Eorex EM428M1684RBA-75FE 256mb (4mã 4bankã 16) double data rate sdram Datasheet

eorex
EM42AM1684RBA
Preliminary
256Mb (4M×4Bank×16)
Double DATA RATE SDRAM
Features
Description
• Internal Double-Date-Rate architecture with 2
Accesses per clock cycle.
• Single 2.5V ±0.2V Power Supply
• 2.5V SSTL-2 compatible I/O
• Burst Length (B/L) of 2, 4, 8
• 2,2.5,3 Clock read latency
• Bi-directional,intermittent data strobe(DQS)
• All inputs except data and DM are sampled
at the positive edge of the system clock.
• Data Mask (DM) for write data
• Sequential & Interleaved Burst type available
• Auto Precharge option for each burst accesses
• DQS edge-aligned with data for Read cycles
• DQS center-aligned with data for Write cycles
• DLL aligns DQ & DQS transitions with CLK
transition
• Auto Refresh and Self Refresh
• 8,192 Refresh Cycles / 64ms
The EM42AM1684RBA is high speed Synchronous
graphic RAM fabricated with ultra high performance
CMOS process containing 268,435,456 bits which
organized as 4Meg words x 4 banks by 16 bits.
The 256Mb DDR SDRAM uses a double data rate
architecture to accomplish high-speed operation.
The data path internally prefetches multiple bits and
It transfers the datafor both rising and falling edges
of the system clock.It means the doubled data
bandwidth can be achieved at the I/O pins.
Available packages: FBGA-60B(12mmx10mm).
Ordering Information
Package
Grade
Pb
EM42AM1684RBA-75F
Part No
Organization
16M X 16
133MHz/DDR266 @CL3
Max. Freq
BGA-60B
Commercial
Free
EM42AM1684RBA-6F
16M X 16
166MHz/DDR333 @CL3
BGA-60B
Commercial
Free
* EOREX reserves the right to change products or specification without notice.
Jul. 2006
www.eorex.com
1/19
eorex
Preliminary
EM42AM1684RBA
Pin Assignment
1
2
3
7
8
9
VSSQ
DQ15
VSS
A
VDD
DQ0
VDDQ
DQ14
VDDQ
DQ13
B
DQ2
VSSQ
DQ1
DQ12
VSSQ
DQ11
C
DQ4
VDDQ
DQ3
DQ10
VDDQ
DQ9
D
DQ6
VSSQ
DQ5
DQ8
VSSQ
UDQS
E
LDQS
VDDQ
DQ7
VREF
VSS
UDM
F
LDM
VDD
NC
CLK
/CLK
G
/WE
/CAS
A12
CKE
H
/RAS
/CS
A11
A9
J
BA1
BA0
A8
A7
K
A0
A10/AP
A6
A5
L
A2
A1
A4
VSS
M
VDD
A3
60ball FBGA / (12mm x 10mm x 1.2mm)
Jul. 2006
www.eorex.com
2/19
eorex
Preliminary
EM42AM1684RBA
Pin Description (Simplified)
Pin
Name
45,46
CLK,/CLK
24
/CS
44
CKE
28~32,35~42
A0~A12
26, 27
BA0, BA1
23
/RAS
22
/CAS
21
/WE
16/51
LDQS/UDQS
20/47
LDM/UDM
2, 4, 5, 7, 8, 10,
11, 13, 54, 56, 57,
59, 60, 62, 63, 65
1,18,33/
34,48,66
3, 9, 15, 55.61/
6, 12, 52, 58,64
14,17,19,25,43,
50,53
49
DQ0~DQ15
VDD/VSS
VDDQ/VSSQ
NC/RFU
VREF
Function
(System Clock)
Clock input active on the Positive rising edge except for DQ and
DM are active on both edge of the DQS.
CLK and /CLK are differential clock inputs.
(Chip Select)
/CS enables the command decoder when ”L” and disable the
command decoder when “H”.The new command are overLooked when the command decoder is disabled but previous
operation will still continue.
(Clock Enable)
Activates the CLK when “H” and deactivates when “L”.
