Etron Technology, Inc.

EtronTech
EM68B16CWQH
32M x 16 bit DDRII Synchronous DRAM (SDRAM)
Advanced (Rev. 1.4, Jun. /2014)
Features
Overview
• JEDEC Standard Compliant
• JEDEC standard 1.8V I/O (SSTL_18-compatible)
• Power supplies: VDD & VDDQ = +1.8V ± 0.1V
• Operating temperature: TC = 0~95℃
• Supports JEDEC clock jitter specification
• Fully synchronous operation
• Fast clock rate: 333/400/533MHz
• Differential Clock, CK & CK#
• Bidirectional single/differential data strobe
- DQS & DQS#
4
• internal banks for concurrent operation
• 4-bit prefetch architecture
• Internal pipeline architecture
• Precharge & active power down
• Programmable Mode & Extended Mode registers
• Posted CAS# additive latency (AL): 0, 1, 2, 3, 4, 5, 6
• WRITE latency = READ latency - 1 tCK
• Burst lengths: 4 or 8
• Burst type: Sequential / Interleave
• DLL enable/disable
• Off-Chip Driver (OCD)
- Impedance Adjustment
- Adjustable data-output drive strength
• On-die termination (ODT)
• RoHS compliant
• Auto Refresh and Self Refresh
• 8192 refresh cycles / 64ms
- Average refresh period
The EM68B16C is a high-speed CMOS DoubleData-Rate-Two
(DDR2),
synchronous
dynamic
random-access memory (SDRAM) containing 512
Mbits in a 16-bit wide data I/Os. It is internally
configured as a quad bank DRAM, 4 banks x 8Mb
addresses x 16 I/Os
The device is designed to comply with DDR2 DRAM
key features such as posted CAS# with additive latency,
Write latency = Read latency -1, Off-Chip Driver (OCD)
impedance adjustment, and On Die Termination(ODT).
All of the control and address inputs are
synchronized with a pair of externally supplied
differential clocks. Inputs are latched at the cross point
of differential clocks (CK rising and CK# falling)
All I/Os are synchronized with a pair of bidirectional
strobes (DQS and DQS#) in a source synchronous
fashion. The address bus is used to convey row,
column, and bank address information in RAS #
, CAS# multiplexing style. Accesses begin with the
registration of a Bank Activate command, and then it is
followed by a Read or Write command. Read and write
accesses to the DDR2 SDRAM are 4 or 8-bit burst
oriented; accesses start at a selected location and
continue for a programmed number of locations in a
programmed sequence. Operating the four memory
banks in an interleaved fashion allows random access
operation to occur at a higher rate than is possible with
standard DRAMs. An auto precharge function may be
enabled to provide a self-timed row precharge that is
initiated at the end of the burst sequence. A sequential
and gapless data rate is possible depending on burst
length, CAS latency, and speed grade of the device.
7.8µs @ 0℃ ≦TC≦ +85℃
3.9µs @ +85℃ ＜TC≦ +95℃
• 84-ball 8x12.5x1.2mm (max) FBGA
- Pb and Halogen Free
Table 1. Ordering Information
Part Number
Clock Frequency
Data Rate
EM68B16CWQH-18H*
533MHz
1066Mbps/pin
EM68B16CWQH-25H*
400MHz
800Mbps/pin
EM68B16CWQH-3H*
333MHz
667Mbps/pin
WQ: indicates 8x12.5x1.2mm (max) FBGA package
H: indicates Generation Code
H*: indicates Pb and Halogen Free for FBGA Package
Power Supply
VDD 1.8V, VDDQ 1.8V
VDD 1.8V, VDDQ 1.8V
VDD 1.8V, VDDQ 1.8V
Etron Technology, Inc.
No. 6, Technology Rd. V, Hsinchu Science Park, Hsinchu, Taiwan 30078, R.O.C.
TEL: (886)-3-5782345
FAX: (886)-3-5778671
Etron Technology, Inc. reserves the right to change products or specification without notice.
Package
FBGA
FBGA
FBGA
EtronTech
EM68B16CWQH
Table 2. Speed Grade Information
Speed Grade
Clock Frequency
CAS Latency
tRCD (ns)
tRP (ns)
EM68B16CWQH-18H
533MHz
7
13.125
13.125
EM68B16CWQH-25H
400MHz
5
12.5
12.5
EM68B16CWQH-3H
333MHz
5
15
15
Figure 1. Ball Assignment (FBGA Top View)
1
2
3
7
8
9
A
VDD
NC
VSS
VSSQ
UDQS#
VDDQ
B
DQ14
VSSQ
UDM
UDQS.
VSSQ
DQ15
C
VDDQ
DQ9
VDDQ
VDDQ
DQ8
VDDQ
D
DQ12
VSSQ
DQ11
DQ10
VSSQ
DQ13
E
VDD
NC
VSS
VSSQ
LDQS#
VDDQ
F
DQ6
VSSQ
LDM
LDQS
VSSQ
DQ7
G
VDDQ
DQ1
VDDQ
VDDQ
DQ0
VDDQ
H
DQ4
VSSQ
DQ3
DQ2
VSSQ
DQ5
J
VDDL
VREF
VSS
VSSDL
CK
VDD
CKE
WE#
RAS#
CK#
ODT
BA0
BA1
CAS#
CS#
A10
A1
A2
A0
A3
A5
A6
A4
A7
A9
A11
A8
A12
NC
NC
NC
K
L
NC
M
N
VSS
P
R
VDD
Rev. 1.4
2
VDD
VSS
Jun. /2014
EtronTech
EM68B16CWQH
Figure 2. Block Diagram
CK
CK#
DLL
CLOCK
BUFFER
COMMAND
DECODER
A10/AP
COLUMN
COUNTER
~
A9
A11
A12
BA0
BA1
LDQS
LDQS#
UDQS
UDQS#
MODE
REGISTER
8M x 16
CELL ARRAY
(BANK #1)
Column Decoder
ADDRESS
BUFFER
REFRESH
COUNTER
DATA
STROBE
BUFFER
DQ0
8M x 16
CELL ARRAY
(BANK #2)
Column Decoder
DQ
Buffer
Row
Decoder
~
DQ15
ODT LDM
UDM
Rev. 1.4
8M x 16
CELL ARRAY
(BANK #0)
Column Decoder
Row
Decoder
A0
CONTROL
SIGNAL
GENERATOR
Row
Decoder
CS#
RAS#
CAS#
WE#
Row
Decoder
CKE
3
8M x 16
CELL ARRAY
(BANK #3)
Column Decoder
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EtronTech
EM68B16CWQH
Figure 3. State Diagram
CKEL
OCD
calibration
Initialization
Sequence
SRF H
CKE
PR
Setting
MR,
EMR(1)
EMR(2)
EMR(3)
(E)MRS
Idle
All banks
precharged
ACT
Self
Refreshing
REF
CK
EL
CK
EH
Refreshing
EL
CK
Precharge
Power
Down
Automatic Sequence
Cammand Sequence
Activating
Active
Power
Down
CKEH
CKE
L
WR
Bank
Active
RD
RD
Reading
W
WR
CKEL
L
CKE
RA
CKEL
Writing
WR
RD
A
RD
CKEL = CKE LOW, enter Power Down
RDA
A
WR
WRA
Writing
With
Autoprecharge
PR, PRA
PR, PRA
CKEH = CKE HIGH, exit Power Down,exit Self Refresh
ACT = Activate
RDA
Reading
With
Autoprecharge
PR, PRA
WR(A) = Write (with Autoprecharge)
RD(A) = Read (with Autoprecharge)
PR(A) = Precharge (All)
(E)MRS = (Extended) Mode Register Set
SRF = Enter Self Refresh
Precharging
REF = Refresh
Note: Use caution with this diagram. It is indented to provide a floorplan of the possible state transitions and the
commands to control them, not all details. In particular situations involving more than one bank,
enabling/disabling on-die termination, Power Down entry/exit, timing restrictions during state transitions, among
other things, are not captured in full detail.
Rev. 1.4
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EM68B16CWQH
Ball Descriptions
Table 3. Ball Descriptions
Symbol
Type
Description
CK, CK#
Input
Differential Clock: CK, CK# are driven by the system clock. All SDRAM input signals
are sampled on the crossing of positive edge of CK and negative edge of CK#. Output
(Read) data is referenced to the crossings of CK and CK# (both directions of
crossing).
CKE
Input
Clock Enable: CKE activates (HIGH) and deactivates (LOW) the CK signal. If CKE
goes LOW synchronously with clock, the internal clock is suspended from the next
clock cycle and the state of output and burst address is frozen as long as the CKE
remains LOW. When all banks are in the idle state, deactivating the clock controls the
entry to the Power Down and Self Refresh modes.
BA0, BA1
Input
Bank Address: BA0 and BA1 define to which bank the BankActivate, Read, Write, or
BankPrecharge command is being applied.
A0-A12
Input
Address Inputs: A0-A12 are sampled during the BankActivate command (row
address A0-A12) and Read/Write command (column address A0-A9 with A10 defining
Auto Precharge).
CS#
Input
Chip Select: CS# enables (sampled LOW) and disables (sampled HIGH) the
command decoder. All commands are masked when CS# is sampled HIGH. CS#
provides for external bank selection on systems with multiple banks. It is considered
part of the command code.
RAS#
Input
Row Address Strobe: The RAS# signal defines the operation commands in
conjunction with the CAS# and WE# signals and is latched at the crossing of positive
edges of CK and negative edge of CK#. When RAS# and CS# are asserted "LOW"
and CAS# is asserted "HIGH," either the BankActivate command or the Precharge
command is selected by the WE# signal. When the WE# is asserted "HIGH," the
BankActivate command is selected and the bank designated by BA is turned on to the
active state. When the WE# is asserted "LOW," the Precharge command is selected
and the bank designated by BA is switched to the idle state after the precharge
operation.
CAS#
Input
Column Address Strobe: The CAS# signal defines the operation commands in
conjunction with the RAS# and WE# signals and is latched at the crossing of positive
edges of CK and negative edge of CK#. When RAS# is held "HIGH" and CS# is
asserted "LOW," the column access is started by asserting CAS# "LOW." Then, the
Read or Write command is selected by asserting WE# “HIGH " or “LOW".
WE#
Input
Write Enable: The WE# signal defines the operation commands in conjunction with
the RAS# and CAS# signals and is latched at the crossing of positive edges of CK
and negative edge of CK#. The WE# input is used to select the BankActivate or
Precharge command and Read or Write command.
LDQS,
Input /
LDQS#
Output
Bidirectional Data Strobe: Specifies timing for Input and Output data. Read Data
Strobe is edge triggered. Write Data Strobe provides a setup and hold time for data
and DQM. LDQS is for DQ0~7, UDQS is for DQ8~15. The data strobes LDOS and
UDQS may be used in single ended mode or paired with LDQS# and UDQS# to
provide differential pair signaling to the system during both reads and writes.A control
bit at EMR (1)[A10] enables or disables all complementary data strobe signals.
UDQS
UDQS#
LDM,
Input
UDM
DQ0 - DQ15
Rev. 1.4
Input /
Output
Data Input Mask: Input data is masked when DM is sampled HIGH during a write
cycle. LDM masks DQ0-DQ7, UDM masks DQ8-DQ15.
Data I/O: Bi-directional data bus.
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EM68B16CWQH
ODT
Input
VDD
Supply
Power Supply: +1.8V ±0.1V
VSS
Supply
Ground
VDDL
Supply
DLL Power Supply: +1.8V ±0.1V
VSSDL
Supply
DLL Ground
VDDQ
Supply
DQ Power: +1.8V ±0.1V.
VSSQ
Supply
DQ Ground
VREF
Supply
Reference Voltage for Inputs: +0.5*VDDQ
NC
-
Rev. 1.4
On Die Termination: ODT enables internal termination resistance. It is applied to
each DQ, LDQS/LDQS#, UDQS/UDQS#, LDM, and UDM signal. The ODT pin is
ignored if the EMR (1) is programmed to disable ODT.
No Connect: These pins should be left unconnected.
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EM68B16CWQH
Operation Mode
Table 4 shows the truth table for the operation commands.
Table 4. Truth Table (Note (1), (2))
Command
BankActivate
State
CKEn-1 CKEn DM BA0,1 A10 A0-9, 11-12 CS# RAS# CAS# WE#
Idle(3)
H
H
X
V
Row address
L
L
H
H
Single Bank Precharge
Any
H
H
X
V
L
X
L
L
H
L
All Banks Precharge
Any
H
H
X
X
H
X
L
L
H
L
Write
Active(3)
H
H
X
V
L
H
L
L
Write with AutoPrecharge
H
H
X
V
H
Column
address
L
Active(3)
L
H
L
L
Read
Active(3)
H
H
X
V
L
L
H
L
H
Read and Autoprecharge
Active(3)
H
H
X
V
H
L
H
L
H
Extended Mode Register Set
Idle
H
H
X
V
L
L
L
L
No-Operation
Any
H
X
X
X
X
X
L
H
H
H
Active(4)
H
X
X
X
X
X
L
H
H
L
Device Deselect
Any
H
X
X
X
X
X
H
X
X
X
Refresh
Idle
H
H
X
X
X
X
L
L
L
H
SelfRefresh Entry
Idle
H
L
X
X
X
X
L
L
L
H
SelfRefresh Exit
Idle
L
H
X
X
X
X
H
X
X
X
L
H
H
H
Power Down Mode Entry
Idle
H
L
X
X
X
X
H
X
X
X
L
H
H
H
Power Down Mode Exit
Any
L
H
X
X
X
X
H
X
X
X
L
H
H
H
Data Input Mask Disable
Active
H
X
L
X
X
X
X
X
X
X
Data Input Mask Enable(5)
Active
H
X
H
X
X
X
X
NOTE 1: V=Valid data, X=Don't Care, L=Low level, H=High level
NOTE 2: CKEn signal is input level when commands are provided.
NOTE 3: CKEn-1 signal is input level one clock cycle before the commands are provided.
NOTE 4: These are states of bank designated by BA signal.
NOTE 5: Device state is 4, and 8 burst operation.
NOTE 6: LDM and UDM can be enabled respectively.
X
X
X
Burst Stop
Rev. 1.4
7
(A0 – A9)
Column
address
(A0 – A9)
OP code
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EM68B16CWQH
Functional Description
Read and write accesses to the DDR2 SDRAM are burst oriented; accesses start at a selected location and
continue for a burst length of four or eight in a programmed sequence. Accesses begin with the registration of an
Active command, which is then followed by a Read or Write command. The address bits registered coincident with
the active command are used to select the bank and row to be accessed (BA0, BA1 select the bank; A0-A12 select
the row). The address bits registered coincident with the Read or Write command are used to select the starting
column location for the burst access and to determine if the auto precharge command is to be issued.
Prior to normal operation, the DDR2 SDRAM must be initialized. The following sections provide detailed information
covering device initialization, register definition, command descriptions, and device operation.
z Power-up and Initialization
DDR2 SDRAMs must be powered up and initialized in a predefined manner. Operational procedures other than
those specified may result in undefined operation.
The following sequence is required for POWER UP and Initialization.
1. Apply power and attempt to maintain CKE below 0.2*VDDQ and ODT *1 at a low state (all other inputs may be
undefined.) The VDD voltage ramp time must be no greater than 200ms from when VDD ramps from 300mV to
VDDmin; and during the VDD voltage ramp, |VDD-VDDQ| ≦ 0.3V
- VDD, VDDL and VDDQ are driven from a single power converter output, AND
- VTT is limited to 0.95 V max, AND
- VREF tracks VDDQ/2.
or
- Apply VDD before or at the same time as VDDL.
- Apply VDDL before or at the same time as VDDQ.
- Apply VDDQ before or at the same time as VTT & VREF.
At least one of these two sets of conditions must be met.
2. Start clock and maintain stable condition.
3. For the minimum of 200µs after stable power and clock (CK, CK#), then apply NOP or deselect and take CKE
HIGH.
4. Wait minimum of 400ns then issue precharge all command. NOP or deselect applied during 400ns period.
5. Issue EMRS(2) command. (To issue EMRS (2) command, provide “LOW” to BA0, “HIGH” to BA1.)
6. Issue EMRS (3) command. (To issue EMRS (3) command, provide “HIGH” to BA0 and BA1.)
7. Issue EMRS to enable DLL. (To issue "DLL Enable" command, provide "LOW" to A0, "HIGH" to BA0 and
"LOW" to BA1.)
