DATA SHEET
2G bits DDR2 SDRAM
EDE2108AEBG (256M words 8 bits)
Specifications
Features
Density: 2G bits
Organization
32M words 8 bits 8 banks
Package
60-ball FBGA
Lead-free (RoHS compliant) and Halogen-free
Power supply: VDD, VDDQ 1.8V 0.1V
Data rate
800Mbps (max.)
1KB page size
Row address: A0 to A14
Column address: A0 to A9
Eight internal banks for concurrent operation
Interface: SSTL_18
Burst lengths (BL): 4, 8
Burst type (BT):
Sequential (4, 8)
Interleave (4, 8)
/CAS Latency (CL): 3, 4, 5, 6
Precharge: auto precharge option for each burst
access
Driver strength: normal, weak
Refresh: auto-refresh, self-refresh
Double-data-rate architecture; two data transfers per
clock cycle
The high-speed data transfer is realized by the 4 bits
prefetch pipelined architecture
Bi-directional differential data strobe (DQS and /DQS)
is transmitted/received with data for capturing data at
the receiver
DQS is edge-aligned with data for READs; centeraligned with data for WRITEs
Differential clock inputs (CK and /CK)
DLL aligns DQ and DQS transitions with CK
transitions
Commands entered on each positive CK edge; data
and data mask referenced to both edges of DQS
Data mask (DM) for write data
Posted /CAS by programmable additive latency for
better command and data bus efficiency
/DQS can be disabled for single-ended Data Strobe
operation
Off-Chip Driver (OCD) impedance adjustment is not
supported.
Refresh cycles: 8192 cycles/64ms
Average refresh period
7.8s at 0C TC 85C
3.9s at 85C TC 95C
Operating case temperature range
TC = 0C to +95C
Document No. E1950E11 (Ver.1.1)
Date Published December 2012 (K) Japan
Printed in Japan
URL: http://www.elpida.com
Elpida Memory, Inc. 2012
EDE2108AEBG
Ordering Information
Part number
Die
revision
Organization
(words bits)
Internal
banks
Speed bin
(CL-tRCD-tRP)
Package
EDE2108AEBG-8E-F
E
256M 8
8
DDR2-800 (5-5-5)
60-ball FBGA
Part Number
E D E 21 08 A E BG - 8E - F
Elpida Memory
Type
D: Packaged Device
Environment code
F: Lead Free (RoHS compliant)
and Halogen Free
Product Family
E: DDR2
Speed
8E: DDR2-800 (5-5-5)
Density / Bank
21: 2Gb / 8-bank
Package
BG: FBGA
Organization
08: x8
Power Supply, Interface
A: 1.8V, SSTL_18
Die Rev.
Data Sheet E1950E11 (Ver.1.1)
2
EDE2108AEBG
Pin Configurations
/xxx indicates active low signal.
60-ball FBGA
2
1
3
7
8
9
A
VDD NU/ /RDQS VSS
VSSQ /DQS VDDQ
B
DQ6 VSSQ DM/RDQS
DQS
VSSQ
DQ7
VDDQ
DQ0
VDDQ
C
VDDQ
DQ1 VDDQ
D
DQ4
VSSQ
DQ3
DQ2
VSSQ
DQ5
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
A14
NC
A13
E
F
G
BA2
H
VDD
J
VSS
K
VSS
L
VDD
(Top view)
Pin name
Function
Pin name
Function
A0 to A14
Address inputs
ODT
ODT control
BA0, BA1, BA2
Bank select
VDD
Supply voltage for internal circuit
DQ0 to DQ7
Data input/output
VSS
Ground for internal circuit
DQS, /DQS
Differential data strobe
VDDQ
Supply voltage for DQ circuit
RDQS, /RDQS
Differential data strobe for read
VSSQ
Ground for DQ circuit
/CS
Chip select
VREF
Input reference voltage
/RAS, /CAS, /WE
Command input
VDDL
Supply voltage for DLL circuit
CKE
Clock enable
VSSDL
Ground for DLL circuit
CK, /CK
Differential clock input
NC*
1
DM
Write data mask
NU*
2
Notes: 1. Not internally connected with die.
2. Don’t connect. Internally connected.
Data Sheet E1950E11 (Ver.1.1)
3
No connection
Not usable
EDE2108AEBG
CONTENTS
Specifications.................................................................................................................................................1
Features.........................................................................................................................................................1
Ordering Information......................................................................................................................................2
Part Number ..................................................................................................................................................2
Pin Configurations .........................................................................................................................................3
Electrical Specifications.................................................................................................................................5
Block Diagram .............................................................................................................................................24
Pin Function.................................................................................................................................................25
Command Operation ...................................................................................................................................27
Simplified State Diagram .............................................................................................................................35
Operation of DDR2 SDRAM ........................................................................................................................36
Package Drawing ........................................................................................................................................70
Recommended Soldering Conditions..........................................................................................................71
Data Sheet E1950E11 (Ver.1.1)
4
EDE2108AEBG
Electrical Specifications
All voltages are referenced to VSS (GND)
Execute power-up and Initialization sequence before proper device operation is achieved.
Absolute Maximum Ratings
Parameter
Symbol
Rating
Unit
Notes
Power supply voltage
VDD
1.0 to +2.3
V
1
Power supply voltage for output
VDDQ
0.5 to +2.3
V
1
Input voltage
VIN
0.5 to +2.3
V
1
Output voltage
VOUT
0.5 to +2.3
V
1
Storage temperature
Tstg
55 to +100
C
1, 2
Power dissipation
PD
1.0
W
1
Short circuit output current
IOUT
50
mA
1
Notes: 1. Stresses greater than those listed under Absolute Maximum Ratings may cause permanent damage to
the device. This is a stress rating only and functional operation of the device at these or any other
conditions above those indicated in the operational sections of this specification is not implied. Exposure
to absolute maximum rating conditions for extended periods may affect reliability.
2. Storage temperature is the case surface temperature on the center/top side of the DRAM.
Caution
Exposing the device to stress above those listed in Absolute Maximum Ratings could cause
permanent damage. The device is not meant to be operated under conditions outside the limits
described in the operational section of this specification. Exposure to Absolute Maximum Rating
conditions for extended periods may affect device reliability.
Operating Temperature Condition
Parameter
Symbol
Rating
Unit
Notes
Operating case temperature
TC
0 to +95
C
1, 2
Notes: 1. Operating temperature is the case surface temperature on the center/top side of the DRAM.
2. Supporting 0°C to +85°C with full AC and DC specifications.
Supporting 0°C to +85°C and being able to extend to +95°C with doubling auto-refresh commands in
frequency to a 32ms period (tREFI = 3.9s) and higher temperature self-refresh entry via A7 "1" on
EMRS (2).
Data Sheet E1950E11 (Ver.1.1)
5
EDE2108AEBG
Recommended DC Operating Conditions (SSTL_18)
Parameter
Symbol
min.
typ.
max.
Unit
Notes
Supply voltage
VDD
1.7
1.8
1.9
V
4
Supply voltage for output
VDDQ
1.7
1.8
1.9
V
4
Input reference voltage
VREF
0.49 VDDQ
0.50 VDDQ 0.51 VDDQ
V
1, 2
Termination voltage
VTT
VREF 0.04
VREF
VREF + 0.04
V
3
DC input logic high
VIH (DC)
VREF + 0.125
VDDQ + 0.3
V
DC input logic low
VIL (DC)
0.3
VREF – 0.125
V
AC input logic high
VIH (AC)
VREF + 0.200
V
AC input logic low
VIL (AC)
VREF 0.200
V
Notes: 1. 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 VDDQ of the transmitting device and VREF are expected
to track variations in VDDQ.
2. Peak to peak AC noise on VREF may not exceed 2% VREF (DC).
3. VTT of transmitting device must track VREF of receiving device.
4. VDDQ tracks with VDD, VDDL tracks with VDD. AC parameters are measured with VDD, VDDQ and
VDDL tied together.
Data Sheet E1950E11 (Ver.1.1)
6
EDE2108AEBG
AC Overshoot/Undershoot Specification
Parameter
Pins
Specification
Unit
Maximum peak amplitude allowed for overshoot
Command, Address,
0.5
V
Maximum peak amplitude allowed for undershoot
CKE, ODT
0.5
V
0.66
V-ns
Maximum overshoot area above VDD
Maximum undershoot area below VSS
0.66
V-ns
0.5
V
0.5
V
Maximum overshoot area above VDD
0.23
V-ns
Maximum undershoot area below VSS
0.23
V-ns
Maximum peak amplitude allowed for overshoot
CK, /CK
Maximum peak amplitude allowed for undershoot
Maximum peak amplitude allowed for overshoot
DQ, DQS, /DQS,
0.5
V
Maximum peak amplitude allowed for undershoot
RDQS, /RDQS,
0.5
V
Maximum overshoot area above VDDQ
DM
0.23
V-ns
0.23
V-ns
Maximum undershoot area below VSSQ
Maximum amplitude
Overshoot area
Volts (V)
VDD, VDDQ
VSS, VSSQ
Undershoot area
Time (ns)
Overshoot/Undershoot Definition
Data Sheet E1950E11 (Ver.1.1)
7
EDE2108AEBG
DC Characteristics 1 (TC = 0C to +85C, VDD, VDDQ = 1.8V 0.1V)
Parameter
Symbol
Grade
max.
Unit
Operating current
(ACT-PRE)
IDD0
55
mA
Operating current
(ACT-READ-PRE)
IDD1
65
mA
Precharge power-down
standby current
IDD2P
12
mA
Precharge quiet standby
current
IDD2Q
20
mA
Idle standby current
IDD2N
25
mA
IDD3P-F
25
mA
IDD3P-S
14
mA
Active standby current
IDD3N
45
mA
Operating current
(Burst read operating)
IDD4R
100
mA
Operating current
(Burst write operating)
IDD4W
120
mA
Auto-refresh current
IDD5
150
mA
Active power-down
standby current
Data Sheet E1950E11 (Ver.1.1)
8
Test condition
one bank; tCK = tCK (IDD), tRC = tRC (IDD),
tRAS = tRAS min.(IDD);
CKE is H, /CS is H between valid commands;
Address bus inputs are SWITCHING;
Data bus inputs are SWITCHING
one bank; IOUT = 0mA;
BL = 4, CL = CL(IDD), AL = 0;
tCK = tCK (IDD), tRC = tRC (IDD),
tRAS = tRAS min.(IDD); tRCD = tRCD (IDD);
CKE is H, /CS is H between valid commands;
Address bus inputs are SWITCHING;
Data pattern is same as IDD4W
all banks idle;
tCK = tCK (IDD);
CKE is L;
Other control and address bus inputs are STABLE;
Data bus inputs are FLOATING
all banks idle;
tCK = tCK (IDD);
CKE is H, /CS is H;
Other control and address bus inputs are STABLE;
Data bus inputs are FLOATING
all banks idle;
tCK = tCK (IDD);
CKE is H, /CS is H;
Other control and address bus inputs are SWITCHING;
Data bus inputs are SWITCHING
all banks open;
Fast PDN Exit
tCK = tCK (IDD);
MRS (12) = 0
CKE is L;
Other control and address
bus inputs are STABLE;
Slow PDN Exit
Data bus inputs are
MRS (12) = 1
FLOATING
all banks open;
tCK = tCK (IDD), tRAS = tRAS max.(IDD), tRP = tRP (IDD);
CKE is H, /CS is H between valid commands;
Other control and address bus inputs are SWITCHING;
Data bus inputs are SWITCHING
all banks open, continuous burst reads, IOUT = 0mA;
BL = 4, CL = CL(IDD), AL = 0;
tCK = tCK (IDD), tRAS = tRAS max.(IDD),
tRP = tRP (IDD);
CKE is H, /CS is H between valid commands;
Address bus inputs are SWITCHING;
Data pattern is same as IDD4W
all banks open, continuous burst writes;
BL = 4, CL = CL(IDD), AL = 0;
tCK = tCK (IDD), tRAS = tRAS max.(IDD),
tRP = tRP (IDD);
CKE is H, /CS is H between valid commands;
Address bus inputs are SWITCHING;
Data bus inputs are SWITCHING
tCK = tCK (IDD);
Refresh command at every tRFC (IDD) interval;
CKE is H, /CS is H between valid commands;
Other control and address bus inputs are SWITCHING;
Data bus inputs are SWITCHING
EDE2108AEBG
Parameter
Symbol
Self-refresh current
IDD6*
Operating current
(Bank interleaving)
IDD7
7
Grade
max.
Unit
12
mA
170
mA
Notes: 1.
2.
3.
4.
Test condition
Self-Refresh Mode;
CK and /CK at 0V;
CKE 0.2V;
Other control and address bus inputs are FLOATING;
Data bus inputs are FLOATING
all bank interleaving reads, IOUT = 0mA;
BL = 4, CL = CL(IDD), AL = tRCD (IDD) 1 tCK (IDD);
tCK = tCK (IDD), tRC = tRC (IDD), tRRD = tRRD (IDD),
tFAW = tFAW (IDD), tRCD = 1 tCK (IDD);
CKE is H, /CS is H between valid commands;
Address bus inputs are STABLE during DESELECTs;
Data pattern is same as IDD4W;
IDD specifications are tested after the device is properly initialized.
Input slew rate is specified by AC Input Test Condition.
IDD parameters are specified with ODT disabled.
Data bus consists of DQ, DM, DQS, /DQS, RDQS and /RDQS.
IDD values must be met with all combinations of EMRS bits 10 and 11.
5. Definitions for IDD
L is defined as VIN VIL (AC) (max.)
H is defined as VIN VIH (AC) (min.)
STABLE is defined as inputs stable at an H or L level
FLOATING is defined as inputs at VREF = VDDQ/2
SWITCHING is defined as:
inputs changing between H and L every other clock cycle (once per two clocks) for address and control
signals, and inputs changing between H and L every other data transfer (once per clock) for DQ signals
not including masks or strobes.
6. Refer to AC Timing for IDD Test Conditions.
7. IDD6 will increase by 80% if TC ≥ +85°C and high temperature self-refresh rate option is enabled.
Data Sheet E1950E11 (Ver.1.1)
9
EDE2108AEBG
AC Timing for IDD Test Conditions
For purposes of IDD testing, the following parameters are to be utilized.
