ESMT M12L128168A-6BIG

ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
2M x 16 Bit x 4 Banks
SDRAM
Synchronous DRAM
FEATURES
y
y
y
y
y
y
y
y
y
ORDERING INFORMATION
JEDEC standard 3.3V power supply
LVTTL compatible with multiplexed address
Four banks operation
MRS cycle with address key programs
- CAS Latency ( 2 & 3 )
- Burst Length ( 1, 2, 4, 8 & full page )
- Burst Type ( Sequential & Interleave )
All inputs are sampled at the positive going edge of the
system clock
Burst Read single write operation
DQM for masking
Auto & self refresh
64ms refresh period (4K cycle)
PRODUCT NO.
MAX FREQ. PACKAGE COMMENTS
M12L128168A-5TIG
200MHz
TSOP II
Pb-free
M12L128168A-5BIG
200MHz
BGA
Pb-free
M12L128168A-6TIG
166MHz
TSOP II
Pb-free
M12L128168A-6BIG
166MHz
BGA
Pb-free
M12L128168A-7TIG
143MHz
TSOP II
Pb-free
M12L128168A-7BIG
143MHz
BGA
Pb-free
GENERAL DESCRIPTION
The M12L128168A is 134,217,728 bits synchronous high data rate Dynamic RAM organized as 4 x 2,097,152 words by 16 bits.
Synchronous design allows precise cycle control with the use of system clock I/O transactions are possible on every clock cycle.
Range of operating frequencies, programmable burst length and programmable latencies allow the same device to be useful for a
variety of high bandwidth, high performance memory system applications.
Pin Arrangement (Top View)
VDD
DQ0
VDDQ
DQ1
DQ2
V S SQ
DQ3
DQ4
VDDQ
DQ5
DQ6
V S SQ
DQ7
VDD
LDQM
WE
CAS
RAS
CS
A13
A12
A10 /AP
A0
A1
A2
A3
VDD
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
V SS
DQ15
V S SQ
DQ14
DQ13
VDDQ
DQ12
DQ11
V S SQ
DQ10
DQ9
VDDQ
DQ8
V SS
NC
UDQM
CLK
CKE
NC
A11
A9
A8
A7
A6
A5
A4
V SS
Elite Semiconductor Memory Technology Inc.
1
2
3
A
VSS
DQ15
B
DQ14
C
4
5
6
7
8
9
VSSQ
VDDQ
DQ0
VDD
DQ13
VDDQ
VSSQ
DQ2
DQ1
DQ12
DQ11
VSSQ
VDDQ
DQ4
DQ3
D
DQ10
DQ9
VDDQ
VSSQ
DQ6
DQ5
E
DQ8
NC
VSS
VDD
LDQM
DQ7
F
UDQM
CLK
CKE
CAS
RAS
WE
G
NC
A11
A9
A13
A12
CS
H
A8
A7
A6
A0
A1
A10
J
VSS
A5
A4
A3
A2
VDD
Publication Date: Oct. 2007
Revision: 1.2
1/43
ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
BLOCK DIAGRAM
CKE
Clock
Generator
Bank D
Bank C
Bank B
Address
Mode
Register
Row
Address
Buffer
&
Refresh
Counter
Row Decoder
CLK
Bank A
CAS
WE
Address
L(U)DQM
Column Decoder
Buffer
&
Counter
Data Control Circuit
Input & Output
Buffer
RAS
Column
Latch Circuit
CS
Control Logic
Command Decoder
Sense Amplifier
DQ
PIN DESCRIPTION
PIN
NAME
INPUT FUNCTION
CLK
System Clock
Active on the positive going edge to sample all inputs
Disables or enables device operation by masking or enabling all
inputs except CLK , CKE and L(U)DQM
CS
Chip Select
CKE
Clock Enable
Masks system clock to freeze operation from the next clock cycle.
CKE should be enabled at least one cycle prior new command.
Disable input buffers for power down in standby.
A0 ~ A11
Address
Row / column address are multiplexed on the same pins.
Row address : RA0~RA11, column address : CA0~CA8
A12 , A13
Bank Select Address
Selects bank to be activated during row address latch time.
Selects bank for read / write during column address latch time.
RAS
Row Address Strobe
Latches row addresses on the positive going edge of the CLK with
CAS
Column Address Strobe
RAS low. (Enables row access & precharge.)
Latches column address on the positive going edge of the CLK with
CAS low. (Enables column access.)
Enables write operation and row precharge.
WE
Write Enable
L(U)DQM
Data Input / Output Mask
Makes data output Hi-Z, tSHZ after the clock and masks the output.
Blocks data input when L(U)DQM active.
DQ0 ~ DQ15
Data Input / Output
Data inputs / outputs are multiplexed on the same pins.
VDD / VSS
Power Supply / Ground
Power and ground for the input buffers and the core logic.
VDDQ / VSSQ
Data Output Power / Ground
Isolated power supply and ground for the output buffers to provide
improved noise immunity.
N.C
No Connection
This pin is recommended to be left No Connection on the device.
Elite Semiconductor Memory Technology Inc.
Latches data in starting from CAS , WE active.
Publication Date: Oct. 2007
Revision: 1.2
2/43
ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Value
Unit
Voltage on any pin relative to VSS
VIN, VOUT
-1.0 ~ 4.6
V
Voltage on VDD supply relative to VSS
VDD, VDDQ
-1.0 ~ 4.6
V
TSTG
-55 ~ +150
°C
Power dissipation
PD
1
W
Short circuit current
IOS
50
mA
Storage temperature
Note :
Permanent device damage may occur if ABSOLUTE MAXIMUM RATING are exceeded.