8. Issue a Mode Register Set command for “DLL reset”.
(To issue DLL reset command, provide "HIGH" to A8 and "LOW" to BA0-1)
9. Issue precharge all command.
10. Issue 2 or more auto-refresh commands.
11. Issue a mode register set command with LOW to A8 to initialize device operation. (i.e. to program operating
parameters without resetting the DLL.)
12. At least 200 clocks after step 8, execute OCD Calibration (Off Chip Driver impedance adjustment).If OCD
calibration is not used, EMRS OCD Default command (A9=A8=A7=HIGH) followed by EMRS OCD calibration
Mode Exit command (A9=A8=A7=LOW) must be issued with other operating parameters of EMRS.
13. The DDR2 SDRAM is now ready for normal operation.
NOTE 1: To guarantee ODT off, VREF must be valid and a LOW level must be applied to the ODT pin.
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EM68B16CWQH
z Mode Register Set (MRS)
The mode register stores the data for controlling the various operating modes of DDR2 SDRAM. It controls CAS
latency, burst length, burst sequence, test mode, DLL reset, WR, and various vendor specific options to make
DDR2 SDRAM useful for various applications.The default value of the mode register is not defined, therefore
the mode register must be programmed during initialization for proper operation. The mode register is written by
asserting LOW on CS#, RAS#, CAS#, WE#, BA0 and BA1, while controlling the state of address pins A0 - A12.
The DDR2 SDRAM should be in all bank precharge state with CKE already HIGH prior to writing into the mode
register.The mode register set command cycle time (tMRD) is required to complete the write operation to the
mode register. The mode register contents can be changed using the same command and clock cycle
requirements during normal operation as long as all bank are in the precharge state.The mode register is
divided into various fields depending on functionality.
- Burst Length Field (A2, A1, A0)
This field specifies the data length of column access and selects the Burst Length.
- Addressing Mode Select Field (A3)
The Addressing Mode can be Interleave Mode or Sequential Mode. Both Sequential Mode and Interleave
Mode support burst length of 4 and 8.
-CAS Latency Field (A6, A5, A4)
This field specifies the number of clock cycles from the assertion of the Read command to the first read
data. The minimum whole value of CAS Latency depends on the frequency of CK. The minimum whole
value satisfying the following formula must be programmed into this field. tCAC(min) ≦ CAS Latency X tCK
- Test Mode field: A7; DLL Reset Mode field: A8
These two bits must be programmed to "00" in normal operation.
- (BA0, BA1): Bank addresses to define MRS selection.
Table 5. Mode Register Bitmap
BA1 BA0 A12
0
0
A11
PD
A10
A9
WR
A8 DLL Reset
0
No
1
Yes
A12 Active power down exit time
0
Fast exit (use tXARD)
1
Slow exit (use tXARDS)
BA1 BA0
0
0
0
1
1
0
1
1
MRS Mode
MR
EMR(1)
EMR(2)
EMR(3)
A7
0
1
A8
A7
DLL
TM
A6
A5
A4
CAS Latency
Mode
Normal
Test
A3
BT
A3
0
1
A2
A1
A0
Burst Length
Burst Type
Sequential
Interleave
A2
0
0
Address Field
Mode Register
A1
1
1
A0
0
1
BL
4
8
*1
Write recovery for autoprecharge
A11 A10
A9
WR(cycles)
0
0
0
Reserved
0
0
1
2
0
1
0
3
0
1
1
4
1
0
0
5
1
0
1
6
1
1
0
7
1
1
1
8
A6
0
0
0
0
1
1
1
1
A5
0
0
1
1
0
0
1
1
A4
0
1
0
1
0
1
0
1
CAS Latency
Reserved
Reserved
Reserved
3
4
5
6
7
Note 1:.For DDR2-667/800/1066, WR (write recovery for autoprecharge) min is determined by tCK (avg) max and WR max is
determined by tCK(avg) min. WR [cycles] = RU {tWR[ns]/tCK(avg)[ns]}, where RU stands for round up. The mode register
must be programmed to this value.This is also used with tRP to determine tDAL.
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EM68B16CWQH
z Extended Mode Register Set (EMRS)
- EMR(1)
The extended mode register(1) stores the data for enabling or disabling the DLL, output driver strength, ODT
value selection and additive latency. The default value of the extended mode register is not defined, therefore
the extended mode register must be written after power-up for proper operation. The extended mode register is
written by asserting LOW on CS#, RAS#, CAS#, WE#, BA1 and HIGH on BA0, while controlling the states of
address pins A0 ~ A12. The DDR2 SDRAM should be in all bank precharge with CKE already HIGH prior to
writing into the extended mode register. The mode register set command cycle time (tMRD) must be satisfied to
complete the write operation to the extended mode register. Mode register contents can be changed using the
same command and clock cycle requirements during normal operation as long as all banks are in the
precharge state. A0 is used for DLL enable or disable. A1 is used for enabling a half strength data-output driver.
A3~A5 determine the additive latency, A2 and A6 are used for ODT value selection, A7~A9 are used for OCD
control, A10 is used for DQS# disable.
- DLL Enable/Disable
The DLL must be enabled for normal operation. DLL enable is required during power up initialization, and
upon returning to normal operation after having the DLL disabled. The DLL is automatically disabled when
entering self refresh operation and is automatically re-enabled upon exit of self refresh operation. Any time the
DLL is enabled (and subsequently reset), 200 clock cycles must occur before a Read command can be issued
to allow time for the internal clock to be synchronized with the external clock. Failing to wait for synchronization
to occur may result in a violation of the tAC or tDQSCK parameters.
Table 6. Extended Mode Register EMR (1) Bitmap
BA1 BA0 A12 A11 A10
0
1
Qoff
0
A9
DQS#
A8
A7
A6
OCD program
Rtt
Additive Latency
A6
0
0
1
A2
0
1
0
Rtt(NOMINAL)
ODT Disable
75Ω
1
1
50Ω
BA1 BA0 MRS mode
0
0
MR
0
1
EMR(1)
1
0
EMR(2)
A10
0
1
1
1
EMR(3)
A9
0
0
0
1
1
A8
0
0
1
0
1
A7
0
1
0
0
1
DQS#
Enable
Disable
A5
A4
A3
A1
OCD Calibration Program
Drive(1)
Drive(0)
Adjust mode*1
OCD Calibration default*2
*3
Qoff
Output buffer enabled
Output buffer disabled
A0 Address Field
Rtt D.I.C DLL Extended Mode Register
A0
0
1
150Ω
OCD Calibration mode exit; maintain setting
A12
0
1
A2
A1
0
1
DLL Enable
Enable
Disable
Output Driver
Impedance Control
Full strength
Reduced strength
A5 A4 A3
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
Driver
size
100%
60%
Additive Latency
0
1
2
3
4
5
6
Reserved
NOTE 1: When Adjust mode is issued, AL from previously set value must be applied.
NOTE 2: After setting to default, OCD calibration mode needs to be exited by setting A9-A7 to 000.
NOTE 3: Output disabled – DQs, DQSs, DQSs#.This feature is intended to be used during IDD characterization of read current.
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EM68B16CWQH
- EMR(2)
The extended mode register (2) controls refresh related features. The default value of the extended mode
register (2) is not defined, therefore the extended mode register (2) must be written after power-up for proper
operation. The extended mode register(2) is written by asserting LOW on CS#, RAS#, CAS#, WE#, HIGH on
BA1 and LOW on BA0, while controlling the states of address pins A0 ~ A12. The DDR2 SDRAM should be in
all bank precharge with CKE already HIGH prior to writing into the extended mode register (2). The mode
register set command cycle time (tMRD) must be satisfied to complete the write operation to the extended mode
register (2). Mode register contents can be changed using the same command and clock cycle requirements
during normal operation as long as all banks are in the precharge state.
Table 7. Extended Mode Register EMR (2) Bitmap
BA1 BA0 A12 A11 A10
1
0*1
0
A7
0
1
A9
A8
A7
A6
A5
A4
*1
SRF
A3
A2
*4
0
DCC
A1
A0 Address Field
*3
PASR
Extended Mode Register(2)
High Temperature Self-Refresh Rate Enable
Disable
*2
Enable
BA1 BA0 MRS mode
0
0
MR
0
1
EMR(1)
1
0
EMR(2)
1
1
EMR(3)
A3
0
1
DCC Enable
Disable
Enable
*4
A2 A1 A0 Partial Array Self Refresh for 4 Banks
0
0
0 Full array
0
0
1 Half Array (BA[1:0]=00&01)
0
1
0 Quarter Array (BA[1:0]=00)
0
1
1 Not defined
1
0
0 3/4 array (BA[1:0]=01,10&11)
1
0
1 Half array (BA[1:0]=10&11)
1
1
0 Quarter array (BA[1:0]=11)
1
1
1 Not defined
NOTE 1: The rest bits in EMRS(2) are reserved for future use and all bits in EMRS(2) except A0-A2, A7, BA0 and BA1 must
be programmed to 0 when setting the extended mode register(2) during initialization.
NOTE 2: Due to the migration nature, user needs to ensure the DRAM part supports higher than 85℃ Tcase temperature
self-refresh entry. If the high temperature self-refresh mode is supported then controller can set the EMRS2[A7] bit to
enable the self-refresh rate in case of higher than 85℃ temperature self-refresh operation.
NOTE 3: If PASR (Partial Array Self Refresh) is enabled, data located in areas of the array beyond the specified location will
be lost if self refresh is entered. Data integrity will be maintained if tREF conditions are met and no Self Refresh
command is issued.
NOTE 4: DCC (Duty Cycle Corrector) implemented, user may be given the controllability of DCC thru EMR (2) [A3] bit.
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- EMR(3)
No function is defined in extended mode register(3).The default value of the extended mode register(3) is not
defined, therefore the extended mode register(3) must be programmed during initialization for proper operation.
Table 8. Extended Mode Register EMR (3) Bitmap
BA1 BA0 A12 A11 A10
1
1
A9
A8
A7
A6
0*1
A5
A4
A3
A2
A1
A0 Address Field
Extended Mode Register(3)
NOTE 1: All bits in EMR (3) except BA0 and BA1 are reserved for future use and must be set to 0 when programming the EMR (3).
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z Off-chip drive (OCD) impedance adjustment
DDR2 SDRAM supports driver calibration feature and the following flow chart is an example of sequence.Every
calibration mode command should be followed by “OCD calibration mode exit” before any other command being
issued.All MR should be programmed before entering OCD impedance adjustment and ODT (On Die Termination)
should be carefully controlled depending on system environment.
Figure 4. OCD impedance adjustment sequence
Before entering OCD impedance adjustment, all MR should be programmed and
ODT should be carefully controlled depending on system environment
Start
EMRS:OCD calibration mode exit
EMRS:Drive(1)
DQ &DQS HIGH;DQS# LOW
Test
EMRS:Drive(0)
DQ &DQS LOW;DQS# HIGH
ALL OK
ALL OK
Test
EMRS:OCD calibration mode exit
EMRS:OCD calibration mode exit
EMRS:Enter Adjust Mode
EMRS:Enter Adjust Mode
BL=4 code input to all DQs
Inc, Dec, or NOP
BL=4 code input to all DQs
Inc, Dec, or NOP
EMRS:OCD calibration mode exit
EMRS:OCD calibration mode exit
EMRS:OCD calibration mode exit
End
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- Extended mode register for OCD impedance adjustment
OCD impedance adjustment can be done using the following EMRS mode. In drive mode all outputs are
driven out by DDR2 SDRAM. In Drive (1) mode, all DQ, DQS signals are driven HIGH and all DQS# signals are
driven LOW. In Drive (0) mode, all DQ, DQS signals are driven LOW and all DQS# signals are drive HIGH. In
adjust mode, BL = 4 of operation code data must be used. In case of OCD calibration default, output driver
characteristics have a nominal impedance value of 18 Ohms during nominal temperature and voltage
conditions. Output driver characteristics for OCD calibration default are specified in the following table. OCD
applies only to normal full strength output drive setting defined by EMRS and if half strength is set, OCD default
driver characteristics are not applicable. When OCD calibration adjust mode is used, OCD default output driver
characteristics are not applicable. After OCD calibration is completed or driver strength is set to default,
subsequent EMRS commands not intended to adjust OCD characteristics must specify A7~A9 as ’000’ in order
to maintain the default or calibrated value.
Table 9.OCD drive mode program
A9
A8
A7
operation
0
0
0
1
1
0
0
1
0
1
0
1
0
0
1
OCD calibration mode exit
Drive(1) DQ, DQS, HIGH and DQS# LOW
Drive(0) DQ, DQS, LOW and DQS# HIGH
Adjust mode
OCD calibration default
- OCD impedance adjust
To adjust output driver impedance, controllers must issue the ADJUST EMRS command along with a 4bit burst
code to DDR2 SDRAM as in the following table. For this operation, Burst Length has to be set to BL = 4 via
MRS command before activating OCD and controllers must drive this burst code to all DQs at the same time.
DT0 in the following table means all DQ bits at bit time 0, DT1 at bit time 1, and so forth. The driver output
impedance is adjusted for all DDR2 SDRAM DQs simultaneously and after OCD calibration, all DQs of a given
DDR2 SDRAM will be adjusted to the same driver strength setting.
The maximum step count for adjustment is 16 and when the limit is reached, further increment or decrement
code has no effect. The default setting maybe any step within the 16 step range. When Adjust mode command
is issued, AL from previously set value must be applied.
Table 10.OCD adjust mode program
4bit burst code inputs to all DQs
DT0
DT1
DT2
DT3
0
0
0
0
0
0
0
1
0
0
1
0
0
1
0
0
1
0
0
0
0
1
0
1
0
1
1
0
1
0
0
1
1
0
1
0
Other Combinations
Rev. 1.4
Pull-up driver strength
NOP
Increase by 1 step
Decrease by 1 step
NOP
NOP
Increase by 1 step
Decrease by 1 step
Increase by 1 step
Decrease by 1 step
14
Operation
Pull-down driver strength
NOP
NOP
NOP
Increase by 1 step
Decrease by 1 step
Increase by 1 step
Increase by 1 step
Decrease by 1 step
Decrease by 1 step
Reserved
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EM68B16CWQH
z ODT (On Die Termination)
On Die Termination (ODT) is a feature that allows a DRAM to turn on/off termination resistance for each DQ,
UDQS/UDQS#, LDQS/LDQS#, UDM, and LDM signal via the ODT control pin. The ODT feature is designed to
improve signal integrity of the memory channel by allowing the DRAM controller to independently turn on/off
termination resistance for any or all DRAM devices.
The ODT function is supported for ACTIVE and STANDBY modes. It is turned off and not supported in SELF
REFRESH mode.
Figure 5. Functional representation of ODT
VDDQ
VDDQ
VDDQ
SW1
SW2
SW3
Rval1
Rval2
Rval3
DRAM
Input
Buffer
Input
pin
Rval1
SW1
VSSQ
Rval2
SW2
VSSQ
Rval3
SW3
VSSQ
Switch (sw1, sw2, sw3) is enabled by ODT pin.
Selection among sw1, sw2, and sw3 is determined by “Rtt (nominal)” in EMR.
Termination included on all DQs, DM, DQS, and DQS# pins
Table 11.ODT DC Electrical Characteristics
Parameter/Condition
Symbol
Min.
Nom.
Max.
Unit Note
Rtt effective impedance value for EMRS(A6,A2)=0,1;75Ω Rtt1(eff)
Ω
60
75
90
Rtt effective impedance value for EMRS(A6,A2)=1,0;150Ω Rtt2(eff)
Ω
120
150
180
Rtt effective impedance value for EMRS(A6,A2)=1,1;50Ω Rtt3(eff)
Ω
40
50
60
%
Rtt mismatch tolerance between any pull-up/pull-down pair Rtt(mis)
-6
6
NOTE 1: Measurement Definition for Rtt(eff):
Apply VIH (ac) and VIL (ac) to test pin seperately, then measure current I(VIH(ac)) and I(VIL(ac))
respectively.