DDR2-800
Parameter
5-5-5
Unit
CL (IDD)
5
tCK
tRCD (IDD)
12.5
ns
tRC (IDD)
57.5
ns
tRRD (IDD)
7.5
ns
tFAW (IDD)
35
ns
tCK (IDD)
2.5
ns
tRAS (min.)(IDD)
45
ns
tRAS (max.)(IDD)
70000
ns
tRP (IDD)
12.5
ns
tRFC (IDD)
195
ns
IDD7 Timing Patterns for 8 Banks
The detailed timings are shown in the IDD7 Timing Patterns for 8 Banks tables.
[8 organization]
Speed bins
Timing Patterns
DDR2-800
A0 RA0 D A1 RA1 D A2 RA2 D A3 RA3 D D D A4 RA4 D A5 RA5 D A6 RA6 D A7 RA7 D D D
Remark: A = Active. RA = Read with auto precharge. D = Deselect
Notes: 1. All banks are being interleaved at minimum tRC (IDD) without violating tRRD (IDD) and tFAW (IDD) using
a Burst length = 4.
2. Control and address bus inputs are STABLE during DESELECTs.
3. IOUT = 0mA.
Data Sheet E1950E11 (Ver.1.1)
10
EDE2108AEBG
DC Characteristics 2 (TC = 0C to +85C, VDD, VDDQ = 1.8V 0.1V)
Parameter
Symbol
Value
Unit
Notes
Input leakage current
ILI
2
A
VDD VIN VSS
Output leakage current
ILO
5
A
VDDQ VOUT VSS
VTT + 0.603
V
VTT 0.603
V
Output timing measurement reference level VOTR
0.5 VDDQ
V
1
Output minimum sink DC current
IOL
+13.4
mA
3, 4
Output minimum source DC current
IOH
13.4
mA
2, 4
Minimum required output pull-up under AC
VOH
test load
Maximum required output pull-down under
VOL
AC test load
Notes: 1.
2.
3.
4.
The VDDQ of the device under test is referenced.
VDDQ = 1.7V; VOUT = 1.42V.
VDDQ = 1.7V; VOUT = 0.28V.
The DC value of VREF applied to the receiving device is expected to be set to VTT.
DC Characteristics 3 (TC = 0C to +85C, VDD, VDDQ = 1.8V 0.1V)
Parameter
Symbol
min.
max.
Unit
Notes
AC differential input voltage
VID (AC)
0.5
VDDQ 0.6
V
1, 2
AC differential cross point voltage
VIX (AC)
0.5 VDDQ 0.175
0.5 VDDQ 0.175
V
2
AC differential cross point voltage
VOX (AC)
0.5 VDDQ 0.125
0.5 VDDQ 0.125
V
3
Notes: 1. VID (AC) specifies the input differential voltage |VTR -VCP| required for switching, where VTR is the true
input signal (such as CK, DQS, RDQS) and VCP is the complementary input signal (such as /CK, /DQS,
/RDQS).
The minimum value is equal to VIH (AC) VIL (AC).
2. The typical value of VIX (AC) is expected to be about 0.5 VDDQ of the transmitting device and VIX (AC)
is expected to track variations in VDDQ. VIX (AC) indicates the voltage at which differential input signals
must cross.
3. The typical value of VOX (AC) is expected to be about 0.5 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.
VDDQ
VTR
Crossing point
VID
VIX or VOX
VCP
VSSQ
Differential Signal Levels*1, 2
Data Sheet E1950E11 (Ver.1.1)
11
EDE2108AEBG
ODT DC Electrical Characteristics (TC = 0C to +85C, VDD, VDDQ = 1.8V 0.1V)
Parameter
Symbol
min.
typ.
max.
Unit
Note
Rtt effective impedance value for EMRS (1) (A6, A2) 0, 1 75
Rtt1 (eff)
60
75
90
1
Rtt effective impedance value for EMRS (1) (A6, A2) 1, 0 150
Rtt2 (eff)
120
150
180
1
Rtt effective impedance value for EMRS (1) (A6, A2) 1, 1 50
Rtt3 (eff)
40
50
60
1
Deviation of VM with respect to VDDQ/2
VM
6
6
1
Note: 1. Test condition for Rtt measurements.
Measurement Definition for Rtt (eff)
Apply VIH (AC) and VIL (AC) to test pin separately, then measure current I(VIH (AC)) and I(VIL (AC)) respectively.
VIH (AC), and VDDQ values defined in SSTL18.
Rtt (eff )
VIH ( AC ) VIL( AC )
I (VIH ( AC )) I (VIL( AC ))
Measurement Definition for VM
Measure voltage (VM) at test pin (midpoint) with no load.
2 VM
VM
1 100
VDDQ
Pin Capacitance (TA = 25C, VDD, VDDQ = 1.8V 0.1V)
Parameter
Symbol
Pins
min.
max.
Unit
Notes
CLK input pin capacitance
CCK
CK, /CK
1.0
2.0
pF
1
Input pin capacitance
CIN
/RAS, /CAS,
/WE, /CS,
CKE, ODT,
Address
1.0
1.75
pF
1
Input/output pin capacitance
CI/O
DQ, DQS, /DQS,
RDQS, /RDQS,
DM
2.5
3.5
pF
2
Notes: 1. Matching within 0.25pF.
2. Matching within 0.50pF.
Data Sheet E1950E11 (Ver.1.1)
12
EDE2108AEBG
AC Characteristics (TC = 0C to +85C, VDD, VDDQ = 1.8V 0.1V, VSS, VSSQ = 0V)
New units tCK(avg) and nCK, are introduced in DDR2-667 or faster.
tCK(avg): actual tCK(avg) of the input clock under operation.
nCK: one clock cycle of the input clock, counting the actual clock edges.
-8E
Speed bin
DDR2-800 (5-5-5)
Parameter
Symbol
min.
max.
Unit
Active to read or write command delay
tRCD
12.5
ns
Precharge command period
tRP
12.5
ns
Active to active/auto-refresh command time
tRC
57.5
ns
DQ output access time from CK, /CK
tAC
400
400
ps
Notes
10
DQS output access time from CK, /CK
tDQSCK
350
350
ps
10
CK high-level width
tCH (avg)
0.48
0.52
tCK (avg)
13
CK low-level width
tCL(avg)
0.48
0.52
tCK (avg)
13
CK half period
tHP
Min. (tCL(abs),
tCH(abs))
ps
6, 13
Clock cycle time
(CL = 6)
tCK (avg)
2500
8000
ps
13
(CL = 5)
tCK (avg)
2500
8000
ps
13
(CL = 4)
tCK (avg)
3750
8000
ps
13
(CL = 3)
tCK (avg)
5000
8000
ps
13
DQ and DM input hold time
tDH (base)
125
ps
5
DQ and DM input setup time
tDS (base)
50
ps
4
Control and Address input pulse width for each input
tIPW
0.6
tCK (avg)
DQ and DM input pulse width for each input
tDIPW
0.35
tCK (avg)
Data-out high-impedance time from CK, /CK
tHZ
tAC max.
ps
10
DQS, /DQS low-impedance time from CK, /CK
tLZ (DQS)
tAC min.
tAC max.
ps
10
DQ low-impedance time from CK, /CK
tLZ (DQ)
2 tAC min.
tAC max.
ps
10
DQS-DQ skew for DQS and associated DQ signals
tDQSQ
200
ps
DQ hold skew factor
tQHS
300
ps
7
DQ/DQS output hold time from DQS
tQH
tHP – tQHS
ps
8
DQS latching rising transitions to associated clock edges
tDQSS
0.25
0.25
tCK (avg)
DQS input high pulse width
tDQSH
0.35
tCK (avg)
DQS input low pulse width
tDQSL
0.35
tCK (avg)
DQS falling edge to CK setup time
tDSS
0.2
tCK (avg)
DQS falling edge hold time from CK
tDSH
0.2
tCK (avg)
Mode register set command cycle time
tMRD
2
nCK
Write postamble
tWPST
0.4
0.6
tCK (avg)
Write preamble
tWPRE
0.35
tCK (avg)
Address and control input hold time
tIH (base)
250
ps
5
Address and control input setup time
tIS (base)
175
ps
4
Read preamble
tRPRE
0.9
1.1
tCK (avg)
11
Read postamble
tRPST
0.4
0.6
tCK (avg)
12
Active to precharge command
tRAS
45
70000
ns
Active to auto precharge delay
tRAP
tRCD min.
ns
Active bank A to active bank B command period
tRRD
7.5
ns
Data Sheet E1950E11 (Ver.1.1)
13
EDE2108AEBG
-8E
Speed bin
DDR2-800 (5-5-5)
Parameter
Symbol
min.
max.
Unit
Notes
Four active window period
tFAW
35
ns
/CAS to /CAS command delay
tCCD
2
nCK
Write recovery time
tWR
15
ns
Auto precharge write recovery + precharge time
tDAL
WR RU
(tRP/tCK(avg))
nCK
1, 9
Internal write to read command delay
tWTR
7.5
ns
14
Internal read to precharge command delay
tRTP
7.5
ns
Exit self-refresh to a non-read command
tXSNR
tRFC 10
ns
Exit self-refresh to a read command
tXSRD
200
nCK
Exit precharge power-down to any non-read command
tXP
2
nCK
Exit active power-down to read command
tXARD
2
nCK
3
Exit active power-down to read command
(slow exit/low power mode)
tXARDS
8 AL
nCK
2, 3
CKE minimum pulse width (high and low pulse width)
tCKE
3
nCK
MRS command to ODT update delay
tMOD
0
12
ns
Auto-refresh to active/auto-refresh command time
tRFC
195
ns
Average periodic refresh interval
(0C TC +85C)
tREFI
7.8
s
tREFI
3.9
s
tDELAY
tIS tCK(avg)
tIH
ns
(+85C TC +95C)
Minimum time clocks remains ON after CKE
asynchronously drops low
15
Notes: 1.
2.
3.
4.
For each of the terms above, if not already an integer, round to the next higher integer.
AL: Additive Latency.
MRS A12 bit defines which active power-down exit timing to be applied.
The figures of Input Waveform Timing 1 and 2 are 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.
5. The figures of Input Waveform Timing 1 and 2 are 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.
DQS
CK
/DQS
/CK
tIS
tDS
tDH
tDS
tIH
tIS
tIH
tDH
VDDQ
VIH (AC)(min.)
VIH (DC)(min.)
VREF
VIL (DC)(max.)
VIL (AC)(max.)
VSS
VDDQ
VIH (AC)(min.)
VIH (DC)(min.)
VREF
VIL (DC)(max.)
VIL (AC)(max.)
VSS
Input Waveform Timing 1 (tDS, tDH)
Input Waveform Timing 2 (tIS, tIH)
6. 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;
Data Sheet E1950E11 (Ver.1.1)
14
EDE2108AEBG
7. tQHS accounts for:
a. 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
b. 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 p-channel to n-channel variation of the output drivers.
8. 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.}
Examples:
a. If the system provides tHP of 1315ps into a DDR2-667 SDRAM, the DRAM provides tQH of
975ps (min.)
b. If the system provides tHP of 1420ps into a DDR2-667 SDRAM, the DRAM provides tQH of
1080ps (min.)
9. RU stands for round up. WR refers to the tWR parameter stored in the MRS.
10. 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.)
For example, if the measured jitter into a DDR2-667 SDRAM has tERR(6-10per) min. = 272ps and
tERR(6-10per) max. = +293ps, then tDQSCK min.(derated) = tDQSCK min. tERR(6-10per) max. =
400ps 293ps = 693ps and tDQSCK max.(derated) = tDQSCK max. tERR(6-10per) min. = 400ps +
272ps = +672ps. Similarly, tLZ(DQ) for DDR2-667 derates to tLZ(DQ) min.(derated) = 900ps 293ps =
1193ps and tLZ(DQ) max.(derated)= 450ps + 272ps = +722ps.
11. 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.)
For example, if the measured jitter into a DDR2-667 SDRAM has tJIT(per) min. = 72ps and
tJIT(per) max. = +93ps, then tRPRE min.(derated) = tRPRE min. + tJIT(per) min. = 0.9 tCK(avg) 72ps
= +2178ps and tRPRE max.(derated) = tRPRE max. + tJIT(per) max. = 1.1 tCK(avg) + 93ps = +2843ps.
12. 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.)
For example, if the measured jitter into a DDR2-667 SDRAM has tJIT(duty) min. = 72ps and
tJIT(duty) max. = +93ps, then tRPST min.(derated) = tRPST min. + tJIT(duty) min. = 0.4 tCK(avg)
72ps = +928ps and tRPST max.(derated) = tRPST max. + tJIT(duty) max. = 0.6 tCK(avg) + 93ps =
+1592ps.
13. Refer to the Clock Jitter table.
14. tWTR is at least two clocks (2 tCK or 2 nCK) independent of operation frequency.
15. tMOD max. = 12ns only applies when changing ODT value. (E.g. Changing ODT value from Rtt = 50 to
Rtt = 75) If ODT is disabled and then ODT is turned on, tMOD max. = 8nCK
Data Sheet E1950E11 (Ver.1.1)
15
EDE2108AEBG
ODT AC Electrical Characteristics
Parameter
Symbol
min.
max.
Unit
ODT turn-on delay
tAOND
ODT turn-on
tAON
2
2
tCK
tAC(min)
tAC(max) 700
ps
ODT turn-on (power-down mode)
tAONPD
tAC(min) 2000
2tCK tAC(max) 1000
ps
Notes
1, 3
ODT turn-off delay
tAOFD
2.5
2.5
tCK
5
ODT turn-off
tAOF
tAC(min)
tAC(max) 600
ps
2, 4, 5
ODT turn-off (power-down mode)
tAOFPD
tAC(min) 2000
2.5tCK tAC(max) 1000
ps
ODT to power-down entry latency
tANPD
3
tCK
ODT power-down exit latency
tAXPD
8
tCK
Notes: 1. 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.
2. 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.
3. 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.)
4. 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.)
For example, if the measured jitter into a DDR2-667 SDRAM has tERR(6-10per) min. = 272ps,
tERR(6-10per) max. = +293ps, tJIT(duty) min. = 106ps and tJIT(duty) max. = +94ps, then
tAOF min.(derated) = tAOF min. + { tJIT(duty) max. tERR(6-10per) max. } = 450ps + { 94ps 293ps}
= 837ps and tAOF max.(derated) = tAOF max. + { tJIT(duty) min. tERR(6-10per) min. } = 1050ps +
{ 106ps + 272ps} = +1428ps.