Functional operation should be restricted to recommended operating condition.
Exposure to higher than recommended voltage for extended periods of time could affect device reliability.
DC OPERATING CONDITION
Recommended operating conditions (Voltage referenced to VSS = 0V, TA = -40 to 85 °C )
Parameter
Supply voltage
Symbol
Min
Typ
Max
Unit
VDD, VDDQ
3.0
3.3
3.6
V
Note
Input logic high voltage
VIH
2.0
3.0
VDD+0.3
V
1
Input logic low voltage
VIL
-0.3
0
0.8
V
2
Output logic high voltage
VOH
2.4
-
-
V
IOH = -2mA
Output logic low voltage
VOL
-
-
0.4
V
IOL = 2mA
Input leakage current
IIL
-5
-
5
μA
3
Output leakage current
IOL
-5
-
5
μA
4
Note:
1. VIH(max) = 4.6V AC for pulse width ≤ 10ns acceptable.
2. VIL(min) = -1.5V AC for pulse width ≤ 10ns acceptable.
3. Any input 0V ≤ VIN ≤ VDD + 0.3V, all other pins are not under test = 0V.
4. Dout is disabled , 0V ≤ VOUT ≤ VDD.
CAPACITANCE (VDD = 3.3V, TA = 25 °C , f = 1MHZ)
Parameter
Input capacitance (A0 ~ A11, A13 ~ A12)
Input capacitance
Symbol
Min
Max
Unit
CIN1
2.5
4
pF
CIN2
2.5
4
pF
COUT
2
6.5
pF
(CLK, CKE, CS , RAS , CAS , WE & L(U)DQM)
Data input/output capacitance (DQ0 ~ DQ15)
Elite Semiconductor Memory Technology Inc.
Publication Date: Oct. 2007
Revision: 1.2
3/43
ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
DC CHARACTERISTICS
Recommended operating condition unless otherwise noted，TA = -40 to 85 °C
Parameter
Operating Current
(One Bank Active)
Precharge Standby Current
in power-down mode
Precharge Standby Current
in non power-down mode
Active Standby Current
in power-down mode
Symbol
Test Condition
CAS
Latency
Version
-5
-6
-7
170
160
140
ICC1
Burst Length = 1, tRC ≥ tRC(min), IOL = 0 mA
ICC2P
CKE ≤ VIL(max), tcc = tCK(MIN)
2
ICC2PS
CKE & CLK ≤ VIL (max), tCC = ∞
2
ICC2N
CKE ≥ VIH(min), CS ≥ VIH(min), tCC = tCK(MIN)
Input signals are changed one time during 2tck
45
ICC2NS
CKE ≥ VIH(min), CLK ≤ VIL(max), tcc = ∞
input signals are stable
25
ICC3P
CKE ≤ VIL(max), tCC = tCK(MIN)
6
ICC3PS
CKE & CLK ≤ VIL(max), tCC = ∞
6
ICC3N
Input signals are changed one time during 2clks
mA
1,2
mA
mA
55
mA
35
mA
All other pins ≥ VDD-0.2V or ≤ 0.2V
ICC3NS
CKE ≥ VIH(min), CLK ≤ VIL(max), tCC = ∞
input signals are stable
Operating Current
(Burst Mode)
ICC4
IOL = 0 mA, Page Burst, 2 Banks activated
Refresh Current
ICC5
tRC ≥ tRC(min)
Self Refresh Current
ICC6
CKE ≤ 0.2V
Note :
Note
mA
CKE ≥ VIH(min), CS ≥ VIH(min), tCC=15ns
Active Standby Current
in non power-down mode
(One Bank Active)
Unit
280
210
180
mA
280
210
180
mA
2
1,2
mA
1. Measured with outputs open.
2. Input signals are changed one time during 2 CLKS.
Elite Semiconductor Memory Technology Inc.
Publication Date: Oct. 2007
Revision: 1.2
4/43
ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
AC OPERATING TEST CONDITIONS (VDD = 3.3V ± 0.3V，TA = -40 to 85 °C )
Parameter
Input levels (Vih/Vil)
Input timing measurement reference level
Input rise and fall-time
Output timing measurement reference level
Output load condition
Value
Unit
2.4/0.4
V
1.4
V
tr/tf = 1/1
ns
1.4
V
See Fig. 2
Vtt = 1.4V
3.3V
1200
50
Ω
VOH (DC) =2.4V , IOH = -2 mA
Output
VOL (DC) =0.4V , IOL = 2 mA
Output
Z0 =50
Ω
50pF
50pF
870 Ω
Ω
(Fig. 1) DC Output Load Circuit
(Fig. 2) AC Output Load Circuit
OPERATING AC PARAMETER
(AC operating conditions unless otherwise noted)
Version
Parameter
Symbol
-5
-6
-7
Unit
Note
Row active to row active delay
tRRD(min)
10
12
14
ns
1
RAS to CAS delay
tRCD(min)
15
18
20
ns
1
Row precharge time
tRP(min)
15
18
20
ns
1
42
ns
1
tRAS(min)
Row active time
Row cycle time
38
tRAS(max)
40
100
us
@ Operating
tRC(min)
53
58
63
ns
1
@ Auto refresh
tRFC(min)
55
60
70
ns
1,5
Last data in to col. address delay
tCDL(min)
1
tCK
2
Last data in to row precharge
tRDL(min)
2
tCK
2
Last data in to burst stop
tBDL(min)
1
tCK
2
Refresh period (4,096 rows)
tREF(max)
64
ms
6
Elite Semiconductor Memory Technology Inc.
