The device is CMOS Synchronous Dynamic RAM organized as 8,388,608 - word x 4 -bit x 4 - bank,
4,194,304 - word x 8 - bit x 4 - bank, or 2,097,152 - word x 16 - bit x 4 - bank. These various organizations
provide wide choice for different applications. It is designed with the state-of-the-art technology to meet standard PC100 or high speed PC133 requirement. Four internal independent banks greatly increase the performance efficiency. It is packaged in JEDEC standard pinout and standard plastic 54-pin TSOP package.
Features
• Single 3.3V () power supply
• High speed clock cycle time : 7.5ns/10ns
• Fully synchronous with all signals referenced to a positive clock edge
Voltage on any pin relative to VssVIN, V
Supply voltage relative to VssVDD, V
Short circuit output currentI
Power dissipationP
Operating temperatureT
Storage temperatureT
Caution: Exposing the device to stress above those listed in Absolute Maximum Ratings could cause permanent
damage. The device is not meant to be operated under conditions outside the limits described in the
operational section of this specification. Exposure to Absolute Maximum Rating conditions for extended
periods may affect device reliability.
Maximum A.C. Operating Requirements for LVTTL Compatible
Input High VoltageV
Input Low VoltageV
CMOS Synchronous Dynamic RAM
ParameterSymbolValueUnit
OUT
DDQ
OUT
D
OPT
STG
ParameterSymbolMinMaxUnitNotes
IH
IL
2.0V
-0.30.8V2
-0.5 to + 4.6V
-0.5 to + 4.6V
50mA
1.0W
0 to + 70
-55 to + 125
+ 0.3V1
DD
¢J
¢J
Note: 1. Overshoot limit: VIH(max)=V
2. Undershoot limit: VIL(min)=V
+2.0V with a pulse with
DDQ
-2.0V with a pulse with and -1.5v with a pulse
SSQ
3ns
3ns
Recommended DC Operating Conditions for LVTTL Compatible
ParameterSymbolMinTypMaxUnit
Supply Voltage V
Input High Voltage, all inputsV
Input Low Voltage, all inputsV
Capacitance
(Ta=25°C, f = 1MHZ)
ParameterSymbolMinMaxUnitNotes
Input capacitance (CLK)C
Input capacitance (all input pins except data
pins.)
Data input/output capacitanceC
Notes : 1. Capacitance measured with effective capacitance measuring method.
DD, VDDQ
IH
IL
11
C
12
I/O
3.03.33.6V
2.0
-0.3
2.54pF1
2.55pF1
4.06.5pF1
¡Ð¡Ð
5ns
V
+ 0.3V
DD
0.8V
Document : 1G5-0154 Rev.1 Page 4
Page 5
VG36128401A
≥
≤
≤∞≥≥≥∞≤≤≤∞≥
≥
≥
∞
≤
≥
≤
≥
≤
≥
≤
Preliminary VG36128801A
VG36128161A
VIS
DC Characteristics (Recommended Operating Conditions unless otherwise noted)
Parameter SymbolTest Conditions
Operating current
Precharge standby
current in Power
down mode
Precharge standby
current in Nonpower
down mode
Active standby current
in Power
down mode
Active standby
current in Nonpower
down mode
Operating current
(Burst mode)
Refresh currentI
Self refresh CurrentI
Input Ieakage current
(Inputs)
Intput leakage current
(I/O pins)
Output Low VoltageV
Output High VoltageV
CMOS Synchronous Dynamic RAM
-75-8HUnitNotes
MinMaxMinMax
I
CC1
I
CC2P
I
CC2PS
I
CC2N
I
CC2NS
I
CC3P
I
CC3PS
I
CC3N
I
CC3NS
I
CC4
CC5
CC6
Burst length = 1
One bank active
tRCt
RC(MIN.)
CKEV
CKEV
CKEV
CSV
, Io = 0mA
IL(MAX.) tCK
IL(MAX.) tCK
IH(MIN.) tCK
IH(MIN.)
