue.)
Data for any WRITE burst may be truncated with a
subsequent WRITE command, and data for a fixed-length
WRITE burst may be immediately followed by data for a
WRITE command. The new WRITE command can be issued
on any clock following the previous WRITE command, and
the data provided coincident with the new command applies
to the new command.
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
®
An example is shown in WRITE to WRITE diagram. Data
n + 1 is either the last of a burst of two or the last desired
of a longer burst. The 64Mb SDRAM uses a pipelined
architecture and therefore does not require the 2n rule
associated 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 Random WRITE Cycles, or each subsequent
WRITE may be performed to a different bank.
Data for any WRITE burst may be truncated with a
subsequent READ command, and data for a fixed-length
WRITE burst may be immediately followed by a subsequent
READ command. Once the READ com mand is registered, the data inputs will be ignored, and WRITEs will not
be executed. An example is shown in WRITE to READ.
Data n + 1 is either the last of a burst of two or the last
desired of a longer burst.
Data for a fixed-length WRITE burst may be fol lowed by,
or truncated with, a PRECHARGE command to the same
bank (provided that auto precharge was not activated),
and a full-page WRITE burst may 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 requires a tWR of at
least one clock plus time, regardless of frequency. In
addition, when truncating a WRITE burst, 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. An example is shown in the WRITE to
PRECHARGE diagram. Data n+1 is either the last of a burst
of two or the last desired of a longer burst. Following 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 command 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 disadvantage 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 full-page bursts.
Fixed-length or full-page 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 will be 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 WRITE Burst
Termination, where data n is the last desired data element
of a longer burst.
27
ISSI
IS42S16400
®
WRITE Burst
T0
T1
T2
T3
COMMAND
WRITE
NOP
NOP
NOP
ADDRESS
BANK,
COL n
CLK
DQ
DIN n
DIN n+1
DON'T CARE
WRITE to WRITE
T0
T1
T2
COMMAND
WRITE
NOP
WRITE
ADDRESS
BANK,
COL n
CLK
DQ
BANK,
COL b
DIN n
DIN n+1
DIN b
DON'T CARE
Random WRITE Cycles
T0
T1
T2
T3
COMMAND
WRITE
WRITE
WRITE
WRITE
ADDRESS
BANK,
COL n
BANK,
COL b
BANK,
COL m
BANK,
COL x
DIN b
DIN m
DIN x
CLK
DQ
28
DIN n
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
WRITE to READ
T0
T1
T2
T3
T4
T5
COMMAND
WRITE
NOP
READ
NOP
NOP
NOP
ADDRESS
BANK,
COL n
DOUT b
DOUT b+1
CLK
DQ
BANK,
COL b
DIN n
DIN n+1
DON'T CARE
WRITE to PRECHARGE (tWR @ tCK ≥ 15ns)
T0
T1
T2
T3
T4
T5
T6
CLK
DQM
tRP
COMMAND
WRITE
ADDRESS
BANK a,
COL n
NOP
PRECHARGE
BANK
(a or all)
NOP
NOP
ACTIVE
NOP
BANK a,
ROW
tWR
DQ
DIN n
DIN n+1
DON'T CARE
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
29
ISSI
IS42S16400
®
WRITE to PRECHARGE (tWR @ tCK < 15ns)
T0
T1
T2
T3
T4
T5
T6
CLK
DQM
tRP
COMMAND
WRITE
ADDRESS
BANK a,
COL n
NOP
PRECHARGE
NOP
NOP
BANK
(a or all)
ACTIVE
NOP
BANK a,
ROW
tWR
DQ
DIN n
DIN n+1
DON'T CARE
WRITE Burst Termination
T0
T1
T2
COMMAND
WRITE
BURST
TERMINATE
NEXT
COMMAND
ADDRESS
BANK,
COL n
CLK
DQ
DIN n
(ADDRESS)
(DATA)
DON'T CARE
30
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
PRECHARGE Command
PRECHARGE
The PRECHARGE command (see figure) 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 some 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 to be precharged,
inputs BA0, BA1 select the bank. When all banks are to be
precharged, inputs BA0, BA1 are treated as “Don’t Care.”
Once 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.
CLK
HIGH - Z
CKE
CS
RAS
CAS
WE
A0-A9, A11
ALL BANKS
A10
POWER-DOWN
Power-down occurs if CKE is registered LOW coincident
with a NOP or COMMAND INHIBIT 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 either
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 may not remain in the powerdown state longer than the refresh period (64ms) since no
refresh operations are performed in this mode.
