W94AD6KB / W94AD2KB

W94AD6KB / W94AD2KB
1Gb Mobile LPDDR
Table of Contents1.
2.
3.
4.
GENERAL DESCRIPTION ................................................................................................................................. 4
FEATURES ........................................................................................................................................................ 4
ORDER INFORMATION .................................................................................................................................... 5
BALL CONFIGURATION .................................................................................................................................... 6
4.1
Ball Assignment: LPDDR x16 ............................................................................................................... 6
4.2
Ball Assignment: LPDDR x32 ............................................................................................................... 6
5. BALL DESCRIPTION ......................................................................................................................................... 7
5.1
Signal Descriptions ............................................................................................................................... 7
5.2
Addressing Table.................................................................................................................................. 8
6. BLOCK DIAGRAM.............................................................................................................................................. 9
6.1
Block Diagram ...................................................................................................................................... 9
6.2
Simplified State Diagram .................................................................................................................... 10
7. FUNCTIONAL DESCRIPTION ......................................................................................................................... 11
7.1
Initialization ......................................................................................................................................... 11
7.1.1
Initialization Flow Diagram.................................................................................................... 12
7.1.2
Initialization Waveform Sequence ........................................................................................ 13
7.2
Mode Register Set Operation ............................................................................................................. 13
7.3
Mode Register Definition .................................................................................................................... 14
7.3.1
Burst Length ......................................................................................................................... 14
7.3.2
Burst Definition ..................................................................................................................... 15
7.3.3
Burst Type ............................................................................................................................ 16
7.3.4
Read Latency ....................................................................................................................... 16
7.4
Extended Mode Register Description ................................................................................................. 16
7.4.1
Extended Mode Register Definition ...................................................................................... 17
7.4.2
Partial Array Self Refresh ..................................................................................................... 17
7.4.3
Automatic Temperature Compensated Self Refresh ............................................................ 17
7.4.4
Output Drive Strength ........................................................................................................... 17
7.5
Status Register Read ......................................................................................................................... 18
7.5.1
SRR Register Definition........................................................................................................ 18
7.5.2
Status Register Read Timing Diagram ................................................................................. 19
7.6
Commands ......................................................................................................................................... 20
7.6.1
Basic Timing Parameters for Commands ............................................................................. 20
7.6.2
Truth Table – Commands.................................................................................................. 20
7.6.3
Truth Table - DM Operations ................................................................................................ 21
7.6.4
Truth Table – CKE............................................................................................................. 21
7.6.5
Truth Table - Current State Bank n - Command to Bank n ................................................... 22
7.6.6
Truth Table - Current State Bank n, Command to Bank m ................................................... 23
8. OPERATION .................................................................................................................................................... 25
8.1
Deselect ............................................................................................................................................. 25
8.2
No Operation ...................................................................................................................................... 25
8.2.1
NOP Command .................................................................................................................... 25
8.3
Mode Register Set .............................................................................................................................. 26
8.3.1
Mode Register Set Command .............................................................................................. 26
8.3.2
Mode Register Set Command Timing................................................................................... 26
Publication Release Date: Oct. 02, 2014
Revision: A01-005
-1-
W94AD6KB / W94AD2KB
8.4
Active.................................................................................................................................................. 27
8.4.1
Active Command .................................................................................................................. 27
8.4.2
Bank Activation Command Cycle ......................................................................................... 28
8.5
Read ................................................................................................................................................... 28
8.5.1
Read Command ................................................................................................................... 28
8.5.2
Basic Read Timing Parameters ............................................................................................ 29
8.5.3
Read Burst Showing CAS Latency ....................................................................................... 30
8.5.4
Read to Read ....................................................................................................................... 30
8.5.5
Consecutive Read Bursts ..................................................................................................... 30
8.5.6
Non-Consecutive Read Bursts ............................................................................................. 31
8.5.7
Random Read Bursts ........................................................................................................... 32
8.5.8
Read Burst Terminate .......................................................................................................... 32