Rtt(eff)=
1
1
1
2
VIH (ac ) − VIL (ac )
I(VIH (ac))-I(VIL (ac))
NOTE 2: Measurement Defintion for Rtt (mis): Measure voltage (VM) at test pin (midpoint) with no load.
⎛ 2xVM ⎞
Rtt(mis)= ⎜
− 1⎟ ×100%
⎝ VDDQ
⎠
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z Bank activate command
The Bank Activate command is issued by holding CAS# and WE# HIGH with CS# and RAS# LOW at the rising
edge of the clock. The bank addresses BA0 and BA1 are used to select the desired bank. The row addresses A0
through A12 are used to determine which row to activate in the selected bank. The Bank Activate command must
be applied before any Read or Write operation can be executed. Immediately after the bank active command, the
DDR2 SDRAM can accept a read or write command (with or without Auto-Precharge) on the following clock cycle.
If a R/W command is issued to a bank that has not satisfied the tRCDmin specification, then additive latency must
be programmed into the device to delay the R/W command which is internally issued to the device. The additive
latency value must be chosen to assure tRCDmin is satisfied. Additive latencies of 0, 1, 2, 3, 4, and 5 are supported.
Once a bank has been activated it must be precharged before another Bank Activate command can be applied to
the same bank. The bank active and precharge times are defined as tRAS and tRP, respectively. The minimum time
interval between successive Bank Activate commands to the same bank is determined (tRC). The minimum time
interval between Bank Active commands is tRRD
z Read and Write access modes
After a bank has been activated, a Read or Write cycle can be executed. This is accomplished by setting RAS#
HIGH, CS# and CAS# LOW at the clock’s rising edge. WE# must also be defined at this time to determine whether
the access cycle is a Read operation (WE# HIGH) or a Write operation (WE# LOW). The DDR2 SDRAM provides
a fast column access operation. A single Read or Write Command will initiate a serial Read or Write operation on
successive clock cycles. The boundary of the burst cycle is strictly restricted to specific segments of the page
length. Any system or application incorporating random access memory products should be properly designed,
tested, and qualified to ensure proper use or access of such memory products. Disproportionate, excessive,
and/or repeated access to a particular address or addresses may result in reduction of product life.
z Posted CAS#
Posted CAS# operation is supported to make command and data bus efficient for sustainable bandwidths in DDR2
SDRAM. In this operation, the DDR2 SDRAM allows a CAS# Read or Write command to be issued immediately
after the RAS bank activate command (or any time during the RAS# -CAS#-delay time, tRCD, period). The
command is held for the time of the Additive Latency (AL) before it is issued inside the device. The Read Latency
(RL) is controlled by the sum of AL and the CAS latency (CL). Therefore if a user chooses to issue a R/W
command before the tRCDmin, then AL (greater than 0) must be written into the EMR(1). The Write Latency (WL) is
always defined as RL - 1 (Read Latency -1) where Read Latency is defined as the sum of additive latency plus
CAS latency (RL=AL+CL). Read or Write operations using AL allow seamless bursts (refer to seamless operation
timing diagram examples in Read burst and Write burst section)
z Burst Mode Operation
Burst mode operation is used to provide a constant flow of data to memory locations (Write cycle), or from memory
locations (Read cycle). The parameters that define how the burst mode will operate are burst sequence and burst
length. The DDR2 SDRAM supports 4 bit and 8 bit burst modes only. For 8 bit burst mode, full interleave address
ordering is supported, however, sequential address ordering is nibble based for ease of implementation. The burst
length is programmable and defined by the addresses A0 ~ A2 of the MRS. The burst type, either sequential or
interleaved, is programmable and defined by the address bit 3 (A3) of the MRS. Seamless burst Read or Write
operations are supported. Interruption of a burst Read or Write operation is prohibited, when burst length = 4 is
programmed. For burst interruption of a Read or Write burst when burst length = 8 is used, see the “Burst
Interruption“ section of this datasheet. A Burst Stop command is not supported on DDR2 SDRAM devices.
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Table 12.Burst Definition, Addressing Sequence of Sequential and Interleave Mode
Burst Length
4
8
Start Address
A2
A1
A0
X
0
0
X
0
1
X
1
0
X
1
1
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Sequential
Interleave
0, 1, 2, 3
1, 2, 3, 0
2, 3, 0, 1
3, 0, 1, 2
0, 1, 2, 3, 4, 5, 6, 7
1, 2, 3, 0, 5, 6, 7, 4
2, 3, 0, 1, 6, 7, 4, 5
3, 0, 1, 2, 7, 4, 5, 6
4, 5, 6, 7, 0, 1, 2, 3
5, 6, 7, 4, 1, 2, 3, 0
6, 7, 4, 5, 2, 3, 0, 1
7, 4, 5, 6, 3, 0, 1, 2
0, 1, 2, 3
1, 0, 3, 2
2, 3, 0, 1
3, 2, 1, 0
0, 1, 2, 3, 4, 5, 6, 7
1, 0, 3, 2, 5, 4, 7, 6
2, 3, 0, 1, 6, 7, 4, 5
3, 2, 1, 0, 7, 6, 5, 4
4, 5, 6, 7, 0, 1, 2, 3
5, 4, 7, 6, 1, 0, 3, 2
6, 7, 4, 5, 2, 3, 0, 1
7, 6, 5, 4, 3, 2, 1, 0
z Burst read command
The Burst Read command is initiated by having CS# and CAS# LOW while holding RAS# and WE# HIGH at
the rising edge of the clock. The address inputs determine the starting column address for the burst. The delay
from the start of the command to when the data from the first cell appears on the outputs is equal to the value
of the Read Latency (RL). The data strobe output (DQS) is driven LOW 1 clock cycle before valid data (DQ) is
driven onto the data bus. The first bit of the burst is synchronized with the rising edge of the data strobe (DQS).
Each subsequent data-out appears on the DQ pin in phase with the DQS signal in a source synchronous
manner. The RL is equal to an additive latency (AL) plus CAS Latency (CL). The CL is defined by the Mode
Register Set (MRS), similar to the existing SDR and DDR SDRAMs. The AL is defined by the Extended Mode
Register Set (1) (EMRS (1)).
DDR2 SDRAM pin timings are specified for either single ended mode or differential mode depending on the
setting of the EMRS “Enable DQS” mode bit; timing advantages of differential mode are realized in system
design. The method by which the DDR2 SDRAM pin timings are measured is mode dependent. In single ended
mode, timing relationships are measured relative to the rising or falling edges of DQS crossing at VREF. In
differential mode, these timing relationships are measured relative to the crosspoint of DQS and its complement,
DQS#. This distinction in timing methods is guaranteed by design and characterization. Note that when
differential data strobe mode is disabled via the EMRS, the complementary pin, DQS#, must be tied externally
to VSS through a 20 Ω to 10 KΩresistor to insure proper operation.
z Burst write operation
The Burst Write command is initiated by having CS#, CAS# and WE# LOW while holding RAS# HIGH at the
rising edge of the clock. The address inputs determine the starting column address. Write latency (WL) is
defined by a Read latency (RL) minus one and is equal to (AL + CL -1);and is the number of clocks of delay
that are required from the time the Write command is registered to the clock edge associated to the first DQS
strobe. A data strobe signal (DQS) should be driven LOW (preamble) one clock prior to the WL. The first data
bit of the burst cycle must be applied to the DQ pins at the first rising edge of the DQS following the preamble.
The tDQSS specification must be satisfied for each positive DQS transition to its associated clock edge during
write cycles.
The subsequent burst bit data are issued on successive edges of the DQS until the burst length is completed,
which is 4 or 8 bit burst. When the burst has finished, any additional data supplied to the DQ pins will be
ignored. The DQ Signal is ignored after the burst write operation is complete. The time from the completion of
the burst Write to bank precharge is the write recovery time (WR). DDR2 SDRAM pin timings are specified for
either single ended mode or differential mode depending on the setting of the EMRS “Enable DQS” mode bit;
timing advantages of differential mode are realized in system design. The method by which the DDR2 SDRAM
pin timings are measured is mode dependent.
In single ended mode, timing relationships are measured relative to the rising or falling edges of DQS crossing
at the specified AC/DC levels. In differential mode, these timing relationships are measured relative to the
crosspoint of DQS and its complement, DQS#. This distinction in timing methods is guaranteed by design and
characterization. Note that when differential data strobe mode is disabled via the EMRS, the complementary
pin, DQS#, must be tied externally to VSS through a 20Ω to 10KΩ resistor to insure proper operation.
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z Write data mask
One Write data mask (DM) pin for each 8 data bits (DQ) will be supported on DDR2 SDRAMs, Consistent with
the implementation on DDR SDRAMs. It has identical timings on Write operations as the data bits, and though
used in a uni-directional manner, is internally loaded identically to data bits to insure matched system timing.
DM is not used during read cycles.
z Precharge operation
The Precharge command is used to precharge or close a bank that has been activated. The Precharge
Command is triggered when CS#, RAS# and WE# are LOW and CAS# is HIGH at the rising edge of the clock.
The Precharge Command can be used to precharge each bank independently or all banks simultaneously.
Three address bits A10, BA1, and BA0 are used to define which bank to precharge when the command is
issued.
Table 13.Bank Selection for Precharge by address bits
A10
BA1
BA0
Precharged Bank(s)
LOW
LOW
LOW
LOW
HIGH
LOW
LOW
HIGH
HIGH
DON’T CARE
LOW
HIGH
LOW
HIGH
DON’T CARE
Bank 0 only
Bank 1 only
Bank 2 only
Bank 3 only
ALL Banks
z Burst read operation followed by precharge
Minimum Read to precharge command spacing to the same bank = AL + BL/2 + max (RTP, 2) - 2 clocks. For
the earliest possible precharge, the precharge command may be issued on the rising edge which “Additive
latency (AL) + BL/2 clocks” after a Read command. A new bank active (command) may be issued to the same
bank after the RAS# precharge time (tRP). A precharge command cannot be issued until tRAS is satisfied.
The minimum Read to Precharge spacing has also to satisfy a minimum analog time from the rising clock edge
that initiates the last 4-bit prefetch of a Read to Precharge command. This time is called tRTP (Read to
Precharge). For BL = 4 this is the time from the actual read (AL after the Read command) to Precharge
command. For BL = 8 this is the time from AL + 2 clocks after the Read to the Precharge command.
z Burst Write operation followed by precharge
Minimum Write to Precharge command spacing to the same bank = WL + BL/2 + tWR. For write cycles, a delay
must be satisfied from the completion of the last burst write cycle until the Precharge command can be issued.
This delay is known as a write recovery time (tWR) referenced from the completion of the burst write to the
Precharge command. No Precharge command should be issued prior to the tWR delay, as DDR2 SDRAM does
not support any burst interrupt by a Precharge command. tWR is an analog timing parameter and is not the
programmed value for tWR in the MRS.
z Auto precharge operation
Before a new row in an active bank can be opened, the active bank must be precharged using either the
Precharge Command or the auto-precharge function. When a Read or a Write Command is given to the DDR2
SDRAM, the CAS# timing accepts one extra address, column address A10, to allow the active bank to
automatically begin precharge at the earliest possible moment during the burst read or write cycle. If A10 is
LOW when the READ or WRITE Command is issued, then normal Read or Write burst operation is executed
and the bank remains active at the completion of the burst sequence. If A10 is HIGH when the Read or Write
Command is issued, then the auto-precharge function is engaged. During auto-precharge, a Read Command
will execute as normal with the exception that the active bank will begin to precharge on the rising edge which
is CAS latency (CL) clock cycles before the end of the read burst. Auto-precharge also be implemented during
Write commands. The precharge operation engaged by the Auto precharge command will not begin until the
last data of the burst write sequence is properly stored in the memory array. This feature allows the precharge
operation to be partially or completely hidden during burst Read cycles (dependent upon CAS latency) thus
improving system performance for random data access. The RAS# lockout circuit internally delays the
Precharge operation until the array restore operation has been completed (tRAS satisfied) so that the auto
precharge command may be issued with any Read or Write command.
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z Burst read with auto precharge
If A10 is HIGH when a Read Command is issued, the Read with Auto-Precharge function is engaged. The
DDR2 SDRAM starts an Auto-Precharge operation on the rising edge which is (AL + BL/2) cycles later from the
Read with AP command if tRAS(min) and tRTP are satisfied. If tRAS(min) is not satisfied at the edge, the start point
of Auto-Precharge operation will be delayed until tRAS(min) is satisfied. If tRTP(min) is not satisfied at the edge,
the start point of Auto-precharge operation will be delayed until tRTP(min) is satisfied.
In case the internal precharge is pushed out by tRTP, tRP starts at the point where the internal precharge
happens (not at the next rising clock edge after this event). So for BL = 4 the minimum time from Read with
Auto-Precharge to the next Activate command becomes AL + tRTP + tRP. For BL = 8 the time from Read with
Auto-Precharge to the next Activate command is AL + 2 + tRTP + tRP. Note that both parameters tRTP and tRP
have to be rounded up to the next integer value. In any event internal precharge does not start earlier than two
clocks after the last 4-bit prefetch.
A new bank active (command) may be issued to the same bank if the following two conditions are satisfied
simultaneously:
(1) The RAS# precharge time (tRP) has been satisfied from the clock at which the Auto-Precharge begins.
(2) The RAS# cycle time (tRC) from the previous bank activation has been satisfied.
z Burst write with auto precharge
If A10 is HIGH when a Write Command is issued, the Write with Auto-Precharge function is engaged. The
DDR2 SDRAM automatically begins precharge operation after the completion of the burst write plus Write
recovery time (tWR). The bank undergoing auto-precharge from the completion of the write burst may be
reactivated if the following two conditions are satisfied.
(1) The data-in to bank activate delay time (WR + tRP) has been satisfied.
(2) The RAS# cycle time (tRC) from the previous bank activation has been satisfied.
Table 14.Precharge & Auto Precharge Clariification
Minimum Delay between “From
Unit Notes
Command” to “To Command”
Precharge (to same Bank as Read)
AL+BL/2+max(RTP,2)-2
Read
tCK
1,2
Precharge All
AL+BL/2+max(RTP,2)-2
Precharge (to same Bank as Read w/AP)
AL+BL/2+max(RTP,2)-2
tCK
Read w/AP
1,2
Precharge All
AL+BL/2+max(RTP,2)-2
Precharge (to same Bank as Write)
WL+BL/2+tWR
tCK
Write
2
Precharge All
WL+BL/2+tWR
Precharge (to same Bank as Write w/AP)
WL+BL/2+tWR
tCK
Write w/AP
2
Precharge All
WL+BL/2+tWR
Precharge (to same Bank as Precharge)
1
tCK
Precharge
2
Precharge All
1
Precharge
1
tCK
Precharge All
2
Precharge All
1
NOTE 1: RTP [cycles] =RU {tRTP [ns]/tCK (avg) [ns]}, where RU stands for round up.
NOTE 2: For a given bank, the precharge period should be counted from the latest precharge command, either
one bank precharge or precharge all, issued to that bank.The prechrage period is satisfied after tRP or tRPall(=tRP
for 4 bank device) depending on the latest precharge command issued to that bank.
From Command
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z Refresh command
When CS#, RAS# and CAS# are held LOW and WE# HIGH at the rising edge of the clock, the chip enters the
Refresh mode (REF). All banks of the DDR2 SDRAM must be precharged and idle for a minimum of the
Precharge time (tRP) before the Refresh command (REF) can be applied. An address counter, internal to the
device, supplies the bank address during the refresh cycle. No control of the external address bus is required
once this cycle has started.
When the refresh cycle has completed, all banks of the DDR2 SDRAM will be in the precharged (idle) state. A
delay between the Refresh command (REF) and the next Activate command or subsequent Refresh command
must be greater than or equal to the Refresh cycle time (tRFC).To allow for improved efficiency in scheduling and
switching between tasks, some flexibility in the absolute refresh interval is provided. A maximum of eight
Refresh commands can be posted to any given DDR2 SDRAM, meaning that the maximum absolute interval
between any Refresh command and the next Refresh command is 9 * tREFI.
z Self refresh operation
The Self Refresh command can be used to retain data in the DDR2 SDRAM, even if the rest of the system is
powered down. When in the Self Refresh mode, the DDR2 SDRAM retains data without external clocking. The
DDR2 SDRAM device has a built-in timer to accommodate Self Refresh operation. The Self Refresh Command
is defined by having CS#, RAS#, CAS# and CKE# held LOW with WE# HIGH at the rising edge of the clock.
