FIDELIX CMS3232LAX-75EX 32m(1mx32) low power sdram Datasheet

CMS3232LAx-75Ex
32M(1Mx32) Low Power SDRAM
Revision 0.2
August, 2006
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
Document Title
32M(1Mx32) Low Power SDRAM
Revision History
Revision
No.
History
Draft date
Remark
0.0
Initial Draft
Mar. 3rd, 2005
Preliminary
0.1
Add H(Pb-Free & Halogen Free) descriptions
Nov. 1st, 2005
Final
0.2
Changed min Vcc to 1.70V
Aug. 7th, 2006
Final
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
Features
- Functionality
- Standard SDRAM Functionality
- Programmable burst lengths : 1, 2, 4, 8, or full page
- JEDEC Compatibility
- Low Power Features
- Low voltage power supply : 1.8V
- Auto TCSR(Temperature Compensated Self Refresh)
- Partial Array Self Refresh power-saving mode
- Deep Power Down Mode
- Driver Strength Control
- Operating Temperature Ranges:
- Special (-10℃ to +60℃)
- Commercial (0℃ to +70℃)
- Extended (-25℃ to +85℃)
- Industrial (-40℃ to +85℃)
- LVCMOS Compatible IO Interface
- 90ball FBGA with 0.8mm ball pitch
- CMS3232LAF : Normal
- CMS3232LAG : Pb-Free
- CMS3232LAH : Pb-Free & Halogen Free
Functional Description
The CMS3232LAx-xxxx family is high-performance CMOS
Dynamic RAMs (DRAM) organized as 1M x 32. These devices
feature advanced circuit design to provide ultra-low active current
and extremely low standby current.This is ideal for providing
More Battery Life in portable applications such as wireless
handsets. The device is compatible with the JEDEC standard
LP-SDRAM specifications.
Logic Block Diagram
CKE
CLK
/CS
/WE
/CAS
/RAS
Control
Logic
Bank 1
Bank 0
Refresh
Counter
Row
Add
Mux
Mode
Reg
Enhanced
Mode
Reg
Bank 0
Bank
Row0
Row
Addr
Addr
Latch/
Latch/
Decoder
Decoder
DQM0DQM3
Memory
Array
Data
Output
Reg
2Kx8K
Sense Amp
Bank
Control
Logic
Write Drivers
DQM Mask
READ DATA
LATCH
A0-A10
BS
Addr
Reg
DQ0 DQ31
Data
Input
Reg
Column
Column
Decoder
Decoder
Column
Address
Latch
Selection Guide
Voltage
Device
Frequency
VDD
VDDQ
1.70-1.95V
1.70-VDD
Access Time(tAC)
CL=2
133MHz
CMS3232LAx-75Ex
Rev0.2, Aug. 2006
100MHz
7ns
8ns
tRCD
tRP
20ns
20ns
20ns
20ns
CL=3
CMS3232LAx-75Ex
Pin Configuration
90 ball 0.8mm pitch FBGA(8mm x 13mm)
Top View
1
Rev0.2, Aug. 2006
2
A
DQ26
DQ24
B
DQ28
C
3
4
5
6
7
8
9
VSS
VDD
DQ23
DQ21
VDDQ
VSSQ
VDDQ
VSSQ
DQ19
VSSQ
DQ27
DQ25
DQ22
DQ20
VDDQ
D
VSSQ
DQ29
DQ30
DQ17
DQ18
VDDQ
E
VDDQ
DQ31
NC
NC
DQ16
VSSQ
F
VSS
DQM3
A3
A2
DQM2
VDD
G
A4
A5
A6
A10
A0
A1
H
A7
A8
NC
NC
NC
NC
J
CLK
CKE
A9
BS
/CS
/RAS
K
DQM1
NC
NC
/CAS
/WE
DQM0
L
VDDQ
DQ8
VSS
VDD
DQ7
VSSQ
M
VSSQ
DQ10
DQ9
DQ6
DQ5
VDDQ
N
VSSQ
DQ12
DQ14
DQ1
DQ3
VDDQ
P
DQ11
VDDQ
VSSQ
VDDQ
VSSQ
DQ4
R
DQ13
DQ15
VSS
VDD
DQ0
DQ2
CMS3232LAx-75Ex
Pin Description
Symbol
Type
Description
CLK
Input
Clock : CLK is driven by the system clock. All SDRAM input signals are sampled on the positive
edge of CLK. CLK also increments the internal burst counter and controls the output registers.
CKE
Input
Clock Enable: CKE activates(HIGH) and deactivates(LOW) the CLK signal. Deactivating the
clock provides PRECHARGE POWER-DOWN and SELF REFRESH operation(all banks idle),
ACTIVE POWER-DOWN(row active in any bank) or CLOCK SUSPEND operation(burst/access
in progress). CKE is synchronous except after the device enters power-down and self refresh
modes, where CKE becomes asynchronous until after exiting the same mode. The input buffers,
including CLK, are disabled during power-down and self refresh modes, providing low standby
power. CKE may be tied HIGH.
/CS
Input
Chip Select: CS# enables (registered LOW) and disables (registered HIGH) the command
decoder. All commands are masked when /CS is registered HIGH. /CS provides for external
bank selection on systems with multiple banks. /CS is considered part of the command code.
/CAS, /RAS, /WE
Input
Command Inputs : /CAS, /RAS, and /WE (along with /CS) define the command being entered.
DQM0 ~ DQM3
Input
Input/Output Mask: DQM is sampled HIGH and is an input mask signal for write accesses
and an output enable signal for read accesses. Input data is masked during a WRITE cycle. The
output buffers are placed in a High-Z state (two-clock latency) when during a READ cycle.
DQM0 corresponds to DQ0 – DQ7, DQM1 corresponds to DQ8–DQ15,
DQM2 corresponds to DQ16–DQ23, AND DQM3 corresponds to DQ24–DQ31.
BS
Input
Bank Address Input(s): BS define to which bank the ACTIVE, READ, WRITE or
PRECHARGE command is being applied. These pins also provide the op-code during a LOAD
MODE REGISTER command.
A0-A10
Input
Address Inputs: A0–A10 are sampled during the ACTIVE command (row-address A0–A10)
and READ/WRITE command (column-address 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 BS (A10 LOW). The address inputs also provide the op-code during a LOAD
MODE REGISTER command.
DQ
I/O
Data Input/Output : Data bus
NC
-
VDDQ
Supply
DQ Power: Provide isolated power to DQs for improved noise immunity.
VSSQ
Supply
DQ Ground: Provide isolated ground to DQs for improved noise immunity.
VDD
Supply
Power Supply: Voltage dependent on option.
VSS
Supply
Ground.
Rev0.2, Aug. 2006
No Connect
CMS3232LAx-75Ex
FUNCTIONAL DESCRIPTION
Initialization
The Fidelix 32Mb SDRAM is a dual-bank DRAM that
o per a te s a t 1 .8 V an d i nclu des a synchronous interface (all signals are registered on the positive edge of the
clock sig nal , C L K). Ea ch of 16,777,216-bit banks is
organized as 2,048 rows by 256 columns by 32 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
a c c e s s e d ( B S s e l e c t the bank, A0- A10 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.The SDRAM must be initialized prior to normal operation. The following sections provide detailed information regarding device initialization,
register definition, command descriptions and device operation.
SDRAMs must be powered up and initialized in a predefined
manner. Operational procedures other than those specified
may result in undefined operation. Once power is applied to
VDD and VDDQ(simultaneously) and the clock is stable (meets
the clock specifications in the AC characteristics), the SDRAM
requires a 100µs delay prior to issuing any command other than
a COMMAND INHIBIT or NOP. The COMMAND INHIBIT or
NOP should be applied at least once during the 100µs delay.
After the 100µs delay, a PRECHARGE command should be
applied. All banks must then be precharged, thereby placing the
device in the all banks idle state. Once in the idle state, two
AUTO REFRESH cycles must be performed. After the AUTO
REFRESH cycles are complete, the SDRAM is ready for mode
register programming. Because the mode register will power up
in an unknown state, it should be loaded prior to applying any
operational command. Refer to Figure 1.
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
Figure 1. Initialize and Load Mode Register[1.2.3.]