The power-down state is exited by registering a NOP or
COMMAND INHIBIT and CKE HIGH at the desired clock
edge (meeting tCKS). See figure below.
BANK SELECT
BA0, BA1
BANK ADDRESS
POWER-DOWN
CLK
≥ tCKS
tCKS
CKE
COMMAND
NOP
All banks idle
NOP
Input buffers gated off
Enter power-down mode
Exit power-down mode
ACTIVE
tRCD
tRAS
tRC
DON'T CARE
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
31
ISSI
IS42S16400
CLOCK SUSPEND
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 pins at the time
of a suspended internal clock edge is ignored; any data
present on the DQ pins remains driven; and burst counters
are not incremented, as long as the clock is suspended.
(See following examples.)
Clock suspend mode is exited by registering CKE HIGH;
the internal clock and related operation will resume on the
subsequent positive clock edge.
Clock Suspend During WRITE Burst
T0
T1
NOP
WRITE
T2
T3
T4
T5
NOP
NOP
DIN n+1
DIN n+2
CLK
CKE
INTERNAL
CLOCK
COMMAND
BANK a,
COL n
ADDRESS
DQ
DIN n
DON'T CARE
Clock Suspend During WRITE Burst
T0
T1
T2
COMMAND
READ
NOP
NOP
ADDRESS
BANK a,
COL n
T3
T4
T5
T6
NOP
NOP
NOP
CLK
CKE
INTERNAL
CLOCK
DQ
DIN n
DIN n+1
DIN n+2
DIN n+3
DON'T CARE
32
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
BURST READ/SINGLE WRITE
®
Four cases where CONCURRENT AUTO PRECHARGE
occurs are defined below.
The burst read/single write mode is entered by programming
the write burst mode bit (M9) in the mode register to a logic 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
sequence, just as in the normal mode of operation (M9 = 0).
READ with Auto Precharge
1. Interrupted by a READ (with or without auto precharge):
A READ to bank m will interrupt a READ on bank n, CAS
latency later. The PRECHARGE to bank n will begin
when the READ to bank m is registered.
2. 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
PRECHARGE to bank n will begin when the WRITE to
bank m is registered.
CONCURRENT AUTO PRECHARGE
An access command (READ or WRITE) to another bank
while an access command with auto precharge enabled is
executing is not allowed by SDRAMs, unless the SDRAM
supports CONCURRENT AUTO PRECHARGE. ISSI
SDRAMs support CONCURRENT AUTO PRECHARGE.
Fig CAP 1 - READ With Auto Precharge interrupted by a READ
T0
T1
T2
T3
T4
T5
T6
T7
NOP
NOP
NOP
NOP
CLK
NOP
COMMAND
BANK n
READ - AP
BANK n
Page Active
NOP
READ - AP
BANK m
READ with Burst of 4
Interrupt Burst, Precharge
tRP - BANK n
Internal States
BANK m
ADDRESS
Idle
Page Active
tRP - BANK m
READ with Burst of 4
BANK n,
COL a
Precharge
BANK m,
COL b
DQ
DOUT a
DOUT a+1
DOUT b
DOUT b+1
CAS Latency - 3 (BANK n)
DON'T CARE
CAS Latency - 3 (BANK m)
Fig CAP 2 - READ With Auto Precharge interrupted by a WRITE
T0
T1
T2
T3
NOP
NOP
NOP
T4
T5
T6
T7
NOP
NOP
NOP
CLK
COMMAND
WRITE - AP
BANK n
BANK n
READ with Burst of 4
Internal States
Interrupt Burst, Precharge
Page Active
BANK m
ADDRESS
WRITE - AP
BANK m
tRP - BANK n
Page Active
tRP - BANK m
WRITE with Burst of 4
BANK n,
COL a
Idle
Write-Back
BANK m,
COL b
DQM
DOUT a
DQ
DIN b
DIN b+1
DIN b+2
DIN b+3
CAS Latency - 3 (BANK n)
DON'T CARE
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
33
ISSI
IS42S16400
WRITE with Auto Precharge
®
one clock prior to the READ to bank m.
4. Interrupted by a WRITE (with or without auto precharge):
AWRITE 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 registered. The last valid data WRITE to bank n will
be data registered one clock prior to a WRITE to bank m.