Input signals are changed one
time during 2 CLK cycles.
CKEV
CLKV
IH(MIN.) tCK
IL(MAX.)
Input signals are stable.
CKEV
CKEV
CKEV
CSV
IL(MAX.) tCK
IL(MAX.) tCK
IH(MIN.) tCK
IH(MIN.)
Input signals are changed one
time during 2CLKs
CKEV
CLKV
IH(MIN.) tCK
IL(MAX.)
Input signals are stable.
t
CKtCK(MIN.)
Io = 0mA
All banks Active
tRC = 4 x t
RC(MIN)
CKE 0.2V
l
LI
VIN0, V
INVDD(MAX.)
Pins not under test = 0V
l
LO
V
DQ# in H - Z., Dout Disabled
OLIOL
OHIOH
0, V
OUT
OUTVDD(MAX.)
= 2mA0.40.4V4
= -2mA2.42.4V4
x4120100mA1
x 8125105
x16135115
= min.
=
= min.
=
= min.
=
= min.
=
x4115105
x 8130120mA2
x16160150
-11-11uA
-1.51.5-1.51.5uA
22mA
22
2020mA
77
77mA
55
3030mA
2020
190190mA3
11mA
Notes : 1. I
Document : 1G5-0154 Rev.1 Page 5
depends on output loading and cycle rates. Specified values are obtained with the output open.
CC1
In addition to this, I
2. I
depends on output loading and cycle rates. Specified values are obtained with the output open.
CC4
In addition to this, I
3. I
is measured on condition that addresses are changed only one time during t
CC5
4. For LVTTL compatible.
is measured on condition that addresses are changed only one time during t
CC1
is measured on condition that addresses are changed only one time during t
CC4
CK(MIN.)
.
CK(MIN.)
.
CK(MIN.)
.
Page 6
VIS
±
VG36128401A
Preliminary VG36128801A
VG36128161A
CMOS Synchronous Dynamic RAM
AC Characteristics : (Ta = 0 to 70°C V
Test Conditions for LVTTL Compatible :
AC input Levels (VIH/VIL)2.0/0.8VInput timing reference level/
Input rise and fall time1nsOutput load condition50pF
AC Test Load Circuits (for LVTTL interface) :
V
DDQ
Device
Under
Test
V
V
DDQ
OUT
= 3.3V 0.3V ,V
DD
Z = 50
= 0V)
SS
Output timing reference level
Ω
1.4V
50PF
Document : 1G5-0154 Rev.1 Page 6
Page 7
VG36128401A
±
Preliminary VG36128801A
VG36128161A
VIS
AC Characteristics : (Ta = 0 to 70°C VDD = 3.3V0.3V, VSS = 0V)
symbolA.C. Parameter-75-8H
t
RC
t
RCD
t
RP
t
RRD
t
RAS
t
CK2
t
CK3
t
CH
t
CL
t
AC2
t
AC3
t
T
t
CCD
t
OH
t
LZ
t
HZ2
t
HZ3
t
IS
t
IH
t
SRX
t
PDE
t
RSC
t
DPL
t
DAL2
t
DAL3
t
BDL
t
REF
Row cycle time6070
RAS to CAS delay2020
Precharge to refresh/row activate command1520
Row activate to row activate delay1520
Row activate to precharge time 37.5100,00050100,000
Clock cycle time
Clock high time2.253
Clock low time2.253
Access time from CLK
(positive edge)
Transition time of CLK (Rise and Fall)110110
CAS to CAS Delay time11CLK
Data output hold time2.53
Data output low impedance00
Data output high impedance
Data/Address/Control Input setup time12
Data/Address/Control Input hold time0.51
Minimum CKE ”High”for Self-Refresh exit11CLK
Power Down Exit set-up time22ns
Mode Register Set Cycle22CLK
Data-in to precharge21CLK
Data-in to ACT (REF) Command CL22clk+t
Last data in to burst stop11CLK
Refresh time6464ms
CMOS Synchronous Dynamic RAM
Min.Max.Min.Max.