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
CLK
CKE
/CS
/RAS
/CAS
/WE
ADDR
Key
Key
Key
BS
BS
A10/AP
RAa
HiZ
DQ
DQM
HiZ
High level is necessary
tRC
tRP
Precharge
(All Bank)
Auto
Refresh
tRC
Auto
Refresh
Normal
MRS
Extended
MRS
Row Active
a Bank
Note :
1. The two AUTO REFRESH commands at T4 and T9 may be applied before either LOAD MODE REGISTER (LMR) command.
2. PRE = PRECHARGE command, LMR = LOAD MODE REGISTER command, AR = AUTO REFRESH command, ACT = ACTIVE command, RA = Row Address, BA = Bank
Address
3. The Load Mode Register for both MR/EMR and 2 Auto Refresh commands can be in any order; However, all must occur prior to an Active command.
Register Definition
There are two mode registers which contain settings to
achieve low power consumption. The two registers : Mode
Register and Extended Mode Register are discussed below.
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 Table 1. The
mode register is programmed via the LOAD MODE REGISTER command and will retain the stored information until it is
programmed again or the device loses power. Mode Register
bits M0-M2 specify the burst length, M3 specifies the type of
Rev0.2, Aug. 2006
burst (sequential or interleaved), M4-M6 specify the CAS
latency, M7 and M8 specify the operating mode, M9 specifies
the write burst mode, M10 and M11 should be set to zero.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.
Burst Length
Read and write accesses to the SDRAM are burst oriented. The
burst length is programmable, as shown in Table 2. 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
CMS3232LAx-75Ex
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.
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 when the
burst length is set to two; by A2-A7 when the burst length is
set to four; and by A3-A7 when the burst length is set to eight.
M11BS
M10A10
Reserved(Set to ‘0’)
M9-A9
M8-A8
WB
M7-A7
Burst Type
The burst type can be set to either Sequential or Interleaved
by using the M3 bit in the Mode register. The ordering of
accesses within a burst is determined by the burst length, the
burst type and the starting column address, as shown in
Table 2. [4.5.6.7.8.9.10.]
M6-A6
M5-A5
M4-A4
M3-A3
CAS Latency
Op Mode
BT
Burst Length
M2 M1 M0
M3
M3=0
M3=1
1
1
000
001
2
2
010
4
4
011
8
8
100
Reserved
Reserved
101
Reserved
Reserved
110
Reserved
Reserved
111
Full Page
Reserved
M2-A2
M1-A1
M0-A0
Burst Length
Burst Type
0
Sequential
1
Interleaved
M9
Write Burst Mode
0
Prog. Burst Length
1
Single Mode Access
CAS Latency
M8
M7
M6-M0
Operating Mode
000
Reserved
0
0
Defined
Standard Operation
001
1
-
-
-
All other states reserved
010
2
011
3
100
Reserved
101
Reserved
110
Reserved
111
Reserved
M6 M5 M4
Note :
4. For full-page accesses: y = 256
5. For a burst length of two, A1-A7 select the block-of-two burst; A0 selects the starting column within the block.
6. For a burst length of four, A2-A7 select the block-of-four burst; A0-A1 select the starting column within the block.
7. For a burst length of eight, A3-A7 select the block-of-eight burst; A0-A2 select the starting column within the block.
8. For a full-page burst, the full row is selected and A0-A7 select the starting column.
9. Whenever a boundary of the block is reached within a given sequence above, the following access wraps within the block.
10. For a burst length of one, A0-A7 select the unique column to be accessed,and mode register bit M3 is ignored.
Table 1. Mode Register Definition.
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
Burst Length
Starting Column 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
4
00
0-1-2-3
0-1-2-3
01
1-2-3-0
1-0-3-2
10
2-3-0-1
2-3-0-1
11
3-0-1-2
3-2-1-0
000
0-1-2-3-4-5-6-7
0-1-2-3-4-5-6-7
001
1-2-3-4-5-6-7-0
1-0-3-2-5-4-7-6
010
2-3-4-5-6-7-0-1
2-3-0-1-6-7-4-5
011
3-4-5-6-7-0-1-2
3-2-1-0-7-6-5-4
100
4-5-6-7-0-1-2-3
4-5-6-7-0-1-2-3
101
5-6-7-0-1-2-3-4
5-4-7-6-1-0-3-2
110
6-7-0-1-2-3-4-5
6-7-4-5-2-3-0-1
111
7-0-1-2-3-4-5-6
7-6-5-4-3-2-1-0
n=A0-A8(location 0-y)
Bn, Bn+1, Bn+2…..Bn,…
Not supported
A2 A1 A0
8
Full Page(y)
Table 2. Burst Length Definition.
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
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 one, two,
or three clocks. If a READ command is registered at clock
edge r, and the latency is q clocks, the data will be available
by clock edge r + q. The DQs will start driving as a result of
the clock edge one cycle earlier (r + q- 1), and provided that
the relevant access times are met, the data will be valid by
clock edge r + q. 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 Figure 2.
Rev0.2, Aug. 2006
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 (non-burst) accesses.
CMS3232LAx-75Ex
T0
T1
T2
CLK
Command
Read
NOP
tLZ
tOH
Dout
DQ
tAC
CAS Latency=1
T0
T1
T2
T3
Read
NOP
NOP
CLK
Command
tLZ
tOH
Dout
DQ
tAC
CAS Latency=2
T0
T1
T2
T3
T4
CLK
Command
Read
NOP
NOP
NOP
tLZ
tOH
DQ
Dout
tAC
CAS Latency=3
Figure 2. CAS Latency
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
EXTENDED MODE REGISTER
The Extended Mode Register controls additional functions such
as Partial Array Self Refresh (PASR), and Output Drive
Strength.The Extended Mode Register is programmed via the
Mode Register Set command (BS=1) and retains the stored
information until it is programmed again or the device loses
power. The Extended Mode Register must be programmed with
M8 through M10 set to “0”. The Extended Mode Register must
be loaded when all banks are idle and no bursts are in progress,
and the controller must wait the specified time initiating any
subsequent operation. Violating either of these requirements
results in unspecified operation.
PARTIAL ARRAY SELF REFRESH
AUTO TEMPERATURE COMPENSATED SELF REFRESH
Driver Strength Control
Every cell in the DRAM requires refreshing due to the capacitor
losing its charge over time. The refresh rate is dependent on
temperature. At higher temperatures a capacitor loses charge
quicker than at lower temperatures, requiring the cells to be
refreshed more often. In order to save power consumption,
according to the temperature, Mobile-SDRAM includes the
internal temperature sensor and control units to control the self
refresh cycle automatically.
The driver strength feature allows one to reduce the drive
strength of the I/O’s on the device during low frequency
operation. This allows systems to reduce the noise associated
with the I/O’s switching.
The Partial Array Self Refresh (PASR) feature allows the
controller to select the amount of memory that will be refreshed
during SELF REFRESH. The refresh options are all banks
(banks 0, 1); one bank (bank 0 or 1 by M7). WRITE and READ
commands occur to any bank selected during standard
operation, but only the selected banks in PASR will be
refreshed during SELF REFRESH. The data in banks 1 will be
lost when the one bank option with M7=0 is used. Similarly the
data will be lost in bank 0 when the one bank option with M7=1
is used down
.
Table 4. Extended Mode Register Definition
EM11BS
1
EM10A10
EM9A9
EM8A8
All must be set to ‘0’
Rev0.2, Aug. 2006
EM7A7
Bank
Up/Down
EM6A6
EM5A5
Driver Strength
EM4A4
EM3A3
0
0
EM2A2
EM1A1
PASR
EM0A0
CMS3232LAx-75Ex
Table 5. Extended Mode Register Table[11.12.].
A7
A2
A1
A0
Self Refresh Coverage
0
0
0
0
All Banks (Bank 0,1)
1
0
0
1
RFU
0
1
0
One Bank (Bank 0)
0
1
1
RFU
1
X
X
RFU
0
0
0
All Banks (Bank 0,1)
0
0
1
RFU
0
1
0
One Bank (Bank1)
0
1
1
RFU
1
X
X
RFU
A6
A5
Driver Strength
0
0
100%
0
1
75%
1
0
50%
1
1
25%
Note :
11.
12.