5. For tAOFD of DDR2-800, the 1/2 clock of nCK in the 2.5 nCK 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. For
example, if an input clock has a worst case tCH(avg) of 0.48, the tAOF min. should be derated by
subtracting 0.02 tCK(avg) from it, whereas if an input clock has a worst case tCH(avg) of 0.52, the tAOF
max. should be derated by adding 0.02 tCK(avg) to it. Therefore, we have;
tAOF min.(derated) = tAC min. [0.5 Min.(0.5, tCH(avg) min.)] tCK(avg)
tAOF max.(derated) = tAC max. + 0.6 + [Max.(0.5, tCH(avg) max.) 0.5] tCK(avg)
or
tAOF min.(derated) = Min.(tAC min., tAC min. [0.5 tCH(avg) min.] tCK(avg))
tAOF max.(derated) = 0.6 + Max.(tAC max., tAC max. + [tCH(avg) max. 0.5] tCK(avg))
where tCH(avg) min. and tCH(avg) max. are the minimum and maximum of tCH(avg) actually measured
at the DRAM input balls.
Data Sheet E1950E11 (Ver.1.1)
16
EDE2108AEBG
AC Input Test Conditions
Parameter
Symbol
Value
Unit
Notes
Input reference voltage
VREF
0.5 VDDQ
V
1
Input signal maximum peak to peak swing
VSWING(max.)
1.0
V
1
Input signal minimum slew rate
SLEW
1.0
V/ns
2, 3
Notes: 1. Input waveform timing is referenced to the input signal crossing through the VIH/IL (AC) level applied to
the device under test.
2. 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 as shown in the below figure.
3. 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.
VDDQ
VIH (AC)(min.)
VIH (DC)(min.)
VSWING(max.)
VREF
VIL (DC)(max.)
VIL (AC)(max.)
Falling slew =
VREF
VSS
TR
TF
VIL (AC)(max.)
Rising slew =
TF
AC Input Test Signal Wave forms
Measurement point
DQ
VTT
RT =25
Output Load
Data Sheet E1950E11 (Ver.1.1)
17
VIH (AC) min. VREF
TR
EDE2108AEBG
Clock Jitter
Frequency (Mbps)
800
Parameter
Symbol
min.
max.
Unit
Notes
Average clock period
tCK (avg)
2500
8000
ps
1
Clock period jitter
tJIT (per)
100
100
ps
5
Clock period jitter during
DLL locking period
tJIT
(per, lck)
80
80
ps
5
Cycle to cycle period jitter
tJIT (cc)
200
ps
6
Cycle to cycle clock period jitter during
DLL locking period
tJIT (cc, lck)
160
ps
6
Cumulative error across 2 cycles
tERR (2per)
150
150
ps
7
Cumulative error across 3 cycles
tERR (3per)
175
175
ps
7
Cumulative error across 4 cycles
tERR (4per)
200
200
ps
7
Cumulative error across 5 cycles
tERR (5per)
200
200
ps
7
Cumulative error across
n=6,7,8,9,10 cycles
Cumulative error across
n=11, 12,…49,50 cycles
tERR
(6-10per)
tERR
(11-50per)
300
300
ps
7
450
450
ps
7
Average high pulse width
tCH (avg)
0.48
0.52
tCK (avg)
2
Average low pulse width
tCL (avg)
0.48
0.52
tCK (avg)
3
Duty cycle jitter
tJIT (duty)
100
100
ps
4
Notes: 1. tCK (avg) is calculated as the average clock period across any consecutive 200cycle window.
N
tCK (avg ) tCKj N
j 1
N = 200
2. tCH (avg) is defined as the average high pulse width, as calculated across any consecutive 200 high
pulses.
N
tCH (avg ) tCHj (N tCK (avg ))
j 1
N = 200
3. tCL (avg) is defined as the average low pulse width, as calculated across any consecutive 200 low pulses.
N
tCL(avg ) tCLj (N tCK (avg ))
j 1
N = 200
4. 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) is not subject to production test.
tJIT (duty) = Min./Max. of {tJIT (CH), tJIT (CL)}, where:
tJIT (CH) = {tCHj- tCH (avg) where j = 1 to 200}
tJIT (CL) = {tCLj tCL (avg) where j = 1 to 200}
Data Sheet E1950E11 (Ver.1.1)
18
EDE2108AEBG
5. tJIT (per) is defined as the largest deviation of any single tCK from tCK (avg).
tJIT (per) = Min./Max. of { tCKj tCK (avg) where j = 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
subject to production test.
6. tJIT (cc) is defined as the absolute difference in clock period between two consecutive clock cycles:
tJIT (cc) = Max. of |tCKj+1 tCKj|
tJIT (cc) is 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
subject to production test.
7. tERR (nper) is defined as the cumulative error across multiple consecutive cycles from tCK (avg).
tERR (nper) is not subject to production test.
n
tERR(nper ) tCKj n tCK(avg ))
j 1
2 n 50 for tERR (nper)
8. 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 hold at all times.
(minimum and maximum of spec values are to be used for calculations in the table below.)
Parameter
Symbol
min.
max.
Absolute clock period
tCK (abs)
tCK (avg) min. + tJIT (per) min.
tCK (avg) max. + tJIT (per) max. ps
tCH (avg) min. tCK (avg) min.
+ tJIT (duty) min.
tCL (avg) min. tCK (avg) min.
+ tJIT (duty) min.
tCH (avg) max. tCK (avg) max.
ps
+ tJIT (duty) max.
tCL (avg) max. tCK (avg) max.
ps
+ tJIT (duty) max.
Absolute clock high pulse
width
Absolute clock low pulse
width
tCH (abs)
tCL (abs)
Example: For DDR2-667, tCH(abs) min. = ( 0.48 3000 ps ) - 125ps = 1315ps
Data Sheet E1950E11 (Ver.1.1)
19
Unit
EDE2108AEBG
Input Slew Rate Derating
For all input signals the total tIS, tDS (setup time) and tIH, tDH (hold time) required is calculated by adding the data
sheet tIS (base), tDS (base) and tIH (base), tDH (base) value to the tIS, tDS and tIH, tDH derating value
respectively.
Example: tDS (total setup time) = tDS (base) + tDS.
Setup (tIS, tDS) nominal slew rate for a rising signal is defined as the slew rate between the last crossing of VREF
(DC) and the first crossing of VIH (AC) min. Setup (tIS, tDS) nominal slew rate for a falling signal is defined as the
slew rate between the last crossing of VREF (DC) and the first crossing of VIL (AC) max. If the actual signal is
always earlier than the nominal slew rate line between shaded ‘VREF (DC) to AC region’, use nominal slew rate for
derating value (See the figure of Slew Rate Definition Nominal).
If the actual signal is later than the nominal slew rate line anywhere between shaded ‘VREF (DC) to AC region’, the
slew rate of a tangent line to the actual signal from the AC level to DC level is used for derating value (see the figure
of Slew Rate Definition Tangent).
Hold (tIH, tDH) nominal slew rate for a rising signal is defined as the slew rate between the last crossing of
VIL (DC) max. and the first crossing of VREF (DC). Hold (tIH, tDH) nominal slew rate for a falling signal is defined
as the slew rate between the last crossing of VIH (DC) min. and the first crossing of VREF (DC). If the actual signal
is always later than the nominal slew rate line between shaded ‘DC level to VREF (DC) region’, use nominal slew
rate for derating value (See the figure of Slew Rate Definition Nominal).
If the actual signal is earlier than the nominal slew rate line anywhere between shaded ‘DC to VREF (DC) region’,
the slew rate of a tangent line to the actual signal from the DC level to VREF (DC) level is used for derating value
(see the figure of Slew Rate Definition Tangent).
Although for slow slew rates the total setup time might be negative (i.e. a valid input signal will not have reached
VIH/IL (AC) at the time of the rising clock transition) a valid input signal is still required to complete the transition and
reach VIH/IL (AC).
For slew rates in between the values listed in the tables below, the derating values may obtained by linear
interpolation.
These values are typically not subject to production test. They are verified by design and characterization.
[Derating Values of tDS/tDH with Differential DQS (DDR2-800)]
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
tDS tDH tDS tDH tDS tDH tDS tDH tDS tDH tDS tDH tDS tDH tDS tDH tDS tDH Unit
DQ
slew
rate
(V/ns)
2.0
+100 +45
+100 +45
+100 +45
ps
1.5
+67
+21
+67
+21
+67
+21
+79
+33
ps
1.0
0
0
0
0
0
0
+12
+12
+24
+24
ps
0.9
5
14
5
14
+7
2
+19
+10
+31
+22
ps
0.8
13
31
1
19
+11
7
+23
+5
+35
+17
ps
0.7
10
42
+2
30
+14
18
+26
6
+38
+6
ps
0.6
10
59
+2
47
+14
35
+26
23
+38
11
ps
0.5
24
89
12
77
0
65
+12
53
ps
0.4
52
140 40
Data Sheet E1950E11 (Ver.1.1)
20
128 28
116 ps
EDE2108AEBG
[Derating Values of tIS/tIH (DDR2-800)]
CK, /CK Differential Slew Rate
2.0 V/ns
Command/address
slew rate (V/ns)
1.5 V/ns
1.0 V/ns
tIS
tIH
tIS
tIH
tIS
tIH
Unit
4.0
+150
+94
+180
+124
+210
+154
ps
3.5
+143
+89
+173
+119
+203
+149
ps
3.0
+133
+83
+163
+113
+193
+143
ps
2.5
+120
+75
+150
+105
+180
+135
ps
2.0
+100
+45
+130
+75
+160
+105
ps
1.5
+67
+21
+97
+51
+127
+81
ps
1.0
0
0
+30
+30
+60
+60
ps
0.9
5
14
+25
+16
+55
+46
ps
0.8
13
31
+17
1
+47
+29
ps
0.7
22
54
+8
24
+38
+6
ps
0.6
34
83
4
53
+26
23
ps
0.5
60
125
30
95
0
65
ps
0.4
100
188
70
158
40
128
ps
0.3
168
292
138
262
108
232
ps
0.25
200
375
170
345
140
315
ps
0.2
325
500
295
470
265
440
ps
0.15
517
708
487
678
457
648
ps
0.1
1000
1125
970
1095
940
1065
ps
Data Sheet E1950E11 (Ver.1.1)
21
Notes
EDE2108AEBG
Single-ended DQS
VDDQ
VIH (AC) min.
VIH (DC) min.
VREF (DC)
VIL (DC) max.
VIL (AC) max.
VSS
DQS
Differential DQS, /DQS
CK, /CK
DQS
CK
tDS1
tDH1
tDS1
tDH1
/DQS
/CK
tDS
tIS
tDH
tIH
tDS
tIS
tDH
tIH
VDD
VIH (AC) min.
VREF to AC
region
VIH (DC) min.
VREF (DC)
DC to VREF
region
nominal
slew rate
nominal
slew rate
DC to VREF
region
VIL (DC) max.
VREF to AC
region
VIL (AC) max.
VSS
TFS
TRH TRS
VIH (AC) min. - VREF (DC)
Setup slew rate
=
Rising signal
TRS
VREF (DC) - VIL (AC) max.
Setup slew rate
=
Falling signal
TFS
Hold slew rate
Rising signal
=
TFH
VREF (DC) - VIL (DC) max.
Hold slew rate
Falling signal
TRH
Slew Rate Definition Nominal
Data Sheet E1950E11 (Ver.1.1)
22
=
VIH (DC) min. - VREF (DC)
TFH
EDE2108AEBG
Single-ended DQS
DQS
VDDQ
VIH (AC) min.
VIH (DC) min.
VREF (DC)
VIL (DC) max.
VIL (AC) max.
VSS
Differential DQS, /DQS
CK, /CK
DQS
CK
tDS1
tDH1
tDS1
tDH1
tDS
tIS
tDH
tIH
/DQS
/CK
tDS
tIS
tDH
tIH
VDD
VIH (AC) min.
VREF to AC
region
nominal
line
nominal
line
VIH (DC) min.
VREF (DC)
DC to VREF
region
tangent
line
tangent
line
nominal
line
VIL (DC) max.
DC to VREF
region
VREF to AC
region
nominal
line
VIL (AC) max.
VSS
TFS
TRH
tangent line [VREF (DC) - VIL (AC) max.]
Setup slew rate
=
Falling signal
TFS
Hold slew rate
Rising signal
=
TRS
TFH
tangent line [VIH (AC) min. - VREF (DC)]
Setup slew rate
=
Rising signal
TRS
tangent line [VREF (DC) - VIL (DC) max.]
Hold slew rate
Falling signal
TRH
Slew Rate Definition Tangent
Data Sheet E1950E11 (Ver.1.1)
23
=
tangent line [VIH (DC) min. - VREF (DC)]
TFH
EDE2108AEBG
Bank 7
Bank 6
Bank 5
Bank 4
Bank 3
Bank 2
Bank 1
Address,
BA0, BA1, BA2
Mode
register
Row
address
buffer
and
refresh
counter
Row decoder
CK
/CK
CKE
Clock
generator
Block Diagram
Memory cell array
Bank 0
Control logic
/CS
/RAS
/CAS
/WE
Command decoder
Sense amp.
Column decoder
Column
address
buffer
and
burst
counter
Data control circuit
Latch circuit
CK, /CK
DLL
Input & Output buffer
DQS, /DQS
RDQS, /RDQS
ODT
DM
DQ
Data Sheet E1950E11 (Ver.1.1)
24
EDE2108AEBG
Pin Function
CK, /CK (input pins)
CK and /CK are differential clock inputs. All address and control input signals are sampled on the crossing of the
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).
/CS (input pin)
All commands are masked when /CS is registered high. /CS provides for external rank selection on systems with
multiple ranks. /CS is considered part of the command code.
/RAS, /CAS, /WE (input pins)
/RAS, /CAS and /WE (along with /CS) define the command being entered.
A0 to A14 (input pins)
Provided the row address for Active commands and the column address and Auto Precharge bit for Read/Write
commands to select one location out of the memory array in the respective bank. The address inputs also provide
the op-code during mode register set commands.
[Address Pins Table]
Address (A0 to A14)
Part number
Row address
Column address
EDE2108AEBG
AX0 to AX14
AY0 to AY9
Note
A10 (AP) (input pin)
A10 is sampled during a precharge command to determine whether the precharge applies to one bank (A10 = low)
or all banks (A10 = high). If only one bank is to be precharged, the bank is selected by BA0, BA1 and BA2.
BA0, BA1, BA2 (input pins)
BA0, BA1 and BA2 define to which bank an active, read, write or precharge command is being applied. BA0 and
BA1 also determine if the mode register or extended mode register is to be accessed during a MRS or EMRS (1),
EMRS (2) cycle.
