• Refresh Mode: RAS-Only,CAS-before-RAS (CBR), and Hidden
• Single power supply:
5V±10% or 3.3V ± 10%
• Byte Write and Byte Read operation via two CAS
• Industrial temperature range -40°C to 85°C
PRODUCT SERIES OVERVIEW
Part No.RefreshVoltage
IS41C440522K5V ± 10%
IS41C440544K5V ± 10%
IS41LV440522K3.3V ± 10%
IS41LV440544K3.3V ± 10%
JUNE 2001
DESCRIPTION
The ISSI 4405x Series is a 4,194,304 x 4-bit high-performance
CMOS Dynamic Random Access Memory. The Fast
Page Mode allows 2,048 or 4096 random accesses within
a single row with access cycle time as short as 20 ns per
4-bit word.
These features make the 4405x Series ideally suited for
high-bandwidth graphics, digital signal processing,
high-performance computing systems, and peripheral
applications.
The 4405x Series is packaged in a 24-pin 300-mil SOJ
with JEDEC standard pinouts.
KEY TIMING PARAMETERS
Parameter-50-60Unit
RAS Access Time (tRAC)5060ns
CAS Access Time (tCAC)1315ns
Column Address Access Time (tAA)
Fast Page Mode Cycle Time (tPC)
Read/Write Cycle Time (tRC)84104ns
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Rev. C
06/24/01
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IS41C4405X
IS41LV4405X S ERIESISSI
®
Functional Description
The IS41C4405x and IS41LV4405x are CMOS DRAMs
optimized for high-speed
During READ or WRITE cycles, each bit is uniquely
addressed through the 11 or 12 address bits. These are
entered 11 bits (A0-A10) at a time for the 2K refresh
device or 12 bits (A0-A11) at a time for the 4K refresh
device. The row address is latched by the Row Address
Strobe (RAS). The column address is latched by the
Column Address Strobe (CAS). RAS is used to latch the
first nine bits and CAS is used the latter ten bits.
bandwidth, low power applications.
Memory Cycle
A memory cycle is initiated by bring RAS LOW and it is
terminated by returning both RAS and CAS HIGH. To
ensures proper device operation and data integrity any
memory cycle, once initiated, must not be ended or
aborted before the minimum tRAS time has expired. A new
cycle must not be initiated until the minimum precharge
time tRP, tCP has elapsed.
Read Cycle
A read cycle is initiated by the falling edge of CAS or OE,
whichever occurs last, while holding WE HIGH. The
column address must be held for a minimum time specified by tAR. Data Out becomes valid only when tRAC, tAA,
tCAC and tOEA are all satisfied. As a result, the access time
is dependent on the timing relationships between these
parameters.
Auto Refresh Cycle
To retain data, 2,048 refresh cycles are required in each
32 ms period, or 4,096 refresh cycles are required in each
64ms period. There are two ways to refresh the memory:
1. By clocking each of the 2,048 row addresses (A0
through A10) or 4096 row addresses (A0 through A11) with
RAS at least once every 32 ms or 64ms respectively.
Any read, write, read-modify-write or RAS-only cycle
refreshes the addressed row.
2.
Using a CAS-before-RAS refresh cycle. CAS-before-RAS
refresh is activated by the falling edge of RAS, while
holding CAS LOW. In CAS-before-RAS refresh cycle,
an internal 9-bit counter provides the row addresses
and the external address inputs are ignored.
CAS-before-RAS is a refresh-only mode and no data
access or device selection is allowed. Thus, the output
remains in the High-Z state during the cycle.
Power-On
After application of the VCC supply, an initial pause of
200 µs is required followed by a minimum of eight
initialization cycles (any combination of cycles containing
a RAS signal).
During power-on, it is recommended that RAS track with
VCC or be held at a valid VIH to avoid current surges.
Write Cycle
A write cycle is initiated by the falling edge of CAS and
WE, whichever occurs last. The input data must be valid
at or before the falling edge of CAS or WE, whichever
occurs last.