EM11 (BS) must be “1” to select the Extended Mode Register(vs. the base Mode Register).
RFU: Reserved for Future Use
Table 6. Commands[13.14.15.16.17.18.19.20.] .
CKE
/CS
COMMAND INHIBIT(NOP)
X
H
X
NO OPERATION(NOP)
H
L
H
ACTIVE(Select bank and activate row)[15.]
H
L
L
READ(Select bank and column, and start READ burst)[16.]
H
L
WRITE(Select bank and column, and start WRITE burst)[16.]
H
BURST TERMINATE
PRECHARGE(Deactivate row in bank or banks)[17.]
Name(Function)
AUTO REFRESH or SELF REFRESH(Enter Self Refresh Mode) )
/RAS
/CAS
/WE
DQM
ADDR
DQ
X
X
X
X
X
H
H
X
X
X
H
H
X
Bank/
Row
X
H
L
H
L/H
Bank/
Col
X
L
H
L
L
L/H
Bank/
Col
Valid
H
L
H
H
L
X
X
Active
H
L
L
H
L
X
Code
X
H
L
L
L
H
X
X
X
LOAD MODE REGISTER)[14.]
H
L
L
L
L
X
Opcode
X
Write Enable/Output Enable)[20.]
H
-
-
-
-
L
-
Active
Write Inhibit/Output High-Z)
H
-
-
-
-
H
L
L
H
H
L
X
[20.]
Deep Power Down(Enter DPD Mode)
Rev0.2, Aug. 2006
[18. 19.]
High Z
X
X
CMS3232LAx-75Ex
Table 6. Commands[13.14.15.16.17.18.19.20.].
Note :
13.
14.
15.
16.
17.
18.
19.
20.
CKE is HIGH for all commands shown except SELF REFRESH.
A0-A10 define the op-code written to the mode register.
A0-A10 provide row address, and BS determine which bank is made active.
A0-A7 provide column address; A10 HIGH enables the auto precharge feature (non-persistent), while A10 LOW disables the auto precharge feature; BS determine which
bank is being read from or written to.
A10 LOW: BS determine the bank being precharged. A10 HIGH: All banks precharged and BS is “Don’t Care.”
This command is AUTO REFRESH if CKE is HIGH, SELF REFRESH if CKE is LOW.
Internal refresh counter controls row addressing; all inputs and I/Os are “Don’t Care” except for CKE.
Activates or deactivates the DQs during WRITEs (zero-clock delay) and READs (two-clock delay).
DQM0 controls DQ 0-7, DQM1 controls DQ 8-15, DQM2 controls DQ 16-23 and DQM3 controls DQ 24-31.
Commands
Table 6. provides a reference of all the commands available
with the state of the control signals for executing a specific
command.
COMMAND INHIBIT
The COMMAND INHIBIT function effectively deselects the
SDRAM by preventing new commands from being executed by
the SDRAM, regardless of whether the CLK signal is enabled.
Operations already in progress are not affected.
LOAD MODE REGISTER
The mode register is loaded via inputs A0-A10, BS. The
LOAD MODE REGISTER and LOAD EXTENDED MODE
REG I S T ER co mman ds c a n o nl y be issu e d wh e n all
banks are idle, and a subsequent executable command cannot
be issued until tMRD is met. Table 1. and Table 4. provide the
definition for the Mode Register and Extended Mode Register.
NO OPERATION (NOP)
The NO OPERATION (NOP) command is used to perform a
NOP to an SDRAM which is selected (/CS is LOW). This prevents unwanted commands from being registered during idle
or wait states. Operations already in progress are not affected.
ACTIVE
The ACTIVE command is used to activate a row in a particular
bank for a subsequent access. The value on the BS inputs
selects the bank, and the address provided on inputs
A0-A10 selects the row. This row remains active for accesses
until a PRECHARGE command is issued to that bank. A
PRECHARGE command must be issued before opening a
different row in the same bank.
READ
READ command is used to initiate a burst read access to an
active row. The value on the BS inputs selects the bank,
and the address provided on inputs A0-A7 selects the starting
column location. The value on input A10 determines whether or
not auto precharge is used. If auto precharge is selected, the
row being accessed will be precharged at the end of the READ
burst. If auto precharge is not selected, the row will remain
open for subsequent accesses. Read data appears on the DQs
subject to the logic level on the DQM inputs two clocks earlier. If
a given DQM signal was registered HIGH, the corresponding
DQs will be High-Z two clocks later; if the DQM signal was
registered LOW, the DQs will provide valid data.
Rev0.2, Aug. 2006
WRITE
The WRITE command is used to initiate a burst write access
to an active row. The value on the BS inputs selects the
bank, and the address provided on inputs A0-A7 selects the
starting column location. The value on input A10 determines
whether or not auto precharge is used. If auto precharge is
selected, the row being accessed will be precharged at the end
of the WRITE burst. If auto precharge is not selected, the row
will remain open for subsequent accesses. Input data appearing
on the DQs is written to the memory array subject to the DQM
input logic level appearing coincident with the data. If a given
DQM signal is registered LOW, the corresponding data will be
written to memory; if the DQM signal is registered 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 active
row in a particular bank or the active row in all banks. The
bank(s) will be available for a subsequent row access a specified time (tRP) after the PRECHARGE command is issued.
Input A10 determines whether one or all banks are to be precharged, and in the case where only one bank is to be precharged, inputs BS select the bank. Otherwise BS is treated as
“Don’t Care.” Once a bank has been pre-charged, it is in the
idle state and must be activated prior to any READ or WRITE
commands being issued to that bank.
AUTO PRECHARGE
AUTO PRECHARGE is accomplished by using A10 to enable
auto precharge in conjunction with a specific READ or WRITE
command. AUTO PRECHARGE thus performs the same
PRECHARGE command described above , without requiring an
explicit command. A PRECHARGE of the bank/row that is
addressed with the READ or WRITE command is automatically
performed upon completion of the READ or WRITE burst.
AUTO PRECHARGE does not apply in the full page mode burst.
Auto precharge is nonpersistent in that it is either enabled or
disabled for each individual READ or WRITE command.
Auto precharge ensures that the precharge is initiated at the
earliest valid stage within a burst. The user must not issue
another command to the same bank until the precharge time
(tRP) is completed.
BURST TERMINATE
The BURST TERMINATE command is used to truncate either
fixed-length or full-page bursts. The most recently registered
READ or WRITE command prior to the BURST TERMINATE
command will be truncated.
CMS3232LAx-75Ex
AUTO REFRESH
AUTO REFRESH is used during normal operation of the
SDRAM. This command is nonpersistent, so it must be issued
each time a refresh is required. All active banks must be
PRECHARGED prior to issuing an AUTO REFRESH command.
The AUTO REFRESH command should not be issued until the
minimum tRP has been met after the PRECHARGE command.
The addressing is generated by the internal refresh controller.
The address bits thus are a “Don’t Care” during an AUTO
REFRESH command. The Fidelix 32Mb SDRAM requires
2,048 AUTO REFRESH cycles every 64ms (tREF), regardless
of width option. Providing a distributed AUTO REFRESH
command every 31.25µs will meet the refresh requirement and
ensure that each row is refreshed.
Alternatively, 2,048 AUTO REFRESH commands can be issued
in a burst at the minimum cycle rate (tRFC), once every 64ms.
SELF REFRESH
The SELF REFRESH command 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 command is
initiated like an AUTO REFRESH command except CKE is
disabled (LOW). Once the SELF REFRESH command is registered, all the inputs to the SDRAM become “Don’t Care” with
the exception of CKE, which must remain LOW. Once self
refresh mode is engaged, the SDRAM provides its own internal
clocking, causing it to perform its own AUTO REFRESH cycles.
The SDRAM must remain in self refresh mode for a minimum
period equal to tRAS and may remain in self refresh mode for
an indefinite period beyond that. The procedure for exiting self
refresh requires a sequence of commands. First, CLK must be
stable (meet the clock specifications in the AC characteristics)
prior to CKE going back HIGH. Once CKE is HIGH, the SDRAM
must have NOP commands issued (a minimum of two clocks)
for tXSR because time is required for the completion of any
internal refresh in progress. Upon exiting the self refresh mode,
AUTO REFRESH commands must be issued every 31.25µs or
less as both SELF REFRESH and AUTO REFRESH utilize he
row refresh counter.