CL27.510
CL37.510
CL256
CL356
CL246
CL346
RP
CL32clk+t
RP
1clk+t
1clk+t
RP
RP
unitnote
ns
ns
ns
ns
9
Document : 1G5-0154 Rev.1 Page 7
Page 8
VG36128401A
Preliminary VG36128801A
VG36128161A
VIS
Basic Features and Function Description
1.Simplified State Diagram
CMOS Synchronous Dynamic RAM
Mode
Register
Set
MRS
IDLE
Self
Refresh
y
r
t
n
e
F
L
t
E
S
ACT
i
x
e
F
L
E
S
C
K
REF
C
K
E
E
AUTO
Refresh
WRITE
SUSPEND
WRITEA
SUSPEND
Write (Write recovery)
CKE
CKE
Auto Precharge
CKE
Write with
CKE
WRITE
WRITEA
Power
Down
B
S
T
READ
READA
Active
Power
Down
Read
CKE
CKE
Read with
Auto Precharge
CKE
CKE
READ
SUSPEND
READA
SUSPEND
ROW
ACTIVE
T
S
B
e
t
i
r
W
r
e
t
i
r
W
Read (write recovery)
A
u
P
R
E
(
P
h
e
t
i
g
r
w
y
a
r
h
e
e
t
v
i
o
r
c
e
W
o
t
u
A
R
e
a
d
w
t
o
P
r
e
c
h
r
e
c
h
a
r
g
e
t
e
r
m
i
n
a
PRE
c
e
r
p
Write
i
t
h
a
r
g
e
A
(
w
r
i
t
t
i
o
n
)
CKE
CKE
R
A
R
u
t
o
P
r
a
e
R
o
t
u
e
r
e
c
r
P
(
E
R
P
e
a
e
a
d
e
c
h
a
d
P
o
v
a
h
c
e
d
w
i
t
h
r
g
e
h
t
e
i
g
w
r
a
h
c
e
r
e
r
y
)
)
n
o
i
t
a
n
i
m
r
e
t
e
g
r
POWER
ON
Precharge
Precharge
Automatic sequence
Manual input
Note: After the AUTO refresh operation, precharge operation is
performed automatically and enter the IDLE state.
Document : 1G5-0154 Rev.1 Page 8
Page 9
VG36128401A
Preliminary VG36128801A
VG36128161A
VIS
2. Truth Table
2.1 Command Truth Table
FUNCTIONSymbol
Device deselectDESLHXHXXXXXX
No operationNOPHXLHHHXXX
Mode register setMRSHXLLLLLLV
Bank activate ACTHXLLHHVVV
ReadREADHXLHLHVLV
Read with auto prechargeREADAHXLHLHVHV
WriteWRITHXLHLLVLV
Write with auto prechargeWRITAHXLHLLVHV
Precharge select bankPREHXLLHLVLX
Precharge all banksPALLHXLLHLXHX
Burst stopBSTHXLHHLXXX
CBR (Auto) refreshREFHHLLLHXXX
Self refreshSELFHLLLLHXXX
IdlePower down entryHLXXXXX
Power downPower down exitLHXXXXX
n -1n -1UL
CKE
CSRASCASWE
LHHXXXX
Add -
ressn - 1n
H : High level, L : Low level
X : High or Low level (Don’t care), V : Valid Data input
Document : 1G5-0154 Rev.1 Page 9
Page 10
VG36128401A
→→→
→→→
Preliminary VG36128801A
VG36128161A
VIS
2.4 Operative Command Table Notes 1
Current
state
IdleHXXXXDESLNop or Power down2
Row activeHXXXXDESLNop
ReadHXXXXDESL
WriteHXXXXDESL
CMOS Synchronous Dynamic RAM
(1/3)
CS RAS CAS WEAddressCommandActionNotes
LHHXXNOP or BSTNop or Power down2
LHLHBA, CA, A10 READ/READA ILLEGAL3
LHLLBA, CA, A10 WRIT/WRITA ILLEGAL3
LLHHBR, RAACTRow active
LLHLBA, A10PRE/PALLNop
LLLHXREF/SELFRefresh or Self refresh4
LLLLOp - CodeMPSMode register access
LHHXXNOP or BSTNop
LHLHBA, CA, A10 READ/READA Begin read : Determine AP5