Publication Date: Oct. 2007
Revision: 1.2
5/43
ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
Version
Parameter
Symbol
-5
Col. address to col. address delay
Number of valid
Output data
-6
tCCD(min)
1
CAS latency = 3
2
CAS latency = 2
1
Unit
Note
tCK
3
ea
4
-7
Note : 1. The minimum number of clock cycles is determined by dividing the minimum time required with clock cycle time and then
rounding off to the next higher integer.
2. Minimum delay is required to complete write.
3. All parts allow every cycle column address change.
4. In case of row precharge interrupt, auto precharge and read burst stop.
5. A new command may be given tRFC after self refresh exit.
6. A maximum of eight consecutive AUTO REFRESH commands (with tRFCmin) can be posted to any given SDRAM, and the
maximum absolute interval between any AUTO REFRESH command and the next AUTO REFRESH command is
8x15.6 μ s.)
AC CHARACTERISTICS (AC operating condition unless otherwise noted)
Parameter
-5
Symbol
MIN
CLK cycle time
CAS latency = 3
CAS latency = 2
CLK to valid
output delay
CAS latency = 3
Output data
hold time
CAS latency = 3
CAS latency = 2
CAS latency = 2
tCC
5
10
tSAC
tOH
-6
MAX
1000
MIN
6
10
-7
MAX
1000
MIN
7
10
1000
4.5
5.4
5.4
6
6
6
2
2.5
2.5
2
2.5
2.5
Unit
Note
ns
1
ns
1,2
ns
2
MAX
CLK high pulsh width
tCH
2
2.5
2.5
ns
3
CLK low pulsh width
tCL
2
2.5
2.5
ns
3
Input setup time
tSS
1.5
1.5
1.5
ns
3
Input hold time
tSH
1
1
1
ns
3
CLK to output in Low-Z
tSLZ
1
1
1
ns
2
ns
-
CLK to output
in Hi-Z
Note :
CAS latency = 3
CAS latency = 2
tSHZ
4.5
5.4
5.4
6
6
6
1. Parameters depend on programmed CAS latency.
2. If clock rising time is longer than 1ns. (tr/2 - 0.5) ns should be considered.
3. Assumed input rise and fall time (tr & tf) =1ns.
If tr & tf is longer than 1ns. transient time compensation should be considered.
i.e., [(tr + tf)/2 – 1] ns should be added to the parameter.
Elite Semiconductor Memory Technology Inc.
Publication Date: Oct. 2007
Revision: 1.2
6/43
ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
SIMPLIFIED TRUTH TABLE
COMMAND
Register
CKEn-1
CKEn
H
X
H
L
Mode Register set
Auto Refresh
Entry
Self
Refresh
Exit
Refresh
Bank Active & Row Addr.
Read &
Column Address
Write &
Column Address
Auto Precharge Disable
Auto Precharge Enable
Auto Precharge Disable
Auto Precharge Enable
Burst Stop
Precharge
Bank Selection
All Banks
Clock Suspend or
Active Power Down
Entry
H
L
L
L
L
X
A13
A11
A10/AP
A12
A9~A0
OP CODE
L
L
L
H
X
X
H
X
L
H
X
H
H
X
H
X
X
X
V
CS RAS CAS
WE
DQM
L
H
H
X
L
H
L
H
X
L
H
L
H
X
V
H
X
L
H
L
L
X
V
H
X
L
H
H
L
X
H
X
L
L
H
L
X
H
L
H
X
X
X
L
V
V
V
X
X
X
X
H
X
X
X
L
H
H
H
H
X
X
X
L
V
V
V
Exit
L
H
Entry
H
L
Exit
L
H
Precharge Power Down Mode
DQM
H
No Operating Command
H
X
X
H
X
X
X
L
H
H
H
X
Row Address
Column
L
Address
H
(A0~A8)
Column
L
Address
H
(A0~A8)
X
V
L
X
H
Note
1,2
3
3
3
3
4
4,5
4
4,5
6
X
X
X
X
X
X
X
V
X
X
X
7
(V = Valid , X = Don’t Care. H = Logic High , L = Logic Low )
Note :
1.OP Code : Operating Code
A0~A11 & A13~A12 : Program keys. (@ MRS)
2.MRS can be issued only at all banks precharge state.
A new command can be issued after 2 CLK cycles of MRS.
3.Auto refresh functions are as same as CBR refresh of DRAM.
The automatical precharge without row precharge of command is meant by “Auto”.
Auto/self refresh can be issued only at all banks idle state.
4.A13~A12 : Bank select addresses.
If A13 and A12 are “Low” at read ,write , row active and precharge ,bank A is selected.
If A13 is “Low” and A12 is “High” at read ,write , row active and precharge ,bank B is selected.
If A13 is “High” and A12 is “Low” at read ,write , row active and precharge ,bank C is selected.
If A13 and A12 are “High” at read ,write , row active and precharge ,bank D is selected
If A10/AP is “High” at row precharge , A13 and A12 is ignored and all banks are selected.
5.During burst read or write with auto precharge. new read/write command can not be issued.
Another bank read/write command can be issued after the end of burst.
New row active of the associated bank can be issued at tRP after the end of burst.
6.Burst stop command is valid at every burst length.