8.5.9
Read to Write ....................................................................................................................... 33
8.5.10 Read to Precharge ............................................................................................................... 34
8.5.11 Burst Terminate of Read ...................................................................................................... 35
8.6
Write ................................................................................................................................................... 35
8.6.1
Write Command ................................................................................................................... 35
8.6.2
Basic Write Timing Parameters ............................................................................................ 36
8.6.3
Write Burst (min. and max. tDQSS) ...................................................................................... 37
8.6.4
Write to Write........................................................................................................................ 37
8.6.5
Concatenated Write Bursts................................................................................................... 38
8.6.6
Non-Concatenated Write Bursts ........................................................................................... 38
8.6.7
Random Write Cycles ........................................................................................................... 39
8.6.8
Write to Read ....................................................................................................................... 39
8.6.9
Non-Interrupting Write to Read ............................................................................................. 39
8.6.10 Interrupting Write to Read .................................................................................................... 40
8.6.11 Write to Precharge ............................................................................................................... 40
8.6.12 Non-Interrupting Write to Precharge ..................................................................................... 40
8.6.13 Interrupting Write to Precharge ............................................................................................ 41
8.7
Precharge ........................................................................................................................................... 41
8.7.1
Precharge Command ........................................................................................................... 42
8.8
Auto Precharge................................................................................................................................... 42
8.9
Refresh Requirements........................................................................................................................ 42
8.10 Auto Refresh ...................................................................................................................................... 43
8.10.1 Auto Refresh Command ....................................................................................................... 43
8.10.2 Auto Refresh Cycles Back-to-Back ...................................................................................... 43
8.11 Self Refresh ........................................................................................................................................ 44
8.11.1 Self Refresh Command ........................................................................................................ 44
8.11.2 Self Refresh Entry and Exit .................................................................................................. 45
8.12 Power Down ....................................................................................................................................... 46
8.12.1 Power-Down Entry and Exit .................................................................................................. 46
8.13 Deep Power Down.............................................................................................................................. 47
8.13.1 Deep Power-Down Entry and Exit ........................................................................................ 47
8.14 Clock Stop .......................................................................................................................................... 48
8.14.1 Clock Stop Mode Entry and Exit ........................................................................................... 48
9. ELECTRICAL CHARACTERISTICS................................................................................................................. 49
9.1
Absolute Maximum Ratings ................................................................................................................ 49
Publication Release Date: Oct. 02, 2014
Revision: A01-005
-2-
W94AD6KB / W94AD2KB
9.2
9.3
Input / Output Capacitance ................................................................................................................. 49
Electrical Characteristics and AC/DC Operating Conditions ............................................................... 50
9.3.1
Electrical Characteristics and AC/DC Operating Conditions ................................................. 50
9.4
DC Characteristics.............................................................................................................................. 51
9.4.1
IDD Specification and Test Conditions (x16) ........................................................................ 51
9.4.2
IDD Specification and Test Conditions (x32) ........................................................................ 52
9.5
AC Characteristics and Operating Condition ...................................................................................... 54
9.5.1
CAS Latency Definition (With CL = 3) .................................................................................. 56
9.5.2
Output Slew Rate Characteristics ......................................................................................... 57
9.5.3
AC Overshoot/Undershoot Specification .............................................................................. 57
9.5.4
AC Overshoot and Undershoot Definition............................................................................. 57
10. PACKAGE DIMENSIONS ................................................................................................................................ 58
10.1 LPDDR x16 ........................................................................................................................................ 58
10.2 LPDDR x32 ........................................................................................................................................ 59
11. REVISION HISTORY ....................................................................................................................................... 60
Publication Release Date: Oct. 02, 2014
Revision: A01-005
-3-
W94AD6KB / W94AD2KB
1. GENERAL DESCRIPTION
W94AD6KB / W94AD2KB is a high-speed Low Power double data rate synchronous dynamic random
access memory (LPDDR SDRAM), An access to the LPDDR SDRAM is burst oriented. Consecutive
memory location in one page can be accessed at a burst length of 2, 4, 8 and 16 when a bank and
row is selected by an ACTIVE command. Column addresses are automatically generated by the
LPDDR SDRAM internal counter in burst operation. Random column read is also possible by providing
its address at each clock cycle. The multiple bank nature enables interleaving among internal banks to
hide the pre-charging time. By setting programmable Mode Registers, the system can change burst
length, latency cycle, interleave or sequential burst to maximize its performance. The device supports
special low power functions such as Partial Array Self Refresh (PASR) and Automatic Temperature
Compensated Self Refresh (ATCSR).
2. FEATURES
 VDD = 1.7~1.95V