ODT must be turned off before issuing Self Refresh command, by either driving ODT pin LOW or using EMRS
command. Once the Command is registered, CKE must be held LOW to keep the device in Self Refresh mode.
The DLL is automatically disabled upon entering Self Refresh and is automatically enabled upon exiting Self
Refresh. When the DDR2 SDRAM has entered Self Refresh mode all of the external signals except CKE, are
“don’t care”. For proper Self Refresh operation all power supply pins (VDD, VDDQ, VDDL and VREF) must be at valid
levels. The DRAM initiates a minimum of one refresh command internally within tCKE period once it enters Self
Refresh mode. The clock is internally disabled during Self Refresh Operation to save power. The minimum time
that the DDR2 SDRAM must remain in Self Refresh mode is tCKE. The user may change the external clock
frequency or halt the external clock one clock after Self Refresh entry is registered, however, the clock must be
restarted and stable before the device can exit Self Refresh operation.
The procedure for exiting Self Refresh requires a sequence of commands. First, the clock must be stable prior
to CKE going back HIGH. Once Self Refresh Exit is registered, a delay of at least tXSNR must be satisfied before
a valid command can be issued to the device to allow for any internal refresh in progress. CKE must remain
HIGH for the entire Self Refresh exit period tXSRD for proper operation except for Self Refresh re-entry. Upon
exit from Self Refresh, the DDR2 SDRAM can be put back into Self Refresh mode after waiting at least tXSNR
period and issuing one refresh command(refresh period of tRFC). NOP or deselect commands must be
registered on each positive clock edge during the Self Refresh exit interval tXSNR. ODT should be turned off
during tXSRD.
The use of Self Refresh mode introduces the possibility that an internally timed refresh event can be missed
when CKE is raised for exit from Self Refresh mode. Upon exit from Self Refresh, the DDR2 SDRAM requires a
minimum of one extra auto refresh command before it is put back into Self Refresh mode.
Rev. 1.4
20
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EtronTech
EM68B16CWQH
z Power-Down
Power-down is synchronously entered when CKE is registered LOW along with NOP or Deselect command. No
read or write operation may be in progress when CKE goes LOW. These operations are any of the following:
read burst or write burst and recovery. CKE is allowed to go LOW while any of other operations such as row
activation, precharge or autoprecharge, mode register or extended mode register command time, or
autorefresh is in progress.
The DLL should be in a locked state when power-down is entered. Otherwise DLL should be reset after exiting
power-down mode for proper read operation.
If power-down occurs when all banks are precharged, 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. For
Active Power-down two different power saving modes can be selected within the MRS register, address bit A12.
When A12 is set to “LOW” this mode is referred as “standard active power-down mode” and a fast power-down
exit timing defined by the tXARD timing parameter can be used. When A12 is set to “HIGH” this mode is referred
as a power saving “LOW power active power-down mode”. This mode takes longer to exit from the power-down
mode and the tXARDS timing parameter has to be satisfied. Entering power-down deactivates the input and
output buffers, excluding CK, CK#, ODT and CKE. Also the DLL is disabled upon entering precharge powerdown or slow exit active power-down, but the DLL is kept enabled during fast exit active power-down. In powerdown mode, CKE LOW and a stable clock signal must be maintained at the inputs of the DDR2 SDRAM, and
all other input signals are “Don’t Care”. Power-down duration is limited by 9 times tREFI of the device.
The power-down state is synchronously exited when CKE is registered HIGH (along with a NOP or Deselect
command). A valid, executable command can be applied with power-down exit latency, tXP, tXARD or tXARDS, after
CKE goes HIGH. Power-down exit latencies are defined in the AC spec table of this data sheet.
z Asynchronous CKE LOW Event
DRAM requires CKE to be maintained “HIGH” for all valid operations as defined in this datasheet. If CKE
asynchronously drops “LOW” during any valid peration DRAM is not guaranteed to preserve the contents of
array. If this event occurs, memory controller must satisfy DRAM timing specification tDelay efore turning off the
clocks. Stable clocks must exist at the input of DRAM before CKE is raised “HIGH” again. DRAM must be fully
re-initialized. DRAM is ready for normal operation after the initialization sequence.
z Input clock frequency change during precharge power down
DDR2 SDRAM input clock frequency can be changed under following condition: DDR2 SDRAM is in
precharged power down mode. ODT must be turned off and CKE must be at logic LOW level. A minimum of 2
clocks must be waited after CKE goes LOW before clock frequency may change. SDRAM input clock
frequency is allowed to change only within minimum and maximum operating frequency specified for the
particular speed grade. During input clock frequency change, ODT and CKE must be held at stable LOW levels.
Once input clock frequency is changed, stable new clocks must be provided to DRAM before precharge power
down may be exited and DLL must be RESET via EMRS after precharge power down exit. Depending on new
clock frequency an additional MRS command may need to be issued to appropriately set the WR, CL etc.
During DLL re-lock period, ODT must remain off. After the DLL lock time, the DRAM is ready to operate with
new clock frequency.
z No operation command
The No Operation Command should be used in cases when the DDR2 SDRAM is in an idle or a wait state. The
purpose of the No Operation Command (NOP) is to prevent the DDR2 SDRAM from registering any unwanted
commands between operations. A No Operation Command is registered when CS# is LOW with RAS#, CAS#,
and WE# held HIGH at the rising edge of the clock. A No Operation Command will not terminate a previous
operation that is still executing, such as a burst read or write cycle.
z Deselect command
The Deselect Command performs the same function as a No Operation Command. Deselect Command occurs
when CS# is brought HIGH at the rising edge of the clock, the RAS#, CAS#, and WE# signals become don’t
cares.
Rev. 1.4
21
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EtronTech
EM68B16CWQH
Table 15. Absolute Maximum DC Ratings
Symbol
Parameter
Values
Unit Note
VDD
Voltage on VDD pin relative to Vss
-1.0 ~ 2.3
V
1,3
VDDQ
Voltage on VDDQ pin relative to Vss
-0.5 ~ 2.3
V
1,3
VDDL
Voltage on VDDL pin relative to Vss
-0.5 ~ 2.3
V
1,3
Voltage on any pin relative to Vss
- 0.5 ~ 2.3
V
1,4
VIN, VOUT
TSTG
Storage temperature
- 55~100
1,2
°C
NOTE1: Stress greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the
devices. 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.
NOTE2: Storage temperature is the case temperature on the center/top side of the DRAM.
NOTE3: When VDD and VDDQ and VDDL are less than 500mV, Vref may be equal to or less than 300mV.
NOTE4: Voltage on any input or I/O may not exceed voltage on VDDQ.
Table 16. Operating Temperature Condition
Symbol
TOPER
Parameter
Values
Normal operating temperature
Unit Note
0~85
°C
1
Extended operating temperature
85~95
1,2
°C
NOTE1: Operating temperature is the case surface temperature on center/top of the DRAM.
NOTE2: If TC exceeds 85°C, the DRAM must be refreshed externally at 2x refresh. It is required to set tREFI=3.9µs
in auto refresh mode and to set ‘1’ for EMRS (2) bit A7 in self refresh mode.
Table 17. Recommended DC Operating Conditions (SSTL_1.8)
Symbol
Parameter
Min.
Typ.
Max.
Unit Note
VDD
Power supply voltage
1.7
1.8
1.9
V
1
VDDL
Power supply voltage for DLL
1.7
1.8
1.9
V
5
VDDQ
Power supply voltage for I/O Buffer
1.7
1.8
1.9
V
1,5
VREF
Input reference voltage
0.49 x VDDQ
0.5 x VDDQ
0.51 x VDDQ
mV
2,3
VTT
Termination voltage
VREF - 0.04
VREF
VREF + 0.04
V
4
NOTE1: There is no specific device VDD supply voltage requirement for SSTL_18 compliance. However under all
conditions VDDQ must be less than or equal to VDD.
NOTE2: The value of VREF may be selected by the user to provide optimum noise margin in the system. Typically
the value of VREF is expected to be about 0.5 x VDDQ of the transmitting device and VREF is expected to track
variations in VDDQ.
NOTE3: Peak to peak ac noise on VREF may not exceed +/-2 % VREF (dc).
NOTE4: VTT of transmitting device must track VREF of receiving device.
NOTE5: VDDQ tracks with VDD, VDDL tracks with VDD. AC parameters are measured with VDD, VDDQ and VDDL tied
together
Rev. 1.4
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EtronTech
EM68B16CWQH
Table 18. Input logic level
Symbol
Parameter
-18
-25/3
Unit
Min.
Max.
Min.
Max.
VREF + 0.125
VDDQ + 0.3
VREF + 0.125
VDDQ + 0.3
V
VIH (DC)
DC Input logic High Voltage
VIL (DC)
DC Input Low Voltage
- 0.3
VREF - 0.125
- 0.3
VREF - 0.125
V
VIH (AC)
AC Input High Voltage
VREF + 0.2
-
VREF + 0.2
VDDQ + Vpeak
V
VIL (AC)
AC Input Low Voltage
-
VREF - 0.2
VSSQ - Vpeak
VREF - 0.2
V
VID (AC)
AC Differential Voltage
0.5
VDDQ + 0.6
0.5
VDDQ
V
0.5 x VDDQ +
0.5 x VDDQ 0.5 x VDDQ +
0.5 x VDDQ V
0.175
0.175
0.175
0.175
NOTE1: Refer to Overshoot/undershoot specification for Vpeak value: maximum peak amplitude allowed for
overshoot and undershoot.
VIX (AC)
AC Differential crosspoint Voltage
Table 19. AC Input test conditions
Symbol
VREF
VSWING(max)
Parameter
Value
Input reference voltage
Input signal maximum peak to peak swing
Unit Note
0.5 x VDDQ
V
1
1.0
V
1
Slew Rate Input signal minimum slew rate
1.0
V/ns 2, 3
NOTE1: Input waveform timing is referenced to the input signal crossing through the VIH /IL (ac) level applied to the
device under test.
NOTE2: The input signal minimum slew rate is to be maintained over the range from VREF to VIH(ac) min for rising
edges and the range from VREF to VIL (ac) max for falling edges .
NOTE3: AC timings are referenced with input waveforms switching from VIL (ac) to VIH (ac) on the positive
transitions and VIH (ac) to VIL (ac) on the negative transitions.
Table 20. Differential AC output parameters
Symbol
Value
Parameter
Min.
Unit Note
Max.
Vox(AC)
AC Differential Cross Point Voltage
0.5 x VDDQ - 0.125 0.5 x VDDQ + 0.125 V
1
NOTE1: The typical value of VOX (ac) is expected to be about 0.5 x VDDQ of the transmitting device and VOX (ac) is
expected to track variations in VDDQ. VOX (ac) indicates the voltage at which differential output signals must
cross.
Table 21. AC overshoot/undershoot specification for address and control pins
(A0-A12, BA0-BA1, CS#, RAS#, CAS#, WE#, CKE, ODT)
-18
-25
-3
Unit
Maximum peak amplitude allowed for overshoot area
0.5
0.5
0.5
V
Maximum peak amplitude allowed for undershoot area
0.5
0.5
0.5
V
Parameter
Maximum overshoot area above VDD
0.5
0.66
0.8
V-ns
Maximum undershoot area below VSS
0.5
0.66
0.8
V-ns
Rev. 1.4
23
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EtronTech
EM68B16CWQH
Table 22. AC overshoot/undershoot specification for clock, data, strobe, and mask pins
(DQ, UDQS, LDQS, UDQS#, LDQS#, DM, CK, CK#)
Parameter
-18
-25
-3
Unit
Maximum peak amplitude allowed for overshoot area
0.5
0.5
0.5
V
Maximum peak amplitude allowed for undershoot area
0.5
0.5
0.5
V
Maximum overshoot area above VDD
0.19
0.23
0.23
V-ns
Maximum undershoot area below VSS
0.19
0.23
0.23
V-ns
Table 23. Output AC test conditions
Symbol
VOTR
Parameter
Value
Output timing measurement reference level
Unit Note
0.5xVDDQ
V
1
NOTE1: The VDDQ of the device under test is referenced.
Table 24. Output DC current drive
Symbol
IOH(dc)
Parameter
Output minimum source DC current
Value
Unit Note
-13.4
mA
1, 3, 4
IOL(dc)
Output minimum sink DC current
mA 2, 3, 4
13.4
NOTE1: VDDQ = 1.7 V; VOUT = 1420 mV. (VOUT - VDDQ) /IOH must be less than 21 Ω for values of VOUT between VDDQ
and VDDQ - 280 mV.
NOTE2: VDDQ = 1.7 V; VOUT = 280 mV. VOUT/IOL must be less than 21 Ω for values of VOUT between 0 V and 280 mV.
NOTE3: The dc value of VREF applied to the receiving device is set to VTT
NOTE4: The values of IOH (dc) and IOL (dc) are based on the conditions given in Notes 1 and 2. They are used to
test device drive current capability to ensure VIH min plus a noise margin and VIL max minus a noise
margin are delivered to an SSTL_18 receiver. The actual current values are derived by shifting the desired
driver operating point (see JEDEC standard: Section 3.3 of JESD8-15A) along a 21 Ω load line to define a
convenient driver current for measurement.
Table 25. Capacitance (VDD = 1.8V, f = 1MHz, TOPER = 25 °C)
Symbol
Value
Parameter
Min.
Max.
Unit
CIN
Input Capacitance : Command and Address
1.0
1.75
pF
CCK
Input Capacitance (CK, CK#)
1.0
2.0
pF
CI/O
DM, DQ, DQS Input/Output Capacitance
2.5
3.5
pF
DCIN
Delta Input Capacitance: Command and Address
-
0.25
pF
DCCK
Delta Input Capacitance: CK, CK#
-
0.25
pF
DCIO
Delta Input/Output Capacitance: DM, DQ, DQS
-
0.5
pF
NOTE: These parameters are periodically sampled and are not 100% tested.
Rev. 1.4
24
Jun. /2014
EtronTech
EM68B16CWQH
Table 26. IDD specification parameters and test conditions (VDD = 1.8V ± 0.1V, TOPER = 0~85 °C)
Parameter & Test Condition
Operating one bank active-precharge current:
tCK =tCK (min), tRC = tRC (min), tRAS = tRAS(min); CKE is HIGH, CS# is
HIGH between valid commands; Address bus inputs are SWITCHING;
Data bus inputs are SWITCHING
Operating one bank active-read-precharge current:
IOUT = 0mA; BL = 4, CL = CL (min), AL = 0; tCK = tCK (min),tRC = tRC (min),
tRAS = tRAS(min), tRCD = tRCD (min);CKE is HIGH, CS# is HIGH between
valid commands;Address bus inputs are switching; Data pattern is same
as IDD4W
Precharge power-down current:
All banks idle;tCK =tCK (min); CKE is LOW; Other control and address bus
inputs are STABLE; Data bus inputs are FLOATING
Precharge quiet standby current:
All banks idle; tCK =tCK (min); CKE is HIGH, CS# is HIGH; Other control
and address bus inputs are STABLE; Data bus inputs are FLOATING
Precharge standby current:
All banks idle; tCK = tCK (min); CKE is HIGH, CS# is HIGH; Other control
and address bus inputs are SWITCHING; Data bus inputs are
SWITCHING
Active power-down current:
MRS(A12)=0
All banks open; tCK =tCK (min); CKE is LOW; Other control
and address bus inputs are STABLE; Data bus inputs are
MRS(A12)=1
FLOATING
Active standby current:
All banks open; tCK = tCK(min), tRAS = tRAS (max), tRP = tRP (min); CKE is
HIGH, CS# is HIGH between valid commands; Other control and
address bus inputs are SWITCHING; Data bus inputs are SWITCHING
Operating burst write current:
All banks open,continuous burst writes; BL = 4, CL = CL (min), AL = 0;
tCK= tCK (min), tRAS = tRAS (max), tRP = tRP (min); CKE is HIGH, CS# is
HIGH between valid commands; Address bus inputs are switching; Data
bus inputs are switching
Operating burst read current:
All banks open, continuous burst reads, IOUT = 0mA; BL = 4, CL = CL
(min), AL = 0; tCK = tCK (min), tRAS = tRAS (max), tRP = tRP (min); CKE is
HIGH, CS# is HIGH between valid commands; Address bus inputs are
SWITCHING; Data bus inputs are SWITCHING
Burst refresh current:
tCK = tCK (min); refresh command at every tRFC (min) interval; CKE is
HIGH, CS# is HIGH between valid commands; Other control and
address bus inputs are SWITCHING; Data bus inputs are SWITCHING
Self refresh current:
CK and CK# at 0V; CKE ≤ 0.2V;Other control and address bus inputs
are FLOATING; Data bus inputs are FLOATING
Operating bank interleave read current:
All bank interleaving reads, IOUT= 0mA; BL = 4, CL = CL (min), AL =tRCD
(min) - 1 x tCK (min); tCK = tCK (min), tRC = tRC (min), tRRD = tRRD (min), tRCD
= tRCD (min); CKE is HIGH, CS# is HIGH between valid commands;
Address bus inputs are STABLE during DESELECTs.Data pattern is
same as IDD4R
Rev. 1.4
-18
-25
Max.