LHLLBA, CA, A10 WRIT/WRITA Begin write : Determine AP5
LLHHBA, RAACTILLEGAL3
LLHLBA, A10PRE/PALLPrecharge6
LLLHXREF/SELFILLEGAL
LLLLOp - CodeMRSILLEGAL
Continue burst to end Row active
LHHHXNOP
LHHLXBST
LHLHBA, CA, A10 READ/READA Term burst, new read : Determine AP7
LHLLBA, CA, A10 WRIT/WRITA Term burst, start write : Determine AP7,8
LLHHBA, RAACTILLEGAL3
LLHLBA, A10PRE/PALLTerm burst, precharging
LLLHXREF/SELFILLEGAL
LLLLOp - CodeMRSILLEGAL
LHHHXNOP
LHHLXBST
LHLHBA, CA, A10 READ/READA Term burst, start read : determine AP7,8
LHLLBA, CA, A10 WRIT/WRITA Term burst, new write : Determine AP7
LLHHBA, RAACTILLEGAL3
LLHLBA, A10PRE/PALLTerm burst, precharging9
LLLHXREF/SELFILLEGAL
LLLLOp - CodeMRSILLEGAL
Continue burst to end Row active
Burst end Row active
Continue burst to end Write recovering
Continue burst to end Write recovering
Burst stop Row active
Document : 1G5-0154 Rev.1 Page 10
Page 11
VG36128401A
→
→→→
→→→
→→→
→
Preliminary VG36128801A
VG36128161A
VIS
Current stateCS RAS CAWEAddressCommandActionNotes
Read with auto
precharge
Write with auto
precharge
prechargingHXXXXDESL
Row activatingHXXXXDESL
CMOS Synchronous Dynamic RAM
HXXXXDESL
LHHHXNOP
LHHLXBSTIllegal for single bank, but legal for
LHLHBA, CA, A10 READ/READA Illegal for single bank, but legal for
LHLLBA, CA, A10 WRIT/WRITAILLEGAL
LLHHBA, RAACTILLEGAL3
Nop Enter row active after t
Nop Enter row active after t
Nop Enter row active after t
Nop Enter precharge after t
Nop Enter precharge after t
Nop Enter precharge after t
RC
RC
Nop Enter idle after 2 Clocks
Nop Enter idle after 2 Clocks
ILLEGAL
DPL
DPL
DPL
DPL
DPL
DPL
Note 1. All entries assume that CKE was active (High level) during the preceding clock cycle.
2. If both banks are idle, and CKE is inactive (Low level), the device will enter Power down mode.
All input buffers except CKE will be disabled.
3. Illegal to bank in specified states; Function may be legal in the bank indicated by Bank Address (BA),
depending on the state of that bank.
4. If both banks are idle, and CKE is inactive (Low level), the device will enter Self refresh mode.
All input buffers except CKE will be disabled.
5. Illegal if t
6. Illegal if t
7. Must satisfy burst interrupt condition.
8. Must satisfy bus contention, bus turn around, and/or write recovery requirements.
9. Must mask preceding data which don’t satisfy t
10. Illegal if t
11. Illegal for single bank, but for multibanks interleave
Document : 1G5-0154 Rev.1 Page 12
is not satisfied.
RCD
is not satisfied.
RAS
is not satisfied.
RRD
DPL
.