Rev0.2, Aug. 2006
DEEP POWER DOWN
Deep Power Down Mode is an operating mode to achieve maximum
power reduction by cutting the power of the whole memory array of
the device.
Data will not be retained once the device enters DPD Mode.
Full initialization is required when the device exits from DPD Mode.
The DC value of DPD Mode can’t be zero due to transistor’s leakage
current; a reverse PN diode leakage current which is called ‘Junction
leakage current’ and a punch-through leakage current.
[Figure29.30]
CMS3232LAx-75Ex
Absolute Maximum Ratings
Voltage on VDD/VDDQ Supply
Relative to VSS …………………………………...-0.5V to + 2.6V
Voltage on Inputs, NC or I/O Pins
Relative to VSS ……………………………….…. –0.5V to +2.6V
Storage Temperature(plastic) ………….……. -55℃ to + 150℃
Power Dissipation ……………………….….………………1W
*Stresses greater than those listed under “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.
Operating Range
Device
Range
Ambient Temperature
CMS3232LAx-75ES
Special
-10℃ to +60℃
CMS3232LAx-75EC
Commercial
0℃ to +70℃
CMS3232LAx-75EE
Extended
-25℃ to +85℃
CMS3232LAx-75EI
Industrial
-40℃ to +85℃
VDD
VDDQ
1.70V to 1.95V
1.70V to VDD
DC ELECTRICAL CHARACTERISTICS AND OPERATING CONDITIONS[21,22]
Parameter / Condition
Symbol
Min
Max
Units
Supply Voltage
VDD
1.70
1.95
V
I/O Supply Voltage
VDDQ
1.70
1.95
V
VIH
0.8* VDDQ
VDDQ +0.3
V
0.3
Input High Voltage : Logic 1 All Inputs [23.]
Input Low Voltage : Logic 0 All Inputs [23.]
VIL
-0.3
Data Output High Voltage : Logic 1 : All Inputs(-0.1mA)
VOH
0.9* VDDQ
Data Output Low Voltage : Logic 0 : All Inputs(0.1mA)
VOL
Input Leakage Current :
Any Input 0V=VIN=VDD (All other pins not under test=0V)
II
Output Leakage Current : DQs are disabled ; 0V= VOUT=VDDQ
lOZ
V
V
0.2
V
-5
5
㎂
-5
5
㎂
Table 7. AC OPERATING CONDITIONS[21.22.23.24.25.26.]
Parameter / Condition
Symbol
Value
Units
Input High Voltage : Logic 1 All Inputs
VIH
0.9* VDDQ
V
Input Low Voltage : Logic 0 All Inputs
VIL
0.2
V
0.5*VDDQ
V
Input and Output Measurement Reference Level
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
Table 8. IDD Specifications and Conditions [21.22.26.27.].
Parameter
Description
-75
Units
IDD1
Operating Current : Active Mode ; Burst =1 ; Read or Write ; tRC= tRC(min);
CAS Latency =3 [28.29.30.]
45
㎃
IDD2p
Precharge Standby Current in Power Down Mode ; CKE=LOW ; All banks Idle
250
㎂
IDD2n
Precharge Standby Current in non ower down Mode; CKE=HIGH ; All banks Idle
9
㎃
IDD3p
Active Standby Current in Power Down Mode ; CS#=HIGH ; CKE=LOW ; All
banks active after tRCD met ; No access in progress[28.30.31.]
1.5
㎃
IDD3n
Active Standby Current in non Power Down Mode ; CS#=HIGH ; CKE=HIGH ; All
banks active after tRCD met ; No access in progress[28.30.31.]
13
㎃
IDD4
Operating Current : Burst Mode ; Continuous Burst ; Read or Write ; All banks
Active ; CAS Latency =3[28.29.30.]
45
㎃
IDD5
Auto Refresh Current : tRC=tRC(min) CAS Latency=3 ; CKE,CS#=HIGH[28.29.30.32.32.]
60
㎃
IDD6
Self Refresh Current : CKE <=0.2V, 2 Banks
200
㎂
Self Refresh Current : CKE <=0.2V, 1 Banks
150
㎂
Deep power down
10
㎂
IDD7
Note :
21. The minimum specifications are used only to indicate cycle time at which proper operation over the full temperature range (-40°C = TA = +85°C for IT parts) is ensured.
22. An initial pause of 100µs is required after power-up, followed by two AUTO REFRESH commands, before proper device operation is ensured. (VDD and VDDQ must be
powered up simultaneously. VSS and VSSQ must be at same potential.) The two AUTO REFRESH command wake-ups should be repeated any time the tREF refresh
requirement is exceeded.
23. All states and sequences not shown are illegal or reserved.
24. In addition to meeting the transition rate specification, the clock and CKE must transit between VIH and VIL (or between VIL and VIH) in a monotonic manner.
25. tHZ defines the time at which the output achieves the open circuit condition; it is not a reference to VOH or VOL. The last valid data element will meet tOH before going High-Z.
26. AC timing and IDD tests have VIL and VIH, with timing referenced to VIH/2 = crossover point. If the input transition time is longer than tT (MAX), then the timing is referenced
at VIL (MAX) and VIH (MIN) and no longer at the VIH/2 crossover point.
27. IDD specifications are tested after the device is properly initialized.
28. IDD is dependent on output loading and cycle rates. Specified values are obtained with minimum cycle time and the outputs open.
29. The IDD current will increase or decrease proportionally according to the amount of frequency alteration for the test condition.
30. Address transitions average one transition every two clocks.
31. Other input signals are allowed to transition no more than once every two clocks and are otherwise at valid VIH or VIL levels.
32. CKE is HIGH during refresh command period tRFC (MIN) else CKE is LOW. The IDD 6 limit is actually a nominal value and does not result in a fail value
Capacitance
Parameter
Description
CIN
Input Capacitance
COUT
Output Capacitance
VDDQ/2
AC Test Loads
50Ω
Z0=50Ω
OUTPUT
30pF
Rev0.2, Aug. 2006
Test Conditions
TA=25℃, f=1Mhz, VDD(typ)
Max
Units
4
pF
6
pF
CMS3232LAx-75Ex
AC Characteristics
AC Characteristics
Symbol
Parameter
tCLKS3
Clock Period[33.]
-75
Min
Max
Units
7.5
ns
tCLKS2
10
ns
Clock High Time
tCH
2.5
ns
Clock Low Time
tCL
2.5
ns
Address Setup Time to Clock
tCAS
2.0
ns
Address Hold Time to Clock
tCAH
1.0
ns
CKE Setup Time to Clock
tCKS
2.0
ns
CKE Hold Time to Clock
tCKH
1.0
ns
Clock Access Time
CL=3
tAC(3)
7
ns
CL=2
tAC(2)
8
ns
CL=1
tAC(1)
-
ns
Output Hold Time from Clock
tOH
2.5
ns
Data In Setup Time to Clock
tCDS
2.0
ns
Data In Hold Time to Clock
tCDH
1.0
ns
/CS, /RAS, /CAS, /WE, /DQM Setup Time to Clock
tCMS
2.0
ns
/CS, /RAS, /CAS, /WE, /DQM Hold Time to Clock
tCMH
1.0
ns
Data High Impedance Time[25.]
CL=3
tHZ(3)
7
ns
CL=2
tHZ(2)
8
ns
CL=1
tHZ(1)
-
ns
120000
ns
Active to Precharge Command
tRAS
48
Active to Active Command Period
tRC
80
Active to Read/Write Delay
tRCD
20
Refresh Period(2048 rows)
tREF
Auto Refresh Period
tRFC
80
Precharge Command Period
tRP
20
ns
Active Banka to Active Bankb Command
tRRD
15
ns
tT
0.5
Transition Time[34.]
ns
ns
64
ms
ns
1.2
ns
[35.]