7.DQM sampled at positive going edge of a CLK and masks the data-in at the very CLK (write DQM latency is 0), but
makes Hi-Z state the data-out of 2 CLK cycles after.(Read DQM latency is 2)
Elite Semiconductor Memory Technology Inc.
Publication Date: Oct. 2007
Revision: 1.2
7/43
ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
MODE REGISTER FIELD TABLE TO PROGRAM MODES
Register Programmed with MRS
Address
A13~A12
A11~A10/AP
A9
Function
RFU
RFU
W.B.L.
Test Mode
A8
A7
A6
TM
CAS Latency
A5
A4
A3
CAS Latency
A2
BT
A1
A0
Burst Length
Burst Type
Burst Length
A8
A7
Type
A6
A5
A4
Latency
A3
Type
A2
A1
A0
BT = 0
BT = 1
0
0
Mode Register Set
0
0
0
Reserved
0
Sequential
0
0
0
1
1
0
1
Reserved
0
0
1
Reserved
1
Interleave
0
0
1
2
2
1
0
Reserved
0
1
0
2
0
1
0
4
4
1
1
Reserved
0
1
1
3
0
1
1
8
8
1
0
0
Reserved
1
0
0
Reserved Reserved
1
0
1
Reserved
1
0
1
Reserved Reserved
1
1
0
Reserved
1
1
0
Reserved Reserved
1
1
1
Reserved
1
1
1
Full Page Reserved
Full Page Length : 512
POWER UP SEQUENCE
1.Apply power and start clock, Attempt to maintain CKE = ”H”, DQM = ”H” and the other pin are NOP condition at the inputs.
2. Maintain stable power , stable clock and NOP input condition for a minimum of 200us.
3. Issue precharge commands for all banks of the devices.
4. Issue 2 or more auto-refresh commands.
5. Issue mode register set command to initialize the mode register.
cf.) Sequence of 4 & 5 is regardless of the order.
The device is now ready for normal operation.
Note :
1. RFU(Reserved for future use) should stay “0” during MRS cycle.
2. If A9 is high during MRS cycle, “ Burst Read single write” function will be enabled.
Elite Semiconductor Memory Technology Inc.
Publication Date: Oct. 2007
Revision: 1.2
8/43
ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
BURST SEQUENCE (BURST LENGTH = 4)
Initial Adrress
Sequential
Interleave
A1
A0
0
0
0
1
2
3
0
1
2
3
0
1
1
2
3
0
1
0
3
2
1
0
2
3
0
1
2
3
0
1
1
1
3
0
1
2
3
2
1
0
BURST SEQUENCE (BURST LENGTH = 8)
Initial
Sequential
Interleave
A2
A1
A0
0
0
0
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
0
0
1
1
2
3
4
5
6
7
0
1
0
3
2
5
4
7
6
0
1
0
2
3
4
5
6
7
0
1
2
3
0
1
6
7
4
5
0
1
1
3
4
5
6
7
0
1
2
3
2
1
0
7
6
5
4
1
0
0
4
5
6
7
0
1
2
3
4
5
6
7
0
1
2
3
1
0
1
5
6
7
0
1
2
3
4
5
4
7
6
1
0
3
2
1
1
0
6
7
0
1
2
3
4
5
6
7
4
5
2
3
0
1
1
1
1
7
0
1
2
3
4
5
6
7
6
5
4
3
2
1
0
Elite Semiconductor Memory Technology Inc.
Publication Date: Oct. 2007
Revision: 1.2
9/43
ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
DEVICE OPERATIONS
CLOCK (CLK)
POWER-UP
The clock input is used as the reference for all SDRAM
operations. All operations are synchronized to the positive
going edge of the clock. The clock transitions must be
monotonic between VIL and VIH. During operation with CKE
high all inputs are assumed to be in valid state (low or high) for
the duration of setup and hold time around positive edge of the
clock for proper functionality and Icc specifications.
1.Apply power and start clock, Attempt to maintain CKE =
“H”, DQM = “H” and the other pins are NOP condition at
the inputs.
2.Maintain stable power, stable clock and NOP input
condition for minimum of 200us.
3.Issue precharge commands for both banks of the
devices.
4.Issue 2 or more auto-refresh commands.
5.Issue a mode register set command to initialize the
mode register.
cf.) Sequence of 4 & 5 is regardless of the order.
CLOCK ENABLE(CKE)
The clock enable (CKE) gates the clock onto SDRAM. If CKE
goes low synchronously with clock (set-up and hold time same
as other inputs), the internal clock suspended from the next
clock cycle and the state of output and burst address is frozen
as long as the CKE remains low. All other inputs are ignored
from the next clock cycle after CKE goes low. When all banks
are in the idle state and CKE goes low synchronously with
clock, the SDRAM enters the power down mode from the next
clock cycle. The SDRAM remains in the power down mode
ignoring the other inputs as long as CKE remains low. The
power down exit is synchronous as the internal clock is
suspended. When CKE goes high at least “1CLK + tSS” before
the high going edge of the clock, then the SDRAM becomes
active from the same clock edge accepting all the input
commands.
BANK ADDRESSES (A13~A12)
This SDRAM is organized as four independent banks of
2,097,152 words x 16 bits memory arrays. The A13~A12
inputs are latched at the time of assertion of RAS and CAS
to select the bank to be used for the operation. The banks
addressed A13~A12 are latched at bank active, read, write,
mode register set and precharge operations.
ADDRESS INPUTS (A0~A11)
The 21 address bits are required to decode the 2,097,152
word locations are multiplexed into 12 address input pins
(A0~A11). The 12 row addresses are latched along with RAS
and A13~A12 during bank active command. The 9 bit column
addresses are latched along with CAS , WE and A13~A12
during read or with command.