Page 13
VIS
→
VG36128401A
Preliminary VG36128801A
VG36128161A
CMOS Synchronous Dynamic RAM
2.5 Command Truth Table for CKE
CKE
Current state
Self refresh
(S.R.)
Self refresh
recovery
Power down
(P.D.)
Both banks idle
Any state other
than listed above
Note 1. H : Hight level, L : low level, X : High or low level (Don't care)
2. CKE Low to High transition will re-enable CLK and other inputs asynchronously. A minimum setup time
must be satisfied before any command other than EXIT.
3. Power down and Self refresh can be entered only from the both banks idle state.
4. Must be legal command as defined in Operative Command Table.
Full page burst is an extension of the above tables of Sequential Addressing, with the length being 2048 /
1024 / 512 for 32M x 4 / 16M x 8 / 8M X16 devices, respectively.
Sequential Addressing
Sequence (decimal)
Interleave Addressing Sequence (decimal)
Document : 1G5-0154 Rev.1 Page 15
Page 16
VG36128401A
Preliminary VG36128801A
VG36128161A
VIS
6 Address Bits of Bank-Select and precharge
6.1 Quad banks controlled by A12 & A13
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13
Row
(Activate command)
CMOS Synchronous Dynamic RAM
A12A13Result
00
01
10
11
Select Bank A
“Activate “ command
Select Bank B
“Activate” command
Select Bank C
“Activate” command
Select Bank D
“Activate” command
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13
Row
(Precharge command)
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13
Col.
(CAS strobes)
A10 A12 A13 Result
000Precharge Bank A
001Precharge Bank B
010Precharge Bank C
011Precharge Bank D
1XXPrecharge All Banks
0Disables Auto - Precharge (End of Burst)
1Enables Auto - Precharge (End of Burst)
A12A13Result
00
01
10
11
Enables Read/Write
commands for Bank A
Enables Read/Write
commands for Bank B
Enables Read/Write
commands for Bank C
Enables Read/Write
commands for Bank D
Document : 1G5-0154 Rev.1 Page 16
Page 17
VIS
7.Precharge
VG36128401A
Preliminary VG36128801A
VG36128161A
CMOS Synchronous Dynamic RAM
The precharge command can be asserted anytime after t
Soon after the precharge command is asserted, the precharge operation is performed and the synchronous DRAM
enters the idle state after t
The earliest timing in a read cycle that a precharge command can be asserted without losing any data in the burst is
as follows.
PrechargeE
CLK
Command
CAS latency = 2
DQ
is satisfied. The parameter tRP is the time required to perform the precharge.
RP(min.)
T0T1
Read
RAS(min)
T2
Q0
is satisfied.
T3
Q1
T4T5
PRE
T6
Q3Q2
Burst lengh=4
T7
Hi - Z
Command
CAS latency = 3
DQ
CAS latency = 2 : One clock earlier than the last output data.
3 : Two clocks earlier than the last output data.
In order to write all data to the memory cell correctly, the asynchronous parameter ”t
fied. The t
minimum number of clocks can be calculated by dividing t
last data word is valid. In the following table, minus means clocks before the reference; plus means time
after the reference.
DPL(min.)
In summary, the precharge command can be asserted relative to the reference clock that indicates the
specification defines the earliest time that a precharge command can be asserted. The
CAS latencyReadWrite
Read
Q0
DPL(min.)
2-1+ t
3-2+ t
by the clock cycle time.
DPL(min.)
DPL(min.)
PRE
Q1
Q2
” must be satis-
DPL
(t
Q3
RAS
is satisfied)
Hi - Z
Document : 1G5-0154 Rev.1 Page 17
Page 18
VG36128401A
Preliminary VG36128801A
VG36128161A
VIS
8.Auto Precharge
During a read or write command cycle, A10 controls whether auto precharge is selected. If A10 is high
in the read or write command (Read with Auto precharge command or Write with Auto precharge command), auto precharge is selected and begins automatically after the burst access.
In the write cycle, t
being precharged.