When deactivate the clock,CKE low signifies the power down or
self refresh mode.
(Address)
Row address (A0 to A12) and Calumn address (CA0 to CA8) are
multiplexed on the same pin.
CA10 defines auto precharge at Calumn address.
(Bank Address)
Selects which bank is to be active.
(Row Address Strobe)
Latches Row Addresses on the positive rising edge of the CLK with
/RAS “L”. Enables row access & pre-charge.
(Column Address Strobe)
Latches Column Addresses on the positive rising edge of the CLK
with /CAS low. Enables column access.
(Write Enable)
Latches Column Addresses on the positive rising edge of the CLK
with /CAS low. Enables column access.
(Data Input/Output)
Data Inputs and Outputs are synchronized with both edge of DQS.
(Data Input/Output Mask)
DM controls data inputs.LDM corresponds to the data on
DQ0~DQ7.UDM corresponds to the data on DQ8~DQ15.
(Data Input/Output)
Data inputs and outputs are multiplexed on the same pin.
(Power Supply/Ground)
VDD and VSS are power supply pins for internal circuits.
(Power Supply/Ground)
VDDQ and VSSQ are power supply pins for the output buffers.
(No Connection/Reserved for Future Use)
This pin is recommended to be left No Connection on the device.
(Input)
SSTL-2 Reference voltage for input buffer.
Jul. 2006
www.eorex.com
3/19
eorex
EM42AM1684RBA
Preliminary
Absolute Maximum Rating
Symbol
Item
VIN, VOUT
VDD, VDDQ
TOP
TSTG
Rating
Units
Input, Output Voltage
-0.3 ~ +3.6
V
Power Supply Voltage
-0.3 ~ +3.6
Commercial
0 ~ +70
Extended
-25 ~ +85
-55 ~ +150
V
°C
Operating Temperature Range
Storage Temperature Range
°C
PD
Power Dissipation
1
W
IOS
Short Circuit Current
50
mA
Note: 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.
Capacitance (VCC=2.5V, f=1MHz, TA=25°C)
Symbol
Parameter
Min.
CCLK
Clock Capacitance(CLK,/CLK)
Input Capacitance for CKE, Address, /CS,
/RAS, /CAS, /WE
DM,Data&DQS Input/Output Capacitance
CI
CO
Typ.
Max.
Units
2.5
4.0
pF
2.5
4.5
pF
4.0
6.5
pF
Recommended DC Operating Conditions (TA=-0°C ~+70°C)
Symbol
VDD
VDDQ
VREF
VTT
Parameter
Power Supply Voltage
Power Supply Voltage (for I/O Buffer)
I/O Logic high Voltage
Min.
Typ.
Max.
Units
2.3
2.3
1.15
2.5
2.5
1.25
2.7
2.7
1.35
V
V
V
VREF+0.04
V
I/O Termination Voltage
VREF-0.04
VIH
Input Logic High Voltage
VREF+0.18
VDDQ+0.3
V
VIL
Input Logic Low Voltage
-0.3
VREF-0.18
V
Jul. 2006
www.eorex.com
4/19
eorex
EM42AM1684RBA
Preliminary
Recommended DC Operating Conditions
(VDD=2.5V±0.2V, TA=0°C ~ 70°C)
Symbol
Parameter
(Note 1)
Max.
Test Conditions
Burst length=2,
tRC≥tRC(min.), IOL=0mA,
One bank active
-5
-6
-75
110
95
85
Units
IDD1
Operating Current
IDD2P
Precharge Standby Current in
Power Down Mode
CKE≤VIL(max.), tCK=min
4.5
mA
IDD2N
Precharge Standby Current in
Non-power Down Mode
CKE≥VIL(min.), tCK=min,
/CS≥VIH(min.)
Input signals are changed one time
during 2 clks
40
mA
IDD3P
Active Standby Current in
Power Down Mode
CKE≤VIL(max.), tCK=min
15
mA
IDD3N
Active Standby Current in
Non-power Down Mode
45
mA
IDD4
Operating Current (Burst
(Note 2)
Mode)
IDD5
Refresh Current
IDD6
Self Refresh Current
(Note 3)
CKE≥VIH(min.), tCK=min,
/CS≥VIH(min.)