3. 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 CAS latency 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 to bank n will be data-in registered
Fig CAP 3 - WRITE With Auto Precharge interrupted by a READ
T0
T1
T2
T3
T4
T5
T6
T7
NOP
NOP
NOP
NOP
CLK
NOP
COMMAND
BANK n
WRITE - AP
BANK n
Page Active
NOP
READ - AP
BANK m
WRITE with Burst of 4
Interrupt Burst, Write-Back
Precharge
tWR - BANK n
tRP - BANK n
Internal States
BANK m
Page Active
READ with Burst of 4
BANK n,
COL a
ADDRESS
DQ
DIN a
tRP - BANK m
Precharge
BANK m,
COL b
DIN a+1
DOUT b
DOUT b+1
CAS Latency - 3 (BANK m)
DON'T CARE
Fig CAP 4 - WRITE With Auto Precharge interrupted by a WRITE
T0
T1
T2
T3
NOP
NOP
T4
T5
T6
T7
NOP
NOP
NOP
CLK
NOP
COMMAND
BANK n
WRITE - AP
BANK n
Page Active
WRITE with Burst of 4
WRITE - AP
BANK m
Interrupt Burst, Write-Back
tWR - BANK n
Internal States
BANK m
ADDRESS
DQ
Precharge
Page Active
WRITE with Burst of 4
BANK n,
COL a
DIN a
tRP - BANK n
tRP - BANK m
Write-Back
BANK m,
COL b
DIN a+1
DIN a+2
DIN b
DIN b+1
DIN b+2
DIN b+3
DON'T CARE
34
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
INITIALIZE AND LOAD MODE REGISTER
T0
T1
Tn+1
tCH
tCK
CLK
To+1
tCL
Tp+1
Tp+2
Tp+3
tCKS tCKH
CKE
tCMH tCMS
tCMH tCMS
tCMH tCMS
NOP
PRECHARGE
AUTO
REFRESH
COMMAND
NOP
AUTO
REFRESH
NOP
Load MODE
REGISTER
NOP
ACTIVE
DQM/
DQML, DQMH
tAS tAH
A0-A9, A11
ALL BANKS
A10
CODE
tAS tAH
ROW
CODE
ROW
SINGLE BANK
BA0, BA1
BANK
ALL BANKS
DQ
tRP
T
Power-up: VCC
and CLK stable
Precharge
all banks
tRFC
AUTO REFRESH
T = 100µs Min.
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
tRFC
AUTO REFRESH
tMRD
Program MODE REGISTER (2, 3, 4)
DON'T CARE
35
ISSI
IS42S16400
®
POWER-DOWN MODE CYCLE
T0
T1
tCK
CLK
tCKS tCKH
T2
tCL
Tn+1
Tn+2
tCH
tCKS
tCKS
CKE
tCMS tCMH
COMMAND
PRECHARGE
NOP
NOP
NOP
ACTIVE
DQM/
DQML, DQMH
ROW
A0-A9, A11
ALL BANKS
A10
ROW
SINGLE BANK
tAS tAH
BA0, BA1
BANK
BANK
DQ High-Z
Two clock cycles
Precharge all
active banks
All banks idle, enter
power-down mode
Input buffers gated
off while in
power-down mode
All banks idle
Exit power-down mode
DON'T CARE
CAS latency = 2, 3
36
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
CLOCK SUSPEND MODE
T0
T1
tCK
CLK
T2
tCL
tCKS tCKH
T3
T4
T5
T6
NOP
NOP
NOP
T7
T8
T9
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
READ
NOP
NOP
WRITE
NOP
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
A0-A9, A11
COLUMN m(2)
tAS tAH
COLUMN n(2)
A10
tAS tAH
BA0, BA1
BANK
BANK
tAC
tAC
DOUT m
DQ
tLZ
tHZ
DOUT m+1
tDS
tDH
DOUT e
DOUT e+1
tOH
DON'T CARE
UNDEFINED
CAS latency = 2, burst length = 2
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
37
ISSI
IS42S16400
®
AUTO-REFRESH CYCLE
T0
T1
tCK
CLK
T2
tCL
Tn+1
To+1
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
PRECHARGE
NOP
Auto
Refresh
NOP
Auto
Refresh
NOP
ACTIVE
DQM/
DQML, DQMH
A0-A9, A11
ROW
ALL BANKS
A10
ROW
SINGLE BANK
BA0, BA1
DQ
BANK
BANK(s)
tAS tAH
High-Z
tRP
tRFC
tRFC
DON'T CARE
CAS latency = 2, 3
38
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
SELF-REFRESH CYCLE
T0
T1
tCK
CLK
T2
tCH
tCKS tCKH
Tn+1
To+1
To+2
tCL
tCKS
≥ tRAS
CKE
tCKS
tCMS tCMH
COMMAND
PRECHARGE
NOP
Auto
Refresh
NOP
NOP
Auto
Refresh
DQM/
DQML, DQMH
A0-A9, A11
ALL BANKS
A10
SINGLE BANK
tAS tAH
BA0, BA1
BANK
DQ High-Z
tXSR
tRP
Precharge all
active banks
Enter self
refresh mode
CLK stable prior to exiting
Exit self refresh mode
self refresh mode
(Restart refresh time base)
DON'T CARE