Write Recovery Time
tWR
2
tCK
Write Recovery Time[36.]
tWR
15
ns
Exit Self Refresh to Active Command[37.]
tXSR
80
ns
READ/WRITE command to READ/WRITE command[38.]
tCCD
1
tCK
CKE to clock disable or power-down entry mode[39.]
tCKED
1
tCK
CKE to clock enable or power-down exit setup mode[39.]
tPED
1
tCK
DQM to input data delay[38.]
tDQD
0
tCK
DQM to data mask during WRITEs[38.]
tDQM
0
tCK
DQM to data high-impedance during READs
[38.]
tDQZ
2
tCK
WRITE command to input data delay[38.]
tDWD
0
tCK
Data-in to ACTIVE command[40.]
tDAL
tWR+tRP
ns
Data-in to PRECHARGE command[41.]
tDPL
2
tCK
Last data-in to burst STOP command[38.]
tBDL
1
tCK
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
AC Characteristics
AC Characteristics
Symbol
Parameter
-75
Min
Max
Units
Last data-in to new READ/WRITE command[38.]
tCDL
1
tCK
Last data-in to PRECHARGE command[41.]
tRDL
2
tCK
LOAD MODE REGISTER command to ACTIVE or REFRESH command[42.]
tMRD
2
tCK
CL=3
tROH(3)
3
tCK
CL=2
tROH(2)
2
tCK
CL=1
tROH(1)
1
tCK
Data-out to high-impedance from PRECHARGE command
[38.]
Note :
33. The clock frequency must remain constant (stable clock is defined as a signal cycling within timing constraints specified for the clock pin) during access or precharge states
(READ, WRITE, including tWR, and PRECHARGE commands). CKE may be used to reduce the data rate.
34. AC characteristics assume tT = 1ns.
35. Auto precharge mode only.
36. Precharge mode only.
37. CLK must be toggled a minimum of two times during this period.
38. Required clocks are specified by JEDEC functionality and are not dependent on any timing parameter.
39. Timing actually specified by tCKS; clock(s) specified as a reference only at minimum cycle rate.
40. Timing actually specified by tWR plus tRP; clock(s) specified as a reference only at minimum cycle rate.
41. Timing actually specified by tWR.
42. JEDEC and PC100 specify three clocks.
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
Operation
Figure 3. The starting column and bank addresses are provided
with the READ command, and auto precharge is either enabled
or disabled for that burst access. 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. Figure 2.
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 fullpage burst will
continue until terminated. (The burst will wrap around at the end
of the page). A continuous flow of data can be maintained by
having addtional Read Burst or single Read Command. 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 that 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 Figure 4. for CAS latencies of one, two and
three; data element n + 3 is either the last of a burst of four or
the last desired of a longer burst. Full-speed random read
accesses can be performed to the same bank, as shown in
Figure 5. , or each subsequent READ may be performed to a
different 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”
(activated). This is accomplished via the ACTIVE command,
which selects both the bank and the row to be activated. A
READ or WRITE command may then be issued to that row,
subject to the tRCD specification. tRCD (MIN) should be divided
by the clock period and rounded up to the next whole number to
determine the earliest clock edge after the ACTIVE command
on which a READ or WRITE command can be entered. For
example, a tRCD specification of 20ns with a 125 Mhz clock
(8ns period) results in 2.5 clocks, rounded to 3. (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 t RC. 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 t tRRD.
READs
READ bursts are initiated with a READ command, as shown in
Read Command
CLK
CKE
High
/CS
/RAS
/CAS
/WE
A0-A7
Column
Address
A9
Enable Auto Precharge
A10
Disable Auto Precharge
BS
Bank
Address
Don’t Care
Figure 3. Read Command
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
T0
T1
T2
Command
Read
NOP
NOP
Address
Bank
Col n
T3
T4
T5
Read
NOP
CLK
NOP
X=0cycles
Bank
Col b
Dout
n
DQ
Dout
n+1
Dout
n+2
Dout
n+3
Dout
b
CAS Latency=1
T0
T1
T2
T3
T4
T5
T6
CLK
X=1cycles
Command
Read
Address
Bank
Col n
NOP
NOP
Read
NOP
NOP
Bank
Col b
Dout
n
DQ
NOP
Dout
n+1
Dout
n+2
Dout
n+3
Dout
b
CAS Latency=2
Figure 4. Consecutive Burst Reads -Transition from Burst of 4 Read to a Single read for CAS Latency 1,2,3
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
T0
T1
T2
Read
NOP
NOP
T3
T4
T5
T6
T7
CLK
Command
NOP
Read
NOP
NOP
NOP
X=2cycles
Address
Bank
Col n
Bank
Col b
Dout
n
DQ
Dout
n+1
Dout
n+2
Dout
n+3
CAS Latency=3
Figure 4. Consecutive Burst Reads -Transition from Burst of 4 Read to a Single read for CAS Latency 1,2,3
T3
T0
T1
T2
Command
Read
Read
Read
Read
Address
Bank
Col n
Bank
Col a
Bank
Col x
Bank
Col m
T4
CLK
DQ
Dout
n
Dout
a
Dout
x
NOP
Dout
m
CAS Latency=1
Figure 5. Random Read Accesses for CAS Latency =1,2,3
Rev0.2, Aug. 2006
Dout
b
CMS3232LAx-75Ex
T3
T0
T1
T2
Command
Read
Read
Read
Read
Address
Bank
Col n
Bank
Col a
Bank
Col x
Bank
Col m
T5
T4
CLK
Dout
n
DQ
NOP
Dout
a
NOP
Dout
x
Dout
m
CAS Latency=2
T3
T0
T1
T2
Command
Read
Read
Read
Read
Address
Bank
Col n
Bank
Col a
Bank
Col x
Bank
Col m
T4
T5
T6
CLK
Dout
n
DQ
NOP
Dout
a
NOP
Dout
x
NOP
Dout
m
CAS Latency=3
Figure 5. Random Read Accesses for CAS Latency =1,2,3
A Read Burst can be terminated by 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
Rev0.2, Aug. 2006
a single-cycle delay should occur between the last read data
and the WRITE command. The DQM input is used to avoid I/O
contention, as shown in Figure 6. and Figure 7. . 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
CMS3232LAx-75Ex
was active on the clock just prior to the WRITE command that
truncated the READ command. The DQM signal must be asserted prior to the WRITE command (DQM latency is zero
clocks for input buffers) to ensure that the written data is not
masked. Figure 6. shows the case where the clock frequency
T0
T1
T2
allows for bus contention to be avoided without adding a NOP
cycle, and Figure 7. shows the case where the additional NOP
is needed.
T3
T4
CLK
DQM
tCK
Command
Read
Address
Bank
Col n
NOP
NOP
NOP
Write
Bank
Col b
tHZ
Dout
n
DQ
CAS Latency=3
tDS
Figure 6. Read to Write
Rev0.2, Aug. 2006
Din
b
CMS3232LAx-75Ex
T0
T2
T1
T3
T5
T4
CLK
DQM
tCK
Command
Read
Address
Bank
Col n
NOP
NOP
NOP
NOP
Write
Bank
Col b
tHZ
Dout
n
DQ
Din
b
CAS Latency=3
tDS
Figure 7. Read to Write with extra clock cycle
T0
T1
T2
T3
T4
T5
T6
T7
T8
CLK
CMD
Read
Write
Read masked by write
DQM
Din
n
DQ
CMD
Din
n+1
Read
Din
n+2
Write
Din
n+3
Read masked by DQM
DQM
Din
n
DQ
CMD
Read
Din
n+2
Din
n+3
Din
n+1
Din
n+2
Write
Read CAS=2
DQM
DQ
Din
n+1
Dout
n
Din
n
Figure 8. Read Interrupted by Write and DQM ; CAS Latency =2
Rev0.2, Aug. 2006
Din
n+3
CMS3232LAx-75Ex
A fixed-length READ burst or a full-page burst may be followed by, or truncated with, a PRECHARGE command to the
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 Figure 9. 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 comman-
T0
T2
T1
d, 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). 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 Figure 10. for each possible CAS latency; data
element n + 3 is the last desired data element of a longer burst.