[Bank Select Signal Table]
BA0
BA1
BA2
Bank 0
L
L
L
Bank 1
H
L
L
Bank 2
L
H
L
Bank 3
H
H
L
Bank 4
L
L
H
Bank 5
H
L
H
Bank 6
L
H
H
Bank 7
H
H
H
Remark: H: VIH. L: VIL.
Data Sheet E1950E11 (Ver.1.1)
25
EDE2108AEBG
CKE (input pin)
CKE high activates, and CKE low deactivates, internal clock signals and device input buffers and output drivers.
Taking CKE low provides precharge power-down and self-refresh operation (all banks idle), or active power-down
(row active in any bank). CKE is synchronous for power down entry and exit, and for self-refresh entry. CKE is
asynchronous for self-refresh exit. CKE must be maintained high throughout read and write accesses. Input buffers,
excluding CK, /CK and CKE are disabled during power-down. Input buffers, excluding CKE, are disabled during selfrefresh.
DM (input pins)
DM is an input mask signal for write data. Input data is masked when DM is sampled high coincident with that input
data during a Write access. DM is sampled on both edges of DQS. Although DM pins are input only, the DM
loading matches the DQ and DQS loading.
For 8 configuration, DM function will be disabled when RDQS function is enabled by EMRS.
DQ (input/output pins)
Bi-directional data bus.
DQS, /DQS (input/output pins)
Output with read data, input with write data for source synchronous operation. Edge-aligned with read data,
centered in write data. Used to capture write data. /DQS can be disabled by EMRS.
RDQS, /RDQS (output pins)
Differential Data Strobe for READ operation only. DM and RDQS functions are switch able by EMRS. These pins
exist only in 8 configuration. /RDQS output will be disabled when /DQS is disabled by EMRS.
ODT (input pins)
ODT (On Die Termination control) is a registered high signal that enables termination resistance internal to the
DDR2 SDRAM. When enabled, ODT is only applied to each DQ, DQS, /DQS, RDQS, /RDQS, and DM signal for 8
configurations. The ODT pin will be ignored if the Extended Mode Register (EMRS) is programmed to disable ODT.
Any time the EMRS enables the ODT function; ODT may not be driven high until eight clocks after the EMRS has
been enabled.
VDD, VSS, VDDQ, VSSQ (power supply)
VDD and VSS are power supply pins for internal circuits. VDDQ and VSSQ are power supply pins for the output
buffers.
VDDL and VSSDL (power supply)
VDDL and VSSDL are power supply pins for DLL circuits.
VREF (Power supply)
SSTL_18 reference voltage: (0.50 0.01) VDDQ
Data Sheet E1950E11 (Ver.1.1)
26
EDE2108AEBG
Command Operation
Command Truth Table
The DDR2 SDRAM recognizes the following commands specified by the /CS, /RAS, /CAS, /WE and address pins.
CKE
Function
Symbol
Previous Current
cycle
cycle
/CS
Mode register set
MRS
H
H
L
L
L
L
L
L
L
EMRS(1)
H
H
L
L
L
L
H
L
L
EMRS(2)
H
H
L
L
L
L
L
H
L
Extended mode
register set (1)
Extended mode
register set (2)
A14 to
A0 to
/RAS /CAS /WE BA0 BA1 BA2 A11
A10 A9
Notes
MRS OPCODE
EMRS (1)
OPCODE
EMRS (2)
OPCODE
1
1
1
Auto-refresh
REF
H
H
L
L
L
H
1
Self-refresh entry
SELF
H
L
L
L
L
H
1
Self-refresh exit
SELFX
L
H
H
1, 6
L
H
L
H
H
H
Single bank precharge
PRE
H
H
L
L
H
L
BA
L
1, 2
Precharge all banks
PALL
H
H
L
L
H
L
H
1
Bank activate
ACT
H
H
L
L
H
H
BA
RA
Write
WRIT
H
H
L
H
L
L
BA
CA
L
CA
1, 2, 3
Write with auto precharge
WRITA
H
H
L
H
L
L
BA
CA
H
CA
1, 2, 3
1, 2, 7
Read
READ
H
H
L
H
L
H
BA
CA
L
CA
1, 2, 3
Read with auto precharge
READA
H
H
L
H
L
H
BA
CA
H
CA
1, 2, 3
No operation
NOP
H
L
H
H
H
1
Device deselect
DESL
H
H
1
Power-down mode entry
PDEN
H
L
H
1, 4
H
L
L
H
H
H
L
H
H
L
H
L
H
H
H
Power-down mode exit
PDEX
1, 4
Remark: H: VIH. L: VIL. : VIH or VIL. BA : Bank Address. RA : Row Address. CA : Column Address.
Notes: 1. All DDR2 commands are defined by states of /CS, /RAS, /CAS, /WE and CKE at the rising edge of the
clock.
2. Bank select (BA0, BA1 and BA2), determine which bank is to be operated upon.
3. Burst reads or writes should not be terminated other than specified as Reads interrupted by a Read in
burst read command [READ] or Writes interrupted by a Write in burst write command [WRIT].
4. The power-down mode does not perform any refresh operations. The duration of power-down is therefore
limited by the refresh requirements of the device. One clock delay is required for mode entry and exit.
5. The state of ODT does not affect the states described in this table. The ODT function is not available
during self-refresh.
6. Self-refresh exit is asynchronous.
7. 8-bank device sequential bank activation restriction: No more than 4 banks may be activated in a rolling
tFAW window. Converting to clocks is done by dividing tFAW (ns) by tCK (ns) and rounding up to next
integer value. As an example of the rolling window, if (tFAW/tCK) rounds up to 10 clocks, and an activate
command is issued in clock N, no more than three further activate commands may be issued in clock N+1
through N+9.
Data Sheet E1950E11 (Ver.1.1)
27
EDE2108AEBG
CKE Truth Table
CKE
*3
Previous
1
cycle (n-1)*
Current
*1
cycle (n)
Command(n)
/CS, /RAS, /CAS, /WE
Operation (n)
L
L
Maintain power-down
11, 13, 14
L
H
DESL or NOP
Power-down exit
4, 8, 11, 13
L
L
Maintain self-refresh
11, 14
L
H
DESL or NOP
Self-refresh exit
4, 5, 9
Bank Active
H
L
DESL or NOP
Active power-down entry
4, 8, 10, 11, 13
All banks idle
H
L
DESL or NOP
Precharge power-down entry
4, 8, 10, 11, 13
H
L
SELF
Self-refresh entry
6, 9, 11, 13
H
H
Refer to the Command Truth Table
Current state*
2
Power-down
Self-refresh
Any state other than
listed above
*3
Notes
7
Remark: H: VIH. L: VIL. : Don’t care.
Notes: 1. CKE (n) is the logic state of CKE at clock edge n; CKE (n1) was the state of CKE at the previous clock
edge.
2. Current state is the state of the DDR SDRAM immediately prior to clock edge n.
3. Command (n) is the command registered at clock edge n, and operation (n) is a result of Command (n).
4. All states and sequences not shown are illegal or reserved unless explicitly described elsewhere in this
document.
5. On self-refresh exit, [DESL] or [NOP] commands must be issued on every clock edge occurring during the
tXSNR period. Read commands may be issued only after tXSRD (200 clocks) is satisfied.
6. Self-refresh mode can only be entered from the all banks idle state.
7. Must be a legal command as defined in the command truth table.
8. Valid commands for power-down entry and exit are [NOP] and [DESL] only.
9. Valid commands for self-refresh exit are [NOP] and [DESL] only.
10. Power-down and self-refresh can not be entered while read or write operations, (extended) mode register
set operations or precharge operations are in progress. See section Power-Down and Self-Refresh
Command for a detailed list of restrictions.
11. Minimum CKE high time is 3 clocks; minimum CKE low time is 3 clocks.
12. The state of ODT does not affect the states described in this table. The ODT function is not available
during self-refresh. See section ODT (On Die Termination).
13. The power-down does not perform any refresh operations. The duration of power-down mode is therefore
limited by the refresh requirements outlined in section automatic refresh command.
14.“” means “don’t care” (including floating around VREF) in self-refresh and power-down. However ODT
must be driven high or low in power-down if the ODT function is enabled (bit A2 or A6 set to 1 in
EMRS (1)).
Data Sheet E1950E11 (Ver.1.1)
28
EDE2108AEBG
Function Truth Table
The following tables show the operations that are performed when each command is issued in each state of the
DDR2 SDRAM.
Current state
/CS
/RAS /CAS /WE
Address
Command
Operation
Idle
H
DESL
Nop
L
H
H
H
NOP
Nop
L
H
L
H
BA, CA, A10 (AP)
READ/READA
ILLEGAL
1
1
Bank(s) active
Read
L
H
L
L
BA, CA, A10 (AP)
WRIT/WRITA
ILLEGAL
L
L
H
H
BA, RA
ACT
Row activating
L
L
H
L
BA
PRE
Nop
Notes
L
L
H
L
A10 (AP)
PALL
Nop
L
L
L
H
REF
Auto-refresh
2
L
L
L
H
SELF
Self-refresh
2
L
L
L
L
BA, MRS-OPCODE
MRS
Mode register accessing
2
L
L
L
L
BA, EMRS-OPCODE EMRS (1) (2)
Extended mode register accessing 2
H
DESL
Nop
L
H
H
H
NOP
Nop
L
H
L
H
BA, CA, A10 (AP)
READ/READA
Begin Read
L
H
L
L
BA, CA, A10 (AP)
WRIT/WRITA
Begin Write
L
L
H
H
BA, RA
ACT
ILLEGAL
L
L
H
L
BA
PRE
Precharge
L
L
H
L
A10 (AP)
PALL
Precharge all banks
L
L
L
H
REF
ILLEGAL
L
L
L
H
SELF
ILLEGAL
L
L
L
L
BA, MRS-OPCODE
MRS
ILLEGAL
L
L
L
L
BA, EMRS-OPCODE EMRS (1) (2)
ILLEGAL
Continue burst to end
-> Row active
Continue burst to end
-> Row active
H
DESL
L
H
H
H
NOP
L
H
L
H
BA, CA, A10 (AP)
READ/READA
Burst interrupt
1
1, 4
L
H
L
L
BA, CA, A10 (AP)
WRIT/WRITA
ILLEGAL
1
L
L
H
H
BA, RA
ACT
ILLEGAL
1
L
L
H
L
BA
PRE
ILLEGAL
1, 8
8
L
L
H
L
A10 (AP)
PALL
ILLEGAL
L
L
L
H
REF
ILLEGAL
L
L
L
H
SELF
ILLEGAL
MRS
ILLEGAL
L
L
L
L
BA, MRS-OPCODE
L
L
L
L
BA, EMRS-OPCODE EMRS (1) (2)
Data Sheet E1950E11 (Ver.1.1)
29
ILLEGAL
EDE2108AEBG
Current state
/CS
/RAS /CAS /WE
Address
Command
Write
H
DESL
L
H
H
H
NOP
L
H
L
H
BA, CA, A10 (AP)
READ/READA
ILLEGAL
L
H
L
L
BA, CA, A10 (AP)
WRIT/WRITA
Burst interrupt
1, 4
L
L
H
H
BA, RA
ACT
ILLEGAL
1
L
L
H
L
BA
PRE
ILLEGAL
1, 8
L
L
H
L
A10 (AP)
PALL
ILLEGAL
8
L
L
L
H
REF
ILLEGAL
L
L
L
H
SELF
ILLEGAL
MRS
ILLEGAL
Read with auto
precharge
Write with auto
Precharge
Operation
Notes
Continue burst to end
-> Write recovering
Continue burst to end
-> Write recovering
L
L
L
L
BA, MRS-OPCODE
L
L
L
L
BA, EMRS-OPCODE EMRS (1) (2)
ILLEGAL
H
DESL
L
H
H
H
NOP
Continue burst to end
-> Precharging
Continue burst to end
-> Precharging
1
L
H
L
H
BA, CA, A10 (AP)
READ/READA
ILLEGAL
1, 7
L
H
L
L
BA, CA, A10 (AP)
WRIT/WRITA
ILLEGAL
1, 7
L
L
H
H
BA, RA
ACT
ILLEGAL
1, 7
L
L
H
L
BA
PRE
ILLEGAL
1, 7, 8
L
L
H
L
A10 (AP)
PALL
ILLEGAL
7, 8
L
L
L
H
REF
ILLEGAL
L
L
L
H
SELF
ILLEGAL
L
L
L
L
BA, MRS-OPCODE
MRS
ILLEGAL
L
L
L
L
BA, EMRS-OPCODE EMRS (1) (2)
ILLEGAL
Continue burst to end
->Write recovering with auto
precharge
Continue burst to end
->Write recovering with auto
precharge
H
DESL
L
H
H
H
NOP
L
H
L
H
BA, CA, A10 (AP)
READ/READA
ILLEGAL
1, 7
L
H
L
L
BA, CA, A10 (AP)
WRIT/WRITA
ILLEGAL
1, 7
L
L
H
H
BA, RA
ACT
ILLEGAL
1, 7
L
L
H
L
BA
PRE
ILLEGAL
1, 7, 8
L
L
H
L
A10 (AP)
PALL
ILLEGAL
7, 8
L
L
L
H
REF
ILLEGAL
L
L
L
H
SELF
ILLEGAL
L
L
L
L
BA, MRS-OPCODE
MRS
ILLEGAL
L
L
L
L
BA, EMRS-OPCODE EMRS (1) (2)
Data Sheet E1950E11 (Ver.1.1)
30
ILLEGAL
EDE2108AEBG
Current state
/CS
/RAS /CAS /WE
Address
Command
Operation
Precharging
H
DESL
Nop -> Enter idle after tRP
L
H
H
H
NOP
Nop -> Enter idle after tRP
Row activating
Write recovering
Notes
L
H
L
H
BA, CA, A10 (AP)
READ/READA
ILLEGAL
1
L
H
L
L
BA, CA, A10 (AP)
WRIT/WRITA
ILLEGAL
1
L
L
H
H
BA, RA
ACT
ILLEGAL
1
L
L
H
L
BA
PRE
Nop -> Enter idle after tRP
L
L
H
L
A10 (AP)
PALL
Nop -> Enter idle after tRP
L
L
L
H
REF
ILLEGAL
L
L
L
H
SELF
ILLEGAL
L
L
L
L
BA, MRS-OPCODE
MRS
ILLEGAL
L
L
L
L