 Differential clock inputs (CK and CK )
 VDDQ = 1.7~1.95V
 Bidirectional, data strobe (DQS)
 Data width: x16 / x32
 CAS Latency: 2 and 3
 Clock rate: 200MHz (-5),166MHz (-6)
 Burst Length: 2, 4, 8 and 16
 Standard Self Refresh Mode
 Burst Type: Sequential or Interleave
 Partial Array Self-Refresh(PASR)
 64 ms Refresh period
 Auto Temperature Compensated Self Refresh
(ATCSR)
 Interface: LVCMOS compatible
 Support package:
 Power Down Mode
 Deep Power Down Mode (DPD Mode)
60 balls VFBGA (x16)
 Programmable output buffer driver strength
90 balls VFBGA (x32)
 Operating Temperature Range
 Four internal banks for concurrent operation
 Data mask (DM) for write data
Extended: -25°C ~ +85°C
 Clock Stop capability during idle periods
Industrial: -40°C ~ +85°C
 Auto Pre-charge option for each burst access
 Double data rate for data output
Publication Release Date: Oct. 02, 2014
Revision: A01-005
-4-
W94AD6KB / W94AD2KB
3. ORDER INFORMATION
PART NUMBER
VDD/VDDQ
I/O WIDTH
TYPE
OTHERS
W94AD6KBHX5I
1.8V/1.8V
16
60VFBGA
200MHz, -40°C~85°C
W94AD6KBHX5E
1.8V/1.8V
16
60VFBGA
200MHz, -25°C~85°C
W94AD2KBJX5I
1.8V/1.8V
32
90VFBGA
200MHz, -40°C~85°C
W94AD2KBJX5E
1.8V/1.8V
32
90VFBGA
200MHz, -25°C~85°C
W94AD6KBHX6I
1.8V/1.8V
16
60VFBGA
166MHz, -40°C~85°C
W94AD6KBHX6E
1.8V/1.8V
16
60VFBGA
166MHz, -25°C~85°C
W94AD2KBJX6I
1.8V/1.8V
32
90VFBGA
166MHz, -40°C~85°C
W94AD2KBJX6E
1.8V/1.8V
32
90VFBGA
166MHz, -25°C~85°C
Publication Release Date: Oct. 02, 2014
Revision: A01-005
-5-
W94AD6KB / W94AD2KB
4. BALL CONFIGURATION
4.1 Ball Assignment: LPDDR x16
A
B
C
D
E
F
1
VSS
VDDQ
VSSQ
VDDQ
VSSQ
VSS
2
DQ15
DQ13
DQ11
DQ9
UDQS
UDM
G
CKE
CK
H
A9
J
K
A6
VSS
60 BALL VFBGA
3
4 5 6
VSSQ
DQ14
DQ12
DQ10
DQ8
NC
7
VDDQ
DQ1
DQ3
DQ5
DQ7
A13
8
DQ0
DQ2
DQ4
DQ6
LDQS
LDM
9
VDD
VSSQ
VDDQ
VSSQ
VDDQ
VDD
CK
WE
CAS
RAS
A11
A12
CS
BA0
BA1
A7
A4
A8
A5
A10/AP
A2
A0
A3
A1
VDD
(Top View) Ball Configuration
4.2
Ball Assignment: LPDDR x32
A
B
C
D
E
F
1
VSS
VDDQ
VSSQ
VDDQ
VSSQ
VDD
2
DQ31
DQ29
DQ27
DQ25
DQS3
DM3
G
CKE
CK
H
A9
J
K
L
M
N
P
R
A6
A4
VSSQ
VDDQ
VSSQ
VDDQ
VSS
90 BALL VFBGA
3
4 5 6
VSSQ
DQ30
DQ28
DQ26
DQ24
NC
7
VDDQ
DQ17
DQ19
DQ21
DQ23
NC
8
DQ16
DQ18
DQ20
DQ22
DQS2
DM2
9
VDD
VSSQ
VDDQ
VSSQ
VDDQ
VSS
CK
WE
CAS
RAS
A11
A12
CS
BA0
BA1
A7
DM1
DQS1
DQ9
DQ11
DQ13
DQ15
A8
A5
DQ8
DQ10
DQ12
DQ14
VSSQ
A10/AP
A2
DQ7
DQ5
DQ3
DQ1
VDDQ
A0
DM0
DQS0
DQ6
DQ4
DQ2
DQ0
A1
A3
VDDQ
VSSQ
VDDQ
VSSQ
VDD
(Top View) Ball Configuration
Publication Release Date: Oct. 02, 2014
Revision: A01-005
-6-
W94AD6KB / W94AD2KB
5. BALL DESCRIPTION
5.1 Signal Descriptions
SIGNAL NAME
TYPE FUNCTION
A [n:0]
Input
Address
BA0, BA1
Input
Bank Select
DQ0~DQ15 (×16)
DQ0~DQ31 (×32)
I/O
Data Input/
Output
DESCRIPTION
Provide 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 opcode during a MODE
REGISTER SET command.
A10 is used for Auto Pre-charge Select.
Define to which bank an ACTIVE, READ, WRITE or
PRECHARGE command is being applied.
Data bus: Input / Output.
CS enables (registered LOW) and disables (registered
HIGH) the command decoder. All commands are
CS
Input
RAS
Input
CAS
Input
WE
Input
UDM, LDM (x16);
DM0 to DM3 (x32)
CK / CK
Input
Input
Chip Select
masked when CS is registered HIGH. CS provides
for external bank selection on systems with multiple
banks. CS is considered part of the command code.
Row Address RAS , CAS and WE (along with CS ) define the
Strobe
command being entered.
Column
Address
Referred to RAS .
Strobe
Write Enable
Input Mask
Clock Inputs
Referred to RAS .
Input Data Mask: DM is an input mask signal for write
data. Input data is masked when DM is sampled HIGH
along 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.
x16: LDM: DQ0 - DQ7, UDM: DQ8 – DQ15
x32: DM0: DQ0 - DQ7, DM1: DQ8 – DQ15,
DM2: DQ16 – DQ23, DM3: DQ24 – DQ31.
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 .Input
and output data is referenced to the crossing of CK and
CK (both directions of crossing). Internal clock signals
are derived from CK/ CK .
Publication Release Date: Oct. 02, 2014
Revision: A01-005
-7-
W94AD6KB / W94AD2KB
SIGNAL NAME
TYPE FUNCTION
CKE
Input
LDQS,UDQS (x16);
DQS0~DQ3 (x32)
I/O
VDD
VSS
Supply
Supply
VDDQ
Supply
VSSQ
Supply
NC
-
5.2
DESCRIPTION
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
Clock Enable (row ACTIVE in any bank). CKE is synchronous for all
functions except for SELF REFRESH EXIT, which is
achieved asynchronously. Input buffers, excluding CK,
CK and CKE, are disabled during power down and self
refresh mode which are contrived for low standby power
consumption.
Output with read data, input with write data. Edgealigned with read data, centered with write data. Used
to capture write data.
Data Strobe
x16: LDQS: DQ0~DQ7; UDQS: DQ8~DQ15.
x32: DQS0: DQ0~DQ7; DQS1: DQ8~DQ15;
DQS2: DQ16~DQ23; DQS3: DQ24~DQ31.
Power
Power supply for input buffers and internal circuit.
Ground
Ground for input buffers and internal circuit.
Power for I/O Power supply separated from VDD, used for output
Buffer
drivers to improve noise.
Ground for I/O Ground for output drivers.
Buffer
No Connect No internal electrical connection is present.
Addressing Table
Item
1Gb
Number of banks
4
Bank address balls
BA0,BA1
Auto precharge ball
A10/AP
x16
Row addresses
A0-A13
Column addresses
A0-A9
tREFI (µS)
x32
7.8
Row addresses
A0-A12
Column addresses
A0-A9
tREFI (µS)
7.8
Publication Release Date: Oct. 02, 2014
Revision: A01-005
-8-
W94AD6KB / W94AD2KB
6. BLOCK DIAGRAM
6.1 Block Diagram
CK
CK
CLOCK
BUFFER
CKE
CONTROL
CS
RAS
SIGNAL
GENERATOR
COMMAND
CAS
DECODER
COLUMN DECODER
A10
COLUMN DECODER
ROW DECODER
ROW DECODER
WE
CELL ARRAY
BANK #0
MODE
REGISTER
A0
CELL ARRAY
BANK #1
SENSE AMPLIFIER
SENSE AMPLIFIER
ADDRESS
BUFFER
DQ0~15 (x16)
DATA CONTROL
DQ
COLUMN
COUNTER
COUNTER
UDM, LDM (x16)
DM0~3 (x32)
UDQS, LDQS (x16)
DQS0~3 (x32)
COLUMN DECODER
COLUMN DECODER
ROW DECODER
REFRESH
CELL ARRAY
BANK #2
SENSE AMPLIFIER
DQ0~31 (x32)
BUFFER
CIRCUIT
ROW DECODER
An
BA0
BA1
CELL ARRAY
BANK #3
SENSE AMPLIFIER
Publication Release Date: Oct. 02, 2014
Revision: A01-005
-9-
W94AD6KB / W94AD2KB
6.2
Simplified State Diagram
Power
applied
Power
On
Self
Refresh
DPDSX
Deep
Power
Down
Precharge
All Bank
SRR
Read
Read
REFS
REFSX
SRR
DPDS
Idle
All banks
precharged
MRS
MRS
EMRS
Auto
Refresh
REFA
CKEL
CKEH
Precharge
Power
Down
ACT
Active
Power
Down
CKEH
CKEL
Burst
Stop
Row
Active
READ
WRITE
BST
WRITE
READ
WRITEA
WRITE
READA
READ
WRITEA
READA
READ
READA
PRE
WRITE A
PRE
PRE
PRE
Precharge
PREALL
READ A
Automatic Sequence
Command Sequence
ACT=Active
EMRS=Ext. Mode Reg. Set
REFSX=Exit Self Refresh
BST=Burst Terminate
MRS=Mode Register Set
READ=Read w/o Auto Precharge
CKEL=Enter Power-Down
PRE=Precharge
READA=Read with Auto Precharge
CKEH=Exit Power-Down
PREALL=Precharge All Bank WRITE=Write w/o Auto Precharge
DPDS=Enter Deep Power-Down REFA=Auto Refresh
WRITEA=Write with Auto Precharge
DPDSX=Exit Deep Power-Down REFS=Enter Self Refresh
SRR = Status Register Read
Note: Use caution with this diagram.It is indented to provide a floorplan of the possible state transitions and commands
to control them,not alldetails.In particular situations involving more than one bank are not captured in full detall.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 10 -
W94AD6KB / W94AD2KB
7. FUNCTIONAL DESCRIPTION
7.1 Initialization
LPDDR SDRAM must be powered up and initialized in a predefined manner. Operations procedures
other than those specified may result in undefined operation. If there is any interruption to the device
power, the initialization routine should be followed. The steps to be followed for device initialization are
listed below.
The Mode Register and Extended Mode Register do not have default values. If they are not
programmed during the initialization sequence, it may lead to unspecified operation. The clock stop
feature is not available until the device has been properly initialized from Step 1 through 11.
 Step
1: Provide power, the device core power (VDD) and the device I/O power (VDDQ) must be
brought up simultaneously to prevent device latch-up. Although not required, it is
recommended that VDD and VDDQ are from the same power source. Also assert and hold
Clock Enable (CKE) to a LVCMOS logic high level.