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Rev. C
06/24/01
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IS41C4405X
IS41LV4405X S ERIESISSI
®
ABSOLUTE MAXIMUM RATINGS
(1)
SymbolParametersRatingUnit
VTVoltage on Any Pin Relative to GND5V–1.0 to +7.0V
3.3V–0.5 to +4.6
CCSupply Voltage5V–1.0 to +7.0V
V
3.3V–0.5 to +4.6
IOUTOutput Current50mA
PDPower Dissipation1W
ACommercial Operation Temperature0 to +70°C
T
Industrial Operation Temperature-40 to +85
TSTGStorage Temperature–55 to +125°C
Note:
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.
RECOMMENDED OPERATING CONDITIONS (Voltages are referenced to GND.)
1. An initial pause of 200 µs is required after power-up followed by eight RAS refresh cycles (RAS-Only or CBR) before proper device
operation is assured. The eight RAS cycles wake-up should be repeated any time the t
2. Dependent on cycle rates.
3. Specified values are obtained with minimum cycle time and the output open.
4. Column-address is changed once each Fast Page cycle.
5. Enables on-chip refresh and address counters.
REF refresh requirement is exceeded.
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tCASCAS Pulse Width
tCPCAS Precharge Time
tCSHCAS Hold Time
tRCDRAS to CAS Delay Time
tASRRow-Address Setup Time0—0—ns
tRAHRow-Address Hold Time8—10—ns
(20)
(20)
0—0—ns
8—10—ns
tASCColumn-Address Setup Time
tCAHColumn-Address Hold Time
tARColumn-Address Hold Time30—40—ns
(referenced to RAS)
tRADRAS to Column-Address Delay Time
(11)
10251230ns
tRALColumn-Address to RAS Lead Time25—30—ns
tRPCRAS to CAS Precharge Time5—5—ns
tRSHRAS Hold Time8—10—ns
tRHCPRAS Hold Time from CAS Precharge30—35—ns
(19, 24)
(15, 16)
(15, 24)
(21)
0—0—ns
5—5—ns
315315ns
—12—15ns
tCLZCAS to Output in Low-Z
tCRPCAS to RAS Precharge Time
tODOutput Disable Time
tOEOutput Enable Time
tOEDOutput Enable Data Delay (Write)12—15—ns
tOEHCOE HIGH Hold Time from CAS HIGH5—5—ns
tOEPOE HIGH Pulse Width10—10—ns
tOESOE LOW to CAS HIGH Setup Time5—5—ns
tRCSRead Command Setup Time
(17, 20)
0—0—ns
tRRHRead Command Hold Time0—0—ns
(referenced to RAS)
(12)
tRCHRead Command Hold Time0—0—ns
(referenced to CAS)
tWCHWrite Command Hold Time
(12, 17, 21)
(17)
8—10—ns
tWCRWrite Command Hold Time40—50—ns
(referenced to RAS)
tWPWrite Command Pulse Width
(17)
(17)
8—10—ns
tWPZWE Pulse Widths to Disable Outputs7—7—ns
6
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Integrated Silicon Solution, Inc. — 1-800-379-4774
Rev. C
06/24/01
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IS41C4405X
IS41LV4405X S ERIESISSI
Notes:
1. An initial pause of 200 µs is required after power-up followed by eight RAS refresh cycle (RAS-Only or CBR) before proper device
operation is assured. The eight RAS cycles wake-up should be repeated any time the t
IH (MIN) and VIL (MAX) are reference levels for measuring timing of input signals. Transition times, are measured between VIH and
2. V
IL (or between VIL and VIH) and assume to be 1 ns for all inputs.
V
3. In addition to meeting the transition rate specification, all input signals must transit between V
monotonic manner.
4. If CAS and RAS = V
5. If CAS = V
IL, data output may contain data from the last valid READ cycle.
IH, data output is High-Z.
6. Measured with a load equivalent to one TTL gate and 50 pF.
7. Assumes that t
amount that t
8. Assumes that t
RCD - tRCD (MAX). If tRCD is greater than the maximum recommended value shown in this table, tRAC will increase by the
RCD exceeds the value shown.
RCD• tRCD (MAX).