CAS latency = 2, 3
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
39
ISSI
IS42S16400
®
READ WITHOUT AUTO PRECHARGE
T0
T1
T2
tCK
CLK
tCL
T3
T4
T5
T6
T7
T8
NOP
ACTIVE
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
ACTIVE
NOP
READ
NOP
NOP
NOP
PRECHARGE
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
COLUMN m(2)
A0-A9, A11
ROW
tAS tAH
A10
ROW
tAS tAH
DISABLE AUTO PRECHARGE
BANK
BANK
BA0, BA1
ROW
ALL BANKS
ROW
SINGLE BANK
DQ
tRCD
tRAS
tRC
40
BANK
BANK
tAC
tLZ
CAS Latency
tAC
DOUT m
tAC
DOUT m+1
tAC
DOUT m+2
tHZ
DOUT m+3
tOH
tOH
tOH
tOH
DON'T CARE
tRP
UNDEFINED
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
READ WITH AUTO PRECHARGE
T0
T1
T2
tCK
CLK
tCL
T3
T4
T5
T6
T7
T8
NOP
ACTIVE
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
ACTIVE
NOP
READ
NOP
NOP
NOP
NOP
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
A0-A9, A11
ROW
tAS tAH
A10
ROW
tAS tAH
BA0, BA1
BANK
COLUMN m(2)
ROW
ENABLE AUTO PRECHARGE
ROW
BANK
BANK
tAC
DQ
tRCD
tLZ
CAS Latency
tRAS
tRC
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
tAC
DOUT m
tAC
DOUT m+1
tAC
DOUT m+2
tHZ
DOUT m+3
tOH
tOH
tOH
tOH
DON'T CARE
tRP
UNDEFINED
41
ISSI
IS42S16400
®
SINGLE READ WITHOUT AUTO PRECHARGE
T0
T1
T2
tCK
CLK
tCL
T3
T4
T5
T6
T7
T8
ACTIVE
NOP
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
ACTIVE
NOP
READ
NOP
NOP
PRECHARGE
NOP
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
COLUMN m(2)
A0-A9, A11
ROW
tAS tAH
A10
ROW
tAS tAH
DISABLE AUTO PRECHARGE
BANK
BANK
BA0, BA1
ROW
ALL BANKS
ROW
SINGLE BANK
BANK
tAC
BANK
tOH
DOUT m
DQ
tRCD
tRAS
tLZ
CAS Latency
tHZ
DON'T CARE
tRP
UNDEFINED
tRC
42
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
SINGLE READ WITH AUTO PRECHARGE
T0
T1
tCK
CLK
T2
tCL
T3
T4
T5
T6
T7
NOP
NOP
T8
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
ACTIVE
NOP
NOP
NOP
READ
ACTIVE
NOP
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
A0-A9, A11
ROW
tAS tAH
A10
ROW
tAS tAH
BA0, BA1
BANK
COLUMN m(2)
ROW
ENABLE AUTO PRECHARGE
ROW
BANK
BANK
tOH
tAC
DOUT m
DQ
tHZ
tRCD
tRAS
DON'T CARE
CAS Latency
tRP
UNDEFINED
tRC
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
43
ISSI
IS42S16400
®
ALTERNATING BANK READ ACCESSES
T0
T1
tCK
CLK
T2
tCL
T3
T4
T5
T6
T7
T8
NOP
READ
NOP
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
ACTIVE
NOP
READ
NOP
ACTIVE
ACTIVE
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
A0-A9, A11
COLUMN m(2)
ROW
tAS tAH
A10
ROW
tAS tAH
BA0, BA1
BANK 0
COLUMN b(2)
ROW
ENABLE AUTO PRECHARGE
ROW
ENABLE AUTO PRECHARGE
ROW
BANK 0
ROW
BANK 3
tLZ
BANK 3
tOH
tOH
DQ
DOUT m
tAC
tRCD - BANK 0
tRRD
tOH
DOUT m+1
tAC
BANK 0
tAC
tOH
DOUT m+2
tOH
DOUT m+3
tAC
tAC
tRP - BANK 0
CAS Latency - BANK 0
tRCD - BANK 3
DOUT b
tAC
tRCD - BANK 0
CAS Latency - BANK 3
tRAS - BANK 0
tRC - BANK 0
DON'T CARE
44
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
READ - FULL-PAGE BURST
T0
T1
tCK
CLK
T2
tCL
T3
T4
T5
T6
Tn+1
NOP
NOP
NOP
Tn+2
Tn+3
Tn+4
NOP
NOP
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
ACTIVE
NOP
READ
NOP
NOP
BURST TERM
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
A0-A9, A11
ROW
tAS tAH
A10
ROW
tAS tAH
BA0, BA1
BANK
COLUMN m(2)
BANK
tAC
DQ
tLZ
tRCD
CAS Latency
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
tAC
DOUT m
tAC
DOUT m+1
tOH
tOH
each row (x4) has
1,024 locations
tAC
DOUT m+2
tOH
tAC
DOUT m-1
tAC
DOUT m
tHZ
DOUT m+1
tOH
tOH
tOH
DON'T CARE
Full page Full-page burst not self-terminating.