Step 2: Once the system has established consistent device power and CKE is driven high, it is safe
to apply stable clock.

Step 3: There must be at least 200μS of valid clocks before any command may be given to the
DRAM. During this time NOP or DESELECT commands must be issued on the command
bus.

Step 4: Issue a PRECHARGE ALL command.

Step 5: Provide NOPs or DESELECT commands for at least tRP time.

Step 6: Issue an AUTO REFRESH command followed by NOPs or DESELECT command for at
least tRFC time. Issue the second AUTO REFRESH command followed by NOPs or
DESELECT command for at least tRFC time. Note as part of the initialization sequence
there must be two Auto Refresh commands issued. The typical flow is to issue them at
Step 6, but they may also be issued between steps 10 and 11.

Step 7: Using the MRS command, program the base mode register. Set the desired operation
modes.

Step 8: Provide NOPs or DESELECT commands for at least tMRD time.

Step 9: Using the MRS command, program the extended mode register for the desired operating
modes. Note the order of the base and extended mode register programmed is not
important.

Step 10: Provide NOP or DESELECT commands for at least tMRD time.

Step 11: The DRAM has been properly initialized and is ready for any valid command.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 11 -
W94AD6KB / W94AD2KB
7.1.1
Initialization Flow Diagram
1
VDD and VDDQ Ramp: CKE must be held high
2
Apply stable clocks
3
Wait at least 200µs with NOP or DESELECT on command bus
4
PRECHARGE ALL
5
Assert NOP or DESELCT for tRP time
6
Issue two AUTO REFRESH commands each followed by
NOP or DESELECT commands for tRFC time
7
Configure Mode Register
8
Assert NOP or DESELECT for tMRD time
9
Configure Extended Mode Register
10
Assert NOP or DESELECT for tMRD time
11
LPDDR SDRAM is ready for any valid command
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 12 -
W94AD6KB / W94AD2KB
7.1.2
Initialization Waveform Sequence
VDD
VDDQ
200µs
tCK
tRP
tRFC
tRFC
tMRD
tMRD
CK
CK
CKE
Command
NOP
PRE
ARF
Address
A10
All
Banks
ARF
MRS
MRS
ACT
CODE
CODE
RA
CODE
CODE
RA
BA0,BA1
BA
BA0 = L
BA1 = L
BA0 = L
BA1 = H
DM
DQ, DQS
(High-Z)
Load
Mode Reg.
VDD / VDDQ powered up
Clock stable
Load
Ext. Mode Reg.
= Don't Care
7.2
Mode Register Set Operation
The Mode Register is used to define the specific mode of operation of the LPDDR SDRAM. This
definition includes the definition of a burst length, a burst type, a CAS latency as shown in the
following figure.
The Mode Register is programmed via the MODE REGISTER SET command (with BA0=0 and
BA1=0) and will retain the stored information until it is reprogrammed, the device goes into Deep
Power Down mode, or the device loses power.
Mode Register bits A0-A2 specify the burst length, A3 the type of burst (sequential or interleave), A4A6 the CAS latency. A logic 0 should be programmed to all the undefined addresses bits to ensure
future compatibility.
The Mode Register must be loaded when all banks are idle and no bursts are in progress, and the
controller must wait the specified time tMRD before initiating any subsequent operation. Violating either
of these requirements will result in unspecified operation.
Reserved states should not be used, as unknown operation or incompatibility with future versions may
result.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 13 -
W94AD6KB / W94AD2KB
7.3
Mode Register Definition
BA1
BA0
An...A7 (see Note 1)
0
0
0 (see Note 2)
A6
0
0
0
0
1
1
1
1
A5
0
0
1
1
0
0
1
1
A4
0
1
0
1
0
1
0
1
CAS Latency
Reserved
Reserved
2
3
Reserved
Reserved
Reserved
Reserved
A6
A5
A4
CAS Latency
A3
0
1
Burst Type
Sequential
Interleave
A3
A2
BT
A1
A0
Burst Length
A2
0
0
0
0
1
1
1
1
A1
0
0
1
1
0
0
1
1
A0
0
1
0
1
0
1
0
1
Address Bus
Mode Register
Burst Length
Reserved
2
4
8
16
Reserved
Reserved
Reserved
NOTE:
1.MSB depends on LPDDR SDRAM density.
2.Alogic 0 should be programmed to all unused / undefined address bits to future compatibility.
7.3.1 Burst Length
Read and write accesses to the LPDDR SDRAM are burst oriented, with the burst length and burst
type being programmable.
The burst length determines the maximum number of column locations that can be accessed for a
given READ or WRITE command. Burst lengths of 2, 4, or 8 locations are available for both the
sequential and the interleaved burst types.
When a READ or WRITE command is issued, a block of columns equal to the burst length is
effectively selected. All accesses for that burst take place within the block, meaning that the burst will
wrap within the block if a boundary is reached.
The block is uniquely selected by A1−An when the burst length is set to two, by A2−An when the burst
length is set to 4, by A3−An when the burst length is set to 8 (where An is the most significant column
address bit for a given configuration). The remaining (least significant) address bit(s) is (are) used to
select the starting location within the block. The programmed burst length applies to both read and
write bursts.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 14 -
W94AD6KB / W94AD2KB
7.3.2
BURST
LENGTH
Burst Definition
STARTING COLUMN
ADDRESS
A3
A2
A1
0
0–1
0–1
1
1–0
1–0
0
0
0–1–2–3
0–1–2–3
0
1
1–2–3–0
1–0–3–2
1
0
2–3–0–1
2–3–0–1
1
1
3–0–1–2
3–2–1–0
0
0
0
0–1–2–3–4–5–6–7
0–1–2–3–4–5–6–7
0
0
1
1–2–3–4–5–6–7–0
1–0–3–2–5–4–7–6
0
1
0
2–3–4–5–6–7–0–1
2–3–0–1–6–7–4–5
0
1
1
3–4–5–6–7–0–1–2
3–2–1–0–7–6–5–4
1
0
0
4–5–6–7–0–1–2–3
4–5–6–7–0–1–2–3
1
0
1
5–6–7–0–1–2–3–4
5–4–7–6–1–0–3–2
1
1
0
6–7–0–1–2–3–4–5
6–7–4–5–2–3–0–1
1
1
1
7–0–1–2–3–4–5–6
7–6–5–4–3–2–1–0
0
0
0
0
0-1-2-3-4-5-6-7-8-9-A-B-C-D-E-F
0-1-2-3-4-5-6-7-8-9-A-B-C-D-E-F
0
0
0
1
1-2-3-4-5-6-7-8-9-A-B-C-D-E-F-0
1-0-3-2-5-4-7-6-9-8-B-A-D-C-F-E
0
0
1