Input signals are changed one time
during 2 clks
READ
tCK ≥ tCK(min.), IOL=0mA,
All banks active
WRITE
100
mA
110
tRC≥ tRFC (min.), All banks active
CKE≤0.2V
mA
160
mA
2
mA
*All voltages referenced to VSS.
Note 1: IDD1 depends on output loading and cycle rates.
Specified values are obtained with the output open.
Input signals are changed only one time during tCK (min.)
Note 2: IDD4 depends on output loading and cycle rates.
Specified values are obtained with the output open.
Input signals are changed only one time during tCK (min.)
Note 3: Min. of tRFC (Auto refresh Row Cycle Times) is shown at AC Characteristics.
Recommended DC Operating Conditions (Continued)
Symbol
Parameter
Test Conditions
IIL
Input Leakage Current
IOL
Output Leakage Current
0≤VI≤VDDQ, VDDQ=VDD
All other pins not under test=0V
0≤VO≤VDDQ, DOUT is disabled
VOH
High Level Output Voltage
IO=-15.2mA
VOL
Low Level Output Voltage
IO=+15.2mA
Jul. 2006
Min.
Max.
Units
-5
+5
uA
-5
+5
uA
VTT+0.76
V
VTT-0.76
V
www.eorex.com
5/19
eorex
EM42AM1684RBA
Preliminary
Block Diagram
Auto/ Self
Refresh Counter
A0
A1
DM
A5
A6
A7
A8
A9
Address Register
A4
Row Decoder
A3
Row Add. Buffer
A2
Memory
Array
Write DQM
Control
Data In
DOi
S/ A & I/ O Gating
A10
A11
Data Out
Col. Decoder
A12
BA0
BA1
Col. Add. Buffer
Mode Register Set
Col Add. Counter
Burst Counter
Timing Register
/CLK
CLK
CKE
/CS
/ RAS
/ CAS
Jul. 2006
/ WE
DM
DQS
www.eorex.com
6/19
eorex
EM42AM1684RBA
Preliminary
AC Operating Test Conditions
(VDD=2.5V±0.2V, TA=0°C ~70°C)
Item
Conditions
Output Reference Level
1.25V/1.25V
Output Load
See diagram as below
Input Signal Level
VREF+0.31V/ VREF-0.31V
Transition Time of Input Signals
1ns
Input Reference Level
VDDQ/2
AC Operating Test Characteristics
(VDD=2.5V±0.2V, TA=0°C ~70°C)
Symbol
-6
Parameter
Min.
Max.
Min.
-7.5
Max.
Units
tDQCK
DQ output access from CLK,/CLK
-0.7
0.7
-0.75
0.75
ns
tDQSCK
DQS output access from CLK,/CLK
-0.6
0.6
-0.75
0.75
ns
tCL,tCH
CL low/high level width
0.45
0.55
0.45
0.55
tCK
6
12
7.5
12
ns
6
12
7.5
12
tCK
tDH,tDS
tDIPW
tHZ,tLZ
tDQSQ
tDQSS
tDSL,tDS
Clock Cycle Time
CL=2
CL=2.5
DQ and DM hold/setup time
DQ and DM input pulse width for
each input
Data out high/low impedance time
from CLK,/CLK
DQS-DQ skew for associated DQ
signal
Write command to first latching DQS
transition
0.5
ns
1.75
1.75
ns
-0.7
0.7
-0.75
0.45
0.75
DQS input valid window
0.75
0.5
1.25
0.75
tWPRES
tWPST
tIH,tIS
tRPRE
Mode Register Set command cycle
time
Write Preamble setup time
Write Preamble
Address/control input hold/setup
time
Read Preamble
1.25
0.35
tCK
21
2
tCK
0
0
ns
0.6
0.4
0.8
Jul. 2006
tCK
0.35
0.4
0.9
ns
ns
H
tMRD
ns
0.45
0.6
1.0
1.1
0.9
tCK
ns
1.1
tCK
www.eorex.com
7/19
eorex
EM42AM1684RBA
Preliminary
AC Operating Test Characteristics (Continued)
(VDD=2.5V±0.2V, TA=0°C ~70°C)
Symbol
tRPST
Parameter
-6
Min.