T3
T4
T5
CLK
Command
T6
T7
tRP
Read
NOP
NOP
NOP
Precharge
NOP
NOP
Active
X=0cycles
Address
Bank a
Col n
Bank
(a or all)
Dout
n
DQ
Dout
n+1
Dout
n+2
Dout
n+3
T3
T4
Bank a
Row
CAS Latency=1
T0
T2
T1
T5
CLK
Command
T6
T7
tRP
Read
NOP
NOP
NOP
Precharge
NOP
NOP
Active
X=1cycles
Address
Bank a
Col n
Bank
(a or all)
Dout
n
DQ
Dout
n+1
Dout
n+2
CAS Latency=2
Figure 9. Read to Precharge
Rev0.2, Aug. 2006
Bank a
Row
Dout
n+3
CMS3232LAx-75Ex
T0
T1
T2
T3
T4
T5
CLK
Command
T6
T7
tRP
Read
NOP
NOP
NOP
Precharge
NOP
NOP
Active
X=2cycles
Address
Bank a
Col n
Bank
(a or all)
Dout
n
DQ
Dout
n+1
Bank a
Row
Dout
n+2
Dout
n+3
T5
T6
CAS Latency=3
Figure 9. Read to Precharge
T0
T1
T2
Read
NOP
NOP
T3
T4
T7
CLK
Command
NOP
Burst
Terminate
X=0cycles
Address
Bank a
Col n
DQ
Dout
n
Dout
n+1
Dout
n+2
Dout
n+3
CAS Latency=1
Figure 10. Terminating a Read Burst
Rev0.2, Aug. 2006
NOP
NOP
NOP
CMS3232LAx-75Ex
T0
T1
T2
Read
NOP
NOP
T3
T4
T5
T6
T7
CLK
Command
NOP
Burst
Terminate
NOP
NOP
NOP
X=1cycles
Address
Bank a
Col n
Dout
n
DQ
Dout
n+1
Dout
n+2
Dout
n+3
T3
T4
T5
CAS Latency=2
T0
T1
T2
Read
NOP
NOP
T6
T7
CLK
Command
NOP
Burst
Terminate
NOP
NOP
X=2cycles
Address
Bank a
Col n
DQ
Dout
n
Dout
n+1
CAS Latency=3
Figure 10. Terminating a Read Burst
Rev0.2, Aug. 2006
Dout
n+2
Dout
n+3
NOP
CMS3232LAx-75Ex
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
CLOCK
CKE
HIGH
*note 45.
tRC
/CS
tRP
tRCD
/RAS
*note 46.
/CAS
ADDR
RAa
CAa
RAb
CAb
BS
A10/AP
RAa
RAb
tOH
CL=2
Qa0
Qa1
Qa2
Qa3
Qb0
Qb1
Qb2
Qb3
tRAC
tSAC
*note 47.
tSHZ
*note 48.
tDPL
tOH
DQ
CL=3
Qa0
Qa1
Qa2
Qa3
Qb0
Qb1
Qb2
Qb3
tRAC
*note 47.
tSAC
tSHZ
*note 48.
tDPL
/WE
DQM
Row Active
(A-Bank)
Read
(A-Bank)
Precharge
(A-Bank)
Row Active
(A-Bank)
Write
(A-Bank)
Precharge
(A-Bank)
Don’t Care
Note :
45. Minimum row cycle times is required to complete internal DRAM operation.
46. Row precharge can interrupt burst on any cycle.[CAS Latency -1] number of valid output data is available after Row precharge. Last valid output will be Hi-Z(t SHZ) after
the clock.
47. Access time from Row active command. tCC *(tRCD + CAS latency - 1) + tSAC
48. Out put will be Hi-Z after the end of burst. (1,2,3,8 & Full page bit burst)
Figure 11. Read & Write Cycle at Same Bank @Burst Length=4, tDPL =2CLK (100Mhz)
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
CLOCK
CKE
HIGH
*note 45.
tRC
/CS
tRCD
tRP
/RAS
*note 46.
/CAS
ADDR
RAa
CAa
RAb
CAb
BS
A10/AP
RAa
RAb
tOH
CL=2
Qa0
Qa1
Qa2
Qa3
Qb0
Qb1
Qb2
Qb3
tRAC
tSAC
*note 47.
DQ
tSHZ
*note 48.
tDPL
tOH
Qa0
CL=3
Qa1
Qa2
Qa3
Qb0
Qb1
Qb2
Qb3
tRAC
*note 47.
tSAC
tSHZ
*note 48.
tDPL
/WE
DQM
Row Active
(A-Bank)
Read
(A-Bank)
Precharge
(A-Bank)
Row Active
(A-Bank)
Write
(A-Bank)
Don’t Care
Figure 12. Read & Write Cycle at Same Bank @Burst Length=4, tDPL=2CLK (133Mhz)
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
CLOCK
CKE
HIGH
/CS
/RAS
*note 49.
/CAS
ADDR
RAa
RBb CAa
RCc CBb
RDd CCc
RAa
RBb
RCc
RDd
CDd
BS
A10/AP
CL=2
QAa0 QAa1
QAa2 QBb0
QBb1 QBb2
QCc0 QCc1
QCc2 QDd0 QDd1 QDd2
DQ
CL=3
QAa0 QAa1
QAa2 QBb0
QBb1 QBb2
QCc0 QCc1
QCc2 QDd0 QDd1 QDd2
/WE
DQM
Row Active
(A-Bank)
Read
(A-Bank)
Row Active
(B-Bank)
Read
(B-Bank)
Read
(C-Bank)
Read
(D-Bank)
Precharge
(D-Bank)
Precharge
(C-Bank)
Row Active
(C-Bank)
Precharge
(A-Bank)
Precharge
(B-Bank)
Don’t Care
Note :
49. Row precharge will interrupt writing. Last data input, tDPL before Row precharge, will be written.
Figure 13. Page Read Cycle at Same Bank @ Burst Length=4
WRITE
WRITE bursts are initiated with a WRITE command,as shown
Rev0.2, Aug. 2006
in Figure 14. The starting column and bank addresses are
provided with the WRITE command, and auto precharge is
CMS3232LAx-75Ex
either enabled or disabled for that access. If auto precharge is
enabled, the row being accessed is precharged at the completion of the burst. 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 fixedlength burst, assuming no other commands have been initiated,
the DQs will remain High-Z and any additional input data will be
ignored (see Figure 15.). A fullpage burst will continue until
terminated. (wrap around at the end of the page) An example is
shown in Figure 16. . Data n + 1 is either the last of a burst of
two or the last desired of a longer burst.
A WRITE command can be initiated on any clock cycle following a previous WRITE command. Full-speed random write
accesses within a page can be performed to the same bank,
as shown in Figure 17. , or each subsequent WRITE may be
performed to a different bank.
Write Command
CLK
CKE
High
/CS
/RAS
/CAS
/WE
A0-A7
Column
Address
A9
Enable Auto Precharge
A10
Disable Auto Precharge
BS
Bank
Address
Don’t Care
Figure 14. Write Command
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
T0
T1
T2
Command
Write
NOP
NOP
Address
Bank
Col n
T3
CLK
Din
n
DQ
NOP
Din
n+1
Figure 15. Write Burst - Burst length of 2
T0
T1
T2
Command
Write
NOP
Write
Address
Bank
Col n
CLK
DQ
Din
n
Bank
Col b
Din
n+1
Din
b
Figure 16. Write to Write - Transition from a burst of 2 to a single write
Data for a fixed-length WRITE burst a full-page WRITE burst
may be followed by, or 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
Rev0.2, Aug. 2006
prior to, and the clock edge coincident with, the PRECHARGE
command. An example is shown in Figure 19.
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.
CMS3232LAx-75Ex
T0
T1
T2
T3
Command
Write
Write
Write
Write
Address
Bank
Col n
Bank
Col a
Bank
Col x
Bank
Col m
Din
n
Din
a
Din
x
Din
m
CLK
DQ
Figure 17. Random Write Cycles
T0
T1
T2
Command
Write
NOP
Read
Address
Bank
Col n
DQ
Din
n
T3
T4
T5
CLK
NOP
NOP
Bank
Col b
Din
n+1
Dout
b
Figure 18. Write to Read Burst of 2 Write and Read(CAS Latency =2)
Rev0.2, Aug. 2006
NOP
Dout
b+1
CMS3232LAx-75Ex
T0
CLK
T2
T1
T3
T4
T5
T6
Active
NOP
NOP
NOP
Active
tWR @ tCK >=15ns
DQM
tRP
Command
Write
Address
Bank
Col n
NOP
Precharge
NOP
Bank
(a or all)
Bank a
Row
tWR
DQ
DQM
Din
n+1
Din
n
tWR @ tCK <=15ns
tRP
Command
Write
Address
Bank
Col n
NOP
NOP
Precharge
NOP
Bank
(a or all)
Bank a
Row
tWR
DQ
Din
n+1
Din
n
Figure 19. Write to Precharge
T0
T1
T2
CLK
Burst
Terminate
Next
Command
Command
Write
Address
Bank
Col n
(Address)
Din
n
(Data)
DQ
Figure 20. Terminating a Write Burst
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
Rev0.2, Aug. 2006
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
CMS3232LAx-75Ex
command. This is shown in Figure 20. , where data n is the last
desired data element of a longer burst.