When using auto precharge in the read cycle, knowing when the precharge starts is important because
the next activate command to the bank being precharged cannot be executed until the precharge cycle
ends. Once auto precharge has started, an activate command to the bank can be asserted after tRP has
been satisfied.
A Read or Write command without auto - precharge can be terminated in the midst of a burst operation.
However, a Read or Write command with auto - precharge can not be interrupted by the same bank commands before the entire burst operation is completed. Therefore use of the same bank Read, Write, Precharge or Burst Stop command is prohibited during a read or write cycle with auto - precharge. It should be
noted that the device will not respond to the Auto - Precharge command if the device is programmed for full
page burst read or write cycles.
The timing when the auto precharge cycle begins depends both on both the CAS Iatency programmed
into the mode register and whether the cycle is read or write.
CMOS Synchronous Dynamic RAM
DAL(min.)
must be satisfied before asserting the next activate command to the bank
8.1 Read with Auto Precharge
During a READA cycle, the auto precharge begins one clock earlier (CL = 2) or two clocks earlier
(CL = 3) than the last word output.
READ with AUTO PRECHARGE
T0T1
CLK
Command
CAS latency = 2
DQ
Command
READA B
READA B
QB0
T3
QB1
T2
No New Command to Bank B
No New Command to Bank B
T4
Auto precharge starts
Auto precharge starts
T5
QB3QB2
T6
Burst lengh = 4
T7
Hi - Z
T8
CAS latency = 3
DQ
Remark READA means READ with AUTO PRECHARGE
Document : 1G5-0154 Rev.1 Page 18
QB0
QB1
QB2
QB3
Hi - Z
Page 19
VG36128401A
Preliminary VG36128801A
VG36128161A
VIS
8.2 Write with Auto Precharge
During a write cycle, the auto precharge starts at the timing that is equal to the value of t
after the last data word input to the device.
WRITE with AUTO PRECHRGE
CLK
Command
CAS latency = 2
CMOS Synchronous Dynamic RAM
T0T1
WRITA B
T2
No New Command to Bank B
T3
T4T5
AUTO PRECHARGE starts
t
DPL
T6
DPL(min.)
Burst lengh = 4
T7
T8
DQ
Command
CAS latency = 3
DQ
Remark WRITA means WRITE with AUTO Precharge
DB0
WRITA B
DB0
DB1
No New Command to Bank B
DB1
DB2
DB3DB2
AUTO PRECHARGE starts
t
DPL
DB3
In summary, the auto precharge cycle begins relative to a reference clock that indicates the last data
word is valid.
In the table below, minus means clocks before the reference; plus means clocks after the reference.
CAS latencyReadWrite
2-1+ t
3-2+ t
DPL(min.)
DPL(min.)
Hi - Z_
Hi - Z
Document : 1G5-0154 Rev.1 Page 19
Page 20
VG36128401A
Preliminary VG36128801A
VG36128161A
VIS
8.3 Multibank Operation- Read with Auto Precharge
During a READA cycle interrupted by a Read, Write command of another banks, the auto-pre-
charge scheduled time would not be changed.
Multibank Operation
CLK
Command
CAS latency=2
CMOS Synchronous Dynamic RAM
T0 T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14
READA ARead B
Burst lengh=8
Auto precharge bank A starts
DQ
Command
CAS latency=3
DQ
READA A
QA0QA1
Read B
QA0
QB0
QA1
QB0
Similiar top.21
QB2 QB3 QB4 QB5 QB6 QB7 QB1
Auto precharge bank A starts
QB2 QB3 QB4 QB5 QB6 QB7 QB1
Hi-Z
Hi-Z
Document : 1G5-0154 Rev.1 Page 20
Page 21
VG36128401A
Preliminary VG36128801A
VG36128161A
VIS
8.4 Multibank Operation- Write with Auto Precharge
During a WRITEA cycle interrupted by a Read, Write command of another banks, the auto-pre-
charge scheduled time would not be changed.