9. If CAS is LOW at the falling edge of RAS, data out will be maintained from the previous cycle. To initiate a new cycle and clear the data
output buffer, CAS and RAS must be pulsed for t
10. Operation with the t
greater than the specified t
11. Operation within the t
greater than the specified t
12. Either t
13. t
RCH or tRRH must be satisfied for a READ cycle.
OFF (MAX) defines the time at which the output achieves the open circuit condition; it is not a reference to VOH or VOL.
RCD (MAX) limit ensures that tRAC (MAX) can be met. tRCD (MAX) is specified as a reference point only; if tRCD is
RCD (MAX) limit, access time is controlled exclusively by tCAC.
RAD (MAX) limit ensures that tRCD (MAX) can be met. tRAD (MAX) is specified as a reference point only; if tRAD is
RAD (MAX) limit, access time is controlled exclusively by tAA.
CP.
14. tWCS, tRWD, tAWD and tCWD are restrictive operating parameters in LATE WRITE and READ-MODIFY-WRITE cycle only. If tWCS• t WCS
(MIN), the cycle is an EARLY WRITE cycle and the data output will remain open circuit throughout the entire cycle. If tRWD• t RWD (MIN),
AWD• t AWD (MIN) and tCWD• t CWD (MIN), the cycle is a READ-WRITE cycle and the data output will contain data read from the selected
t
cell. If neither of the above conditions is met, the state of I/O (at access time and until CAS and RAS or OE go back to VIH) is
indeterminate. OE held HIGH and WE taken LOW after CAS goes LOW result in a LATE WRITE (OE-controlled) cycle.
15. Output parameter (I/O) is referenced to corresponding CAS input.
16. During a READ cycle, if OE is LOW then taken HIGH before CAS goes HIGH, I/O goes open. If OE is tied permanently LOW, a LATE
WRITE or READ-MODIFY-WRITE is not possible.
17. Write command is defined as WE going low.
18. LATE WRITE and READ-MODIFY-WRITE cycles must have both t
OD and tOEH met (OE HIGH during WRITE cycle) in order to ensure
that the output buffers will be open during the WRITE cycle. The I/Os will provide the previously written data if CAS remains LOW and
OE is taken back to LOW after t
OEH is met.
19. The I/Os are in open during READ cycles once tOD or tOFF occur.
20. Determined by falling edge of CAS.
21. Determined by rising edge of CAS.
22. These parameters are referenced to CAS leading edge in EARLY WRITE cycles and WE leading edge in LATE WRITE or
READ-MODIFY-WRITE cycles.
23. CAS must meet minimum pulse width.
24. The 3 ns minimum is a parameter guaranteed by design.
25. Enables on-chip refresh and address counters.
REF refresh requirement is exceeded.
IH and VIL (or between VIL and VIH) in a
®
8
Integrated Silicon Solution, Inc. — 1-800-379-4774
Rev. C
06/24/01
Page 9
IS41C4405X
IS41LV4405X S ERIESISSI
FAST-PAGE-MODE READ CYCLE
t
RC
t
RAS
CAS
t
CRP
t
ASR
t
RAH
t
RAD
t
RCD
t
ASC
t
AR
RAS
t
CSH
t
CAS
t
RAL
t
RSH
t
CLCH
t