-3
IDD0
95
90
85
mA
IDD1
105
100
95
mA
IDD2P
8
8
8
mA
IDD2Q
40
35
35
mA
IDD2N
45
40
40
mA
30
30
30
mA
15
15
15
mA
IDD3N
65
60
60
mA
IDD4W
175
135
125
mA
IDD4R
175
135
125
mA
IDD5
100
90
85
mA
IDD6
6
6
6
mA
IDD7
220
180
160
mA
Symbol
25
IDD3P
Unit
Jun. /2014
EtronTech
EM68B16CWQH
Table 27. Electrical Characteristics and Recommended A.C. Operating Conditions
(VDD = 1.8V ± 0.1V, TOPER= 0~85 °C)
-18
Symbol
tCK(avg)
Parameter
Average clock period
-25
Min.
Max.
-3
Min.
Max.
Min.
Max.
CL=3
-
-
5
8
5
8
CL=4
3.75
8
3.75
8
3.75
8
CL=5
3
8
2.5
8
3
8
CL=6
2.5
8
2.5
8
-
CL=7
1.875
8
-
-
-
-
tCH(avg)
tCL(avg)
Average clock HIGH pulse width
0.48
0.52
0.48
0.52
0.48
0.52
Average Clock LOW pulse width
0.48
0.52
0.48
0.52
0.48
0.52
WL
Write command to DQS associated clock
edge
DQS latching rising transitions to
associated clock edges
tDQSS
RL-1
ns
ns
ns
ns
ns
tCK
tCK
Specific
Notes
15, 33, 34
15, 33, 34
15, 33, 34
15, 33, 34
15, 33, 34
34, 35
34, 35
tCK
RL-1
RL-1
Unit
-0.25
0.25
-0.25
0.25
-0.25
0.25
tCK
28
28
tDSS
tDSH
DQS falling edge to CK setup time
0.2
-
0.2
-
0.2
-
DQS falling edge hold time from CK
0.2
-
0.2
-
0.2
-
tCK
tCK
tDQSH
DQS input HIGH pulse width
0.35
-
0.35
-
0.35
-
tCK
tDQSL
tWPRE
tWPST
DQS input LOW pulse width
0.35
-
0.35
-
0.35
-
Write preamble
0.35
-
0.35
-
0.35
-
Write postamble
0.4
0.6
0.4
0.6
0.4
0.6
tCK
tCK
tCK
10
tIS(base)
Address and Control input setup time
0.125
-
0.175
-
0.2
-
ns
5, 7, 9, 22,
27
tIH(base)
Address and Control input hold time
0.2
-
0.25
-
0.275
-
ns
5, 7, 9, 23,
27
tIPW
Control & Address input pulse width for
each input
0.6
-
0.6
-
0.6
-
tCK
tDS(base
DQ & DM input setup time
0
-
0.05
-
0.1
-
ns
6, 7, 8, 20,
26, 29
DQ & DM input hold time
0.075
-
0.125
-
0.175
-
ns
6, 7, 8, 21,
26, 29
tDIPW
DQ and DM input pulse width for each
input
0.35
-
0.35
-
0.35
-
tCK
tAC
tDQSCK
DQ output access time from CK, CK#
-0.35
0.35
-0.4
0.4
-0.45
0.45
38
DQS output access time from CK, CK#
-0.325
0.325
-0.35
0.35
-0.4
0.4
ns
ns
tHZ
Data-out high-impedance time from CK,
CK#
DQS(DQS#) low-impedance time from
CK, CK#
-
tAC(max)
-
tAC(max)
-
tAC(max)
ns
18, 38
tAC(min)
tAC(max)
tAC(min)
tAC(max)
tAC(min)
tAC(max)
ns
18, 38
tLZ(DQ)
tDQSQ
DQ low-impedance time from CK, CK#
2tAC(min)
tAC(max)
2tAC(min)
tAC(max)
2tAC(min)
tAC(max)
ns
18, 38
DQS-DQ skew for DQS and associated
DQ signals
-
0.175
-
0.2
-
0.24
ns
13
tHP
tQHS
CK half pulse width
min(tCL,tCH)
-
min(tCL,tCH)
-
min(tCL,tCH)
-
11, 12, 35
DQ hold skew factor
-
0.25
-
0.3
-
0.34
)
tDH(base
)
tLZ(DQS)
38
tHP -tQHS
-
tHP -tQHS
-
-
tHP -tQHS
Read preamble
0.9
1.1
0.9
1.1
0.9
1.1
Read postamble
0.4
0.6
0.4
0.6
0.4
0.6
Active to active command period
10
-
10
-
10
-
CAS# to CAS# command delay
2
-
2
-
2
-
Write recovery time
15
-
15
-
15
-
ns
ns
ns
tCK
tCK
ns
tCK
ns
tDAL
Auto Power write recovery + precharge
time
WR + tRP
-
WR + tRP
-
WR + tRP
-
ns
14, 31
tWTR
Internal Write to Read Command Delay
7.5
-
7.5
-
7.5
-
ns
3, 24, 30
tQH
tRPRE
tRPST
tRRD
tCCD
tWR
Rev. 1.4
DQ/DQS output hold time from DQS
26
12, 36
37
19, 39
19, 40
4, 30
30
Jun. /2014
EtronTech
tRTP
Internal read to precharge command
delay
tCKE
CKE minimum pulse width
tXSNR
Exit self refresh to non-read command
delay
tXSRD
Exit self refresh to a read command
tXP
Exit precharge power down to any
command
tXARD
Exit active power down to read command
tXARDS
Exit active power down to read
command(slow exit, lower power)
tAOND
ODT turn-on delay
tAON
ODT turn-on
tAONPD
ODT turn-on (Power-Down mode)
tAOFD
ODT turn-off delay
tAOF
ODT turn-off
tAOFPD
ODT turn-off (Power-Down mode)
tANPD
tAXPD
tMRD
tMOD
tOIT
EM68B16CWQH
7.5
-
7.5
-
7.5
-
ns
3, 30
3
-
3
-
3
-
tCK
25
tRFC+10
-
tRFC+10
-
tRFC+10
-
ns
30
200
-
200
-
200
-
tCK
3
-
2
-
2
-
tCK
3
-
2
-
2
-
tCK
1
10-AL
-
8-AL
-
7-AL
-
tCK
1, 2
2
2
2
2
2
2
tCK
16
tAC(min)
tAC(max)
+2.575
tAC(min)
tAC(max)
+0.7
tAC(min)
tAC(max)
+0.7
ns
6, 16, 38
2 tCK
+tAC(max)+1
ns
2.5
tCK
17, 42
ns
17, 41, 42
3 tCK
2 tCK
t (min)+2
t (min)+2
+tAC(max)+1 AC
+tAC(max)+1 AC
tAC(min)+2
2.5
2.5
tAC(max)
tAC(min)
+0.6
2.5 tCK
+tAC(max)+1
tAC(min)+2
2.5
tAC(min)
tAC(min)+2
2.5
tAC(max)
+0.6
2.5
tAC(min)
tAC(max)
+0.6
2.5 tCK
2.5 tCK
t C(min)+2
+tAC(max)+1 A
+tAC(max)+1
ns
ODT to power down entry latency
4
-
3
-
3
-
ODT power down exit latency
11
-
8
-
8
-
Mode register set command cycle time
2
-
2
-
2
-
MRS command to ODT update delay
0
12
0
12
0
12
OCD drive mode output delay
0
12
0
12
0
12
tCK
tCK
tCK
ns
ns
tIS+ tCK +tIH
-
tIS+ tCK +tIH
-
tIS+ tCK +tIH
-
ns
15
30
30
tDelay
Minimum time clocks remains ON after
CKE asynchronously drops LOW
tRFC
Refresh to active/Refresh command time
105
-
105
-
105
-
ns
43
tREFI
Average periodic @ 0℃≦TC≦ +85℃
refesh interval
@ +85℃＜TC≦ +95℃
-
7.8
-
7.8
-
7.8
µs
43
µs
ns
ns
ns
ns
43
tRCD
tRP
tRC
tRAS
Rev. 1.4
-
3.9
-
3.9
-
3.9
RAS# to CAS# Delay time
13.125
-
12.5
-
15
-
Row precharge Delay time
13.125
-
12.5
-
15
-
Row cycle Delay time
58.125
-
57.5
-
60
-
Row active Delay time
45
70k
45
70k
45
70k
27
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EM68B16CWQH
General notes, which may apply for all AC parameters:
NOTE 1: DDR2 SDRAM AC timing reference load
The below figure represents the timing reference load used in defining the relevant timing parameters of the part.
It is not intended to be either a precise representation of the typical system environment or a depiction of the actual
load presented by a production tester.
Figure 6. AC timing reference load
VDDQ
DQ
DUT DQS
Ouput
25Ω
DQS#
VTT=VDDQ/2
Timing reference
point
The output timing reference voltage level for single ended signals is the crosspoint with VTT. The output timing
reference voltage level for differential signals is the crosspoint of the true (e.g. DQS) and the complement (e.g.
DQS#) signal.
NOTE 2: Slew Rate Measurement Levels
a) Output slew rate for falling and rising edges is measured between VTT - 250 mV and VTT + 250 mV for single
ended signals. For differential signals (e.g. DQS – DQS#) output slew rate is measured between DQS – DQS#
= - 500 mV and DQS – DQS# = + 500 mV. Output slew rate is guaranteed by design, but is not necessarily
tested on each device.
b) Input slew rate for single ended signals is measured from VREF (dc) to VIH (ac), min for rising edges and from
VREF(dc) to VIL(ac),max for falling edges.For differential signals (e.g. CK – CK#) slew rate for rising edges is
measured from CK – CK# = - 250 mV to CK -CK# = + 500 mV (+ 250 mV to - 500 mV for falling edges).
c) VID is the magnitude of the difference between the input voltage on CK and the input voltage on CK#, or
betweenDQS and DQS# for differential strobe.
NOTE 3: DDR2 SDRAM output slew rate test load
Output slew rate is characterized under the test conditions as bellow
Figure 7. Slew rate test load
VDDQ
DQ
DUT DQS
Ouput
25Ω
DQS#
VTT=VDDQ/2
Test point
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EM68B16CWQH
NOTE 4: Differential data strobe
DDR2 SDRAM pin timings are specified for either single ended mode or differential mode depending on the
setting of the EMRS “Enable DQS” mode bit; timing advantages of differential mode are realized in system
design. The method by which the DDR2 SDRAM pin timings are measured is mode dependent. In single ended
mode, timing relationships are measured relative to the rising or falling edges of DQS crossing at VREF. In
differential mode, these timing relationships are measured relative to the crosspoint of DQS and its complement,
DQS#. This distinction in timing methods is guaranteed by design and characterization. Note that when
differential data strobe mode is disabled via the EMRS, the complementary pin, DQS#, must be tied externally to
VSS through a 20 Ω to 10 kΩ resistor to insure proper operation
NOTE 5: AC timings are for linear signal transitions.
NOTE 6:All voltages are referenced to VSS.
NOTE 7: These parameters guarantee device behavior, but they are not necessarily tested on each device.They
may be guaranteed by device design or tester correlation.
NOTE 8: Tests for AC timing, IDD, and electrical (AC and DC) characteristics, may be conducted at nominal
reference/supply voltage levels, but the related specifications and device operation are guaranteed for the full
voltage range specified.
Specific notes for dedicated AC parameters
NOTE 1:User can choose which active power down exit timing to use via MRS (bit 12). tXARD is expected to be
used for fast active power down exit timing. tXARDS is expected to be used for slow active power down exit
timing where a lower power value is defined by each vendor data sheet.
NOTE 2: AL=Additive Latency.
NOTE 3:This is a minimum requirement. Minimum read to precharge timing is AL+BL/2 provided that the tRTP and
tRAS (min) have been satisfied.
NOTE 4: A minimum of two clocks (2* tCK) is required irrespective of operating frequency.
NOTE 5: Timings are specified with command/address input slew rate of 1.0 V/ns.
NOTE 6:Timings are specified with DQs, DM, and DQS’s (in single ended mode) input slew rate of 1.0V/ns.
NOTE 7:Timings are specified with CK/CK# differential slew rate of 2.0 V/ns. Timings are guaranteed for DQS
signals with a differential slew rate of 2.0 V/ns in differential strobe mode and a slew rate of 1 V/ns in single
ended mode.
NOTE 8:Data setup and hold time derating.
For all input signals the total tDS (setup time) and tDH (hold time) required is calculated by adding the data sheet.
tDS(base) and tDH(base) value to the ∆tDS and ∆tDH derating value respectively.
Example: tDS (total setup time) =tDS (base) + ∆tDS.For slew rates in between the values listed in Tables 28, the
derating values may obtained by linear interpolation.These values are typically not subject to production test.
They are verified by design and characterization.
Table 28. DDR2-667/800/1066 tDS/tDH derating with differential data strobe
△tDS, △tDH derating values for DDR2-667, DDR2-800, DDR2-1066 (All units in ‘ps’; the note applies to the entire table)
DQS,DQS# Differential Slew Rate
4.0 V/ns
3.0 V/ns
2.0 V/ns
1.8 V/ns
1.6 V/ns
1.4 V/ns
1.2 V/ns
1.0 V/ns
0.8 V/ns
△tD
S
DQ
Slew
Rate
V/ns
2.0
1.5
1.0
0.9
0.8
0.7
0.6
0.5
0.4
Rev. 1.4
△tD
H
△tD
S
△tD
H
△tD
S
△tD
H
100
45
67
21
0
0
0
0
-
-
-5
-14
-
-
-
-
-13
-31
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
△tD
S
△tD
H
100
45
100
45
-
-
-
-
-
-
-
-
-
-
-
-
67
21
67
21
79
33
-
-
-
-
-
-
-
-
-
-
0
0
12
12
24
24
-
-
-
-
-
-
-
-
-5
-14
7
-2
19
10
31
22
-
-
-
-
-
-
-1
-19
11
-7
23
5
35
17
-
-
-
-
-10
-42
2
-30
14
-18
26
-6
38
6
-
-
-
-
-10
-59
2
-47
14
-35
26
-23
38
-11
-
-
-
-
-
-24
-89
-12
-77
0
-65
12
-53
-
-
-
-
-
-
-
-52
-140
-40
-128
-28
-116
29
△tD
S
△tD
H
△tD
S
△tD
H
△tD
S
△tD
H
△tD
S
△tD
H
△tD
S
△tD
H
Jun. /2014
EtronTech
EM68B16CWQH
NOTE 9:tIS and tIH (input setup and hold) derating
For all input signals the total tIS (setup time) and tIH (hold time) required is calculated by adding the data sheet
tIS(base) and tIH(base) value to the ∆tIS and ∆tIH derating value respectively. Example: tIS (total setup time) =
tIS(base) + ∆tIS
For slew rates in between the values listed in Tables 29, the derating values may obtained by linear
interpolation.These values are typically not subject to production test. They are verified by design and
characterization.