PRECHARGE
The PRECHARGE command (see Figure 21. ) 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 BS select the bank.
W hen all b a nk s ar e to be precharged, inputs BS is
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.
Rev0.2, Aug. 2006
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 any bank, this mode is
referred to as active power-down. Entering power-down
deactivates the input and output buffers, excluding CKE, for
maximum power savings while in standby. The device may
not remain in the power-down 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 22. .
CMS3232LAx-75Ex
Precharge Command
CLK
CKE
High
/CS
/RAS
/CAS
/WE
A0-A9
All banks
A10
Bank Selected
BS
Bank
Address
Don’t Care
Figure 21. Precharge Command
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
CLK
>=tCKS
tCKS
CKE
NOP
Command
All banks Idle
NOP
Active
tRCD
tRAS
Input buffers gated off
tRC
Enter Power Down Mode
Exit Power Down Mode
Figure 22. Power Down
CLOCK SUSPEND
The clock suspend mode occurs when a column access/
burst is in progress and CKE is registered LOW. In the clock
suspend mode, the internal clock is deactivated, “freezing”
the synchronous logic. For each positive clock edge on which
CKE is sampled LOW, the next internal positive clock edge is
suspended. Any command or data present on the input pins
at the time of a suspended internal clock edge is ignored; any
data present on the DQ pins remains driven; and burstcounters are not incremented, as long as the clock is suspended. (See examples in Figure 23. and Figure 24. .) Clock
Rev0.2, Aug. 2006
suspend mode is exited by registering CKE HIGH; the internal
clock and related operation will resume on the subsequent
positive clock edge.
BURST READ/SINGLE WRITE
In this mode, all WRITE commands result in the access of a
single column location (burst of one), regardless of the programmed burst length. The burst read/single write mode is entered
by programming the write burst mode bit (M9) in the mode
register to a logic 1. READ commands access columns
according to the programmed burst length and sequence.
CMS3232LAx-75Ex
T0
T1
T2
T3
T4
T5
CLK
CKE
Internal
CLK
Command
NOP
Write
Address
Bank
Col n
DQ
Din
n
NOP
NOP
Din
n+1
Din
n+2
Figure 23. Clock Suspend During Write Burst
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
T0
T1
T2
T3
T4
T5
T6
CLK
CKE
Internal
CLK
Command
Read
Address
Bank
Col n
NOP
NOP
Dout
n
DQ
NOP
Dout
n+1
NOP
Dout
n+2
NOP
Dout
n+3
Figure 24. Clock Suspend During Read Burst - Burst of 4 (CAS latency =2)
Concurrent Auto Precharge
If an access command with Auto Precharge is being execeuted
an access command (either a Read or Write ) is not allowed by
SDRAM’s. If this feature is allowed then the SDRAM supports
Concurrent Auto Precharge. Fidelix SDRAMs support
Concurrent Auto Precharge. Four casees where Concurrent
Auto Precharge occurs are defined below.
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. (Figure 25. )
2. Interrupted by a Write(with or without auto precharge): A
Write to bank m will interrupt a Read on bank n when registered.
Rev0.2, Aug. 2006
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. (Figure 26. )
Write with Auto Precharge
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 one clock prior to the Read to
bank m.(Figure 27. )
4. Interrupted by a Write ( with or without auto Precharge): A
Write to bank m will interrupt a Write on bank n when registered.
The Precharge to bank n will begin after tWR is met ,where tWR
begins when the Write to bank m is registered. The latest valid
data Write to bank n will be data registered one clock prior to a
Write to bank m.( Figure 28. )
CMS3232LAx-75Ex
T0
T1
T2
Read-AP
Bank n
NOP
T3
T4
T5
T6
NOP
NOP
NOP
T7
CLK
Command
NOP
Read
Bank m
Internal States
NOP
tRP - Bank m
tRP - Bank n
Bank n
Page
Active
Bank m
Page Active
Read with a Burst of 4
Idle
Read with Burst of 4
Bank n
Col a
Address
Interrupt Burst, Precharge
Precharge
Bank m
Col d
Dout
a
DQ
Dout
a+1
Dout
d
Dout
d+1
CAS Latency=3(Bank n)
CAS Latency=3(Bank m)
Figure 25. Read with Auto Precharge Interrupted by a Read(CAS Latency =3)
T0
T1
T2
Read-AP
Bank n
NOP
NOP
T3
T4
T5
T6
T7
CLK
Command
NOP
Write
Bank m
NOP
tRP - Bank n
Internal States
Bank n
Page
Active
Bank m
Page Active
Address
NOP
Read with a Burst of 4
NOP
tWR - Bank m
Interrupt Burst, Precharge
Write with Burst of 4
Idle
Write-Bank
Bank m
Col d
Bank n
Col a
DQM
Dout
a
DQ
Din
d
Din
d+1
Din
d+2
CAS Latency=3(Bank n)
Figure 26. Read With Auto Precharge Interrupted by a Write(Read CAS Latency =3)
Rev0.2, Aug. 2006
Din
d+3
CMS3232LAx-75Ex
T0
T1
T2
Write-AP
Bank n
NOP
T3
T4
T5
T6
NOP
NOP
NOP
T7
CLK
Command
NOP
Internal States
NOP
tRP - Bank m
tWR- Bank n
Page
Active
Bank n
Read-AP
Bank m
Write with a Burst of 4
Interrupt Burst, Write-Bank
Precharge
tRP - Bank n
Bank m
Page Active
Read with Burst of 4
Bank n
Col a
Address
Din
a
DQ
Precharge
Bank m
Col d
Din
a+1
Dout
d
Dout
d+1
CAS Latency=3(Bank m)
Figure 27. Write with Auto Precharge Interrupted by a Read with Auto Precharge (CAS Latency =3)
T0
T1
T2
NOP
Write-AP
Bank n
NOP
T3
T4
T5
T6
NOP
NOP
T7
CLK
Command
NOP
Internal States
Bank n
Write-AP
Bank m
tWR -Bank n
Page
Active
Write with a Burst of 4
NOP
tRP -Bank n
Interrupt Burst, Write-Bank
Precharge
tWR - Bank m
Bank m
Address
DQ
Page Active
Write with Burst of 4
Bank n
Col a
Din
a
Write-Bank
Bank m
Col d
Din
a+1
Din
a+2
Din
d
Din
d+1
Din
d+2
Figure 28. Write with Auto Precharge Interrupted by a Write with Auto Precharge
Rev0.2, Aug. 2006
Din
d+3
CMS3232LAx-75Ex
DEEP POWER DOWN MODE ENTRY
The Deep Power Down Mode is entered by having burst termination command, while CKE is low. The Deep Power Down
Mode has to be maintained for a minimum of 100us.
The following diagram illustrates Deep Power Down mode entry.
CLK
CKE
tRP
Command
NOP
Precharge
All Bank
NOP
NOP
Precharge
If needed
Burst
Terminate
Deep Power Down
Entry
Figure 29. Deep Power Down Mode Entry
DEEP POWER DOWN MODE EXIT SEQUENCE
The Deep Power Down Mode is exited by asserting CKE high.