0
2-3-4-5-6-7-8-9-A-B-C-D-E-F-0-1
2-3-0-1-6-7-4-5-A-B-8-9-E-F-C-D
0
0
1
1
3-4-5-6-7-8-9-A-B-C-D-E-F-0-1-2
3-2-1-0-7-6-5-4-B-A-9-8-F-E-D-C
0
1
0
0
4-5-6-7-8-9-A-B-C-D-E-F-0-1-2-3
4-5-6-7-0-1-2-3-C-D-E-F-8-9-A-B
0
1
0
1
5-6-7-8-9-A-B-C-D-E-F-0-1-2-3-4
5-4-7-6-1-0-3-2-D-C-F-E-9-8-B-A
0
1
1
0
6-7-8-9-A-B-C-D-E-F-0-1-2-3-4-5
6-7-4-5-2-3-0-1-E-F-C-D-A-B-8-9
0
1
1
1
7-8-9-A-B-C-D-E-F-0-1-2-3-4-5-6
7-6-5-4-3-2-1-0-F-E-D-C-B-A-9-8
1
0
0
0
8-9-A-B-C-D-E-F-0-1-2-3-4-5-6-7
8-9-A-B-C-D-E-F-0-1-2-3-4-5-6-7
1
0
0
1
9-A-B-C-D-E-F-0-1-2-3-4-5-6-7-8
9-8-B-A-D-C-F-E-1-0-3-2-5-4-7-6
1
0
1
0
A-B-C-D-E-F-0-1-2-3-4-5-6-7-8-9
A-B-8-9-E-F-C-D-2-3-0-1-6-7-4-5
1
0
1
1
B-C-D-E-F-0-1-2-3-4-5-6-7-8-9-A
B-A-9-8-F-E-D-C-3-2-1-0-7-6-5-4
1
1
0
0
C-D-E-F-0-1-2-3-4-5-6-7-8-9-A-B
C-D-E-F-8-9-A-B-4-5-6-7-0-1-2-3
1
1
0
1
D-E-F-0-1-2-3-4-5-6-7-8-9-A-B-C
D-C-F-E-9-8-B-A-5-4-7-6-1-0-3-2
1
1
1
0
E-F-0-1-2-3-4-5-6-7-8-9-A-B-C-D
E-F-C-D-A-B-8-9-6-7-4-5-2-3-0-1
1
1
1
1
F-0-1-2-3-4-5-6-7-8-9-A-B-C-D-E
F-E-D-C-B-A-9-8-7-6-5-4-3-2-1-0
2
4
8
16
A0
ORDER OF ACCESSES WITHIN A BURST
(HEXADECIMAL NOTATION)
SEQUENTIAL
INTERLEAVED
Notes:
1.
2.
3.
4.
For a burst length of two, A1-An selects the two data element block; A0 selects the first access within the block.
For a burst length of four, A2-An selects the four data element block; A0-A1 selects the first access within the block.
For a burst length of eight, A3-An selects the eight data element block; A0-A2 selects the first access within the block.
For the burst length of sixteen, A4-An selects the sixteen data element block; A0-A3 selects the first access within the
block.
5. Whenever a boundary of the block is reached within a given sequence, the following access wraps within the block.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 15 -
W94AD6KB / W94AD2KB
7.3.3 Burst Type
Accesses within a given burst may be programmed to be either sequential or interleaved; this is
referred to as the burst type and is selected via bit A3. The ordering of accesses within a burst is
determined by the burst length, the burst type and the starting column address, as shown in the
previous table.
7.3.4 Read Latency
The CAS latency is the delay between the registration of a READ command and the availability of the
first piece of output data. The latency should be set to 2 or 3 clocks, as shown in section 7.3 Mode
Register Definition figure.
If a READ command is registered at a clock edge n and the latency is 3 clocks, the first data element
will be valid at n + 2 tCK + tAC. If a READ command is registered at a clock edge n and the latency is 2
clocks, the first data element will be valid at n + tCK + tAC.
7.4
Extended Mode Register Description
The Extended Mode Register controls functions beyond those controlled by the Mode Register; these
additional functions include output drive strength selection and Partial Array Self Refresh (PASR).
PASR is effective in Self Refresh mode only.
The Extended Mode Register is programmed via the MODE REGISTER SET command (with BA1=1
and BA0=0) and will retain the stored information until it is reprogrammed, the device is put in Deep
Power Down mode, or the device loses power.
The Extended Mode Register must be loaded when all banks are idle and no bursts are in progress,
and the controller must wait the specified time tMRD before initiating any subsequent operation.
Violating either of these requirements will result in unspecified operation.
Address bits A0-A2 specify PASR, A5-A7 the Driver Strength. A logic 0 should be programmed to all
the undefined addresses bits to ensure future compatibility.
Reserved states should not be used, as unknown operation or incompatibility with future versions may
result.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 16 -
W94AD6KB / W94AD2KB
7.4.1
Extended Mode Register Definition
BA1
BA0
An...A8 (see Note 1)
A7 ~ A5
1
0
0 (see Note 2)
DS
A4
A3
A2
Reserved
A1
A0
Address Bus
PASR
Extended Mode Register
PASR
A7
A6
A5
Drive Strength
A2
A1
A0
0
0
0
Full Strength Driver
0
0
0
All banks
0
0
1
Half Strength Driver
0
0
1
1/2 array (BA1=0)
0
1
0
Quarter Strength Driver
0
1
0
0
1
1
Octant Strength Driver
0
1
1
1
0
Three-Quarters Strength Driver
1
0
0
Reserved
1
0
1
Reserved
0
1/4 array (BA1=BA0=0)
Reserved
1
1
0
Reserved
1
1
1
Reserved
NOTES:
1.MSB depends on mobile DDR SDRAM density.
2.A logic 0 should be programmed to all unused / undefined bits to ensure future compatibility.
7.4.2 Partial Array Self Refresh
With partial array self refresh (PASR), the self refresh may be restricted to a variable portion of the
total array. The whole array (default), 1/2 array, or 1/4 array could be selected. Data outside the
defined area will be lost. Address bits A0 to A2 are used to set PASR.
7.4.3 Automatic Temperature Compensated Self Refresh
The device has an Automatic Temperature Compensated Self Refresh feature. It automatically adjusts
the refresh rate based on the device temperature without any register update needed.
7.4.4 Output Drive Strength
The drive strength could be set to full, half, quarter, octant, and three-quarter strength via address bits
A5, A6 and A7. The half drive strength option is intended for lighter loads or point-to-point
environments.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 17 -
W94AD6KB / W94AD2KB
7.5
Status Register Read
Status Register Read (SRR) is an optional feature in JEDEC, and it is implemented in this device.
With SRR, a method is defined to read registers from the device. The encoding for an SRR command
is the same as a MRS with BA[1:0]=“01”. The address pins (A[n:0]) encode which register is to be read.
Currently only one register is defined at A[n:0]=0. The sequence to perform an SRR command is as
follows:

All reads/writes must be completed

All banks must be closed

MRS with BA=01 is issued (SRR)

Wait tSRR

Read issued to any bank/page

CAS latency cycles later the device returns the registers data as it would a normal read

The next command to the device can be issued tSRC after the Read command was issued.
The burst length for the SRR read is always fixed to length 2.
7.5.1 SRR Register Definition
Default: (A[n:0] = 0)
X~DQ16
DQ15~DQ13 DQ12 DQ11 DQ10~DQ8 DQ7~DQ4 DQ3~DQ0
Density
Reserved
DQ15 DQ14
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
DT
DW
Refresh Rate
Rising Edge of DQ Bus
Revision
Manufacturer
Identification Identification
SRR Register 0
DQ13
Density
DQ3
DQ2
DQ1
DQ0
Manufacturer
0
1
0
1
0
1
0
1
128
256
512
1024
2048
Reserved
Reserved
64
1
0
0
0
Winbond
DQ12
Device Type
DQ11
DW
0
1
LPDDR
Reserved
0
1
16 bits
32 bits
DQ7:4
Revision ID
(See Note 1)
Note 1 : The manufacture’s revision number
starts at ‘0000’ and increments by ‘0001’ each
time a change in the manufacturer’s specification
(AC timings, or feature set), IBIS (pull up or pull
down characteristics), or process occurs.
DQ10
DQ9
DQ8
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Refresh Rate
Reserved
Reserved
Reserved
Reserved
1
0.5
0.25
Reserved
Note 2 : The refresh rate multiplier is based on the memory’s temperature sensor.
Note 3 : Required average periodic refresh interval = tREFI * multiplier.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 18 -
W94AD6KB / W94AD2KB
7.5.2
Status Register Read Timing Diagram
tSRC
tSRR
tRP
CK
CK
Command
CMD
BA1,BA0
An~A0
NOP
MRS
NOP
READ
NOP
NOP
NOP
CMD
01
0
CL=3
DQS
DQ
DQ:Reg out
PCHA, or PCH
= Don’t Care
Notes:
1.
2.
3.
4.
5.
6.
7.
SRR can only be issued after power-up sequence is complete.
SRR can only be issued with all banks precharged.
SRR CL is unchanged from value in the mode register.
SRR BL is fixed at 2.
tSRR = 2 (min).
tSRC = CL + 1; (min time between read to next valid command)
No commands other than NOP and DES are allowed between the SRR and the READ.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 19 -
W94AD6KB / W94AD2KB
7.6
Commands
All commands (address and control signals) are registered on the positive edge of clock (crossing of
CK going high and CK going low).
7.6.1
Basic Timing Parameters for Commands
tCK
tCH
tCL
CK
CK
tIS tIH
Input
Valid
Valid
Valid
= Don't Care
NOTE: Input = A0–An, BA, CKE, CS, RAS, CAS, WE
7.6.2
Truth Table – Commands
NAME (FUNCTION)
CS
RAS CAS
WE
BA
A10/AP ADDR NOTES
DESELECT (NOP)
H
X
X
X
X
X
X
2
NO OPERATION (NOP)
L
H
H
H
X
X
X
2
ACTIVE (Select Bank and activate row)
L
L
H
H
Valid
Row
Row
READ (Select bank and column and start read burst)
L
H
L
H
Valid
L
Col
READ with AP (Read Burst with Auto Precharge)
L
H
L
H
Valid
H
Col
WRITE (Select bank and column and start write burst)
L
H
L
L
Valid
L
Col
WRITE with AP (Write Burst with Auto Precharge)
L
H
L
L
Valid
H
Col
3
BURST TERMINATE
L
H
H
L
X
X
X
4, 5
PRECHARGE (Deactivate row in selected bank)
L
L
H
L
Valid
L
X
6
PRECHARGE ALL (Deactivate rows in all banks)
L
L
H
L
X
H
X
6
AUTO REFRESH or enter SELF REFRESH
L
L
L
H
X
X
X
7, 8, 9
MODE REGISTER SET
L
L
L
L
Valid
Op-code
3
10
Notes:
1. All states and sequences not shown are illegal or reserved.
2. DESELECT and NOP are functionally interchangeable.
3. Auto precharge is non-persistent. A10 High enables Auto precharge, while A10 Low disables Auto precharge.
4. Burst Terminate applies to only Read bursts with Auto precharge disabled. This command is undefined and should not be used
for Read with Auto precharge enabled, and for Write bursts.
5. This command is BURST TERMINATE if CKE is High and DEEP POWER DOWN entry if CKE is Low.
6. If A10 is low, bank address determines which bank is to be precharged. If A10 is high, all banks are precharged and BA0~BA1
are don’t care.
7. This command is AUTO REFRESH if CKE is High and SELF REFRESH if CKE is low.
8. All address inputs and I/O are ‘don’t care’ except for CKE. Internal refresh counters control bank and row addressing.
9. All banks must be precharged before issuing an AUTO-REFRESH or SELF REFRESH command.
10. BA0 and BA1 value select between MRS and EMRS.
11. CKE is HIGH for all commands shown except SELF REFRESH and DEEP POWER-DOWN.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 20 -
W94AD6KB / W94AD2KB
7.6.3
Truth Table - DM Operations
FUNCTION
DM
DQ
NOTES
Write Enable
L
Valid
1
Write Inhibit
H
X
1
Note:
1.
Used to mask write data, provided coincident with the corresponding data.
7.6.4
Truth Table – CKE
CKEn-1
CKEn
CURRENT STATE
COMMAND n
ACTION n
NOTES
L
L
Power Down
X
Maintain Power Down
L
L
Self Refresh
X
Maintain Self Refresh
L
L
Deep Power Down
X
Maintain Deep Power Down
L
H
Power Down
NOP or DESELECT
Exit Power Down
5, 6, 9
L
H
Self Refresh
NOP or DESELECT
Exit Self Refresh
5, 7, 10
L
H
Deep Power Down
NOP or DESELECT
Exit Deep Power Down
5, 8
H
L
All Banks Idle
NOP or DESELECT
Precharge Power Down Entry
5
H
L
Bank(s) Active
NOP or DESELECT
Active Power Down Entry
5
H
L
All Banks Idle
AUTO REFRESH
Self Refresh Entry
H
L
All Banks Idle
BURST TERMINATE
Enter Deep Power Down
H
H
See the other Truth Tables
Notes:
1. CKEn is the logic state of CKE at clock edge n; CKEn-1 was the state of CKE at the previous clock edge.
2. Current state is the state of LPDDR immediately prior to clock edge n.
3. COMMAND n is the command registered at clock edge n, and ACTION n is the result of COMMAND n.
4. All states and sequences not shown are illegal or reserved.
5. DESELECT and NOP are functionally interchangeable.
6. Power Down exit time (tXP) should elapse before a command other than NOP or DESELECT is issued.
7. SELF REFRESH exit time (tXSR) should elapse before a command other than NOP or DESELECT is issued.
8. The Deep Power-Down exit procedure must be followed as discussed in the Deep Power-Down section of the Functional
Description.
9. The clock must toggle at least once during the tXP period.
10. The clock must toggle at least once during the tXSR time.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 21 -
W94AD6KB / W94AD2KB
7.6.5
Truth Table - Current State Bank n - Command to Bank n
CURRENT
CS
STATE
RAS CAS WE
COMMAND
ACTION
NOTES
H
X
X
X
DESELECT
NOP or Continue previous operation
L
H
H
H
No Operation
NOP or Continue previous operation
L
L
H
H
ACTIVE
Select and activate row
L
L
L
H
AUTO REFRESH
Auto refresh
10
L
L
L
L
MRS
Mode register set
10
L
H
L
H
READ
Select column & start read burst
L
H
L
L
WRITE
Select column & start write burst
L
L
H
L
PRECHARGE
Deactivate row in bank or banks
4
L
H
L
H
READ
Select column & start new read burst
5, 6
L
H
L
L
WRITE
Select column & start write burst
5, 6, 13
L
L
H
L
PRECHARGE
Truncate read burst, start precharge
L
H
H
L
BURST TERMINATE
Burst terminate
11
L
H
L
H
READ
Select column & start read burst
5, 6, 12
L
H
L
L
WRITE
Select column & start new write burst
5, 6
L
L
H
L
PRECHARGE
Truncate write burst, start precharge
12
Any
Idle
Row Active
Read (Auto
precharge
Disabled)
Write (Auto
precharge
Disabled)
Notes:
1. The table applies when both CKEn-1 and CKEn are HIGH, and after tXSR or tXP has been met if the previous state was Self
Refresh or Power Down.
2. DESELECT and NOP are functionally interchangeable.