When RAS , CAS and WE are high , The SDRAM
performs no operation (NOP). NOP does not initiate any new
operation, but is needed to complete operations which require
more than single clock cycle like bank activate, burst read,
auto refresh, etc. The device deselect is also a NOP and is
CS
high.
CS
MODE REGISTER SET (MRS)
The mode register stores the data for controlling the
various operating modes of SDRAM. It programs the CAS
latency, burst type, burst length, test mode and various
vendor specific options to make SDRAM useful for variety
of different applications. The default value of the mode
register is not defined, therefore the mode register must
be written after power up to operate the SDRAM. The
mode register is written by asserting low on CS , RAS ,
CAS and WE (The SDRAM should be in active mode
with CKE already high prior to writing the mode register).
The state of address pins A0~A11 and A13~A12 in the
same cycle as CS , RAS , CAS and WE going low is
the data written in the mode register. Two clock cycles is
required to complete the write in the mode register. The
mode register contents can be changed using the same
command and clock cycle requirements during operation
as long as all banks are in the idle state. The mode
register is divided into various fields into depending on
functionality. The burst length field uses A0~A2, burst type
uses A3, CAS latency (read latency from column address)
use A4~A6, vendor specific options or test mode use
A7~A8, A10/AP~A11 and A13~A12. The write burst length
is programmed using A9. A7~A8, A10/AP~A11 and
A13~A12 must be set to low for normal SDRAM
operation. Refer to the table for specific codes for various
burst length, burst type and CAS latencies.
BANK ACTIVATE
NOP and DEVICE DESELECT
entered by asserting
The device is now ready for normal operation.
high disables the
command decoder so that RAS , CAS , WE and all the
address inputs are ignored.
Elite Semiconductor Memory Technology Inc.
The bank activate command is used to select a random
row in an idle bank. By asserting low on RAS and CS
with desired row and bank address, a row access is
initiated. The read or write operation can occur after a
time delay of tRCD(min) from the time of bank activation. tRCD
is the internal timing parameter of SDRAM, therefore it is
dependent on operating clock frequency. The minimum
number of clock cycles required between bank activate
and read or write command should be calculated by
Publication Date: Oct. 2007
Revision: 1.2
10/43
ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
DEVICE OPERATIONS (Continued)
dividing tRCD(min) with cycle time of the clock and then rounding
of the result to the next higher integer. The SDRAM has four
internal banks in the same chip and shares part of the internal
circuitry to reduce chip area, therefore it restricts the activation
of four banks simultaneously. Also the noise generated during
sensing of each bank of SDRAM is high requiring some time
for power supplies to recover before another bank can be
sensed reliably. tRRD(min) specifies the minimum time required
between activating different bank. The number of clock cycles
required between different bank activation must be calculated
similar to tRCD specification. The minimum time required for the
bank to be active to initiate sensing and restoring the complete
row of dynamic cells is determined by tRAS(min). Every SDRAM
bank activate command must satisfy tRAS(min) specification
before a precharge command to that active bank can be
asserted. The maximum time any bank can be in the active
state is determined by tRAS (max) and tRAS(max) can be
calculated similar to tRCD specification.
BURST READ
The burst read command is used to access burst of data on
consecutive clock cycles from an active row in an active bank.
The burst read command is issued by asserting low on CS
and RAS with WE being high on the positive edge of the
clock. The bank must be active for at least tRCD(min) before the
burst read command is issued. The first output appears in CAS
latency number of clock cycles after the issue of burst read
command. The burst length, burst sequence and latency from
the burst read command is determined by the mode register
which is already programmed. The burst read can be initiated
on any column address of the active row. The address wraps
around if the initial address does not start from a boundary
such that number of outputs from each I/O are equal to the
burst length programmed in the mode register. The output
goes into high-impedance at the end of burst, unless a new
burst read was initiated to keep the data output gapless. The
burst read can be terminated by issuing another burst read or
burst write in the same bank or the other active bank or a
precharge command to the same bank. The burst stop
command is valid at every page burst length.
BURST WRITE
The burst write command is similar to burst read command
and is used to write data into the SDRAM on consecutive clock
cycles in adjacent addresses depending on burst length and
burst sequence. By asserting low on CS , CAS and WE
with valid column address, a write burst is initiated. The data
inputs are provided for the initial address in the same clock
cycle as the burst write command. The input buffer is
deselected at the end of the burst length, even though the
internal writing can be completed yet. The writing can be
complete by issuing a burst read and DQM for blocking data
inputs or burst write in the same or another active bank. The
burst stop command is valid at every burst length. The write
burst can also be terminated by using DQM for blocking data
and precharge the bank tRDL after the last data input to be
written into the active row. See DQM OPERATION also.
Elite Semiconductor Memory Technology Inc.
DQM OPERATION
The DQM is used mask input and output operations. It
works similar to OE during operation and inhibits writing
during write operation. The read latency is two cycles from
DQM and zero cycle for write, which means DQM masking
occurs two cycles later in read cycle and occurs in the
same cycle during write cycle. DQM operation is
synchronous with the clock. The DQM signal is important
during burst interrupts of write with read or precharge in
the SDRAM. Due to asynchronous nature of the internal
write, the DQM operation is critical to avoid unwanted or
incomplete writes when the complete burst write is
required. Please refer to DQM timing diagram also.