completion Use BURST TERMINATE command.
UNDEFINED
45
ISSI
IS42S16400
®
READ - DQM OPERATION
T0
T1
T2
tCK
CLK
tCL
T3
T4
T5
T6
T7
T8
NOP
NOP
NOP
NOP
NOP
NOP
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
ACTIVE
NOP
READ
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
COLUMN m(2)
A0-A9, A11
ROW
tAS tAH
A10
ROW
tAS tAH
DISABLE AUTO PRECHARGE
BANK
BANK
BA0, BA1
ENABLE AUTO PRECHARGE
tAC
DQ
tLZ
tRCD
CAS Latency
tOH
DOUT m
tHZ
tAC
tLZ
tOH
DOUT m+2
tAC
tOH
DOUT m+3
tHZ
DON'T CARE
UNDEFINED
46
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
WRITE - WITHOUT AUTO PRECHARGE
T0
T1
tCK
CLK
T2
tCL
T3
T4
T5
T6
NOP
NOP
NOP
T7
T8
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
ACTIVE
NOP
WRITE
PRECHARGE
NOP
ACTIVE
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
A0-A9, A11
ROW
tAS tAH
A10
ROW
tAS tAH
BA0, BA1
COLUMN m(3)
ROW
ALL BANKS
ROW
SINGLE BANK
DISABLE AUTO PRECHARGE
BANK
BANK
tDS
DQ
tDH
DIN m
BANK
tDS tDH
DIN m+1
tRCD
tRAS
tRC
tDS tDH
DIN m+2
tDS
BANK
tDH
DIN m+3
tWR(2)
tRP
DON'T CARE
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
47
ISSI
IS42S16400
®
WRITE - WITH AUTO PRECHARGE
T0
T1
tCK
CLK
T2
tCL
T3
T4
T5
T6
T7
T8
T9
NOP
NOP
NOP
NOP
NOP
NOP
ACTIVE
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
ACTIVE
NOP
WRITE
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
A0-A9, A11
ROW
tAS tAH
A10
ROW
tAS tAH
BA0, BA1
BANK
COLUMN m(2)
ROW
ENABLE AUTO PRECHARGE
ROW
BANK
tDS
DQ
tDH
DIN m
tRCD
tRAS
tRC
BANK
tDS tDH
DIN m+1
tDS tDH
DIN m+2
tDS
tDH
DIN m+3
tWR
tRP
DON'T CARE
48
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
SINGLE WRITE - WITHOUT AUTO PRECHARGE
T0
T1
tCK
CLK
T2
tCL
T3
T4
T5
T6
T7
T8
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
ACTIVE
NOP
WRITE
NOP(4)
NOP(4)
PRECHARGE
NOP
ACTIVE
NOP
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
A0-A9, A11
ROW
tAS tAH
A10
ROW
tAS tAH
BA0, BA1
COLUMN m(3)
ROW
ALL BANKS
ROW
SINGLE BANK
DISABLE AUTO PRECHARGE
BANK
BANK
BANK
BANK
tDS tDH
DQ
DIN m
tRCD
tRAS
tRC
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
tWR(3)
tRP
DON'T CARE
49
ISSI
IS42S16400
®
SINGLE WRITE - WITH AUTO PRECHARGE
T0
T1
tCK
CLK
T2
tCL
T3
T4
T5
T6
T7
NOP
NOP
NOP
T8
T9
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
ACTIVE
NOP(3)
NOP(3)
NOP(3)
WRITE
ACTIVE
NOP
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
A0-A9, A11
ROW
tAS tAH
A10
ROW
tAS tAH
BA0, BA1
BANK
COLUMN m(2)
ROW
ENABLE AUTO PRECHARGE