Table 29. Derating values for DDR2-667, DDR2-800, DDR2-1066
Command/
Address Slew rate
(V/ns)
△tIS and △tIH Derating Values for DDR2-667, DDR2-800, DDR2-1066
CK,CK# Differential Slew Rate
2.0 V/ns
1.5 V/ns
1.0 V/ns
△tIS
△tIH
△tIS
△tIH
△tIS
△tIH
4.0
+150
+94
+180
+124
+210
+154
3.5
+143
+89
+173
+119
+203
+149
3.0
+133
+83
+163
+113
+193
+143
2.5
+120
+75
+150
+105
+180
+135
2.0
+100
+45
+130
+75
+160
+105
1.5
+67
+21
+97
+51
+127
+81
1.0
0
0
+30
+30
+60
+60
0.9
-5
-14
+25
+16
+55
+46
0.8
-13
-31
+17
-1
+47
+29
0.7
-22
-54
+8
-24
+38
+6
0.6
-34
-83
-4
-53
+26
-23
0.5
-60
-125
-30
-95
0
-65
0.4
-100
-188
-70
-158
-40
-128
0.3
-168
-292
-138
-262
-108
-232
0.25
-200
-375
-170
-345
-140
-315
0.2
-325
-500
-295
-470
-265
-440
0.15
-517
-708
-487
-678
-457
-648
0.1
-1000
-1125
-970
-1095
-940
-1065
Units
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
Notes
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
NOTE 10: The maximum limit for this parameter is not a device limit. The device will operate with a greater value
for this parameter, but system performance (bus turnaround) will degrade accordingly.
NOTE 11: MIN (tCL, tCH) refers to the smaller of the actual clock LOW time and the actual clock HIGH time as
provided to the device (i.e. this value can be greater than the minimum specification limits for tCL and tCH).
NOTE 12: tQH = tHP – tQHS, where:
tHP = minimum half clock period for any given cycle and is defined by clock HIGH or clock LOW (tCH, tCL).
tQHS accounts for:
1) The pulse duration distortion of on-chip clock circuits; and
2) The worst case push-out of DQS on one transition followed by the worst case pull-in of DQ on the next
transition, both of which are, separately, due to data pin skew and output pattern effects, and p-channel
to n-channel variation of the output drivers.
NOTE 13: tDQSQ: Consists of data pin skew and output pattern effects, and p-channel to n-channel variation of the
output drivers as well as output slew rate mismatch between DQS / DQS# and associated DQ in any given cycle.
NOTE 14: tDAL = WR + RU{ tRP[ns] / tCK[ns] }, where RU stands for round up.WR refers to the tWR parameter stored
in the MRS. For tRP, if the result of the division is not already an integer, round up to the next highest integer. tCK
refers to the application clock period.
NOTE 15: The clock frequency is allowed to change during self–refresh mode or precharge power-down mode. In
case of clock frequency change during precharge power-down.
NOTE 16: ODT turn on time min is when the device leaves high impedance and ODT resistance begins to turn on.
ODT turn on time max is when the ODT resistance is fully on. Both are measured from tAOND, which is interpreted
as 2 clock cycles after the clock edge that registered a first ODT HIGH counting the actual input clock edges.
NOTE 17: ODT turn off time min is when the device starts to turn off ODT resistance. ODT turn off time max is
when the bus is in high impedance. Both are measured from tAOFD, which is interpreted differently per speed bin.
For DDR2-1066, if tCK(avg) = 1.875 ns is assumed, tAOFD is 0.9375 ns (= 0.5 x 1.875 ns) after the second trailing
clock edge counting from the clock edge that registered a first ODT LOW and by counting the actual input clock
edges.
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NOTE 18: tHZ and tLZ transitions occur in the same access time as valid data transitions. These parameters are
referenced to a specific voltage level which specifies when the device output is no longer driving (tHZ), or begins
driving (tLZ).
NOTE 19: tRPST end point and tRPRE begin point are not referenced to a specific voltage level but specify when the
device output is no longer driving (tRPST), or begins driving (tRPRE). The actual voltage measurement points are not
critical as long as the calculation is consistent.
NOTE 20: Input waveform timing tDS with differential data strobe enabled MR[bit10]=0, is referenced from the input
signal crossing at the VIH(ac) level to the differential data strobe crosspoint for a rising signal, and from the input
signal crossing at the VIL(ac) level to the differential data strobe crosspoint for a falling signal applied to the device
under test. DQS, DQS# signals must be monotonic between VIL(dc)max and VIH(dc)min.
NOTE 21: Input waveform timing tDH with differential data strobe enabled MR[bit10]=0, is referenced from the
differential data strobe crosspoint to the input signal crossing at the VIH(dc) level for a falling signal and from the
differential data strobe crosspoint to the input signal crossing at the VIL(dc) level for a rising signal applied to the
device under test. DQS, DQS# signals must be monotonic between VIL(dc)max and VIH(dc)min.
NOTE 22: Input waveform timing is referenced from the input signal crossing at the VIH(ac) level for a rising signal
and VIL(ac) for a falling signal applied to the device under test.
NOTE 23: Input waveform timing is referenced from the input signal crossing at the VIL(dc) level for a rising signal
and VIH(dc) for a falling signal applied to the device under test.
NOTE 24: tWTR is at lease two clocks (2 x tCK ) independent of operation frequency.
NOTE 25: tCKEmin of 3 clocks means CKE must be registered on three consecutive positive clock edges. CKE
must remain at the valid input level the entire time it takes to achieve the 3 clocks of registration. Thus, after any
CKE transition, CKE may not transition from its valid level during the time period of tIS + 2 x tCK + tIH.
NOTE 26: If tDS or tDH is violated, data corruption may occur and the data must be re-written with valid data before
a valid READ can be executed.
NOTE 27: These parameters are measured from a command/address signal (CKE, CS#, RAS#, CAS#, WE#, ODT,
BA0, A0, A1, etc.) transition edge to its respective clock signal (CK/CK#) crossing. The spec values are not
affected by the amount of clock jitter applied (i.e. tJIT(per), tJIT(cc), etc.), as the setup and hold are relative to the
clock signal crossing that latches the command/address. That is, these parameters should be met whether clock
jitter is present or not.
NOTE 28: These parameters are measured from a data strobe signal (LDQS/UDQS) crossing to its respective
clock signal (CK/CK#) crossing. The spec values are not affected by the amount of clock jitter applied (i.e. tJIT(per),
tJIT(cc), etc.), as these are relative to the clock signal crossing. That is, these parameters should be met whether
clock jitter is present or not.
NOTE 29: These parameters are measured from a data signal ((L/U) DM, (L/U) DQ0, (L/U) DQ1, etc.) transition
edge to its respective data strobe signal (LDQS/UDQS/LDQS#/UDQS#) crossing.
NOTE 30: For these parameters, the DDR2 SDRAM device is characterized and verified to support tnPARAM =
RU{tPARAM / tCK(avg)}, which is in clock cycles, assuming all input clock jitter specifications are satisfied.
NOTE 31: tDAL [tCK] = WR [tCK] + tRP [tCK] = WR + RU {tRP [ps] / tCK(avg) [ps] }, where WR is the value programmed
in the mode register set.
NOTE 32: New units, ‘tCK(avg)’ is introduced in DDR2-667, DDR2-800 and DDR2-1066. Unit ‘tCK(avg)’ represents
the actual tCK(avg) of the input clock under operation.
NOTE 33: Input clock jitter spec parameter. These parameters and the ones in the table below are referred to as
'input clock jitter spec parameters' and these parameters apply to DDR2-667, DDR2-800 and DDR2-1066 only.
The jitter specified is a random jitter meeting a Gaussian distribution.
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Table 30. Input clock jitter spec parameter
-18
Parameter
Clock period jitter
Cumulative error across 4 cycles
Cumulative error across 5 cycles
Cumulative error across n cycles,
n=6...10, inclusive
Cumulative error across n cycles,
n=11...50, inclusive
Duty cycle jitter
Units Notes
Max.
Min.
Max.
Min.
Max.
-90
90
-100
100
-125
125
ps
33
-80
80
-80
80
-100
100
ps
33
-180
180
-200
200
-250
250
ps
33
tJIT (cc,lck)
-160
160
-160
160
-200
200
ps
33
tERR (2per)
-132
132
-150
150
-175
175
ps
33
tERR (3per)
-157
157
-175
175
-225
225
ps
33
tERR (4per)
-175
175
-200
200
-250
250
ps
33
tERR (5per)
-188
188
-200
200
-250
250
ps
33
-250
250
-300
300
-350
350
ps
33
-425
425
-450
450
-450
450
ps
33
-75
75
-100
100
-125
125
ps
33
Clock period jitter during DLL locking
tJIT (per,lck)
period
Cycle to cycle clock period jitter
tJIT (cc)
Cumulative error across 3 cycles
-3
Min.
tJIT (per)
Cycle to cycle clock period jitter
during DLL locking period
Cumulative error across 2 cycles
-25
Symbol
tERR (610per)
tERR (1150per)
tJIT (duty)
Definitions:
- tCK(avg)
tCK(avg) is calculated as the average clock period across any consecutive 200 cycle window.
⎡N
⎤
=
avg
/N
t CK ( ) ⎢∑
t
CK j ⎥
=
1
j
⎣
⎦
where N=200
- tCH(avg) and tCL(avg)
tCH(avg) is defined as the average HIGH pulse width, as calculated across any consecutive 200 HIGH pulses.
⎡
⎤
t CH ( avg ) = ⎢∑ t CH ⎥ / ( N × t CK ( avg ) )
N
⎣ j =1
j
⎦
where N=200
tCL(avg) is defined as the average LOW pulse width, as calculated across any consecutive 200 LOW pulses.
⎡
⎤
t CL ( avg ) = ⎢∑ t CL ⎥ / ( N × t CK ( avg ) )
N
⎣ j =1
j
⎦
where N=200
tJIT (duty) is defined as the cumulative set of tCH jitter and tCL jitter. tCH jitter is the largest deviation of
any single tCH from tCH(avg). tCL jitter is the largest deviation of any single tCL from tCL(avg).
- tJIT(duty) = Min/max of {tJIT(CH), tJIT(CL)}
where,
tJIT(CH) = {tCHi- tCH(avg) where i=1 to 200}
tJIT(CL) = {tCLi- tCL(avg) where i=1 to 200}
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EM68B16CWQH
- tJIT(per), tJIT(per,lck)
tJIT(per) is defined as the largest deviation of any single tCK from tCK(avg).
tJIT(per) = Min/max of {tCKi- tCK(avg) where i=1 to 200}
tJIT(per) defines the single period jitter when the DLL is already locked.
tJIT(per,lck) uses the same definition for single period jitter, during the DLL locking period only.
tJIT(per) and tJIT(per,lck) are not guaranteed through final production testing.
- tJIT(cc), tJIT(cc,lck)
tJIT(cc) is defined as the difference in clock period between two consecutive clock cycles:
tJIT(cc) = Max of |tCKi+1 – tCKi|
tJIT(cc) defines the cycle to cycle jitter when the DLL is already locked.
tJIT(cc,lck) uses the same definition for cycle to cycle jitter, during the DLL locking period only.
tJIT(cc) and tJIT(cc,lck) are not guaranteed through final production testing.
- tERR(2per), tERR (3per), tERR (4per), tERR (5per), tERR (6-10per) and tERR (11-50per)
tERR is defined as the cumulative error across multiple consecutive cycles from tCK(avg).
⎡ i +N −1
⎤
t ERR (nper ) = ⎢ ∑ t CK ⎥ − ( N × t CK ( avg ) )
⎣
j =1
j
⎦
⎧n=2
⎪
⎪n=3
⎪
⎪n=4
where ⎨
⎪n=5
⎪
⎪6 ≤ n ≤ 10
⎪11 ≤ n ≤ 50
⎩
for
for
for
for
for
for
( 2per )
( 3 per )
ERR
( 4 per )
ERR
( 5 per )
ERR
( 6 − 10 per )
ERR
(11 − 50 per )
ERR
t
t
t
t
t
t
ERR
NOTE 34: These parameters are specified per their average values, however it is understood that the following
relationship between the average timing and the absolute instantaneous timing holds at all times. (Min andmax of
SPEC values are to be used for calculations in the table below.)
Table 31. Absolute clock period average values
Parameter
Symbol
Min.
Max.
Units
Absolute clock period
tCK (abs)
tCK(avg),min + tJIT(per),min
tCK(avg),max + tJIT(per),max
ps
Absolute clock HIGH pulse width
tCH (abs)
Absolute clock LOW pulse width
tCL (abs)
tCH(avg),min * tCK(avg),min + tCH(avg),max * tCK(avg),max +
tJIT(duty),min
tJIT(duty),max
tCL(avg),min * tCK(avg),min + tCL(avg), max * tCK(avg),max
tJIT(duty),min
+ tJIT(duty), max
ps
ps
NOTE 35: tHP is the minimum of the absolute half period of the actual input clock. tHP is an input parameter but not
an input specification parameter. It is used in conjunction with tQHS to derive the DRAM output timing tQH. The
value to be used for tQH calculation is determined by the following equation;
tHP = Min ( tCH(abs), tCL(abs) ),
where,
tCH(abs) is the minimum of the actual instantaneous clock HIGH time;
tCL(abs) is the minimum of the actual instantaneous clock LOW time;
NOTE 36: tQHS accounts for:
1) The pulse duration distortion of on-chip clock circuits, which represents how well the actual tHP at the input
is transferred to the output; and
2) The worst case push-out of DQS on one transition followed by the worst case pull-in of DQ on the next
transition, both of which are independent of each other, due to data pin skew, output pattern effects, and pchannel to n-channel variation of the output drivers
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NOTE 37: tQH = tHP – tQHS, where: tHP is the minimum of the absolute half period of the actual input clock; and tQHS is
the specification value under the max column. {The less half-pulse width distortion present, the larger the tQH
value is; and the larger the valid data eye will be.}
NOTE 38: When the device is operated with input clock jitter, this parameter needs to be derated by the actual
tERR(6-10per) of the input clock. (output deratings are relative to the SDRAM input clock.)
NOTE 39: When the device is operated with input clock jitter, this parameter needs to be derated by the actual
tJIT(per) of the input clock. (output deratings are relative to the SDRAM input clock.)
NOTE 40: When the device is operated with input clock jitter, this parameter needs to be derated by the actual
tJIT(duty) of the input clock. (output deratings are relative to the SDRAM input clock.)
NOTE 41: When the device is operated with input clock jitter, this parameter needs to be derated by { tJIT(duty),max - tERR(6-10per),max } and { - tJIT(duty),min - tERR(6-10per),min } of the actual input clock. (output
deratings are relative to the SDRAM input clock.)
NOTE 42: For tAOFD of DDR2-667/800/1066, the 1/2 clock of tCK in the 2.5 x tCK assumes a tCH(avg), average input
clock HIGH pulse width of 0.5 relative to tCK(avg). tAOF,min and tAOF,max should each be derated by the same
amount as the actual amount of tCH(avg) offset present at the DRAM input with respect to 0.5.
NOTE 43: If refresh timing is violated, data corruption may occur and the data must be re-writtern with valid data
before a valid READ can be executed.
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Timing Waveforms
Figure 8. Initialization sequence after power-up
tCH tCL
CK
CK#
tIS
CKE
tIS
ODT
Command
EMR
S
PRE
ALL
NOP
tRP
400ns
PRE
ALL
MRS
tMRD
DLL
ENABLE
tMRD
REF
tRP
REF
tRFC
tRFC
DLL
RESET
EMR
S
EMR
S
MRS
tMRD
min 200 Cycle
Follow OCD Flowchart
ANY
CMD
t
OIT
OCD
CAL.MOD
E EXIT
OCD
Default
NOTE 1: To guarantee ODT off, VREF must be valid and a LOW level must be applied to the ODT pin.
Figure 9. OCD drive mode
OCD calibration mode exit
Enter Drive mode
CMD
EMRS
NOP
NOP
NOP
EMRS
CK#
CK
DQS
DQS#
Hi-Z
DQS HIGH & DQS# LOW for Drive(1), DQS LOW & DQS# HIGH for Drive(0)
Hi-Z
DQs HIGH for Drive(1)
DQ
DQs LOW for Drive(0)
tOIT
tOIT
NOTE : Drive mode, both Drive(1) and Drive(0), is used for controllers to measure DDR2 SDRAM Driver
impedance.In this mode, all outputs are driven out tOIT after "enter drive mode" command and all output
drivers are turned-off tOIT after "OCD calibration mode exit" command.