0.4
Max.
0.6
Min.
0.4
42
70k
45
-75
Max.
0.6
Units
tRC
Read Postamble
Active to Precharge command
period
Active to Active command period
60
65
ns
tRFC
Auto Refresh Row Cycle Time
72
75
ns
tRCD
Active to Read or Write delay
18
20
ns
tRP
Precharge command period
18
20
ns
tRRD
Active bank A to B command period
12
15
ns
tCCD
Column address to column address
delay
1
1
tCK
tCDLR
Last data in to Read command
2.5 tCK- tDQSS
2.5 tCK- tDQSS
tCK
tCDLW
Last data in to Write command
0
0
tCK
2
2
tCK
75
75
ns
tXSRD
Last data in to Precharge command
Exit self Refresh to non-read
command
Exit self Refresh to read command
200
200
ns
tREFI
Average periodic refresh interval
tRAS
tDPL
tXSNR
15.6
Jul. 2006
70k
15.6
tCK
ns
us
www.eorex.com
8/19
eorex
Preliminary
EM42AM1684RBA
Simplified State Diagram
Jul. 2006
www.eorex.com
9/19
eorex
EM42AM1684RBA
Preliminary
1. Command Truth Table
Command
Symbol
Ignore Command
DESL
CKE
n-1 n
/CS
/RAS
/CAS
/WE
BA0,
BA1
A10
A12~A0
H
X
H
X
X
X
X
X
X
No Operation
NOP
H
X
L
H
H
H
X
X
X
Burst Stop
BSTH
H
X
L
H
H
L
X
X
X
Read
READ
H
X
L
H
L
H
V
L
V
Read with Auto Pre-charge
READA
H
X
L
H
L
H
V
H
V
Write
WRIT
H
X
L
H
L
L
V
L
V
Write with Auto Pre-charge
WRITA
H
X
L
L
H
H
V
H
V
Bank Activate
ACT
H
X
L
L
H
H
V
V
V
Pre-charge Select Bank
PRE
H
X
L
L
H
L
V
L
X
Pre-charge All Banks
PALL
H
X
L
L
H
L
X
H
X
Mode Register Set
MRS
H
X
L
L
L
L
L
L
V
H = High level, L = Low level, X = High or Low level (Don't care), V = Valid data input
2. CKE Truth Table
Item
Command
Symbol
CKE
n-1 n
H H
Idle
CBR Refresh Command
REF
Idle
Self Refresh Entry
SELF
Self Refresh
Self Refresh Exit
Idle
Power Down Entry
Power Down
Power Down Exit
L
/CS
/RAS
/CAS
/WE
Addr.
L
L
L
H
X
H
L
L
L
L
L
H
X
H
L
H
H
H
X
L
H
H
X
X
X
X
H
L
X
X
X
X
X
H
X
X
X
X
X
Remark H = High level, L = Low level, X = High or Low level (Don't care)
Jul. 2006
www.eorex.com
10/19
eorex
EM42AM1684RBA
Preliminary
3. Operative Command Table
Current
State
Idle
Row
Active
/CS
/R
/C
/W
Addr.