Multibank Operation
CLK
Command
CAS latency=2
CMOS Synchronous Dynamic RAM
T0 T1 T2 T3 T4 T5 T6 T7 T8 T9 T10
WRITA A
Burst lengh=8
Auto precharge bank A starts
Read B
DQ
Command
CAS latency=3
DQ
Multibank Operation
T0 T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11
CLK
Command
CAS latency=2
DQ
DA1
DA1
DA1
DB0
DA0
WRITA A
DA0
WRITA AWrite B
DA0
Read B
DB1
DB2
DB0
DB3
DB1
DB0
DB4
DB2DB3
DB1
Auto precharge bank A starts
DB6
DB5
DB4
Auto precharge bank A starts
DB2
DB3
DB7
DB5
DB4
Burst lengh=8
Hi-Z
Hi-Z
Hi-Z
Auto precharge bank A starts
Command
CAS latency=3
DQ
WRITA AWrite B
DA0
DA1
DB0
DB1
DB2
DB3
DB4
DB5DB6DB7
Document : 1G5-0154 Rev.1 Page 21
Hi-Z
Page 22
VG36128401A
Preliminary VG36128801A
VG36128161A
VIS
9.Read/Write Command Interval
9.1 Read to Read command interval
During a read cycle when a new read command is asserted, it will be effective after the CAS latency,
even if the previous read operation has not completed. READ will be interrupted by another READ.
Each read command can be asserted in every clock without any restriction.
READ to READ Command Interval
CLK
CMOS Synchronous Dynamic RAM
T0T1
Burst lengh=4, CAS latency=2
T2
T3
T4T5
T6
T7
T8
1 cycle
Read B
QA0
QB0
QB2QB1
Command
DQ
Read A
9.2 Write to Write Command Interval
During a write cycle, when a new Write command is asserted, the previous burst will terminated and the
new burst will begin with a new write command. WRITE will be interrupted by another WRITE.
Each write command can be asserted in every clock without any restriction.
WRITE to WRITE Command Interval
T0T1
T2
T3
T4T5
QB3
Burst lengh=4, CAS latency=2
T6
Hi-Z_
T7
T8
CLK
1 cycle
Write B
QB0
QB2QB1
QB3
Hi-Z_
Command
DQ
Write A
QA0
Document : 1G5-0154 Rev.1 Page 22
Page 23
VG36128401A
Preliminary VG36128801A
VG36128161A
VIS
9.3 Write to Read Command Interval
The write command to read command interval is also a minimum of 1 cycle. Only the write data before
the read command will be written. The data bus must be Hi-Z at least one cycle prior to the first D
WRITE to READ Command Interval
CLK
CMOS Synchronous Dynamic RAM
T0T1
1 cycle
.
OUT
Burst lengh=4
T2
T3
T4T5
T6
T7
T8
Command
CAS latency=2
DQ
Command
CAS latency=3
DQ
WRITE A
DA0
Write A
DA0
Read B
Read B
9.4 Read to Write Command Interval
During a read cycle, READ can be interrupted by WRITE.
DQM must be in High at least 3 clocks prior to the write command. There is a restriction to avoid a data
conflict. The data bus must be Hi-Z using DQM before Write.
Hi-Z
Hi-Z
QB0
QB1
QB0
QB1
QB3QB2
QB2
QB3
Document : 1G5-0154 Rev.1 Page 23
Page 24
VG36128401A
Preliminary VG36128801A
VG36128161A
VIS
READ to WRITE Command Interval
CMOS Synchronous Dynamic RAM
CLK
Command
DQM
DQ
CLK
Command
T0T1
Hi-Z
T0T1
Read
Read
1 cycle
T2
D0
Write
CAS latency=2
T7
T8
T8
T9
D1
T3
T4T5
T4T5
D3D2
T6
T2
T3
T6
Burst length=8, CAS latency=2
T7
Write
DQM
DQ
CLK
Command
DQM
DQ
Q0
T0T1
Read
The minimum command interval = (4+1) cycles
T2
Q2
Q2
Hi-Z is
necessary
T4T5
Hi-Z is
necessary
example: Burst length=4, CAS latency=3
Write
D0
Q1D0
T3
D1
T6
T7
D1
D2
T8
D2
Document : 1G5-0154 Rev.1 Page 24
Page 25
VIS
10.BURST Termination
There are two methods to terminate a burst operation other than using a read or a write command.