3. All states and sequences not shown are illegal or reserved.
4. This command may or may not be bank specific. If all banks are being precharged, they must be in a valid state for
precharging.
5. A command other than NOP should not be issued to the same bank while a READ or WRITE burst with Auto Precharge is
enabled.
6. The new Read or Write command could be Auto Precharge enabled or Auto Precharge disabled.
7. Current State Definitions:
Idle: The bank has been precharged, and tRP has been met.
Row Active: A row in the bank has been activated, and tRCD has been met. No data bursts/accesses and no register
accesses are in progress.
Read: A READ burst has been initiated, with Auto Precharge disabled, and has not yet terminated or been terminated.
Write: A WRITE burst has been initiated, with Auto Precharge disabled, and has not yet terminated or been terminated.
8. The following states must not be interrupted by a command issued to the same bank. DESEDECT or NOP commands or
allowable commands to the other bank should be issued on any clock edge occurring during these states. Allowable
commands to the other bank are determined by its current state and this table, and according to next table.
Precharging: Starts with the registration of a PRECHARGE command and ends when tRP is met. Once tRP is met, the bank
will be in the idle state.
Row Activating: Starts with registration of an ACTIVE command and ends when t RCD is met. Once tRCD is met, the bank
will be in the ‘row active’ state.
Read with AP Enabled: Starts with the registration of the READ command with Auto Precharge enabled and ends when tRP
has been met. Once tRP has been met, the bank will be in the idle state.
Write with AP Enabled: Starts with registration of a WRITE command with Auto Precharge enabled and ends when tRP has
been met. Once tRP is met, the bank will be in the idle state.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 22 -
W94AD6KB / W94AD2KB
9. The following states must not be interrupted by any executable command; DESEDECT or NOP commands must be applied
to each positive clock edge during these states.
Refreshing: Starts with registration of an AUTO REFRESH command and ends when t RFC is met. Once tRFC is met, the
LPDDR will be in an ‘all banks idle’ state.
Accessing Mode Register: starts with registration of a MODE REGISTER SET command and ends when tMRD has been
met. Once tMRD is met, the LPDDR will be in an ‘all banks idle’ state.
Precharging All: starts with the registration of a PRECHARGE ALL command and ends when tRP is met. Once tRP is met,
the bank will be in the idle state.
10. Not bank-specific; requires that all banks are idle and no bursts are in progress.
11. Not bank-specific. BURST TERMINATE affects the most recent READ burst, regardless of bank.
12. Requires appropriate DM masking.
13. A WRITE command may be applied after the completion of the READ burst; otherwise, a BURST TERMINATE must be
used to end the READ prior to asserting a WRITE command.
7.6.6
Truth Table - Current State Bank n, Command to Bank m
CURRENT
STATE
CS
RAS
CAS
WE
COMMAND
ACTION
NOTES
H
X
X
X
DESELECT
NOP or Continue previous Operation
L
H
H
H
NOP
NOP or Continue previous Operation
X
X
X
X
ANY
Any command allowed to bank m
L
L
H
H
ACTIVE
Select and activate row
L
H
L
H
READ
Select column & start read burst
8
L
H
L
L
WRITE
Select column & start write burst
8
L
L
H
L
PRECHARGE
Precharge
L
L
H
H
ACTIVE
Select and activate row
L
H
L
H
READ
Select column & start new read burst
8
L
H
L
L
WRITE
Select column & start write burst
8,10
L
L
H
L
PRECHARGE
Precharge
L
L
H
H
ACTIVE
Select and activate row
L
H
L
H
READ
Select column & start read burst
8, 9
L
H
L
L
WRITE
Select column & start new write burst
8
L
L
H
L
PRECHARGE
Precharge
L
L
H
H
ACTIVE
Select and activate row
L
H
L
H
READ
Select column & start new read burst
5, 8
L
H
L
L
WRITE
Select column & start write burst
5, 8, 10
L
L
H
L
PRECHARGE
Precharge
L
L
H
H
ACTIVE
Select and activate row
L
H
L
H
READ
Select column & start read burst
5, 8
L
H
L
L
WRITE
Select column & start new write burst
5, 8
L
L
H
L
PRECHARGE
Precharge
Any
Idle
Row Activating,
Active, or
Precharging
Read with Auto
Precharge
disabled
Write with Auto
Precharge
disabled
Read with
Auto Precharge
Write with Auto
Precharge
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 23 -
W94AD6KB / W94AD2KB
Notes:
1. The table applies when both CKEn-1 and CKEn are HIGH, and after tXSR or tXP has been met if the previous state was Self
Refresh or Power Down.
2. DESELECT and NOP are functionally interchangeable.
3. All states and sequences not shown are illegal or reserved.
4. Current State Definitions:
Idle: The bank has been precharged, and tRP has been met.
Row Active: A row in the bank has been activated, and tRCD has been met. No data bursts/accesses and no register
accesses are in progress.
Read: A READ burst has been initiated, with Auto Precharge disabled, and has not yet terminated or been terminated.
Write: A WRITE burst has been initiated, with Auto Precharge disabled, and has not yet terminated or been terminated.
5. Read with AP enabled and Write with AP enabled: The read with Auto Precharge enabled or Write with Auto Precharge
enabled states can be broken into two parts: the access period and the precharge period. For Read with AP, the precharge
period is defined as if the same burst was executed with Auto Precharge disabled and then followed with the earliest
possible PRECHARGE command that still accesses all the data in the burst. For Write with Auto precharge, the precharge
period begins when tWR ends, with tWR measured as if Auto Precharge was disabled. The access period starts with
registration of the command and ends where the precharge period (or tRP) begins. During the precharge period, of the Read
with Auto Precharge enabled or Write with Auto Precharge enabled states, ACTIVE, PRECHARGE, READ, and WRITE
commands to the other bank may be applied; during the access period, only ACTIVE and PRECHARGE commands to the
other banks may be applied. In either case, all other related limitations apply (e.g. contention between READ data and
WRITE data must be avoided).
6. AUTO REFRESH, SELF REFRESH, and MODE REGISTER SET commands may only be issued when all bank are idle.
7. A BURST TERMINATE command cannot be issued to another bank; it applies to the bank represented by the current state
only.
8. READs or WRITEs listed in the Command column include READs and WRITEs with Auto Precharge enabled and READs
and WRITEs with Auto Precharge disabled.
9. Requires appropriate DM masking.
10. A WRITE command may be applied after the completion of data output, otherwise a BURST TERMINATE command must
be issued to end the READ prior to asserting a WRITE command.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 24 -
W94AD6KB / W94AD2KB
8. OPERATION
8.1
Deselect
The DESELECT function ( CS = High) prevents new commands from being executed by the LPDDR
SDRAM. The LPDDR SDRAM is effectively deselected. Operations already in progress are not
affected.
8.2
No Operation
The NO OPERATION (NOP) command is used to perform a NOP to a LPDDR SDRAM that is