BA, EMRS-OPCODE
EMRS (1) (2)
ILLEGAL
Nop -> Enter bank active after
tRCD
Nop -> Enter bank active after
tRCD
H
DESL
L
H
H
H
NOP
L
H
L
H
BA, CA, A10 (AP)
READ/READA
ILLEGAL
1, 5
L
H
L
L
BA, CA, A10 (AP)
WRIT/WRITA
ILLEGAL
1, 5
L
L
H
H
BA, RA
ACT
ILLEGAL
1
L
L
H
L
BA
PRE
ILLEGAL
L
L
H
L
A10 (AP)
PALL
ILLEGAL
L
L
L
H
REF
ILLEGAL
L
L
L
H
SELF
ILLEGAL
L
L
L
L
BA, MRS-OPCODE
MRS
ILLEGAL
L
L
L
L
BA, EMRS-OPCODE
EMRS (1) (2)
ILLEGAL
Nop -> Enter bank active after
tWR
Nop -> Enter bank active after
tWR
H
DESL
L
H
H
H
NOP
L
H
L
H
BA, CA, A10 (AP)
READ/READA
ILLEGAL
1, 6
L
H
L
L
BA, CA, A10 (AP)
WRIT/WRITA
New write
L
L
H
H
BA, RA
ACT
ILLEGAL
1
L
L
H
L
BA
PRE
ILLEGAL
1
L
L
H
L
A10 (AP)
PALL
ILLEGAL
L
L
L
H
REF
ILLEGAL
L
L
L
H
SELF
ILLEGAL
L
L
L
L
BA, MRS-OPCODE
MRS
ILLEGAL
L
L
L
L
BA, EMRS-OPCODE
EMRS (1) (2)
ILLEGAL
Data Sheet E1950E11 (Ver.1.1)
31
EDE2108AEBG
Current state
/CS
/RAS /CAS /WE
Address
Command
Operation
Write recovering
with auto
precharge
H
DESL
Nop -> Precharging after tWR
L
H
H
H
NOP
Nop -> Precharging after tWR
Refresh
Mode register
accessing
Notes
L
H
L
H
BA, CA, A10 (AP)
READ/READA
ILLEGAL
1
L
H
L
L
BA, CA, A10 (AP)
WRIT/WRITA
ILLEGAL
1
L
L
H
H
BA, RA
ACT
ILLEGAL
1
1
L
L
H
L
BA
PRE
ILLEGAL
L
L
H
L
A10 (AP)
PALL
ILLEGAL
L
L
L
H
REF
ILLEGAL
L
L
L
H
SELF
ILLEGAL
L
L
L
L
BA, MRS-OPCODE
MRS
ILLEGAL
L
L
L
L
BA, EMRS-OPCODE
EMRS (1) (2)
ILLEGAL
H
DESL
Nop -> Enter idle after tRFC
L
H
H
H
NOP
Nop -> Enter idle after tRFC
L
H
L
H
BA, CA, A10 (AP)
READ/READA
ILLEGAL
L
H
L
L
BA, CA, A10 (AP)
WRIT/WRITA
ILLEGAL
L
L
H
H
BA, RA
ACT
ILLEGAL
L
L
H
L
BA
PRE
ILLEGAL
L
L
H
L
A10 (AP)
PALL
ILLEGAL
L
L
L
H
REF
ILLEGAL
L
L
L
H
SELF
ILLEGAL
L
L
L
L
BA, MRS-OPCODE
MRS
ILLEGAL
L
L
L
L
BA, EMRS-OPCODE
EMRS (1) (2)
ILLEGAL
H
DESL
Nop -> Enter idle after tMRD
L
H
H
H
NOP
Nop -> Enter idle after tMRD
L
H
L
H
BA, CA, A10 (AP)
READ/READA
ILLEGAL
L
H
L
L
BA, CA, A10 (AP)
WRIT/WRITA
ILLEGAL
L
L
H
H
BA, RA
ACT
ILLEGAL
L
L
H
L
BA
PRE
ILLEGAL
L
L
H
L
A10 (AP)
PALL
ILLEGAL
L
L
L
H
REF
ILLEGAL
L
L
L
H
SELF
ILLEGAL
L
L
L
L
BA, MRS-OPCODE
MRS
ILLEGAL
L
L
L
L
BA, EMRS-OPCODE
EMRS (1) (2)
ILLEGAL
Data Sheet E1950E11 (Ver.1.1)
32
EDE2108AEBG
Current state
/CS
/RAS /CAS /WE
Address
Command
Operation
Extended Mode
H
DESL
Nop -> Enter idle after tMRD
register accessing L
H
H
H
NOP
Nop -> Enter idle after tMRD
L
H
L
H
BA, CA, A10 (AP)
READ/READA ILLEGAL
L
H
L
L
BA, CA, A10 (AP)
WRIT/WRITA
ILLEGAL
L
L
H
H
BA, RA
ACT
ILLEGAL
Remark:
Notes: 1.
2.
3.
4.
5.
6.
7.
L
L
H
L
BA
PRE
ILLEGAL
L
L
H
L
A10 (AP)
PALL
ILLEGAL
L
L
L
H
REF
ILLEGAL
L
L
L
H
SELF
ILLEGAL
L
L
L
L
BA, MRS-OPCODE
MRS
ILLEGAL
L
L
L
L
BA, EMRS-OPCODE
EMRS (1) (2)
ILLEGAL
Notes
H: VIH. L: VIL. : VIH or VIL.
This command may be issued for other banks, depending on the state of the banks.
All banks must be in "IDLE".
All AC timing specs must be met.
Only allowed at the boundary of 4 bits burst. Burst interruptions at other timings are illegal.
Available in case tRCD is satisfied by AL setting.
Available in case tWTR is satisfied.
The DDR2 SDRAM supports the concurrent auto-precharge feature, a read with auto-precharge
enabled,or a write with auto-precharge enabled, may be followed by any column command to other
banks, as long as that command does not interrupt the read or write data transfer, and all other related
limitations apply. (E.g. Conflict between READ data and WRITE data must be avoided.)
The minimum delay from a read or write command with auto precharge enabled, to a command to a
different bank, is summarized below.
From command
To command (different bank, noninterrupting command)
Minimum delay
(Concurrent AP supported)
Units
Read w/AP
Read or Read w/AP
BL/2
tCK
Write or Write w/AP
(BL/2) + 2
tCK
Precharge or Activate
1
tCK
Read or Read w/AP
(CL 1) + (BL/2) + tWTR
tCK
Write w/AP
Write or Write w/AP
BL/2
tCK
Precharge or Activate
1
tCK
Data Sheet E1950E11 (Ver.1.1)
33
EDE2108AEBG
8. The minimum delay from the read, write and precharge command to the precharge command to the same
bank is summarized below.
[Precharge and Auto Precharge Clarification]
From command
To command
Minimum delay between “From
command” to “To command“
Units
Notes
Read
Precharge (to same bank as read)
AL + (BL/2) + Max.(RTP, 2) 2
tCK
a, b
Precharge all
AL + (BL/2) + Max.(RTP, 2) 2
tCK
a, b
Precharge (to same bank as read w/AP)
AL + (BL/2) + Max.(RTP, 2) 2
tCK
a, b
Precharge all
AL + (BL/2) + Max.(RTP, 2) 2
tCK
a, b
Precharge (to same bank as write)
WL + (BL/2) + tWR
tCK
b
Precharge all
WL + (BL/2) + tWR
tCK
b
Precharge (to same bank as write w/AP)
WL + (BL/2) + WR
tCK
b
Precharge all
WL + (BL/2) + WR
tCK
b
Precharge (to same bank as precharge)
1
tCK
b
Precharge all
1
tCK
b
Read w/AP
Write
Write w/AP
Precharge
Precharge all
Precharge
1
tCK
b
Precharge all
1
tCK
b
a. RTP[cycles] = RU{ tRTP[ns] / tCK[ns] }, where RU stands for round up.
tCK(avg) should be used in place of tCK for DDR2-667/800.
b. 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 precharge period is satisfied after tRP
depending on the latest precharge command issued to that bank.
Data Sheet E1950E11 (Ver.1.1)
34
EDE2108AEBG
Simplified State Diagram
INITIALIZATION
SEQUENCE
CKE_L
SELF
REFRESH
PRE
MRS
EMRS (1)
EMRS (2)
EMRS (3)
LF
SE
(E)MRS
H
E_
IDLE
CK
REF
ALL BANKS
PRECHARGED
AUTO
REFRESH
CK
L
E_L
E_
CK
CK
E_H
ACT
PRECHARGE
POWER
DOWN
CKE_L
ACTIVATING
CKE_L
_L
CKE
ACTIVE
POWER
DOWN
CKE
_H
CKE
_L
BANK
ACTIVE
RE
AD
IT
WRIT
WR
READ
TA
RI
W
A
AD
RE
READ
WRITE
READ
WRIT
WRITA
READA
REA
ITA
DA
WR
PRE, PALL
WRITA
PRE, PALL
READA
PRE, PALL
PRECHARGE
Simplified State Diagram
Data Sheet E1950E11 (Ver.1.1)
35
Automatic sequence
Command sequence
EDE2108AEBG
Operation of DDR2 SDRAM
Read and write accesses to the DDR2 SDRAM are burst oriented; accesses start at a selected location and continue
for the fixed 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 is used to select the bank and row to be accessed BA0, BA1 and BA2 select the bank; A0 to
A14 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.
Power On 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.
Power-Up and Initialization Sequence
The following sequence is required for power up and initialization.
1
1. Apply power and attempt to maintain CKE below 0.2 VDDQ and ODT * at a low state (all other inputs may be
undefined.)
VDD, VDDL and VDDQ are driven from a single power converter output, AND
VTT is limited to 0.95V 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 and 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 200s after stable power and clock (CK, /CK), then apply [NOP] or [DESL] and take CKE
high.
4. Wait minimum of 400ns then issue precharge all command. [NOP] or [DESL] applied during 400ns period.
5. Issue EMRS (2) command. (To issue EMRS (2) command, provide low to BA0 and BA2, high to BA1)
6. Issue EMRS (3) command. (To issue EMRS (3) command, provide low to BA2, 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,
BA2 and A13, A14.)
8. Issue a mode register set command for DLL reset.
(To issue DLL reset command, provide high to A8 and low to BA0 to BA2 and A13, A14)
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, issue EMRS (1) command with A9 = A8 = A7 = 1. Then issue EMRS (1)
command with A9 = A8 = A7 = 0 with other operating parameters of EMRS (1).
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.
tCH tCL
CK
/CK
tIS
CKE
Command
A9=A8=A7=1
PALL
NOP
400ns
EMRS(3)
EMRS(2)
tRP
tMRD
MRS
EMRS(1)
tMRD
DLL enable
tMRD
PALL
tMRD
REF
REF
tRP
tRFC
DLL reset
200 cycles (min)
Power up and Initialization Sequence
Data Sheet E1950E11 (Ver.1.1)
36
MRS
tRFC
EMRS(1)
tMRD
A9=A8=A7=0
EMRS(1)
Any
command
EDE2108AEBG
Programming the Mode Register and Extended Mode Registers
For application flexibility, burst length, burst type, /CAS latency, DLL reset function, write recovery time (tWR)
are user defined variables and must be programmed with a mode register set command [MRS]. Additionally, DLL
disable function, driver impedance, additive /CAS latency, ODT (On Die Termination) and single-ended strobe are
also user defined variables and must be programmed with an extended mode register set command [EMRS].
Contents of the Mode Register (MR) or Extended Mode Registers (EMRS (#)) can be altered by reexecuting the
MRS and EMRS commands. If the user chooses to modify only a subset of the MRS or EMRS variables, all
variables must be redefined when the MRS or EMRS commands are issued.
MRS, EMRS and Reset DLL do not affect array contents, which means reinitialization including those can be
executed any time after power-up without affecting array contents.
DDR2 SDRAM 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, DLL reset, tWR 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 written after power-up for proper operation. The mode register is written by asserting low on /CS, /RAS,
/CAS, /WE, BA0, BA1 and BA2, while controlling the state of address pins A0 to A14.
The DDR2 SDRAM should be in all bank precharge 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 banks are in the precharge state. The mode register is divided into various fields depending
on functionality. Burst length is defined by A0 to A2 with options of 4 and 8 bit burst lengths. The burst length
decodes are compatible with DDR SDRAM. Burst address sequence type is defined by A3, /CAS latency is defined
by A4 to A6. The DDR2 doesn’t support half clock latency mode. A8 is used for DLL reset. Write recovery time tWR
is defined by A9 to A11. Refer to the table for specific codes.
BA2 BA1 BA0 A14 A13 A12 A11 A10 A9
0
0
0
0*1
PD
WR
A12 Active power down exit timing
0
1
Fast exit (use tXARD timing)
Slow exit (use tXARDS timing)
A8
A7
DLL
0
A6
A5
A4
A3
/CAS latency
BT
A2
A1
A0
Burst length
A8
DLL reset
A3
Burst type
0
No
0
Sequential
1
Yes
1
Address field
Mode register
Burst length
Interleave
A2
A1
A0
BL
0
1
0
4
0
1
1
8
/CAS latency
Write recovery for autoprecharge
A11
A10
A9
WR
A6
A5
A4
Latency
0
0
0
MRS
0
0
0
Reserved
0
0
0
Reserved
0
0
1
EMRS(1)
0
0
1
2
0
0
1
Reserved
0
1
0
EMRS(2)
0
1
0
3
0
1
0
Reserved
0
1
1
EMRS(3): Reserved
0
1
1
4
0
1
1
3
1
0
0
5
1
0
0
4
1
0
1
6
1
0
1
5
1
1
0
Reserved
1
1
0
6
1
1
1
Reserved
1
1
1
Reserved
DDR2-533
DDR2-667
DDR2-800
MRS mode
DDR2-400
BA2 BA1 BA0
Notes: 1. A13 and A14 is reserved for future use and must be programmed to 0 when setting the mode register.
2. WR (min.) (Write Recovery for autoprecharge) is determined by tCK (max.) and WR (max.) is determined by tCK (min.).
WR in clock cycles is calculated by dividing tWR (in ns) by tCK (in ns) and rounding up to the next integer
(WR [cycles] = tWR (ns) / tCK (ns)).
The mode register must be programmed to this value. This is also used with tRP to determine tDAL.