Rev. 1.4
35
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EM68B16CWQH
Figure 10. OCD adjust mode
OCD calibration mode exit
OCD adjust mode
CMD
EMRS
NOP
NOP
NOP
NOP
EMRS
NOP
NOP
CK#
CK
WL
DQS_in
tDS tDH
VIH(ac)
DQ_in
WR
DQS#
VIH(dc)
DT0
DT1
DT2
DT3
VIL(ac)
VIL(dc)
DM
NOTE 1: For proper operation of adjust mode, WL = RL - 1 = AL + CL - 1tCK and tDS /tDH should be met as shown in the figure.
NOTE 2: For input data pattern for adjustment, DT0-DT3 is a fixed order and is not affected by burst type
(i.e., sequential or interleave)
Figure 11. ODT update delay timing-tMOD
CMD
EMRS
NOP
NOP
NOP
NOP
NOP
CK#
CK
ODT
tIS
tAOFD
Rtt
Old setting
tMOD, min
tMOD, max
Updating
New setting
NOTE 1: To prevent any impedance glitch on the channel, the following conditions must be met:
- tAOFD must be met before issuing the EMRS command.
- ODT must remain LOW for the entire duration of tMOD window, until tMOD, max is met.
then the ODT is ready for normal operation with the new setting, and the ODT signal may be raised again to turned
on the ODT.
NOTE 2: EMRS command directed to EMR(1), which updates the information in EMR(1)[A6,A2], i.e. Rtt (Nominal).
NOTE 3: "setting" in this diagram is the Register and I/O setting, not what is measured from outside.
Rev. 1.4
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EM68B16CWQH
Figure 12. ODT update delay timing-tMOD, as measured from outside
CK#
CK
CMD
EMRS
NOP
NOP
ODT
NOP
NOP
tIS
tAOFD
Rtt
NOP
tAOND
tMOD, max
New setting
Old setting
NOTE 1: EMRS command directed to EMR(1), which updates the information in EMR(1)[A6,A2], i.e. Rtt (Nominal).
NOTE 2: "setting" in this diagram is measured from outside.
Figure 13. ODT timing for active standby mode
T0
T1
T3
T2
T4
T5
T6
CK#
CK
tIS
CKE
tIS
tIS
VIH(ac)
ODT
Internal
Term Res.
VIL(ac)
tAOND
tAOFD
RTT
tAON,min
tAON,max
Rev. 1.4
37
tAOF,min
tAOF,max
Jun. /2014
EtronTech
EM68B16CWQH
Figure 14. ODT timing for power-down mode
T0
T1
T3
T2
T4
T5
T6
CK#
CK
CKE
tIS
tIS
VIH(AC)
VIL(AC)
ODT
tAOFPD,max
tAOFPD,min
Internal
Term Res.
RTT
tAONPD,min
tAONPD,max
Figure 15. ODT timing mode switch at entering power-down mode
T-5
CK#
T-4
T-3
T-2
CK
T-1
tANPD
T0
T1
T2
T3
T4
tIS
CKE
Entering Slow Exit Active Power Down Mode or Precharge Power Down Mode.
ODT
tIS
VIL(ac)
tAOFD
Internal
Term Res.
Active & Standby mode
timings to be applied.
RTT
tIS
ODT
VIL(ac)
Power Down mode
timings to be applied.
tAOFPD max
Internal
Term Res.
RTT
tIS
VIH(ac)
ODT
tAOND
RTT
Internal
Term Res.
VIH(ac)
ODT
tIS
tAONPD max
RTT
Internal
Term Res.
Rev. 1.4
Active & Standby mode
timings to be applied.
38
Power Down mode
timings to be applied.
Jun. /2014
EtronTech
EM68B16CWQH
Figure 16. ODT timing mode switch at exit power-down mode
T0
CK#
CK
VIH(ac)
T1
T4
T5
T6
T7
T8
T9
T10
T11
tAXPD
tIS
CKE
Exiting from Slow Active Power Down Mode or Precharge power Down Mode.
tIS
ODT
Active & Standby mode
timings to be applied.
VIL(ac)
tAOFD
Internal
Term Res.
RTT
tIS
ODT
Power Down mode
timings to be applied.
VIL(ac)
tAOFPD max
Internal
Term Res.
RTT
tIS
Active & Standby mode
timings to be applied.
VIH(ac)
ODT
tAOND
RTT
Internal
Term Res.
VIH(ac)
Power Down mode
timings to be applied.
tIS
ODT
tAONPD max
Internal
Term Res.
RTT
Figure 17. Bank activate command cycle (tRCD=3, AL=2, tRP=3, tRRD=2, tCCD=2)
T0
T1
T3
T2
Tn
Tn+1
Tn+2
Tn+3
CK#
CK
ADDRESS
Internal RAS# - CAS# delay (>=tRCD min)
Bank A
Row Addr.
tRCD = 1
Bank A
Col. Addr.
Bank A
Activate
Bank A
Addr.
Bank B
Addr.
Bank A
Row Addr.
Bank A
Precharge
Bank B
Precharge
Bank A
Activate
CAS# - CAS# delay time (tCCD)
Additive latency delay (AL)
Read Begins
RAS# - RAS# delay time (>=tRRD)
COMMAND
Bank B
Col. Addr
Bank B
Row Addr.
Bank A
Post CAS#
Read
Bank B
Activate
Bank B
Post CAS#
Read
Bank precharge time (>=tRP)
Bank Active (>=tRAS)
RAS# Cycle time (>=tRC)
Rev. 1.4
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EM68B16CWQH
Figure 18.1. Posted CAS# operation: AL=2
Read followed by a write to the same bank
-1
0
1
2
Active
A-Bank
Read
A-Bank
3
4
5
6
7
8
9
10
11
12
11
12
CK#
CK
CMD
Write
A-Bank
AL=2
WL=RL-1=4
CL=3
DQS
DQS#
>=tRCD
RL=AL+CL=5
DQ
Dout 0 Dout 1 Dout 2 Dout 3
Din 0
Din 1
Din 2
Din 3
[ AL=2 and CL=3, RL= (AL+CL)=5, WL= (RL-1)=4, BL=4]
Figure 18.2. Posted CAS# operation: AL=0
Read followed by a write to the same bank
-1
0
1
2
3
4
5
6
7
8
9
10
CK#
CK
AL=0
CMD
Active
A-Bank
Write
A-Bank
Read
A-Bank
CL=3
DQS
DQS#
WL=RL-1=2
>=tRCD
RL=AL+CL=3
DQ
Dout 0 Dout 1 Dout 2 Dout 3
Din 0
Din 1
Din 2
Din 3
[ AL=0 and CL=3, RL= (AL+CL)=3, WL= (RL-1)=2, BL=4]
Rev. 1.4
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EM68B16CWQH
Figure 19. Data output (read) timing
tCH
CK#
CK
tCL
CK
DQS#
DQS
DQS#
DQS
tRPRE
DQ
tRPST
tDQSQ max
Q
Q
Q
Q
tDQSQ max
tQH
tQH
Figure 20.1. Burst read operation: RL=5 (AL=2, CL=3, BL=4)
CK#
CK
CMD
T0
T1
Posted CAS#
READ A
T2
NOP
T3
NOP
NOP
T4
T5
NOP
T6
NOP
T7
NOP
T8
NOP
NOP
=< tDQSCK
DQS
DQS#
AL=2
CL=3
RL=5
DQs
Dout A0
Dout A1
Dout A2
Dout A3
Figure 20.2. Burst read operation: RL=3 (AL=0, CL=3, BL=8)
CK#
CK
T0
CMD
DQS
DQS#
READ A
T1
NOP
T2
NOP
T3
T4
NOP
T5
NOP
T6
NOP
T7
NOP
NOP
T8
NOP
=< tDQSCK
CL=3
RL=3
DQs
Rev. 1.4
Dout A0
Dout A1
41
Dout A2
Dout A3
Dout A4
Dout A5
Dout A6
Dout A7
Jun. /2014
EtronTech
EM68B16CWQH
Figure 21. Burst read followed by burst write: RL=5, WL= (RL-1) =4, BL=4
T0
CK#
CK
CMD
T1
Post CAS#
READ A
Tn-1
NOP
Tn
Tn+1
Post CAS#
WRITE A
NOP
Tn+2
NOP
Tn+3
NOP
Tn+4
NOP
Tn+5
NOP
NOP
tRTW (Read to Write turn around time)
DQS
DQS#
RL=5
WL = RL-1 = 4
DQs
Dout A0
Dout A1
Dout A2
Dout A3
Din A0
Din A1
Din A2
Din A3
NOTE : The minimum time from the burst read command to the burst write command is defined by a read-to-writeturn-around-time, which is 4 clocks in case of BL = 4 operation, 6 clocks in case of BL = 8 operation.
Figure 22. Seamless burst read operation: RL=5, AL=2, CL=3, BL=4
T0
CK#
CK
CMD
T1
Post CAS#
READ A
NOP
T2
T3
Post CAS#
READ B
T4
NOP
NOP
T5
T6
NOP
T7
NOP
T8
NOP
NOP
DQS
DQS#
AL=2
CL=3
RL=5
DQs
Dout A0
Dout A1
Dout A2
Dout A3
Dout B0
Dout B1
Dout B2
NOTE : The seamless burst read operation is supported by enabling a read command at every other clock for BL =
4 operation, and every 4 clock for BL =8 operation. This operation is allowed regardless of same or different banks
as long as the banks are activated.
Rev. 1.4
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EM68B16CWQH
Figure 23. Read burst interrupt timing: (CL=3, AL=0, RL=3, BL=8)
CK#
CK
CMD
Read A
NOP
NOP
Read B
NOP
NOP
NOP
NOP
NOP
NOP
DQS
DQS#
DQs
A0
A1
A2
A3
B0
B1
B2
B3
B4
B5
B6
B7
NOTE 1: Read burst interrupt function is only allowed on burst of 8. Burst interrupt of 4 is prohibited.
NOTE 2: Read burst of 8 can only be interrupted by another Read command. Read burst interruption by Write
command or Precharge command is prohibited.
NOTE 3: Read burst interrupt must occur exactly two clocks after previous Read command. Any other Read burst
interrupt timings are prohibited.
NOTE 4: Read burst interruption is allowed to any bank inside DRAM.
NOTE 5: Read burst with Auto Precharge enabled is not allowed to interrupt.
NOTE 6: Read burst interruption is allowed by another Read with Auto Precharge command.
NOTE 7: All command timings are referenced to burst length set in the mode register. They are not referenced to
actual burst. For example, Minimum Read to Precharge timing is AL+BL/2 where BL is the burst length set in the
mode register and not the actual burst (which is shorter because of interrupt).
Figure 24. Data input (write) timing
tDQSH
DQS#
tDQSL
DQS
DQS#
DQS
tWPRE
DQ
tWPSL
VIH(ac)
D
VIL(ac)
tDS
DM
Rev. 1.4
VIH(dc)
D
D
VIL(dc)
tDH
tDS
tDH
VIH(dc)
VIH(ac)
DMin
D
DMin
DMin
VIL(ac)
43
DMin
VIL(dc)
Jun. /2014
EtronTech
EM68B16CWQH
Figure 25.1. Burst write operation: RL=5 (AL=2, CL=3), WL=4, BL=4
T0
CK#
CK
T1
Posted CAS#
WRITE A
CMD
T2
NOP
T3
NOP
T4
NOP
Case 1: with tDQSS (max)
DQS
DQS#
T5
T6
NOP
NOP
tDQSS
tDSS tDQSS
T7
NOP
tDSS
Precharge
Completion of the
Burst Write
WL = RL-1 =4
>=tWR
DQs
DNA0
Case 2: with tDQSS (min)
DQS
DQS#
NOP
Tn
tDQSS tDSH
DNA1
DNA2 DNA3
tDQSS tDSH
>=tWR
WL = RL-1 =4
DQs
DNA0
DNA1
DNA2 DNA3
Figure 25.2. Burst write operation: RL=3 (AL=0, CL=3), WL=2, BL=4
CK#
CK
CMD
T0
T1
WRITE A
NOP
T2
T3
NOP
NOP
<=tDQSS
DQS
DQS#
DQs
Rev. 1.4
T4
T5
NOP
NOP
>=tWR
DNA1
Tm+1
NOP
Precharge
Tn
Bank A
Activate
Completion of the
Burst Write
WL = RL-1 =2
DNA0
Tm
>=tRP
DNA2 DNA3
44
Jun. /2014
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EM68B16CWQH
Figure 26. Burst write followed by burst read:
RL=5 (AL=2, CL=3, WL=4, tWTR=2, BL=4)
CK#
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
CK
Write to Read = CL-1+BL/2+tWTR
CKE
DQS
DQS#
NOP
NOP
NOP
Post CAS#
READ A
NOP
NOP
NOP
NOP
NOP
DQS#
DQS
WL = RL-1 = 4
AL=2
CL=3
RL=5
>=tWTR
DQ
DNA0
DNA1
DNA2 DNA3
DOUT A0
NOTE : The minimum number of clock from the burst write command to the burst read command is [CL-1 + BL/2 + tWTR].
This tWTR is not a write recovery time (tWR) but the time required to transfer the 4 bit write data from the input buffer into
sense amplifiers in the array. tWTR is defined in the timing parameter table of this standard.
Figure 27. Seamless burst write operation RL=5, WL=4, BL=4
CK#
T0
T1
T2
T3
T4
T5
T6
T7
T8
CK
CMD
DQS
DQS#
Post CAS#
Write A
NOP
Post CAS#
Write B
NOP
NOP
NOP
NOP
NOP
NOP
DQS#
DQS
WL = RL-1 = 4
DQ
DNA0
DNA1
DNA2 DNA3 DNB0
DNB1
DNB2 DNB3
NOTE : The seamless burst write operation is supported by enabling a write command every other clock for
BL= 4 operation, every four clocks for BL = 8 operation. This operation is allowed regardless of same or
different banks as long as the banks are activated.
Rev. 1.4
45
Jun. /2014
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EM68B16CWQH
Figure 28. Write burst interrupt timing: (CL=3, AL=0, RL=3, WL=2, BL=8)
CK#
CK
CMD
NOP
Write A
NOP
Write B
NOP
NOP
NOP
NOP
NOP
NOP
DQS
DQS#
DQs
A0
A1
A2
A3
B0
B1
B2
B3
B4
B5
B6
B7
NOTE 1: Write burst interrupt function is only allowed on burst of 8. Burst interrupt of 4 is prohibited.
NOTE 2: Write burst of 8 can only be interrupted by another Write command. Write burst interruption by Read command or
Precharge command is prohibited.
NOTE 3: Write burst interrupt must occur exactly two clocks after previous Write command. Any other Write burst interrupt
timings are prohibited.
NOTE 4: Write burst interruption is allowed to any bank inside DRAM.
NOTE 5: Write burst with Auto Precharge enabled is not allowed to interrupt.
NOTE 6: Write burst interruption is allowed by another Write with Auto Precharge command.
NOTE 7: All command timings are referenced to burst length set in the mode register. They are not referenced to actual
burst. For example, minimum Write to Precharge timing is WL + BL/2 + tWR where tWR starts with the rising clock after the
uninterrupted burst end and not from the end of actual burst end.