PRECHARGE
The precharge is performed on an active bank by
asserting low on clock cycles required between bank
activate and clock cycles required between bank activate
and CS , RAS , WE and A10/AP with valid A13~A12 of
the bank to be procharged. The precharge command can
be asserted anytime after tRAS(min) is satisfy from the bank
active command in the desired bank. tRP is defined as the
minimum number of clock cycles required to complete row
precharge is calculated by dividing tRP with clock cycle
time and rounding up to the next higher integer. Care
should be taken to make sure that burst write is
completed or DQM is used to inhibit writing before
precharge command is asserted. The maximum time any
bank can be active is specified by tRAS(max). Therefore,
each bank has to be precharge with tRAS(max) from the
bank activate command. At the end of precharge, the
bank enters the idle state and is ready to be activated
again. Entry to power-down, Auto refresh, Self refresh and
Mode register set etc. is possible only when all banks are
in idle state.
AUTO PRECHARGE
The precharge operation can also be performed by using
auto precharge. The SDRAM internally generates the
timing to satisfy tRAS(min) and “tRP” for the programmed burst
length and CAS latency. The auto precharge command is
issued at the same time as burst write by asserting high on
A10/AP, the bank is precharge command is asserted.
Once auto precharge command is given, no new
commands are possible to that particular bank until the
bank achieves idle state.
FOUR BANKS PRECHARGE
Four banks can be precharged at the same time by using
Precharge all command. Asserting low on CS , RAS ,
and WE with high on A10/AP after all banks have
satisfied tRAS(min) requirement, performs precharge on all
banks. At the end of tRP after performing precharge all, all
banks are in idle state.
Publication Date: Oct. 2007
Revision: 1.2
11/43
ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
DEVICE OPERATIONS (Continued)
AUTO REFRESH
SELF REFRESH
The storage cells of SDRAM need to be refreshed every 64ms
to maintain data. An auto refresh cycle accomplishes refresh of
a single row of storage cells. The internal counter increments
automatically on every auto refresh cycle to refresh all the
rows. An auto refresh command is issued by asserting low on
The self refresh is another refresh mode available in the
SDRAM. The self refresh is the preferred refresh mode for
data retention and low power operation of SDRAM. In self
refresh mode, the SDRAM disables the internal clock and
all the input buffers except CKE. The refresh addressing
and timing is internally generated to reduce power
consumption.
The self refresh mode is entered from all banks idle state
CS , RAS and CAS with high on CKE and WE . The auto
refresh command can only be asserted with all banks being in
idle state and the device is not in power down mode (CKE is
high in the previous cycle). The time required to complete the
auto refresh operation is specified by tRFC(min). The minimum
number of clock cycles required can be calculated by driving
tRFC with clock cycle time and them rounding up to the next
higher integer. The auto refresh command must be followed by
NOP’s until the auto refresh operation is completed. The auto
refresh is the preferred refresh mode when the SDRAM is
being used for normal data transactions. The auto refresh
cycle can be performed once in 15.6us.
Elite Semiconductor Memory Technology Inc.
by asserting low on CS , RAS , CAS and CKE with
high on WE . Once the self refresh mode is entered, only
CKE state being low matters, all the other inputs including
clock are ignored to remain in the refresh.
The self refresh is exited by restarting the external clock
and then asserting high on CKE. This must be followed by
NOP’s for a minimum time of tRFC before the SDRAM
reaches idle state to begin normal operation. It is
recommended to use burst 4096 auto refresh cycles
immediately before and after self refresh.
Publication Date: Oct. 2007
Revision: 1.2
12/43
ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
COMMANDS
Mode register set command
CLK
CKE
( CS , RAS , CAS , WE = Low)
The M12L128168A has a mode register that defines how the device operates. In
this command, A0 through A13 are the data input pins. After power on, the mode
register set command must be executed to initialize the device.
The mode register can be set only when all banks are in idle state.
During 2CLK following this command, the M12L128168A cannot accept any
other commands.
H
CS
RAS
CAS
WE
A12, A13
A10
Add
Fig. 1 Mode register set
command
Activate command
( CS , RAS = Low, CAS , WE = High)
CLK
CKE
CS
The M12L128168A has four banks, each with 4,096 rows.
This command activates the bank selected by A12 and A13 (BS) and a row
address selected by A0 through A11.
This command corresponds to a conventional DRAM’s RAS falling.
H
RAS
CAS
WE
A12, A13
(Bank select)
A10
Row
Add
Row
Fig. 2 Row address strobe and
bank active command
Precharge command
CLK
CKE
( CS , RAS , WE = Low, CAS = High )
This command begins precharge operation of the bank selected by A12 and A13
(BS). When A10 is High, all banks are precharged, regardless of A12 and A13. When
A10 is Low, only the bank selected by A12 and A13 is precharged.
After this command, the M12L128168A can’t accept the activate command to the
precharging bank during tRP (precharge to activate command period).
This command corresponds to a conventional DRAM’s RAS rising.
H
CS
RAS
CAS
WE
A12, A13
(Bank select)
A10
(Precharge select)
Add
Fig. 3 Precharge command
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Publication Date: Oct. 2007
Revision: 1.2
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ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
Write command
CLK
( CS , CAS , WE = Low, RAS = High)
If the mode register is in the burst write mode, this command sets the burst start
address given by the column address to begin the burst write operation. The first
write data in burst can be input with this command with subsequent data on following
clocks.
CKE
H
CS
RAS
CAS
WE
A12, A13
(Bank select)
A10
Add
Col.