Mode Register Set (MRS)
Data Sheet E1950E11 (Ver.1.1)
37
EDE2108AEBG
DDR2 SDRAM Extended Mode Registers Set [EMRS]
EMRS (1) Programming
The extended mode register (1) stores the data for enabling or disabling the DLL, output driver strength, additive
latency, ODT, /DQS disable, RDQS enable. The default value of the extended mode register (1) is not defined,
therefore the extended mode register (1) must be written after power-up for proper operation. The extended mode
register (1) is written by asserting low on /CS, /RAS, /CAS, /WE, high on BA0 and low on BA1, BA2 while controlling
the states of address pins A0 to A14. The DDR2 SDRAM should be in all bank precharge with CKE already high
prior to writing into the extended mode register (1). The mode register set command cycle time (tMRD) must be
satisfied to complete the write operation to the extended mode register (1). 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 setting output driver strength. A3 to A5
determines the additive latency. A10 is used for /DQS enable or disable. A11 is used for RDQS enable. A2 and A6
are used for ODT setting.
BA2 BA1 BA0 A14 A13 A12 A11 A10 A9
0
0
0* 1
1
MRS mode
0
MRS
0
0
0
0
1
A7
0
1
0
EMRS(2)
0
1
1
EMRS(3): Reserved
Qoff* 3
0
Output buffers enabled
1
Output buffers disabled
A5
A4
A3
A2
A1
A0
Address field
Rtt Additive latency Rtt D.I.C DLL
A6
A2
Rtt (nominal )
0
0
ODT Disabled
0
1
75Ω
1
0
150Ω
1
1
50Ω
EMRS(1)
A12
A6
0*2
Qoff RDQS /DQS
BA2 BA1 BA0
A8
Extended mode register
A0
DLL enable
0
Enable
1
Disable
Additive latency
Driver strength control
Output driver
Driver
A1
impedance control
size
0
Normal
100%
1
Weak
60%
A5
A4
A3
Latency
0
0
0
0
0
0
1
1
0
1
0
2
0
1
1
3
A10
/DQS enable
1
0
0
4
0
Enable
1
0
1
5
1
Disable
1
1
0
Reserved
1
1
1
Reserved
A11
RDQS enable
0
Disable
1
Enable
A11
Strobe function matrix
A10
(RDQS enable)
(/DQS enable) RDQS/DM
/RDQS
DQS
/DQS
0 (Disable)
0 (Enable)
DM
High-Z
DQS
/DQS
0 (Disable)
1 (Disable)
DM
High-Z
DQS
High-Z
1 (Enable)
0 (Enable)
RDQS
/RDQS
DQS
/DQS
1 (Enable)
1 (Disable)
RDQS
High-Z
DQS
High-Z
Notes: 1. A13 and A14 are reserved for future use, and must be programmed to 0 when setting the extended mode register.
2. It must be set to 1 first, and then set to 0 in initialization.
Refer to the Power-Up and Initialization Sequence for detailed information.
3. Output disabled - DQ, DQS, /DQS, RDQS, /RDQS. This feature is used in conjunction with DIMM
IDD measurements when IDDQ is not desired to be included.
EMRS (1)
Data Sheet E1950E11 (Ver.1.1)
38
EDE2108AEBG
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 selfrefresh 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.
*1
EMRS (2) Programming
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, BA2 while controlling the states of address pins A0 to A14. 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. A7 is used for high temperature self-refresh rate enable or
disable.
BA2 BA1 BA0 A14 A13 A12
0*1 1
A11
A10
A9
A8
0*1
0
A7
A6
A5
A4
A2
A1
Address field
A0
Extended mode register (2)
0*1
SRF
A7
A3
High Temperature
Self-refresh rate
Enable
0
Disable
1
Enable
Note: 1. The rest bits in EMRS (2) is reserved for future use and all bits in EMRS (2) except A7
must be programmed to 0 when setting the extended mode register (2) during initialization.
EMRS (2)
*1
EMRS (3) Programming: Reserved
BA2 BA1 BA0 A14
0
1
A13 A12
1
A11 A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
Address Field
Extended Mode Register(3)
0*1
Note : 1. EMRS (3) is reserved for future use and all bits must be programmed to 0 when setting
the extended mode register (3) during initialization.
EMRS (3)
Data Sheet E1950E11 (Ver.1.1)
39
EDE2108AEBG
ODT (On Die Termination)
On Die Termination (ODT), is a feature that allows a DRAM to turn on/off termination resistance for each DQ, DQS,
/DQS RDQS, /RDQS, and DM 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 turned off and not supported in self-refresh mode.
ODT must be disabled externally during Reads by driving ODT low.
VDDQ
VDDQ
VDDQ
sw1
sw3
sw2
Rval1
Rval3
Rval2
DRAM
input
buffer
Input
Pin
Rval1
sw1
VSSQ
Rval2
Rval3
sw2
sw3
VSSQ
VSSQ
Switch sw1, sw2 or sw3 is enabled by ODT pin.
Selection between sw1, sw2 or sw3 is determined by Rtt (nominal) in EMRS
Termination included on all DQs, DM, DQS, /DQS, RDQS and /RDQS pins.
Target Rtt () = (Rval1) / 2, (Rval2) / 2 or (Rval3) / 2
Functional Representation of ODT
/CK
CK
Command
EMRS
NOP
tAOFD
ODT
tIS
tMOD (max.)
tMOD (min.)
Rtt
Updating
Old setting
New Setting
Note: tAOFD must be met before issuing EMRS command. ODT must remain low for the entire duration of tMOD window.
ODT update Delay Timing
Data Sheet E1950E11 (Ver.1.1)
40
EDE2108AEBG
/CK
T0
T1
T2
T3
T4
T5
T6
CK
CKE
tIS
tIS
ODT
tAOFD
tAOND
Internal
Term Res.
Rtt
tAON min.
tAOF min.
tAON max.
tAOF max.
ODT Timing for Active and Standby Mode
/CK
T0
T1
T2
T3
T4
T5
T6
CK
CKE
tIS
tIS
ODT
tAOFPD max.
tAOFPD min.
Internal
Term Res.
Rtt
tAONPD min.
tAONPD max.
ODT Timing for Power-Down Mode
Data Sheet E1950E11 (Ver.1.1)
41
EDE2108AEBG
T-5
T-4
T-3
T-2
T-1
T0
T1
T2
T3
T4
/CK
CK
tANPD
tIS
CKE
Entering slow exit active power down mode
or precharge power down mode.
tIS
ODT
Active and standby
mode timings to
be applied.
tAOFD
Internal
Term Res.
Rtt
tIS
ODT
Power down
mode timings to
be applied.
tAOFPD(max.)
Internal
Term Res.
Rtt
tIS
ODT
tAOND
Internal
Term Res.
Active and standby
mode timings to
be applied.
Rtt
tIS
ODT
Power down
mode timings to
be applied.
tAONPD(max.)
Internal
Term Res.
Rtt
ODT Timing Mode Switch at Entering Power-Down Mode
Data Sheet E1950E11 (Ver.1.1)
42
EDE2108AEBG
T0
T1
T4
T5
T6
T7
T8
T9
T10
T11
/CK
CK
tIS
tAXPD
CKE
Exiting from slow active power down mode
or precharge power down mode.
tIS
Active and standby
mode timings to
be applied.
ODT
tAOFD
Internal
Term Res.
Rtt
tIS
Power down
mode timings to
be applied.
ODT
tAOFPD (max.)
Internal
Term Res.
Rtt
tIS
Active and standby
mode timings to
be applied.
ODT
tAOND
Internal
Term Res.
Rtt
tIS
Power down
mode timings to
be applied.
ODT
tAONPD(max.)
Internal
Term Res.
Rtt
ODT Timing Mode Switch at Exiting Power-Down Mode
Data Sheet E1950E11 (Ver.1.1)
43
EDE2108AEBG
Bank Activate Command [ACT]
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, BA1 and BA2 are used to select the desired bank. The row address A0 through
A14 is 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 on the following clock cycle. If a R/W command is issued to a bank that has
not satisfied the tRCD (min.) specification, then additive latency must be programmed into the device to delay when
the R/W command is internally issued to the device. The additive latency value must be chosen to assure tRCD
(min.) is satisfied. Additive latencies of 0, 1, 2, 3 and 4 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 by the /RAS cycle time of the device (tRC), which is equal to
tRAS + tRP. The minimum time interval between successive bank activate commands to the different bank is
determined by (tRRD).
In order to ensure that 8-bank devices do not exceed the instantaneous current supplying capability of 4-bank
devices, a restriction on the number of sequential ACT commands that can be issued must be observed. The rule is
as follows:
Note: 8-bank device sequential bank activation restriction: No more than 4 banks may be activated in a rolling
tFAW window. Converting to clocks is done by dividing tFAW (ns) by tCK (ns) and rounding up to next
integer value. As an example of the rolling window, if (tFAW/tCK) rounds up to 10 clocks, and an activate
command is issued in clock N, no more than three further activate commands may be issued in clock N+1
through N+9.
/CK
T0
T1
T2
T3
Tn
Tn+1
Tn+2
Tn+3
PRE
ACT
CK
Command
ACT
Posted
READ
ACT
Posted
READ
PRE
tRCD(min.)
Address
ROW: 0
COL: 0
ROW: 1
COL: 1
ROW: 0
tCCD
Additive latency (AL)
Bank0 Read begins
tRRD
tRAS
tRP
tRC
Bank0
Active
Bank1
Active
Bank0
Precharge
Bank1
Precharge
Bank Activate Command Cycle (tRCD = 3, AL = 2, tRP = 3, tRRD = 2, tCCD = 2)
Data Sheet E1950E11 (Ver.1.1)
44
Bank0
Active
EDE2108AEBG
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. For example, the 32M bits 4 I/O 4 banks chip has a page length of 2048 bits
(defined by CA0 to CA9, CA11). The page length of 2048 is divided into 512 uniquely addressable boundary
segments (4 bits each). A 4 bits burst operation will occur entirely within one of the 512 groups beginning with the
column address supplied to the device during the read or write command (CA0 to CA9, CA11). The second, third
and fourth access will also occur within this group segment, however, the burst order is a function of the starting
address, and the burst sequence.
A new burst access must not interrupt the previous 4-bit burst operation. The minimum /CAS to /CAS delay is
defined by tCCD, and is a minimum of 2 clocks for read or write cycles.
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 tRCD (min), then AL (greater than 0) must be written into the EMRS. 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).
-1
0
1
2
ACT
READ
3
4
5
6
7
8
9
10
11
12
11
12
/CK
CK
Command
NOP
NOP
WRIT
WL = RL – 1 = 4
CL = 3
AL = 2
DQS, /DQS
tRCD
RL = AL + CL = 5
DQ
out0 out1 out2 out3
in0 in1 in2 in3
tRAC
Read Followed by a Write to the Same Bank
[AL = 2 and CL = 3, RL = (AL + CL) = 5, WL = (RL - 1) = 4]
-1
0
1
2
3
4
5
6
7
8
9
10
/CK
CK
Command
ACT
NOP
AL = 0
READ
NOP
CL = 3
WRIT
NOP
WL = RL – 1 = 2
DQS, /DQS
tRCD
RL = AL + CL = 3
DQ
out0 out1 out2 out3
tRAC
Read Followed by a Write to the Same Bank
[AL = 0 and CL = 3, RL = (AL + CL) = 3, WL = (RL - 1) = 2]
Data Sheet E1950E11 (Ver.1.1)
45
in0 in1 in2 in3
EDE2108AEBG
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. DDR2 SDRAM supports 4 bits burst and 8bits burst modes only. For 8 bits burst mode, full interleave
address ordering is supported, however, sequential address ordering is nibble based for ease of implementation.
The burst type, either sequential or interleaved, is programmable and defined by the address bit 3 (A3) of the MRS,
which is similar to the DDR-I SDRAM operation. Seamless burst read or write operations are supported.
Unlike DDR-I devices, interruption of a burst read or writes operation is limited to ready by Read or Write by Write at
the boundary of Burst 4. Therefore the burst stop command is not supported on DDR2 SDRAM devices.
[Burst Length and Sequence, BL = 4]
Burst length
4
Starting address (A1, A0)
Sequential addressing (decimal)
Interleave addressing (decimal)
00
0, 1, 2, 3
0, 1, 2, 3
01
1, 2, 3, 0
1, 0, 3, 2
10
2, 3, 0, 1
2, 3, 0, 1
11
3, 0, 1, 2
3, 2, 1, 0
[Burst Length and Sequence, BL = 8]
Burst length
8
Starting address (A2, A1, A0) Sequential addressing (decimal)
Interleave addressing (decimal)
000
0, 1, 2, 3, 4, 5, 6, 7
0, 1, 2, 3, 4, 5, 6, 7
001
1, 2, 3, 0, 5, 6, 7, 4
1, 0, 3, 2, 5, 4, 7, 6
010
2, 3, 0, 1, 6, 7, 4, 5
2, 3, 0, 1, 6, 7, 4, 5
011
3, 0, 1, 2, 7, 4, 5, 6
3, 2, 1, 0, 7, 6, 5, 4
100
4, 5, 6, 7, 0, 1, 2, 3
4, 5, 6, 7, 0, 1, 2, 3
101
5, 6, 7, 4, 1, 2, 3, 0
5, 4, 7, 6, 1, 0, 3, 2
110
6, 7, 4, 5, 2, 3, 0, 1
6, 7, 4, 5, 2, 3, 0, 1
111
7, 4, 5, 6, 3, 0, 1, 2
7, 6, 5, 4, 3, 2, 1, 0
Note: Page length is a function of I/O organization and column addressing
32M bits 8 organization (CA0 to CA9); Page Length = 1024 bits
Data Sheet E1950E11 (Ver.1.1)
46
EDE2108AEBG
Burst Read Command [READ]
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-I SDRAMs. The AL is defined by the extended mode register set
(EMRS).
T0
T1
T2
T3
T4
T5
T6
T7
T8
T7
T8
/CK
CK
Command
READ
NOP
tDQSCK
DQS, /DQS
CL = 3
RL = 3
DQ
out0 out1 out2 out3
Burst Read Operation (RL = 3, BL = 4 (AL = 0 and CL = 3))
T0
T1
T2
T3
T4
T5
T6
/CK
CK
Command
READ
NOP
tDQSCK
DQS, /DQS
CL = 3
RL = 3
DQ
out0 out1 out2 out3 out4 out5 out6 out7
Burst Read Operation (RL = 3, BL = 8 (AL = 0 and CL = 3))
Data Sheet E1950E11 (Ver.1.1)
47
EDE2108AEBG
T0
T1
T2
T3
T4
T5
T6
T7
T8
/CK
CK
Command
Posted
READ
NOP
tDQSCK
DQS, /DQS
AL = 2
CL = 3
RL = 5
out0 out1 out2 out3
DQ
Burst Read Operation (RL = 5, BL = 4 (AL = 2, CL = 3))
T0
T1
T3
T4
T5
T6
T7
T8
T9
/CK
CK
Command
Posted
READ
NOP
Posted
WRIT
NOP
NOP
tRTW (Read to Write = 4 clocks)
DQS, /DQS
RL = 5
WL = RL - 1 = 4
out0 out1 out2 out3
DQ
in0
in1
in2
in3
Burst Read Followed by Burst Write (RL = 5, WL = RL-1 = 4, BL = 4)
The minimum time from the burst read command to the burst write command is defined by a read-to-write-turnaround-time, which is 4 clocks in the case of BL = 4 operation, 6 clocks in case of BL =8 operation.