CAH
t
RRH
t
RP
®
ADDRESS
WE
I/O
OE
RowColumnRow
t
t
RCS
t
AA
t
RAC
t
CAC
t
CLC
OpenOpen
t
OE
t
OES
Valid Data
RCH
t
OFF
t
(1)
OD
Don’t Care
Integrated Silicon Solution, Inc. — 1-800-379-4774
Rev. C
06/24/01
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IS41C4405X
IS41LV4405X S ERIESISSI
FAST PAGE MODE READ-MODIFY-WRITE CYCLE
t
RAS
CAS
ADDRESS
WE
t
CRP
t
ASR
t
RAH
Row
t
RAD
t
RCS
t
RCD
t
AR
t
CSH
t
ASC
Column
t
RWD
t
AWD
t
CWD
t
CAS
t
CAH
t
CWL
RASP
t
t
PRWC
t
CAS
t
CP
t
CPWD
t
t
AWD
t
CWD
CAH
t
CWL
t
WP
t
ASC
t
AR
ColumnColumn
t
WP
RSH
t
CAS
t
t
t
CWL
t
RWL
CRP
CAH
t
CP
t
CPWD
t
RAL
t
ASC
t
AWD
t
CWD
t
WP
t
RP
®
OE
I/O
t
RAC
t
CLZ
t
CAC
t
t
t
CLZ
CAC
t
DH
AA
OUT
t
OEA
t
OEZ
t
OED
t
AA
t
CAC
t
OEA
t
OEZ
t
t
DH
t
t
DS
CLZ
OUT
OED
t
DH
t
DS
t
AA
t
OEA
t
OEZ
t
OED
t
DS
OUTINININ
Don’t Care
10
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Rev. C
06/24/01
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IS41C4405X
IS41LV4405X S ERIESISSI
FAST-PAGE-MODE EARLY WRITE CYCLE (OE = DON'T CARE)
tRC
RAS
CAS
tCRP
tRAS
tCSH
tRCD
tAR
tRADtRAL
tRAHtASR
tASC
tCAS
tCAH
tACH
tRSH
tCLCH
tRP
®
ADDRESS
WE
I/O
RowColumnRow
tCWL
tRWL
tWCR
tWCS
tDHR
tDS
tWCH
tWP
tDH
Valid Data
Don’t Care
Integrated Silicon Solution, Inc. — 1-800-379-4774
Rev. C
06/24/01
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IS41C4405X
IS41LV4405X S ERIESISSI
FAST-PAGE-MODE READ WRITE CYCLE (LATE WRITE and READ-MODIFY-WRITE Cycles)
t
RWC
t
RAS
CAS
t
CRP
t
ASR
t
RAH
t
RAD
t
RCD
t
ASC
t
AR
t
CSH
RAS
t
CAH
t
CAS
t
RSH
t
t
t
RAL
ACH
CLCH
t
RP
®
ADDRESS
WE
I/O
OE
RowColumnRow
t
RWD
t
t
RCS
t
AA
t
RAC
t
CAC
t
CLZ
OpenOpen
t
OE
CWD
t
AWD
Valid D
t
OD
t
OUT
DS
Valid D
IN
t
CWL
t
RWL
t
WP
t
DH
t
OEH
Don’t Care
12
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Rev. C
06/24/01
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IS41C4405X
IS41LV4405X S ERIESISSI
FAST PAGE MODE EARLY WRITE CYCLE
t
RAS
CAS
ADDRESS
t
CRP
t
ASR
t
RAH
Row
t
RAD
t
RCD
t
AR
t
CSH
t
ASC
Column
t
CAS
t
CAH
t
AR
RASP
t
PC
t
CAS
t
CP
t
ASC
t
CAH
t
CP
ColumnColumn
t
ASC
t
RHCP
t
RSH
t
CAS
t
RAL
t
CAH
t
CRP
t
RP
®
WE
OE
I/O
t
WCS
t
DS
t
WCR
t
DHR
t
WP
Valid DIN
t
CWL
t
WCH
t
DH
t
WCS
t
DS
t
CWL
t
WCS
t
WCH
t
WP
t
DH
t
DS
t
WP
Valid DINValid DIN
t
CWL
t
WCH
t
DH
Don’t Care
Integrated Silicon Solution, Inc. — 1-800-379-4774
Rev. C
06/24/01
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IS41C4405X
IS41LV4405X S ERIESISSI
AC WAVEFORMS
®
READ CYCLE
RAS
CAS
ADDRESS
WE
I/O
(With WE-Controlled Disable)
tCRP
tRAD
tRAHtASR
RowColumn
OpenOpen
tCSH
tRCDtCP
tAR
tASC
tAA
tRAC
tCAC
tCLZ
tCAS
tCAHtASC
tRCHtRCStRCS
tWHZ
Valid Data
tOEtOD
Column
tCLZ
OE
RAS-ONLY REFRESH CYCLE (OE, WE = DON'T CARE)
t
RAS
RAS
t
CRP
CAS
t
RAH
ADDRESS
I/O
t
ASR
RowRow
Open
t
RC
t
RPC
t
Don’t Care
RP
14
Don’t Care
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