Command
H
X
X
X
X
DESL
NOP
L
H
H
H
X
NOP
NOP
L
H
H
L
X
TERM
NOP
L
H
L
X
BA/CA/A10
READ/WRIT/BW
L
L
H
H
BA/RA
ACT
L
L
H
L
BA, A10
PRE/PREA
L
L
L
H
REFA
L
L
L
L
MRS
Mode register
H
L
X
H
X
H
X
H
X
Op-Code,
Mode-Add
X
X
NOP
(Note 4)
Auto refresh
DESL
NOP
L
H
H
L
BA/CA/A10
READ/READA
L
H
L
L
BA/CA/A10
WRIT/WRITA
NOP
NOP
Begin read,Latch CA,
Determine auto-precharge
Begin write,Latch CA,
Determine auto-precharge
L
L
H
H
BA/RA
ACT
L
L
H
L
BA/A10
PRE/PREA
L
L
L
H
REFA
ILLEGAL
L
L
L
L
MRS
ILLEGAL
H
L
L
X
H
H
X
H
H
X
H
L
X
Op-Code,
Mode-Add
X
X
X
DESL
NOP
TERM
L
H
L
H
BA/CA/A10
READ/READA
Read
Write
Action
ILLEGAL
(Note 1)
Bank active,Latch RA
(Note 3)
ILLEGAL
(Note 1)
Precharge/Precharge all
NOP(Continue burst to end)
NOP(Continue burst to end)
Terminal burst
Terminate burst,Latch CA,
Begin new read,
L
L
H
H
BA/RA
ACT
Determine Auto-precharge
(Note 1)
ILLEGAL
L
L
L
L
H
L
L
H
PRE/PREA
REFA
Terminate burst, PrecharE
ILLEGAL
L
L
L
L
H
L
L
X
H
H
X
H
H
X
H
L
BA, A10
X
Op-Code,
Mode-Add
X
X
X
L
H
L
H
BA/CA/A10
READ/READA
L
H
L
L
BA/CA/A10
WRIT/WRITA
L
L
H
H
BA/RA
ACT
L
L
H
L
BA, A10
PRE/PREA
L
L
L
L
L
L
H
L
X
Op-Code,
REFA
MRS
MRS
DESL
NOP
TERM
ILLEGAL
NOP(Continue burst to end)
NOP(Continue burst to end)
ILLEGAL
Terminate burst with DM=”H”,Latch
CA,Begin read,Determine
(Note 2)
auto-precharge
Terminate burst,Latch CA,Begin
Jul. 2006
new write, Determine
(Note 2)
auto-precharge
ILLEGAL
(Note 1)
Terminate burst with DM=”H”,
Precharge
ILLEGAL
ILLEGAL
www.eorex.com
11/19
eorex
Preliminary
EM42AM1684RBA
3. Operative Command Table (Continued)
Current
State
Read with
AP
Write with AP
Pre-charging
Row
Activating
/CS
/R
/C
/W
Addr.
Command
H
L
L
L
X
H
H
H
X
H
H
L
X
H
L
X
X
X
BA/CA/A10
BA/RA
DESL
NOP
TERM
READ/WRITE
L
L
H
H
BA/A10
ACT
ILLEGAL
L
L
L
L
H
L
L
H
PRE/PREA
REFA
ILLEGAL
ILLEGAL
L
L
L
L
MRS
ILLEGAL
H
L
L
L
X
H
H
H
X
H
H
L
X
H
L
X
X
X
Op-Code,
Mode-Add
X
X
X
BA/CA/A10
DESL
NOP
TERM
READ/WRITE
L
L
H
H
BA/RA
ACT
ILLEGAL
L
L
L
L
H
L
L
H
PRE/PREA
REFA
ILLEGAL
ILLEGAL
L
L
L
L
MRS
ILLEGAL
H
L
L
L
X
H
H
H
X
H
H
L
X
H
L
X
BA/A10
X
Op-Code,
Mode-Add
X
X
X
BA/CA/A10
DESL
NOP
TERM
READ/WRITE
L
L
H
H
BA/RA
ACT
L
L
L
L
H
L
L
H
PRE/PREA
REFA
L
L
L
L
H
L
L
L
X
H
H
H
X
H
H
L
X
H
L
X
BA/A10
X
Op-Code,
Mode-Add
X
X
X
BA/CA/A10
DESL
NOP
TERM
READ/WRITE
L
L
H
H
BA/RA
ACT
ILLEGAL
L
L
L
L
H
L
L
H
PRE/PREA
REFA
ILLEGAL
ILLEGAL
L
L
L
L
BA/A10
X
Op-Code,
Mode-Add
MRS
ILLEGAL
MRS
Action
NOP(Continue burst to end)
NOP(Continue burst to end)
ILLEGAL
(Note 1)
ILLEGAL
(Note 1)
(Note 1)
NOP(Continue burst to end)
NOP(Continue burst to end)
ILLEGAL
(Note 1)
ILLEGAL
(Note 1)
(Note 1)
NOP(idle after tRP)
NOP(idle after tRP)
NOP
(Note 1)
ILLEGAL
(Note 1)
ILLEGAL
(Note 3)
NOP(idle after tRP)
ILLEGAL
ILLEGAL
NOP(Row active after tRCD)
NOP(Row active after tRCD)
NOP
(Note 1)
ILLEGAL
(Note 1)
(Note 1)
Remark H = High level, L = Low level, X = High or Low level (Don't care), AP = Auto Pre-charge
Jul. 2006
www.eorex.com
12/19
eorex
Preliminary
EM42AM1684RBA
3. Operative Command Table (Continued)
Current State
Write
Recovering
Refreshing
/CS
/R
/C
/W
Addr.