After the exit, the following sequence is needed to enter a new command
1. Maintain NOP input conditions for a minimum of 200us
2. Issue precharge commands for all banks of the device
3. Issue 8 or more auto refresh commands
4. Issue a mode register set command to initialize the mode register
5. Issue a extended mode register set command to initialize the extended mode register
The following timing diagram illustrates deep power down exit sequence
CLK
CKE
Precharge
All Bank
Command
Address
NOP
AREF
A10
Precharge
All Bank
Figure 30. Deep Power Down Mode Exit
Rev0.2, Aug. 2006
NOP EMRS NOP Active
Key
Key
Bank a
Row
Normal
MRS
Extended
MRS
Row Active
A Bank
tRP
200 us
Deep Power Down
Exit
MRS
CMS3232LAx-75Ex
Table 9. CKE[50.51.52.53.] .
CKEn-1
CKEn
L
L
L
H
H
L
H
H
Current State
Commandn
Actionn
Power Down
X
Maintain Power Down
Self Refresh
X
Maintain Self Refresh
Clock Suspend
X
Maintain Clock Suspend
Power Down[54.]
Self Refresh[55.]
Command Inhibit or NOP
Command Inhibit or NOP
Exit Power Down
Exit Self Refresh
Clock Suspend[56.]
X
Exit Clock Suspend
All Banks Idle
Command Inhibit or NOP
Power Down Entry
All Banks Idle
Reading or Writing
Auto Refresh
Valid
Self Refresh Entry
Clock Suspend Entry
See Table 10.
Note :
50.
51.
52.
53.
54.
55.
CKEn is the logic state of CKE at clock edge n; CKEn-1 was the state of CKE at the previous clock edge.
Current State is the state of the SDRAM immediatly prior to the clock edge n.
Commandn is the command registered at clock edge n , and Actionn is a result of Commandn.
All states and sequences not shown are illegal or reserved.
Exiting power down at clock edge n will put the device in all the banks idle state in time for clock edge n+1(provided the tCKS is met)
Exiting self refresh at clock edge n will put the device in all the banks idle state once tXSR is met. Command Inhibit or NOP commands should be issued on any clock edges
occuring during the tXSR period. A minimum of two NOP commands must be provided during the tXSR period.
56. After exiting clock suspend at clock edge n, the device will resume operation and recognize the next command at clock edge n+1.
Table 10. Curent State Bank n, Command to Bank n[57.58.59.60.61.62.] .
Current State
Any
Idle
CS#
RAS#
CAS#
WE#
Command(Action)
H
X
X
X
L
H
H
H
NO OPERATION (NOP/Continue previous operation)
L
L
H
H
ACTIVE (Select and activate row)
L
L
L
H
AUTO REFRESH[63.]
L
L
L
L
LOAD MODE REGISTER [63.]
L
L
H
L
PRECHARGE [67.]
COMMAND INHIBIT (NOP/Continue previous operation)
Note :
57. This table applies when CKEn-1 was HIGH and CKEn is HIGH (see Table 9. ) and after tXSR has been met (if the previous state was self refresh).
58. 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.
59. 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.
60. 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 Table 10. and according to
Table 11. . 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.
61. 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.
62. All states and sequences not shown are illegal or reserved.
63. Not bank-specific; requires that all banks are idle.
64. May or may not be bank-specific; if all banks are to be precharged, all must be in a valid state for precharging.
65. Not bank-specific; BURST TERMINATE affects the most recent READ or WRITE burst, regardless of bank.
66. 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.
67. Does not affect the state of the bank and acts as a NOP to that bank.
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
Table 10. Curent State Bank n, Command to Bank n[57.58.59.60.61.62.] .
Current State
Row
Active
Read(Auto
Precharge
Disabled)
Write
(Auto
Precharge
Disabled)
CS#
RAS#
CAS#
WE#
L
H
L
H
READ (Select column and start READ burst)[66.]
Command(Action)
L
H
L
L
WRITE (Select column and start WRITE burst)[66.]
L
L
H
L
PRECHARGE (Deactivate row in bank or banks)[64.]
L
H
L
H
READ (Select column and start new READ burst)[66.]
L
H
L
L
WRITE (Select column and start WRITE burst)[66.]
L
L
H
L
PRECHARGE (Truncate READ burst, start RECHARGE)[64.]
L
H
H
L
BURST TERMINATE[65.]
L
H
L
H
READ (Select column and start READ burst)[66.]
L
H
L
L
WRITE (Select column and start new WRITE burst)[66.]
L
L
H
L
PRECHARGE (Truncate WRITE burst, start PRECHARGE)[64.]
L
H
H
L
BURST TERMINATE[65.]
Table 11. Current State Bank n, Command to Bank m[68.69.70.71.72.73.] .
Current State
Any
Idle
Row Activating,
Active, or
Precharging
Read(Auto
Precharge
Disabled)
Write(Auto
Precharge
Disabled)
Rev0.2, Aug. 2006
CS#
RAS#
CAS#
WE#
Command(Action)
H
X
X
X
COMMAND INHIBIT (NOP/Continue previous operation)
L
H
H
H
NO OPERATION (NOP/Continue previous operation)
X
X
X
X
Any Command Otherwise Allowed to Bank m
L
L
H
H
ACTIVE (Select and activate row)
L
H
L
H
READ (Select column and start READ burst)[74.]
L
H
L
L
WRITE (Select column and start WRITE burst)[74.]
L
L
H
L
PRECHARGE
L
L
H
H
ACTIVE (Select and activate row)
L
H
L
H
READ (Select column and start new READ burst)[74.78.]
L
H
L
L
WRITE (Select column and start WRITE burst)[74.79.]
L
L
H
L
PRECHARGE[76.]
L
L
H
H
ACTIVE (Select and activate row)
L
H
L
H
READ (Select column and start READ burst)[74.79.]
L
H
L
L
WRITE (Select column and start new WRITE burst)[76.80.]
L
L
H
L
PRECHARGE[76.]
CMS3232LAx-75Ex
Table 11. Current State Bank n, Command to Bank m[68.69.70.71.72.73.] .
Current State
Read
(With Auto
Precharge)
Write
(With Auto
Precharge)
CS#
RAS#
CAS#
WE#
L
L
H
L
ACTIVE (Select and activate row)
Command(Action)
L
H
L
H
READ (Select column and start new READ burst)[74.75.81.]
L
H
L
L
WRITE (Select column and start WRITE burst)[74.75.82.]
L
L
H
L
PRECHARGE[76.]
L
L
H
H
ACTIVE (Select and activate row)
L
H
L
H
READ (Select column and start READ burst)[74.75.83.]
L
H
L
L
WRITE (Select column and start new WRITE burst)[74.75.84.]
L
L
H
L
PRECHARGE[76.]
Note :
68. This table applies when CKEn-1 was HIGH and CKEn is HIGH and after tXSR has been met (if the previous state was self refresh).
69. 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.
70. 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.
71. AUTO REFRESH, SELF REFRESH and LOAD MODE REGISTER commands may only be issued when all banks are idle.
72. A BURST TERMINATE command cannot be issued to another bank; it applies to the bank represented by the current state only.
73. All states and sequences not shown are illegal or reserved.
74. 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.
75. CONCURRENT AUTO PRECHARGE: Bank n will initiate the auto precharge command when its burst has been interrupted by bank m’s burst.
76. Burst in bank n continues as initiated.
77. 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.
78. 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.
DQM should be used twwo clock prior to the WRITE command to prevent bus contention.
79. 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,
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.
80. 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.
The last valid WRITE to bank n will be data-in registered one clock prior to the READ to bank m.
81. 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 (Figure 25.) .
82. 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 (Figure 26. ).
83. 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(Figure 27. ).
84. 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 tWR 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 (Figure 28. ).
Rev0.2, Aug. 2006
CMS3232LAx-75Ex
PACKAGE DIMENSION
Unit : millimeters
90 BALL FINE PITCH BGA (8 x 13 x 1.2 mm)
Top View
Bottom View
A1 INDEX MARK
E1
E
1
#A1
2
3
4
5
6
7
8
9
9
A
A
B
B
C
C
D
D
E
E
F
F
G
G
D1
D
H
8
7
6
5
4
3
2
1
e
H
J
J
K
K
L
L
M
M
N
N
P
P
R
R
D/2
e
E/2
Side View
z
b
A1
A
E
Rev0.2, Aug. 2006
A
A1
E
E1
D
D1
e
b
z
Min
0.30
0.40
-
Typ
0.35
8.00
6.40
13.00
11.20
0.80
0.45
-
Unit : mm
Max
1.20
0.40
0.50
0.10