Fig. 4 Column address and
write command
CLK
Read command
( CS , CAS = Low, RAS , WE = High)
Read data is available after CAS latency requirements have been met.
This command sets the burst start address given by the column address.
CKE
H
CS
RAS
CAS
WE
A12, A13
(Bank select)
A10
Add
Col.
Fig. 5 Column address and
read command
CLK
CBR (auto) refresh command
CKE
( CS , RAS , CAS = Low, WE , CKE = High)
This command is a request to begin the CBR refresh operation. The refresh
address is generated internally.
Before executing CBR refresh, all banks must be precharged.
After this cycle, all banks will be in the idle (precharged) state and ready for a
row activate command.
During tRC period (from refresh command to refresh or activate command), the
M12L128168A cannot accept any other command.
H
CS
RAS
CAS
WE
A12, A13
(Bank select)
A10
Add
Fig. 6 Auto refresh command
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Publication Date: Oct. 2007
Revision: 1.2
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ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
Self refresh entry command
( CS , RAS , CAS , CKE = Low , WE = High)
After the command execution, self refresh operation continues while CKE
remains low. When CKE goes to high, the M12L128168A exits the self refresh mode.
During self refresh mode, refresh interval and refresh operation are performed
internally, so there is no need for external control.
Before executing self refresh, all banks must be precharged.
CLK
CKE
CS
RAS
CAS
WE
A12, A13
(Bank select)
A10
Add
Fig. 7 Self refresh entry
command
Burst stop command
CLK
CKE
H
( CS , WE = Low, RAS , CAS = High)
CS
This command terminates the current burst operation.
Burst stop is valid at every burst length.
RAS
CAS
WE
A12, A13
(Bank select)
A10
Add
Fig. 8 Burst stop command
CLK
No operation
( CS = Low , RAS , CAS , WE = High)
This command is not a execution command. No operations begin or terminate by
this command.
CKE
H
CS
RAS
CAS
WE
A12, A13
(Bank select)
A10
Add
Fig. 9 No operation
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Publication Date: Oct. 2007
Revision: 1.2
15/43
ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
BASIC FEATURE AND FUNCTION DESCRIPTIONS
1. CLOCK Suspend
1) Clock Suspended During W rite (BL=4)
2) Clock Suspended During Read (BL=4)
CLK
CMD
WR
RD
CKE
Masked by CKE
Internal
CLK
DQ(CL2)
D0
D1
D2
D3
DQ(CL3)
D0
D1
D2
D3
Q0
Q1
Q2
Q3
Q1
Q2
Q3
Not W ritten
Q0
Suspe nded Dout
2. DQM Operation
2)Read Mask (BL=4)
1)Write Mask (BL=4)
CLK
CMD
RD
WR
DQM
Ma s k e d b y D Q M
Ma s k e d b y D Q M
DQ(CL2)
D0
D1
D3
DQ(CL3)
D0
D1
D3
Q0
Hi-Z
Hi-Z
DQ M t o D at a- i n M as k = 0
Q2
Q3
Q1
Q2
Q3
DQ M to D at a- ou t M ask = 2
*Note2
3)DQM with clcok su sp end ed (F ull Page Read )
CLK
CMD
RD
CKE
Internal
CLK
DQM
DQ( CL2 )
DQ(CL3)
Q0
Hi- Z
Hi-Z
Q2
Q1
Hi- Z
Hi-Z
Q4
Q3
Hi- Z
Hi-Z
Q6
Q7
Q8
Q5
Q6
Q7
*Note : 1. CKE to CLK disable/enable = 1CLK.
2. DQM masks data out Hi-Z after 2CLKs which should masked by CKE ”L”.
3. DQM masks both data-in and data-out.
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ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
3. CAS Interrupt (I)
*N ote1
1)R ea d i nt er ru pt ed by R ead (B L =4)
CL K
C MD
RD
RD
ADD
A
B
DQ ( C L 2 )
QA0
D Q ( CL 3 )
QB0
QB1
QB2
QB3
QA0
QB0
QB1
QB2
QB3
t
C CD
*N ot e 2
2) Wr i t e i n t er ru pt e d b y W ri t e (B L= 2)
3 )W ri t e in t er rup t ed b y R e ad (B L=2 )
CLK
C MD
WR
WR
t CC D
A DD
DQ
WR
tC CD
* No t e 2
A
B
DA0
DB 0
A
D B1
t
CDL
* No t e 3
DQ ( C L 2 )
DA0
D Q ( CL 3 )
DA 0
RD
*N ote 2
B
DB0
DB1
DB 0
DB1
t
CDL
* No t e 3
*Note : 1. By “interrupt” is meant to stop burst read/write by external before the end of burst.
By ” CAS interrupt ”, to stop burst read/write by CAS access ; read and write.
2. tCCD : CAS to CAS delay. (=1CLK)
3. tCDL : Last data in to new column address delay. (=1CLK)
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Publication Date: Oct. 2007
Revision: 1.2
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ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
4. CAS Interrupt (II) : Read Interrupted by Write & DQM
( a) CL =2 , B L= 4
CLK
i)CMD
RD
WR
DQM
DQ
ii)CMD
D0
RD
D1
D2
D3
D1
D2
D3
D1
D2
D3
D1
D2
WR
DQM
Hi-Z
DQ
iii)CMD
D0
WR
RD
DQM
Hi-Z
DQ
iv)CMD
D0
WR
RD
DQM
DQ
Q0
HHi -i -ZZ
D0
D3
*Note1
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ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
(b) CL =3 ,B L= 4
CLK
i)CMD
RD
WR
DQM
DQ
D0
ii)CMD
D1
D2
D3
D1
D2
D3
D1
D2
D3
D1
D2
D3
D1
D2
WR
RD
DQM
DQ
D0
iii)CMD
RD
WR
DQM
D0
DQ
iv)CMD
WR
RD
DQM
Hi-Z
DQ
v)CM D
D0
RD
WR
DQM
DQ
Q0
Hi-Z
D0
D3
*Note1
*Note : 1. To prevent bus contention, there should be at least one gap between data in and data out.