Command
H
L
L
L
X
H
H
H
X
H
H
L
X
H
L
H
X
X
X
BA/CA/A10
DESL
NOP
TERM
READ
L
H
L
L
BA/CA/A10
WRIT/WRITA
L
L
H
H
BA/RA
ACT
ILLEGAL
L
L
L
L
H
L
L
H
PRE/PREA
REFA
ILLEGAL
ILLEGAL
L
L
L
L
MRS
ILLEGAL
H
L
L
L
L
L
L
X
H
H
H
L
L
L
X
H
H
L
H
H
L
X
H
L
X
H
L
H
L
L
L
L
BA/A10
X
Op-Code,
Mode-Add
X
X
X
BA/CA/A10
BA/RA
BA/A10
X
Op-Code,
Mode-Add
DESL
NOP
TERM
READ/WRIT
ACT
PRE/PREA
REFA
MRS
Action
NOP
NOP
NOP
(Note 1)
ILLEGAL
New write, Determine AP
(Note 1)
(Note 1)
NOP(idle after tRP)
NOP(idle after tRP)
NOP
ILLEGAL
ILLEGAL
NOP(idle after tRP)
ILLEGAL
ILLEGAL
Remark H = High level, L = Low level, X = High or Low level (Don't care), AP = Auto Pre-charge
Note 1: ILLEGAL to bank in specified states;
Function may be legal in the bank indicated by Bank Address (BA), depending on the state of
that bank.
Note 2: Must satisfy bus contention, bus turn around, and/or write recovery requirements.
Note 3: NOP to bank precharging or in idle state.May precharge bank indicated by BA.
Note 4: ILLEGAL of any bank is not idle.
Jul. 2006
www.eorex.com
13/19
eorex
EM42AM1684RBA
Preliminary
4. Command Truth Table for CKE
Current State
Self Refresh
Both bank
precharge
power down
All Banks
Idle
Any State Other
than Listed above
CKE
n-1
n
H
X
L
H
L
H
L
H
L
H
L
H
L
L
H
X
L
H
L
H
L
H
L
H
L
H
L
L
H
H
H
L
H
L
H
L
H
L
H
L
L
H
L
H
L
H
/CS
/R
/C
/W
Addr.
X
H
L
L
L
L
X
X
H
L
L
L
L
X
X
H
X
X
H
H
H
L
X
X
X
H
H
H
L
X
X
X
X
X
H
H
L
X
X
X
X
H
H
L
X
X
X
X
X
X
H
L
X
X
X
X
X
H
L
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
L
L
L
L
L
L
L
H
H
H
L
L
L
L
H
H
L
H
L
L
L
H
L
X
H
H
L
L
X
X
X
RA
X
Op-Code
Op-Code
Action
INVALID
Exist Self-Refresh
Exist Self-Refresh
ILLEGAL
ILLEGAL
ILLEGAL
NOP(Maintain self refresh)
INVALID
Exist Power down
Exist Power down
ILLEGAL
ILLEGAL
ILLEGAL
NOP(Maintain Power down)
Refer to function true table
(Note 3)
Enter power down mode
(Note 3)
Enter power down mode
ILLEGAL
ILLEGAL
Row active/Bank active
(Note 3)
Enter self-refresh
Mode register access
Special mode register access
L
X
X
X
X
X
X
Refer to current state
H
H
X
X
X
X
X
Refer to command truth table
Remark: H = High level, L = Low level, X = High or Low level (Don't care)
Notes 1: After CKE’s low to high transition to exist self refresh mode.And a time of tRC(min) has to be
Elapse after CKE’s low to high transition to issue a new command.