ROW
BANK
BANK
tDS tDH
DQ
DIN m
tRCD
tRAS
tRC
50
tWR
tRP
DON'T CARE
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
ALTERNATING BANK WRITE ACCESS
T0
T1
tCK
CLK
T2
tCL
T3
T4
T5
T6
T7
T8
T9
NOP
NOP
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
ACTIVE
NOP
WRITE
NOP
ACTIVE
NOP
WRITE
ACTIVE
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
A0-A9, A11
ROW
tAS tAH
A10
ROW
tAS tAH
BA0, BA1
BANK 0
COLUMN m(2)
COLUMN b(2)
ROW
ENABLE AUTO PRECHARGE
ROW
ENABLE AUTO PRECHARGE
ROW
BANK 0
tDS
DQ
tDH
DIN m
ROW
BANK 1
tDS tDH
DIN m+1
tRCD - BANK 0
tRRD
tRAS - BANK 0
tRC - BANK 0
BANK 1
tDS
tDS tDH
DIN m+2
tDH
DIN m+3
tDS
tDH
DIN b
tWR - BANK 0
tRCD - BANK 1
BANK 0
tDS
tDH
DIN b+1
tDS
tDH
DIN b+2
tRP - BANK 0
tDS
tDH
DIN b+3
tRCD - BANK 0
tWR - BANK 1
DON'T CARE
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
51
ISSI
IS42S16400
®
WRITE - FULL PAGE BURST
T0
T1
tCK
CLK
T2
tCL
T3
T4
T5
Tn+1
Tn+2
NOP
NOP
NOP
NOP
BURST TERM
tDS tDH
tDS tDH
tDS
DIN m+1
DIN m+2
DIN m+3
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
ACTIVE
NOP
WRITE
NOP
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
A0-A9, A11
ROW
tAS tAH
A10
ROW
tAS tAH
BA0, BA1
BANK
COLUMN m(2)
BANK
tDS
DIN m
DQ
tRCD
52
tDH
tDH
tDS
tDH
tDS
tDH
DIN m-1
Full page completed
DON'T CARE
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01
ISSI
IS42S16400
®
WRITE - DQM OPERATIOON
T0
T1
T2
tCK
CLK
tCL
T3
T4
T5
T6
T7
NOP
NOP
NOP
NOP
NOP
tCH
tCKS tCKH
CKE
tCMS tCMH
COMMAND
ACTIVE
NOP
WRITE
tCMS tCMH
DQM/
DQML, DQMH
tAS tAH
COLUMN m(2)
A0-A9, A11
ROW
tAS tAH
A10
ROW
tAS tAH
DISABLE AUTO PRECHARGE
BANK
BANK
BA0, BA1
ENABLE AUTO PRECHARGE
tDS
tDH
DIN m
DQ
tRCD
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION
05/04/01
Rev. C
tDS tDH
tDS
tDH
DIN m+2
DIN m+3
DON'T CARE
53
ISSI
IS42S16400
®
ORDERING INFORMATION
Commercial Range: 0°° C to 70°° C
Frequency
Speed (ns)
Order Part No.
Package
166 MHz
6
IS42S16400-6T
400-mil TSOP II
133 MHz
7
IS42S16400-7T
400-mil TSOP II
100 MHz
10
IS42S16400-10T
400-mil TSOP II
Industrial Range: -40°°C to 85°° C
Frequency
Speed (ns)
Order Part No.
Package
133 MHz
7
IS42S16400-7TI
400-mil TSOP II
100 MHz
10
IS42S16400-10TI
400-mil TSOP II
ISSI
®
Integrated Silicon Solution, Inc.
2231 Lawson Lane
Santa Clara, CA 95054
Tel: 1-800-379-4774
Fax: (408) 588-0806
E-mail: [email protected]
www.issi.com
54
Integrated Silicon Solution, Inc. — 1-800-379-4774
TARGET SPECIFICATION Rev. C
05/04/01