5. Write Interrupted by Precharge & DQM
C LK
CMD
PRE
WR
* N ot e 3
*N o te 2
DQ M
DQ
D0
D1
D2
D3
tR D L ( m in )
M a sk ed
by
D Q M
*Note : 1. To prevent bus contention, DQM should be issued which makes at least one gap between data in and data out.
2. To inhibit invalid write, DQM should be issued.
3. This precharge command and burst write command should be of the same bank, otherwise it is not precharge interrupt
but only another bank precharge of four banks operation.
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Publication Date: Oct. 2007
Revision: 1.2
19/43
ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
6. Precharge
1) Nor mal W rit e (B L=4)
2) Norm al Read (B L= 4)
CLK
CLK
CMD
WR
DQ
D0
PRE
CMD
RD
PRE
CL=2
Q2
Q3
*Note2
D1
D2
DQ( CL2)
D3
tRDL
Q0
Q1
PRE CL= 3
CMD
*Note1
*Note2
DQ ( CL 3 )
Q0
Q1
Q2
Q3
.
7. Auto Precharge
1)Normal W rit e (BL=4)
2)Normal Read (BL=4)
CLK
CMD
DQ
CLK
CMD
WR
D0
D1
D2
D3
DQ( CL 2)
tRDL
RD
D0
D1
D2
D3
D0
D1
D2
(min )
DQ(CL3)
D3
*Note3
Auto Pr ech arge st art s
*Note3
Auto Pr ech arge st art s
*Note : 1. tRDL : Last data in to row precharge delay.
2. Number of valid output data after row precharge : 1,2 for CAS Latency = 2,3 respectively.
3. The row active command of the precharge bank can be issued after tRP from this point.
The new read/write command of other activated bank can be issued from this point.
At burst read/write with auto precharge, CAS interrupt of the same/another bank is illegal.
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Revision: 1.2
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ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
8. Burst Stop & Interrupted by Precharge
1)W rite Burst Stop (BL=8)
1)Write interrupted by precharge (BL=4)
CLK
CLK
CMD
WR
CMD
STOP
DQM
*Note3
WR
tRDL
PRE
*Note4
DQM
DQ
D0
D1
D2
D3
D4
tBDL
D5
DQ
D0
D1
Mask Mask
*Note1
2)Read Burst Stop (BL=4)
2)Read interrupted by precharge (BL=4)
CLK
CLK
CMD
RD
CMD
STOP
*Note2
DQ(CL2)
Q0
DQ(CL3)
Q1
*Note5
RD
PRE
Q0
Q1
Q2
Q3
Q0
Q1
Q2
*Note2
DQ(CL3)
Q0
Q1
DQ(CL2)
Q3
9. MRS
1) Mo d e Re g is te r S e t
CLK
*Note4
CMD
PRE
tRP
*Note:
ACT
MRS
2CLK
1. tBDL : 1 CLK ; Last data in to burst stop delay.
Read or write burst stop command is valid at every burst length.
2. Number of valid output data after burst stop : 1,2 for CAS latency = 2,3 respectiviely.
3. Write burst is terminated. tBDL determinates the last data write.
4. DQM asserted to prevent corruption of locations D2 and D3.
5. Precharge can be issued here or earlier (satisfying tRAS min delay) with DQM.
6. PRE : All banks precharge, if necessary.
MRS can be issued only at all banks precharge state.
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ESMT
M12L128168A
Operation temperature condition -40°C ~85°C
10. Clock Suspend Exit & Power Down Exit
1) Cl o ck S u sp en d (= Ac t ive P ow er Do wn ) Exi t
CLK
CLK
CKE
Inter nal
CLK
2)P ower Down (= Pr ec ha rg e Power Down )
tSS
CKE
tSS
Internal
CLK
*Note1
CMD
RD
*Note2
CMD
NOP AC T
11. Auto Refresh & Self Refresh
1)Auto Refresh & Self Refresh
*Note3
CLK
*Note4
CMD
*Note5
PRE
AR
CMD
CKE
tRP
2)Self Refresh
tRFC
*Note6
CLK
*Note4
CMD
SR
PRE
CMD
CKE
tRP
tRFC
*Note : 1. Active power down : one or more banks active state.
2. Precharge power down : all banks precharge state.
3. The auto refresh is the same as CBR refresh of conventional DRAM.
No precharge commands are required after auto refresh command.
During tRFC from auto refresh command, any other command can not be accepted.
4. Before executing auto/self refresh command, all banks must be idle state.
5. MRS, Bank Active, Auto/Self Refresh, Power Down Mode Entry.
6. During self refresh entry, refresh interval and refresh operation are performed internally.
After self refresh entry, self refresh mode is kept while CKE is low.
During self refresh entry, all inputs expect CKE will be don’t cared, and outputs will be in Hi-Z state.
For the time interval of tRFC from self refresh exit command, any other command can not be accepted.
Before/After self refresh mode, burst auto refresh (4096 cycles) is recommended.
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