T0
T1
T2
T3
T4
T5
T6
T7
T8
/CK
CK
Command
Posted
READ
NOP
A
Posted
READ
NOP
B
DQS, /DQS
AL = 2
CL = 3
RL = 5
out
A0
DQ
out
A1
out
A2
Seamless Burst Read Operation (RL = 5, AL = 2, and CL = 3)
Data Sheet E1950E11 (Ver.1.1)
48
out
A3
out
B0
out
B1
out
B2
EDE2108AEBG
Enabling a read command at every other clock supports the seamless burst read operation. This operation is
allowed regardless of same or different banks as long as the banks are activated.
T0
T1
T2
READ
NOP
READ
T3
T4
T5
T6
T7
T8
T9
T10
T11
CK
/CK
Command
A
NOP
B
DQS, /DQS
RL = 4
out
A0
DQ
out
A1
out
A2
out
A3
out
B0
out out
B1 B2
out
B3
out
B4
out
B5
out
B6
out
B7
Burst interrupt is only
allowed at this timing.
Burst Read Interrupt by Read
Notes: 1. Read burst interrupt function is only allowed on burst of 8. burst interrupt of 4 is prohibited.
2. Read burst of 8 can only be interrupted by another read command. Read burst interruption by write
command or precharge command is prohibited.
3. Read burst interrupt must occur exactly two clocks after previous read command. any other read burst
interrupt timings are prohibited.
4. Read burst interruption is allowed to any bank inside DRAM.
5. Read burst with auto precharge enabled is not allowed to interrupt.
6. Read burst interruption is allowed by another read with auto precharge command.
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).
Data Sheet E1950E11 (Ver.1.1)
49
EDE2108AEBG
Burst Write Command [WRIT]
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). 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 write cycles. The subsequent
burst bit data are issued on successive edges of the DQS until the burst length of 4 is completed. 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 (tWR).
T0
T1
T2
T3
T4
T5
T6
T7
T9
/CK
CK
Command
WRIT
NOP
PRE
NOP
ACT
tDQSS
DQS, /DQS
tWR
WL = RL –1 = 2
in0
DQ
in1
in2
tRP
in3
Completion of
the burst write
Burst Write Operation (RL = 3, WL = 2, BL = 4 tWR = 2 (AL=0, CL=3))
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
T11
/CK
CK
Command
WRIT
PRE
NOP
NOP
tDQSS
DQS, /DQS
tWR
WL = RL –1 = 2
DQ
in0
in1
in2
in3
in4
in5
in6
in7
Completion of
the burst write
Burst Write Operation (RL = 3, WL = 2, BL = 8 (AL=0, CL=3))
Data Sheet E1950E11 (Ver.1.1)
50
tRP
ACT
EDE2108AEBG
T0
T1
T2
T3
T4
T5
T6
T7
T9
/CK
CK
Posted
WRIT
Command
PRE
NOP
tDQSS
DQS, /DQS
tWR
WL = RL −1 = 4
in0
DQ
in1
in2
in3
Completion of
the burst write
Burst Write Operation (RL = 5, WL = 4, BL = 4 tWR = 3 (AL=2, CL=3))
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
/CK
CK
Write to Read = CL - 1 + BL/2 + tWTR (2) = 6
Command
Posted
READ
NOP
NOP
DQS, /DQS
CL = 3
AL = 2
WL = RL –1 = 4
RL = 5
>tWTR
=
in0
DQ
in1
in2
in3
out0
out1
Burst Write Followed by Burst Read (RL = 5, BL = 4, WL = 4, tWTR = 2 (AL=2, CL=3))
The minimum number of clock from the burst write command to the burst read command is CL - 1 + BL/2 + a write
to-read-turn-around-time (tWTR). This tWTR is not a write recovery time (tWR) but the time required to transfer the
4bit write data from the input buffer into sense amplifiers in the array.
T0
T1
T2
T3
T4
T5
T6
T7
T8
/CK
CK
Command
Posted
WRIT
A
NOP
Posted
WRIT
B
NOP
DQS, /DQS
WL = RL − 1 = 4
in
A0
DQ
in
A1
in
A2
in
A3
in
B0
in
B1
in
B2
in
B3
Seamless Burst Write Operation (RL = 5, WL = 4, BL = 4)
Enabling a write command every other clock supports the seamless burst write operation. This operation is allowed
regardless of same or different banks as long as the banks are activated.
Data Sheet E1950E11 (Ver.1.1)
51
EDE2108AEBG
T0
T1
T2
WRIT
NOP
WRIT
T3
T4
T5
T6
T7
T8
T9
T10
T11
CK
/CK
Command
A
NOP
B
DQS, /DQS
WL = 3
DQ
in in in in
A0 A1 A2 A3
in
B0
in in in in in in in
B1 B2 B3 B4 B5 B6 B7
Burst interrupt is only
allowed at this timing.
Write Interrupt by Write (WL = 3, BL = 8)
Notes :1. Write burst interrupt function is only allowed on burst of 8. Burst interrupt of 4 is prohibited.
2. Write burst of 8 can only be interrupted by another write command. Write burst interruption by read
command or precharge command is prohibited.
3. Write burst interrupt must occur exactly two clocks after previous write command. Any other write burst
interrupt timings are prohibited.
4. Write burst interruption is allowed to any bank inside DRAM.
5. Write burst with auto precharge enabled is not allowed to interrupt.
6. Write burst interruption is allowed by another write with auto precharge command.
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 un-interrupted burst end and not from the end of actual burst end.
Data Sheet E1950E11 (Ver.1.1)
52
EDE2108AEBG
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-I 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.
T1
T2
T3
T4
in
in
T5
Tn
DQS
/DQS
DQ
in
in
in
in
in
in
in
DM
Write mask latency = 0
Data Mask Timing
[tDQSS(min.)]
/CK
CK
tWR
Command
WRIT
NOP
WL
tDQSS
DQS, /DQS
DQ
in0
in2 in3
DM
WL
[tDQSS(max.)]
tDQSS
DQS, /DQS
in0
DQ
in2 in3
DM
Data Mask Function, WL = 3, AL = 0 shown
Data Sheet E1950E11 (Ver.1.1)
53
EDE2108AEBG
Precharge Command [PRE]
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,
BA0, BA1 and BA2 are used to define which bank to precharge when the command is issued.
[Bank Selection for Precharge by Address Bits]
A10
BA0
BA1
BA2
Precharged Bank(s)
L
L
L
L
Bank 0 only
L
H
L
L
Bank 1 only
L
L
H
L
Bank 2 only
L
H
H
L
Bank 3 only
L
L
L
H
Bank 4 only
L
H
L
H
Bank 5 only
L
L
H
H
Bank 6 only
L
H
H
H
Bank 7 only
H
All banks 0 to 7
Remark: H: VIH. L: VIL. : VIH or VIL.
Burst Read Operation Followed by Precharge
Minimum read to precharge command spacing to the same bank = AL + BL/2 clocks
For the earliest possible precharge, the precharge command may be issued on the rising edge that is
“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.
T0
T1
T2
T3
T4
T5
T6
T7
T8
/CK
CK
Command
Posted
READ
PRE
NOP
ACT
NOP
NOP
AL + BL/2 clocks
DQS, /DQS
AL = 1
tRP
CL = 3
RL = 4
out0
DQ
out1
out2
out3
tRAS
Burst Read Operation Followed by Precharge (RL = 4, BL = 4 (AL=1, CL=3))
Data Sheet E1950E11 (Ver.1.1)
54
EDE2108AEBG
T0
T1
T2
T3
T4
T5
T6
T7
T8
/CK
CK
Posted
READ
Command
PRE
NOP
ACT
NOP
NOP
AL + BL/2 clocks
DQS, /DQS
AL = 2
tRP
CL = 3
RL = 5
DQ
out0
out1
out2
out3
tRAS(min.)
Burst Read Operation Followed by Precharge (RL = 5, BL = 4 (AL=2, CL=3))
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
/CK
CK
Command
Posted
READ
NOP
NOP
PRE
NOP
ACT
AL + BL/2 Clocks
DQS, /DQS
tRP
CL = 4
AL = 2
RL = 6
out0
DQ
out1
out2
out3
out4
tRAS(min.)
Burst Read Operation Followed by Precharge (RL = 6 (AL=2, CL=4, BL=8))
Data Sheet E1950E11 (Ver.1.1)
55
out5
out6
out7
EDE2108AEBG
Burst Write followed by Precharge
Minimum Write to Precharge Command spacing to the same bank = WL + BL/2 clocks + 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 allows the burst interrupt operation only Read by Read or Write by Write at the boundary of burst 4.
T0
T1
T2
T3
T4
T5
T6
T7
T8
/CK
CK
Command
Posted
WRIT
NOP
PRE
tWR
DQS, /DQS
WL = 3
in0
DQ
in1
in2
in3
Completion of
the burst write
Burst Write Followed by Precharge (WL = (RL-1) =3)
T0
T1
T2
T3
T4
T5
T6
T7
T9
/CK
CK
Command
Posted
WRIT
PRE
NOP
tWR
DQS, /DQS
WL = 4
in0
DQ
in1
in2
in3
Completion of
the burst write
Burst Write Followed by Precharge (WL = (RL-1) = 4)
Data Sheet E1950E11 (Ver.1.1)
56
EDE2108AEBG
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
T11
/CK
CK
Command
Posted
WRIT
NOP
PRE
tWR
DQS, /DQS
WL = 4
DQ
in0
in1
in2
in3
in4
in5
in6
in7
Completion of
the burst write
Burst Write Followed by Precharge (WL = (RL-1) = 4,BL= 8)
Data Sheet E1950E11 (Ver.1.1)
57
EDE2108AEBG
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 can 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 so that the auto precharge
command may be issued with any read or write command.
Burst Read with Auto Precharge [READA]
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 when tRAS (min) is 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. 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.
T0
T1
T2
T3
T4
T5
T6
T7
Tn
/CK
CK
Command
A10 = 1
Posted
READ
NOP
ACT
NOP
ACT
AL + BL/2
DQS, /DQS
tRP
AL = 2
CL = 3
RL = 5
out0 out1 out2 out3
DQ
tRC (min.)
Auto precharge begins
Burst Read with Auto Precharge Followed by an Activation to the Same Bank (tRC limit)
(RL = 5, BL = 4 (AL = 2, CL = 3, tRTP 2tCK))
Data Sheet E1950E11 (Ver.1.1)
58
EDE2108AEBG
T-1
T0
T1
T2
T3
T4
T5
T6
T7
Tn
/CK
CK
A10 = 1
Posted
READ
Command
NOP
ACT
tRAS(min.)
DQS, /DQS
tRP
AL = 2
CL = 3
RL = 5
out1
out0
DQ
out3
out2
tRC (min.)
Auto precharge begins
Burst Read with Auto Precharge Followed by an Activation to the Same Bank (tRAS lockout case)
(RL = 5, BL = 4 (AL = 2, CL = 3))
T0
T1
T2
T3
T4
T5
T6
T7
T8
/CK
CK
Command
A10 = 1
Posted
READ
ACT
NOP
NOP
tRAS(min.)
DQS, /DQS
tRP (min.)
AL = 2
CL = 3
RL = 5
out1
out0
DQ
out2
out3
tRC
Auto precharge begins
Burst Read with Auto Precharge Followed by an Activation to the Same Bank (tRP limit)
(RL = 5, BL = 4 (AL = 2, CL = 3, tRTP 2tCK))
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
CK
/CK
A10 = 1
Command
NOP
READ
ACT
tRAS (min.)
DQS, /DQS
AL = 2
CL = 3
tRP
RL = 5
out0 out1 out2 out3 out4 out5 out6 out7
DQ
tRC
Auto precharge begins
Burst Read with Auto Precharge Followed by an Activation to the Same Bank
(RL = 5, BL = 8 (AL = 2, CL = 3, tRTP 2tCK))
Data Sheet E1950E11 (Ver.1.1)
59
T11
EDE2108AEBG
Burst Write with Auto Precharge [WRITA]
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 writes 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 (tWR + tRP) has been satisfied.
(2) The /RAS cycle time (tRC) from the previous bank activation has been satisfied.
T0
T1
T2
T3
T4
T5
T6
T7
Tm
/CK
CK
A10 = 1
Posted
WRIT
Command
NOP
ACT
DQS, /DQS
tWR
WL = RL –1 = 2
in0
DQ
in1
in2
tRP
in3
tRC (min.)
Completion of the burst write
Auto precharge begins
Burst Write with Auto Precharge (tRC Limit) (WL = 2, tWR =2)
T0
T3
T4
T5
T6
T7
T8
T9
T10
T11
/CK
CK
Command
A10 = 1
Posted
WRIT
NOP
NOP
ACT
DQS, /DQS
tWR (min.)
WL = RL –1 = 4
in0
DQ
in1
in2
tRP (min.)
in3
tRC
Completion of the burst write
Auto precharge begins
Burst Write with Auto Precharge (tWR + tRP) (WL = 4, tWR =2, tRP=3)
Data Sheet E1950E11 (Ver.1.1)
60
EDE2108AEBG
T0
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
T13
CK
/CK
A10 = 1
Command
NOP
WRIT
ACT
DQS, /DQS
WL = RL 1 = 4
tWR
in0
DQ
in1
in2
in3
in4
in5
in6
tRP
in7
tRC
Auto precharge begins
Burst Write with Auto Precharge Followed by an Activation to the Same Bank
(WL = 4, BL = 8, tWR = 2, tRP = 3)
Data Sheet E1950E11 (Ver.1.1)
61
EDE2108AEBG
Refresh Requirements
DDR2 SDRAM requires a refresh of all rows in any rolling 64ms interval. Each refresh is generated in one of two
ways by an explicit automatic refresh command, or by an internally timed event in self-refresh mode. Dividing the
number of device rows into the rolling 64 ms interval defines the average refresh interval, tREFI, which is a guideline
to controllers for distributed refresh timing.