Rev. 1.4
46
Jun. /2014
EtronTech
EM68B16CWQH
Figure 29. Write data mask
Data Mask Timing
DQS
DQS#
DQ
DM
Data Mask Function, WL=3, AL=0, BL=4 shown
VIH(ac)VIH(dc)
VIH(ac)VIH(dc)
VIL(ac)VIL(dc)
VIL(ac)VIL(dc)
tDS tDH
tDS tDH
Case 1: min tDQSS
CK#
CK
tWR
COMMAND
DQS
DQS#
Write
WL
tDQSS
DQ
DM
Case 2: max tDQSS
tDQSS
DQS
DQS#
DQ
DM
Rev. 1.4
47
Jun. /2014
EtronTech
EM68B16CWQH
Figure 30.1. Burst read operation followed by precharge:
(RL=4, AL=1, CL=3, BL=4, tRTP ≦2 clocks)
T0
CK#
T1
T2
T3
T4
T5
T6
T7
T8
CK
Post CAS#
Read A
CMD
NOP
NOP
NOP
Precharge
NOP
Bank A
Active
NOP
NOP
AL+BL'/2 clks
DQS
DQS#
AL=1
CL=3
>=tRP
RL=4
DQ
DOUTA0 DOUTA1 DOUTA2 DOUTA3
>=tRAS
>=tRTP
CL=3
Figure 30.2.Burst read operation followed by precharge:
(RL=4, AL=1, CL=3, BL=8, tRTP≦2 clocks)
CK#
CK
T0
CMD
DQS
DQS#
DQ's
T1
Post CAS#
READ A
T2
NOP
T3
NOP
T4
NOP
NOP
T5
T6
T7
NOP
Precharge A
T8
NOP
NOP
AL + BL/2 clks
CL = 3
AL = 1
RL= 4
DOUT
A0
DOUT
A1
DOUT
A2
DOUT
A3
DOUT
A4
DOUT
A5
DOUT
A6
DOUT
A7
>=tRTP
First 4-bit prefetch
Rev. 1.4
Second 4-bit prefetch
48
Jun. /2014
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EM68B16CWQH
Figure 30.3. Burst read operation followed by precharge:
(RL=5, AL=2, CL=3, BL=4, tRTP≦2 clocks)
T0
T1
T2
T3
T4
T5
T6
T7
T8
CK#
CK
Post CAS#
READ A
CMD
NOP
NOP
NOP
NOP
Precharge A
NOP
Bank A
Activate
NOP
AL + BL/2 clks
DQS
DQS#
CL = 3
AL = 2
>=tRP
RL= 5
DOUT
A0
DQ's
>=tRAS
DOUT
A1
DOUT
A2
DOUT
A3
CL = 3
>=tRTP
Figure 30.4. Burst read operation followed by precharge:
(RL=6, AL=2, CL=4, BL=4, tRTP≦2 clocks)
T0
T1
T2
T3
T4
T5
T6
T7
T8
CK#
CK
CMD
Post CAS#
READ A
NOP
NOP
NOP
Precharge A
NOP
NOP
Bank A
Activate
NOP
AL + BL/2 clks
DQS
DQS#
CL = 4
AL = 2
>=tRP
RL= 6
DOUT
A0
DQ's
>=tRAS
DOUT
A1
DOUT
A2
DOUT
A3
CL = 4
>=tRTP
Rev. 1.4
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Jun. /2014
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EM68B16CWQH
Figure 30.5. Burst read operation followed by precharge:
(RL=4, AL=0, CL=4, BL=8, tRTP>2 clocks)
T0
CK#
T1
T2
T3
T4
T5
T6
T7
T8
CK
Post CAS#
READ A
CMD
NOP
NOP
NOP
NOP
NOP
Precharge A
NOP
Bank A
Activate
AL + 2 + max( tRTP, 2 tCK)*
DQS
DQS#
CL = 4
AL = 0
>=tRP
RL= 4
DQ's
DOUT
A0
>=tRAS
DOUT
A1
DOUT
A2
DOUT
A3
DOUT
A4
DOUT
A5
DOUT
A6
DOUT
A7
>=tRTP
First 4-bit prefetch
Second 4-bit prefetch
*: rounded to next integer.
Figure 31.1. Burst write operation followed by precharge: WL= (RL-1) =3
CK#
T0
T1
T2
T3
T4
T5
T6
T7
T8
CK
CMD
Post CAS#
Write A
NOP
NOP
NOP
NOP
NOP
NOP
NOP
Precharge A
Completion of the Burst Write
DQS
DQS#
DQ's
Rev. 1.4
>=tWR
WL= 3
DNA0
DNA1
50
DNA2 DNA3
Jun. /2014
EtronTech
EM68B16CWQH
Figure 31.2. Burst write followed by precharge: WL= (RL-1) =4
T0
CK#
T1
T2
T3
T4
T5
T6
T7
T9
CK
Post CAS#
Write A
CMD
NOP
NOP
NOP
NOP
NOP
NOP
NOP
Precharge A
Completion of the Burst Write
>=tWR
DQS
DQS#
WL= 4
DQ's
DNA0
DNA1
DNA2 DNA3
Figure 32.1. Burst read operation with auto precharge:
(RL=4,AL=1, CL=3, BL=8, tRTP≦2 clocks)
T0
CK#
CK
T1
Post CAS#
READ A
CMD
T2
NOP
NOP
Autoprecharge
DQS
DQS#
DQ's
T3
T4
NOP
T5
NOP
T6
NOP
NOP
T8
Bank A
Activate
NOP
>= tRP
AL + BL/2 clks
AL = 1
T7
CL = 3
RL= 4
>=tRTP
DOUT
A0
DOUT
A1
DOUT
A2
DOUT
A3
DOUT
A4
DOUT
A5
DOUT
A6
DOUT
A7
tRTP
First 4-bit prefetch
Rev. 1.4
Second 4-bit prefetch
51
Precharge begins here
Jun. /2014
EtronTech
EM68B16CWQH
Figure 32.2. Burst read operation with auto precharge:
(RL=4, AL=1, CL=3, BL=4, tRTP>2 clocks)
T0
CK#
CK
T1
Post CAS#
READ A
CMD
T2
NOP
NOP
T4
NOP
NOP
T5
T6
NOP
NOP
T7
Bank A
Activate
T8
NOP
>= AL+tRTP+tRP
Autoprecharge
DQS
DQS#
T3
AL= 1
CL= 3
RL= 4
DQ's
DoutA0 DoutA1 DoutA2 DoutA3
tRTP
tRP
First 4-bit prefetch
Precharge begins here
Figure 32.3. Burst read operation with auto precharge followed by activation to the same
bank (tRC Limit): RL=5(AL=2, CL=3, internal tRCD=3, BL=4, tRTP≦2 clocks)
CK#
CK
T0
T1
T2
T3
T4
T5
T6
T7
T8
A10= 1
CMD
DQS
DQS#
Post CAS#
READ A
NOP
NOP
NOP
NOP
NOP
NOP
Bank A
Activate
>=tRAS(min) Auto Precharge Begins
AL= 2
CL= 3
>=tRP
RL= 5
DQ's
DoutA0 DoutA1 DoutA2 DoutA3
CL=3
>= tRC
Rev. 1.4
NOP
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EM68B16CWQH
Figure 32.4. Burst read operation with auto precharge followed by an activation to the same
bank (tRP Limit): (RL=5 (AL=2, CL=3, internal tRCD=3, BL=4, tRTP≦2 clocks)
T0
CK#
CK
T1
T2
T3
T4
T5
T6
T7
T8
A10= 1
Post CAS#
READ A
CMD
NOP
NOP
NOP
>=tRAS(min)
NOP
NOP
Bank A
Activate
NOP
NOP
Auto Precharge Begins
DQS
DQS#
AL= 2
>= tRP
CL= 3
RL= 5
DQ's
DoutA0 DoutA1 DoutA2 DoutA3
CL=3
>= tRC
Figure 33.1. Burst write with auto-precharge (tRC Limit): WL=2, WR=2, BL=4, tRP=3
T0
CK#
CK
T1
T2
T3
T4
T5
T6
T7
Tm
A10 = 1
CMD
Post CAS#
WRA Bank A
NOP
NOP
NOP
NOP
NOP
NOP
NOP
Bank A
Active
Completion of the Burst Write
DQS
DQS#
DQ's
Rev. 1.4
Auto Precharge Begins
>=WR
WL= RL-1=2
DNA0
DNA1
>=tRP
DNA2 DNA3
>=tRC
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EtronTech
EM68B16CWQH
Figure 33.2. Burst write with auto-precharge (WR+tRP): WL=4, WR=2, BL=4, tRP=3
T0
CK#
T3
T4
T5
T6
T7
T8
T9
T12
CK
A10 = 1
CMD
Post CAS#
WRA Bank A
NOP
NOP
NOP
NOP
NOP
NOP
NOP
Bank A
Active
Completion of the Burst Write
Auto Precharge Begins
DQS
DQS#
>=WR
>=tRP
WL= RL-1=4
DQ's
DNA0
DNA1
DNA2 DNA3
>=tRC
Figure 34. Refresh command
T0
T1
T2
T3
Tm
Tn
Tn+1
CK#
CK
HIGH
CKE
CMD
Rev. 1.4
>=tRP
Precharge
NOP
>=tRFC
NOP
REF
>=tRFC
REF
54
NOP
ANY
Jun. /2014
EtronTech
EM68B16CWQH
Figure 35. Self refresh operation
T0
CK#
tCH
tCK
T1
T2
T3
T4
T5
T6
Tm
Tn
tCL
CK
>=tXSNR
tRP*
>=tXSRD
CKE
VIH(ac)
VIL(ac)
tAOFD
ODT
tIS
tIS
VIL(ac)
tIS
tIS tIH tIH
tIS
VIH(ac)
Self VIH(dc)
VIL(ac) Refresh VIL(dc)
CMD
tIH
NOP
NOP
NOP
Valid
NOTE 1 Device must be in the "All banks idle" state prior to entering Self Refresh mode.
NOTE 2 ODT must be turned off tAOFD before entering Self Refresh mode, and can be
turned on again when tXSRD timing is satisfied.
NOTE 3 tXSRD is applied for Read or a Read with autoprecharge command.
tXSNR is applied for any command except a Read or a Read with autoprecharge command.
Figure 36. Basic power down entry and exit timing diagram
CK
CK#
CKE
Command
tIH
tIS
VALID
tIH
NOP
tIS
NOP
NOP
tCKE min
tIS tIH
VALID
VALID
or NOP
tXP, tXARD
tXARDS
Exit Power-Down mode
Enter Power-Down mode
tIH
tCKE(min)
Don't Care
Figure 37.1.CKE intensive environment
CK#
CK
tCKE
tCKE
CKE
tCKE
tCKE
NOTE: DRAM guarantees all AC and DC timing & voltage specifications and proper DLL operation with intensive CKE operation
Rev. 1.4
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EM68B16CWQH
Figure 37.2.CKE intensive environment
CK#
CK
CKE
tCKE
tCKE
tCKE
tXP
CMD
tCKE
tXP
REF
REF
tREFI = 3.9 µs
NOTE: The pattern shown above can repeat over a long period of time. With this pattern, DRAM guarantees all AC and DC timing & voltage
specifications and DLL operation with temperature and voltage drift
Figure 38. Read to power-down entry
T0
T1
T2
Tx
Tx+1
Tx+2
Tx+3
Tx+4
Tx+5
Tx+6
Tx+7
Tx+8
Tx+9
Tx+8
Tx+9
CK#
CK
CMD
Read operation starts with a read command and
RD
CKE should be kept HIGH until the end of burst operation
BL=4
CKE
AL+CL
Q
DQ
Q
Q
tIS
Q
DQS
DQS#
T0
T1
T2
Tx
Tx+1
Tx+2
Tx+3
Tx+4
Tx+5
Tx+6
Tx+7
CK#
CK
CMD
RD
CKE should be kept HIGH until the end of burst operation
BL=8
CKE
AL+CL
DQ
Q
Q
Q
Q
Q
Q
Q
Q
tIS
DQS
DQS#
Rev. 1.4
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EM68B16CWQH
Figure 39. Read with autoprecharge to power-down entry
T0
T1
T2
Tx
Tx+1
Tx+2
Tx+3
Tx+4
Tx+5
Tx+6
Tx+7
Tx+8
Tx+9
Tx+8
Tx+9
CK#
CK
CMD
RDA
PRE
BL=4
CKE should be kept HIGH until the end of burst operation
AL+BL/2 with tRTP = 7.5ns
& tRAS min satisfied
CKE
AL+CL
Q
DQ
Q
Q
tIS
Q
DQS
DQS#
T0
T1
T2
Tx
Tx+1
Tx+2
Tx+3
Tx+4
Tx+5
Tx+6
Tx+7
CK#
CK
Start internal precharge
CMD
RD
PRE
BL=8
CKE should be kept HIGH until the end of burst operation
AL+BL/2 with tRTP = 7.5ns
& tRAS min satisfied
CKE
AL+CL
Q
DQ
Q
Q
Q
Q
Q
Q
tIS
Q
DQS
DQS#
Figure 40. Write to power-down entry
CK#
T0
T1
Tm
Tm+1
Tm+2
Tm+3
Tx
Tx+1
Tx+2
Ty
Ty+1
Ty+2
Ty+3
Tx
Tx+1
Tx+2
Tx+3
Tx+4
CK
CMD
WR
BL=4
CKE
WL
Q
DQ
Q
Q
tIS
Q
tWTR
DQS
DQS#
CK#
T0
T1
Tm
Tm+1
Tm+2
Tm+3
Tm+4
Tm+5
CK
CMD
WR
BL=8
CKE
WL
DQ
Q
Q
Q
Q
Q
Q
Q
tIS
Q
tWTR
DQS
DQS#
Rev. 1.4
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EM68B16CWQH
Figure 41. Write with autoprecharge to power-down entry
T0
T1
Tm
Tm+1
Tm+2
Tm+3
Tx
Tx+1
Tx+2
Tx+3
Tx+4
Tx+5
Tx+6
Tx+1
Tx+2
Tx+3
Tx+4
CK#
CK
CMD
WRA
PRE
BL=4
CKE
WL
Q
DQ
Q
Q
tIS
Q
WR*1
DQS
DQS#
T0
T1
Tm
Tm+1
Tm+2
Tm+3
Tm+4
Tm+5
Tx
CK#
CK
Start internal Precharge
CMD
WRA
PRE
BL=8
CKE
WL
Q
DQ
Q
Q
Q
Q
Q
Q
tIS
Q
WR*1
DQS
DQS#
*1: WR is programmed through MRS
Figure 42. Refresh command to power-down entry
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
CK#
CK
CMD
REF
CKE can go to LOW one clock after an Auto-refresh command
CKE
tIS
Figure 43. Active command to power-down entry
T0
CMD
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
ACT
CKE can go to LOW one clock after an Active command
CKE
tIS
Rev. 1.4
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Jun. /2014
EtronTech
EM68B16CWQH
Figure 44. Precharge/precharge-all command to power-down entry
T0
CMD
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
PR or PRA
CKE can go to LOW one clock after a Precharge or Precharge all command
CKE
tIS
Figure 45. MRS/EMRS command to power-down entry
T0
T1
T2
MRS or
EMRS
CMD
T3
T4
T5
T6
T7
T8
T9
T10
T11
tMRD
CKE
tIS
Figure 46. Asynchronous CKE LOW event
Stable clocks
tCK
CK#
CK
CKE
tDelay
CKE asynchronously drops LOW
tIS
Clocks can be turned off after this point
Figure 47. Clock frequency change in precharge power down mode
CK#
CK
T0
CMD
T1
T2
NOP
NOP
T4
Tx
Tx+1
Ty
Ty+1
Ty+2
Ty+3
NOP
NOP
Ty+4
DLL
RESET
Tz
NOP
Valid
Frequency Change Occurs here
CKE
ODT
tIS
tXP
tRP
tAOFD
Minimum 2 clocks required before
changing frequency
Rev. 1.4
200 Clocks
tIS
Stable new clock before power
down exit
59
tIH
ODT is off during DLL RESET
Jun. /2014
EtronTech
EM68B16CWQH
Figure 48. 84-Ball 8x12.5x1.2mm(max.) FBGA Package Outline Drawing Information
P IN A 1 IN D E X
T o p V ie w
B o tto m V ie w
S id e V ie w
D E T A IL : "A "
Symbol
A
A1
A2
A3
D
E
D1
E1
F
e
b
D2
Rev. 1.4
Dimension in inch
Dimension in mm
Min
Nom Max
Min
Nom Max
--0.047
--1.20
0.010
-0.016 0.25
-0.40
0.030 0.031 0.033 0.75 0.80 0.85
0.005 0.006 0.007 0.125 0.155 0.185
0.311 0.315 0.319 7.9
8.0
8.1
0.488 0.492 0.496 12.4 12.5 12.6
-0.252
--6.40
--0.441
--11.2
--0.126
--3.2
--0.031
--0.80
-0.016 0.018 0.020 0.40 0.45 0.50
--0.081
--2.05
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