One is the burst stop command and the other is the precharge command.
10.1 BURST Stop Command
During a read burst. when the burst stop command is asserted, the burst read data are terminated and the data bus goes to high-impedance after the CAS latency from the burst stop command.
During a write burst, when the burst stop command is asserted, any data provided at that cycle
will not be written. The burst write is effectively terminated and no further data can be written until a
new write command is asserted.
Burst Termination
VG36128401A
Preliminary VG36128801A
VG36128161A
CMOS Synchronous Dynamic RAM
CLK
Command
CAS latency=2
DQ
CAS latency=3
DQ
Remark BST: Burst stop command
T0T1
Read
T0T1
T2
T2
Q0
T3
T3
BST
Q1
Q0
T4T5
Q2
Q1
T4T5
Burst lengh=X, CAS Intency=2,3
T6
Hi-Z
Q2
Burst lengh=X, CAS latency=2,3
T6
T7
Hi-Z
T7
CLK
Command
CAS latency=2,3
DQ
Write
Q0
Q0
Q1
Q2
BST
Hi-Z_
Remark BST: Burst command
Document : 1G5-0154 Rev.1 Page 25
Page 26
VG36128401A
Preliminary VG36128801A
VG36128161A
VIS
10.2 PRECHARGE TERMINATION
10.2.1 PRECHARGE TERMINATION in READ Cycle
precharge command is asserted, the burst read operation is terminated and precharge starts.
mand.
mand.
Precharge Termination in READ Cycle
CMOS Synchronous Dynamic RAM
During READ cycle, the burst read operation is terminated by a precharge command. When the
The same bank can be activated again after tRP from the precharge command.
When CAS latency is 2,the read data will remain valid until one clock after the precharge com-
When CAS latency is 3, the read data will remain valid until two clocks after the precharge com-
CLK
Command
CAS latency=2
DQ
command
CAS latency=3
DQ
T0T1
Read
Read
T2
T3
Q0Q3
T4T5
PREACT
Q1
Q0Q3
Q2
PREACT
Q1
T6
t
RP
t
RP
Q2
T7
Hi-Z
Burst lengh= X
T8
Hi-Z
Document : 1G5-0154 Rev.1 Page 26
Page 27
VG36128401A
Preliminary VG36128801A
VG36128161A
VIS
10.2.2 Precharge Termination in WRITE Cycle
PRECHARGE TERMINATION in WRITE Cycle
CMOS Synchronous Dynamic RAM
During WRITE cycle, the burst write operation is terminated by a precharge command. When the precharge command is asserted, the burst write operation is terminated and precharge starts.
The same bank can be activated again after tRP from the precharge command. The
DQM must be high to mask invalid data in.
During WRITE cycle, the write data written prior to the precharge command will be
correctly stored. However, invalid data may be written at the same clock as the precharge command. To prevent this from happening, DQM must be high at the same
clock as the precharge command. This will mask the invalid data.
The burst counter wraps
from the highest order
page address back to zero
during this time interval
Write
Command
Bank B
(Bank D)
Full page burst operation
does not terminate when
the burst length is satisfied;
the burst counter increments
and continues bursting
beginning with the starting
address
The burst counter wraps
from the highest order
page address back to zero
during this time interval
Write
Command
Bank B
(Bank D)
Full page burst operation
does not terminate when
the burst length is satisfied;
the burst counter increments
and continues bursting
beginning with the starting
address