Automatic Refresh Command [REF]
When /CS, /RAS and /CAS are held low and /WE high at the rising edge of the clock, the chip enters the automatic
refresh mode (REF). All banks of the DDR2 SDRAM must be precharged and idle for a minimum of the precharge
time (tRP) before the auto-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 auto-refresh command (REF) and the next activate command or subsequent auto-refresh command
must be greater than or equal to the auto-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 8 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.
T0
T1
T2
T3
/CK
CK
VIH
≥ tRP
CKE
Command
PRE
≥ tRFC
≥ tRFC
NOP
REF
REF
Automatic Refresh Command
Data Sheet E1950E11 (Ver.1.1)
62
NOP
Any
Command
EDE2108AEBG
Self-Refresh Command [SELF]
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.
When the DDR2 SDRAM has entered self-refresh mode all of the external signals except CKE, are “don’t care”.
The clock is internally disabled during self-refresh operation to save power. 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. Once self-refresh exit command is registered,
a delay equal or longer than the tXSNR or tXSRD must be satisfied before a valid command can be issued to the
device. CKE must remain high for the entire self-refresh exit period tXSRD for proper operation. NOP or deselect
commands must be registered on each positive clock edge during the self-refresh exit interval. ODT should also be
turned off during tXSRD.
T0
T1
T2
T3
T4
T5
T6
Tm
Tn
tCK
tCH tCL
/CK
CK
≥ tXSNR
tRP*
≥ tXSRD
CKE
tIS
tIS
tAOFD
ODT
tIS
tIS tIH
Comand
SELF
NOP
NOP
NOP
Valid
Notes: 1. Device must be in the “All banks idle” state prior to entering self refresh mode.
2. ODT must be turned off tAOFD before entering self refresh mode, and can be turned on again
when tXSRD timing is satisfied.
3. tXSRD is applied for a read or a read with autoprecharge command.
4. tXSNR is applied for any command except a read or a read with autoprecharge command.
Self-Refresh Command
Data Sheet E1950E11 (Ver.1.1)
63
EDE2108AEBG
Power-Down [PDEN]
Power-down is synchronously entered when CKE is registered low (along with NOP or deselect command). CKE is
not allowed to go low while mode register or extended mode register command time, or read or write operation is in
progress. CKE is allowed to go low while any of other operations such as row activation, precharge or auto
precharge, or auto-refresh is in progress, but power-down IDD spec will not be applied until finishing those
operations. Timing diagrams are shown in the following pages with details for entry into power-down.
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 idle, this mode is referred to as precharge power-down; if power-down
occurs when there is a row active in any bank, this mode is referred to as active power-down. Entering power-down
deactivates the input and output buffers, excluding CK, /CK, ODT and CKE. Also the DLL is disabled upon entering
precharge power-down or slow exit active power-down, but the DLL is kept enabled during fast exit active powerdown. In power-down mode, CKE low and a stable clock signal must be maintained at the inputs of the DDR2
SDRAM, and ODT should be in a valid state but all other input signals are “Don’t Care”. CKE low must be
maintained until tCKE has been satisfied. 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). CKE high must be maintained until tCKE has been satisfied. A valid, executable command can be
applied with power-down exit latency, tXP, tXARD, or tXARDS, after CKE goes high. Power-down exit latency is
defined at AC Characteristics table of this data sheet.
CK
/CK
tIS tIH
tIS tIH
VALID
NOP
tIH
tIS
tIH
tIS tIH
CKE
Command
NOP
tCKE min
VALID
VALID
VALID
tXP, tXARD,
tXARDS
tCKE min
Enter power-down mode
VIH or VIL
Exit power-down mode
Power-Down
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
/CK
CK
Command
Read operation starts with a read command and
CKE should be kept high until the end of burst operation.
READ
VIH
CKE
DQS
/DQS
AL + CL
DQ
T0
Command
T1
T2
Tx
out
0
Tx+1
out
1
out
2
Tx+2
out
3
BL=4
Tx+3
READ
Tx+4
Tx+5
Tx+6
Tx+7
Tx+8
Tx+9
CKE should be kept high until the end of burst operation.
VIH
CKE
DQS
/DQS
AL + CL
DQ
out
0
out out
1
2
out
3
out
4
Data Sheet E1950E11 (Ver.1.1)
64
out out
5
6
out
7
BL=8
EDE2108AEBG
Read with Auto Precharge 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
/CK
CK
Command
READA
PRE
AL + BL/2
with tRTP = 7.5ns
and tRAS min. satisfied
BL=4
CKE
CKE should be kept high
until the end of burst operation.
DQS
/DQS
AL + CL
DQ
T0
T1
T2
Tx
out
0
out
1
Tx+1
out
2
Tx+2
out
3
Tx+3
Tx+4
Tx+5
Tx+6
Tx+7
Tx+8
Tx+9
Start internal precharge
Command
READA
BL=8
AL + BL/2
with tRTP = 7.5ns
and tRAS min. satisfied
PRE
CKE should be kept high
until the end of burst operation.
CKE
DQS
/DQS
AL + CL
DQ
out
0
out
1
out
2
out
3
out
4
out out
5
6
out
7
Write 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
/CK
CK
Command
WRIT
CKE
tWTR
DQS
/DQS
WL
in
0
DQ
T0
Command
T1
Tm
in
1
Tm+1
in
2
in
3
BL=4
Tm+2 Tm+3
Tm+4 Tm+5
Tx
Tx+1
Tx+2
Tx+3
Tx+4
WRIT
CKE
tWTR
DQS
/DQS
DQ
WL
in
0
in
1
in
2
in
3
in
4
in
5
Data Sheet E1950E11 (Ver.1.1)
65
in
6
in
7
BL=8
EDE2108AEBG
Write with Auto Precharge 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
/CK
CK
Command
WRITA
PRE
CKE
WR*1
DQS
/DQS
WL
in
0
DQ
T0
T1
Tm
in
1
Tm+1
in
2
BL=4
in
3
Tm+2
Tm+3
Tm+4
Tm+5
Tx
Tx+1
Tx+2
Tx+3
Tx+4
/CK
CK
Command
WRITA
CKE
DQS
/DQS
DQ
PRE
WR*1
WL
in
0
in
1
in
2
in
3
in
4
in
5
in
6
in
7
BL=8
Note: 1. WR is programmed through MRS
Data Sheet E1950E11 (Ver.1.1)
66
EDE2108AEBG
Refresh command to Power-Down Entry
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
/CK
CK
Command
REF
CKE can go to low one clock after an auto-refresh command
CKE
Active command to power-down entry
Command
ACT
CKE can go to low one clock after an active command
CKE
Precharge/Precharge all command to power-down entry
Command
PRE or
PALL
CKE can go to low one clock after a precharge or precharge all command
CKE
MRS/EMRS command to power-down entry
Command
MRS or
EMRS
CKE
tMRD
Data Sheet E1950E11 (Ver.1.1)
67
EDE2108AEBG
Asynchronous CKE Low Event
DRAM requires CKE to be maintained high for all valid operations as defined in this data sheet. If CKE
asynchronously drops low during any valid operation DRAM is not guaranteed to preserve the contents of array. If
this event occurs, memory controller must satisfy DRAM timing specification tDELAY before 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
(steps 4 through 13) as described in initialization sequence. DRAM is ready for normal operation after the
initialization sequence. See AC Characteristics table for tDELAY specification
Stable clocks
tCK
/CK
CK
tDELAY
CKE
CKE asynchronously
drops low
Clocks can be
turned off after
this point
Data Sheet E1950E11 (Ver.1.1)
68
EDE2108AEBG
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 and soon. During
DLL relock period, ODT must remain off. After the DLL lock time, the DRAM is ready to operate with new clock
frequency.
Clock Frequency Change in Precharge Power-Down Mode
T0
T1
T2
NOP
NOP
T4
Tx
Tx+1
Ty
Ty+1
Ty+2 Ty+3
Ty+4
Tz
/CK
CK
Command
CKE
NOP
NOP
Frequency change
occurs here
DLL
RESET
NOP
Valid
200 clocks
ODT
tRP
tXP
tAOFD
ODT is off during
DLL RESET
Minmum 2 clocks
required before
changing frequency
Stable new clock
before power down exit
Burst Interruption
Interruption of a burst read or write cycle is prohibited.
No Operation Command [NOP]
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 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.
Deselect Command [DESL]
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.
Data Sheet E1950E11 (Ver.1.1)
69
EDE2108AEBG
Package Drawing
60-ball FBGA
Solder ball: Lead free (Sn-Ag-Cu)
Unit: mm
9.0 ± 0.1
0.2 S B
9.5 ± 0.1
INDEX MARK
0.2 S A
0.2 S
1.20 max.
S
0.35 ± 0.05
0.1 S
M S A B
0.8
B
8.0
A
INDEX MARK
1.6
6.4
0.8
ECA-TS2-0433-01
Data Sheet E1950E11 (Ver.1.1)
70
EDE2108AEBG
Recommended Soldering Conditions
Please consult with our sales offices for soldering conditions of the EDE2108AEBG.
Type of Surface Mount Device
EDE2108AEBG: 60-ball FBGA < Lead free (Sn-Ag-Cu) >
Data Sheet E1950E11 (Ver.1.1)
71
EDE2108AEBG
NOTES FOR CMOS DEVICES
1
PRECAUTION AGAINST ESD FOR MOS DEVICES
Exposing the MOS devices to a strong electric field can cause destruction of the gate
oxide and ultimately degrade the MOS devices operation. Steps must be taken to stop
generation of static electricity as much as possible, and quickly dissipate it, when once
it has occurred. Environmental control must be adequate. When it is dry, humidifier
should be used. It is recommended to avoid using insulators that easily build static
electricity. MOS devices must be stored and transported in an anti-static container,
static shielding bag or conductive material. All test and measurement tools including
work bench and floor should be grounded. The operator should be grounded using
wrist strap. MOS devices must not be touched with bare hands. Similar precautions
need to be taken for PW boards with semiconductor MOS devices on it.
2
HANDLING OF UNUSED INPUT PINS FOR CMOS DEVICES
No connection for CMOS devices input pins can be a cause of malfunction. If no
connection is provided to the input pins, it is possible that an internal input level may be
generated due to noise, etc., hence causing malfunction. CMOS devices behave
differently than Bipolar or NMOS devices. Input levels of CMOS devices must be fixed
high or low by using a pull-up or pull-down circuitry. Each unused pin should be connected
to VDD or GND with a resistor, if it is considered to have a possibility of being an output
pin. The unused pins must be handled in accordance with the related specifications.
3
STATUS BEFORE INITIALIZATION OF MOS DEVICES
Power-on does not necessarily define initial status of MOS devices. Production process
of MOS does not define the initial operation status of the device. Immediately after the
power source is turned ON, the MOS devices with reset function have not yet been
initialized. Hence, power-on does not guarantee output pin levels, I/O settings or
contents of registers. MOS devices are not initialized until the reset signal is received.
Reset operation must be executed immediately after power-on for MOS devices having
reset function.
CME0107
Data Sheet E1950E11 (Ver.1.1)
72
EDE2108AEBG
The information in this document is subject to change without notice. Before using this document, confirm that this is the latest version.
No part of this document may be copied or reproduced in any form or by any means without the prior
written consent of Elpida Memory, Inc.
Elpida Memory, Inc. does not assume any liability for infringement of any intellectual property rights
(including but not limited to patents, copyrights, and circuit layout licenses) of Elpida Memory, Inc. or
third parties by or arising from the use of the products or information listed in this document. No license,
express, implied or otherwise, is granted under any patents, copyrights or other intellectual property
rights of Elpida Memory, Inc. or others.
Descriptions of circuits, software and other related information in this document are provided for
illustrative purposes in semiconductor product operation and application examples. The incorporation of
these circuits, software and information in the design of the customer's equipment shall be done under
the full responsibility of the customer. Elpida Memory, Inc. assumes no responsibility for any losses
incurred by customers or third parties arising from the use of these circuits, software and information.
[Product applications]
Be aware that this product is for use in typical electronic equipment for general-purpose applications.
Elpida Memory, Inc. makes every attempt to ensure that its products are of high quality and reliability.
However, this product is not intended for use in the product in aerospace, aeronautics, nuclear power,
combustion control, transportation, traffic, safety equipment, medical equipment for life support, or other
such application in which especially high quality and reliability is demanded or where its failure or
malfunction may directly threaten human life or cause risk of bodily injury. Customers are instructed to
contact Elpida Memory's sales office before using this product for such applications.
[Product usage]
Design your application so that the product is used within the ranges and conditions guaranteed by
Elpida Memory, Inc., including the maximum ratings, operating supply voltage range, heat radiation
characteristics, installation conditions and other related characteristics. Elpida Memory, Inc. bears no
responsibility for failure or damage when the product is used beyond the guaranteed ranges and
conditions. Even within the guaranteed ranges and conditions, consider normally foreseeable failure
rates or failure modes in semiconductor devices and employ systemic measures such as fail-safes, so
that the equipment incorporating Elpida Memory, Inc. products does not cause bodily injury, fire or other
consequential damage due to the operation of the Elpida Memory, Inc. product.
[Usage environment]
Usage in environments with special characteristics as listed below was not considered in the design.
Accordingly, our company assumes no responsibility for loss of a customer or a third party when used in
environments with the special characteristics listed below.
Example:
1) Usage in liquids, including water, oils, chemicals and organic solvents.
2) Usage in exposure to direct sunlight or the outdoors, or in dusty places.
3) Usage involving exposure to significant amounts of corrosive gas, including sea air, CL 2 , H 2 S, NH 3 ,
SO 2 , and NO x .
4) Usage in environments with static electricity, or strong electromagnetic waves or radiation.
5) Usage in places where dew forms.
6) Usage in environments with mechanical vibration, impact, or stress.
7) Usage near heating elements, igniters, or flammable items.
If you export the products or technology described in this document that are controlled by the Foreign
Exchange and Foreign Trade Law of Japan, you must follow the necessary procedures in accordance
with the relevant laws and regulations of Japan. Also, if you export products/technology controlled by
U.S. export control regulations, or another country's export control laws or regulations, you must follow
the necessary procedures in accordance with such laws or regulations.
If these products/technology are sold, leased, or transferred to a third party, or a third party is granted
license to use these products, that third party must be made aware that they are responsible for
compliance with the relevant laws and regulations.
M01E1007
Data Sheet E1950E11 (Ver.1.1)
73