Notes 2:CKE low to high transition is asynchronous as if restarts internal clock.
Notes 3:Power down and self refresh can be entered only from the idle state of all banks.
Jul. 2006
www.eorex.com
14/19
eorex
Preliminary
EM42AM1684RBA
Mode Register Definition
Mode Register Set
The mode register stores the data for controlling the various operating modes of DDR SDRAM which
contains addressing mode, burst length, /CAS latency, test mode, DLL reset and various vendor’s specific
opinions. The defaults values of the register is not defined, so the mode register must be written after EMRS
setting for proper DDR SDRAM operation. The mode register is written by asserting low on /CS, /RAS, /CAS,
/WE and BA0 ( The DDR SDRAM should be in all bank precharge with CKE already high prior to writing into
the mode register. ) The state of the address pins A0-A12 in the same cycle as /CS, /RAS, /CAS, /WE and
BA0 going low is written in the mode register. Two clock cycles are requested to complete the write operation
in the mode register. The mode register contents can be changed using the same command and clock cycle
requirements during operating as long as all banks are in the idle state. The mode register is divided into
various fields depending on functionality. The burst length uses A0-A2, addressing mode uses A3, /CAS
latency ( read latency from column address ) uses A4-A6. A7 is used for test mode. A8 is used for DDR reset.
A7 must be set to low for normal MRS operation.
Jul. 2006
www.eorex.com
15/19
eorex
Preliminary
EM42AM1684RBA
Address input for Mode Register Set
Jul. 2006
www.eorex.com
16/19
eorex
Preliminary
EM42AM1684RBA
Burst Type (A3)
Burst Length
2
4
8
A2
A1
A0
Sequential Addressing
X
X
0
01
01
X
X
0
10
10
X
0
0
0123
0123
X
0
1
1230
1032
X
1
0
2301
2301
X
1
1
3012
3210
0
0
0
01234567
01234567
0
0
1
12345670
10325476
0
1
0
23456701
23016745
0
1
1
34567012
32107654
1
0
0
45670123
45670123
1
0
1
56701234
54761032
1
1
0
67012345
67452301
1
1
1
70123456
*Page length is a function of I/O organization and column addressing
Interleave Addressing
76543210
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 disable the DLL for the purpose of debug or evaluation
( upon existing Self Refresh Mode, the DLL is enable automatically. ) Any time the DLL is enabled, 200
clock cycles must occur before a READ command can be issued.
Output Drive Strength
The normal drive strength got all outputs is specified to be SSTL-2, Class II. Some vendors might also
support a weak drive strength option, intended for lighter load and/or point to point environments.
Jul. 2006
www.eorex.com
17/19
eorex
Preliminary
EM42AM1684RBA
Extended Mode Register Set ( EMRS )
The Extended mode register stores the data enabling or disabling DLL. The value of the extended mode
register is not defined, so the extended mode register must be written after power up for enabling or
disabling DLL. The extended mode register is written by asserting low on /CS, /RAS, /CAS, /WE and high on
BA0 ( The DDR SDRAM should be in all bank precharge with CKE already prior to writing into the extended
mode register. ) The state of address pins A0-A10 and BA1 in the same cycle as /CS, /RAS, /CAS, and /WE
going low is written in the extended mode register. The mode register contents can be changed using the
same command and clock cycle requirements during operation as long as all banks are in the idle state. A0
is used for DLL enable or disable. High on BA0 is used for EMRS. All the other address pins except A0 and
BA0 must be set to low for proper EMRS operation.
Jul. 2006
www.eorex.com
18/19
eorex
Preliminary
EM42AM1684RBA
Package Description
(60 balls; 0.8mmx1.0mm Pitch; FBGA Package)
Jul. 2006
www.eorex.com
19/19
Similar pages