selected ( CS = Low). This prevents unwanted commands from being registered during idle or wait
states. Operations already in progress are not affected.
8.2.1
NOP Command
CK
CK
CKE
(High)
CS
RAS
CAS
WE
Address
BA0,BA1
= Don't Care
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 25 -
W94AD6KB / W94AD2KB
8.3
Mode Register Set
The Mode Register and the Extended Mode Register are loaded via the address inputs. The MODE
REGISTER SET command can only be issued when all banks are idle and no bursts are in progress,
and a subsequent executable command cannot be issued until tMRD is met.
8.3.1
Mode Register Set Command
CK
CK
CKE
(High)
CS
RAS
CAS
WE
Address
Code
BA0,BA1
Code
= Don't Care
8.3.2
Mode Register Set Command Timing
CK
CK
Command
MRS
NOP
Valid
tMRD
Address
Code
Valid
= Don't Care
NOTE: Code = Mode Register / Extended Mode Register selection
(BA0, BA1) and op-code (A0-An)
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 26 -
W94AD6KB / W94AD2KB
8.4
Active
Before any READ or WRITE commands can be issued to a bank in the LPDDR SDRAM, a row in that
bank must be opened. This is accomplished by the ACTIVE command: BA0 and BA1 select the bank,
and the address inputs select the row to be activated. More than one bank can be active at any time.
Once a row is open, a READ or WRITE command could be issued to that row, subject to the tRCD
specification.
A subsequent ACTIVE command to another row in the same bank can only be issued after the
previous row has been closed. The minimum time interval between two successive ACTIVE
commands on the same bank is defined by tRC.
A subsequent ACTIVE command to another bank can be issued while the first bank is being
accessed, which results in a reduction of total row-access overhead. The minimum time interval
between two successive ACTIVE commands on different banks is defined by tRRD.
The row remains active until a PRECHARGE command (or READ or WRITE command with Auto
Precharge) is issued to the bank.
A PRECHARGE (or READ with Auto Precharge or Write with Auto Precharge) command must be
issued before opening a different row in the same bank.
8.4.1
Active Command
CK
CK
CKE
(High)
CS
RAS
CAS
WE
Address
BA0,BA1
RA
BA
= Don't Care
BA = Bank Address
RA = Row Address
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 27 -
W94AD6KB / W94AD2KB
8.4.2
Bank Activation Command Cycle
CK
CK
Command
ACT
Address
Row
Row
Col
BA0, BA1
BA x
BA y
BA y
NOP
ACT
NOP
tRRD
NOP
RD/WR
NOP
tRCD
= Don't Care
8.5
Read
The READ command is used to initiate a burst read access to an active row, with a burst length as set
in the Mode Register. BA0 and BA1 select the bank, and the address inputs select the starting column
location. The value of A10 determines whether or not Auto Precharge is used. If Auto Precharge is
selected, the row being accessed will be precharged at the end of the read burst; if Auto Precharge is
not selected, the row will remain open for subsequent accesses.
8.5.1
Read Command
CK
CK
CKE
(High)
CS
RAS
CAS
WE
Address
CA
Enable AP
A10
AP
Disable AP
BA0,BA1
BA
= Don't Care
BA = Bank Address
CA = Column Address
AP = Auto Precharge
The basic Read timing parameters for DQs are shown in following figure; they apply to all Read
operations.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
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W94AD6KB / W94AD2KB
8.5.2
Basic Read Timing Parameters
tCK
tCK
tCH
tCL
CK
CK
tDQSCK
tDQSCK
tACmax
tRPST
tRPRE
DQS
tDQSQmax
tAC
tHZ
DQ
tACmin
DQS
DO n+1
DO n
tLZ
DO n+3
DO n+2
tQH
tQH
tDQSCK
tDQSCK
tRPST
tRPRE
tDQSQmax
tHZ
tAC
DQ
DO n
tLZ
tQH
1) DO n = Data Out from column n
2) All DQ are valid tAC after the CK edge.
All DQ are valid tDQSQ after the DQS edge, regardless of tAC
DO n+1
DO n+2
DO n+3
tQH
= Don't Care
During Read bursts, DQS is driven by the LPDDR SDRAM along with the output data. The initial Low
state of the DQS is known as the read preamble; the Low state coincident with last data-out element is
known as the read postamble. The first data-out element is edge aligned with the first rising edge of
DQS and the successive data-out elements are edge aligned to successive edges of DQS. This is
shown in following figure with a CAS latency of 2 and 3.
Upon completion of a read burst, assuming no other READ command has been initiated, the DQs will
go to High-Z.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 29 -
W94AD6KB / W94AD2KB
8.5.3
Read Burst Showing CAS Latency
CK
CK
Command
Address
READ
NOP
NOP
NOP
NOP
NOP
BA Col n
CL=2
DQS
DO n
DQ
CL=3
DQS
DO n
DQ
= Don't Care
1) DO n = Data Out from column n
2) BA, Col n = Bank A, Column n
3) Burst Length = 4; 3 subsequent elements of Data Out appear in the programmed order following DO n
4) Shown with nominal tAC, tDQSCK and tDQSQ
8.5.4 Read to Read
Data from a read burst may be concatenated or truncated by a subsequent READ command. The first
data from the new burst follows either the last element of a completed burst or the last desired
element of a longer burst that is being truncated. The new READ command should be issued X cycles
after the first READ command, where X equals the number of desired data-out element pairs (pairs
are required by the 2n-prefetch architecture). This is shown in following figure.
8.5.5
Consecutive Read Bursts
CK
CK
Command
Address
READ
NOP
BA,Col n
READ
NOP
NOP
NOP
BA,Col b
CL=2
DQS
DQ
DO n
DO b
CL=3
DQS
DO n
DQ
DO b
1) DO n (or b) = Data Out from column n (or column b)
2) Burst Length = 4 or 8 (if 4, the bursts are concatenated; if 8, the second burst interrupts the first)
3) Read bursts are to an active row in the bank
4) Shown with nominal tAC, tDQSCK and tDQSQ
= Don't Care
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 30 -
W94AD6KB / W94AD2KB
8.5.6 Non-Consecutive Read Bursts
A READ command can be initiated on any clock cycle following a previous READ command. Nonconsecutive Reads are shown in following figure.
CK
CK
Command
Address
READ
NOP
NOP
BA,Col n
READ
NOP
NOP
BA,Col b
CL=2
DQS
DQ
DO n
DO b
CL=3
DQS
DO n
DQ
= Don't Care
1) DO n (or b) = Data Out from column n (or column b)
2) BA, Col n (b) = Bank A, Column n (b)
3) Burst Length = 4; 3 subsequent elements of Data Out appear in the programmed order following DO n (b)
4) Shown with nominal tAC, tDQSCK and tDQSQ
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 31 -
W94AD6KB / W94AD2KB
8.5.7 Random Read Bursts
Full-speed random read accesses within a page or pages can be performed as shown in following
figure.
CK
CK
Command
Address
READ
READ
READ
READ
NOP
BA,Col n
BA,Col x
BA,Col b
BA,Col g
NOP
CL=2
DQS
DO n
DQ
DO n'
DO x
DO x'
DO n
DO n'
DO b
DO b'
DO g
DO g'
DO b
DO b'
CL=3
DQS
DQ
DO x
DO x'
= Don't Care
1) DO n ,etc. = Data Out from column n, etc.
n', x', etc. = Data Out elements, according to the programmed burst order
2) BA, Col n = Bank A, Column n
3) Burst Length = 2, 4, 8 or 16 in cases shown (if burst of 4, 8 or 16 the burst is interrupted)
4) Reads are to active rows in any banks
8.5.8 Read Burst Terminate
Data from any READ burst may be truncated with a BURST TERMINATE command, as shown in
following figure. The BURST TERMINATE latency is equal to the read (CAS) latency, i.e., the BURST
TERMINATE command should be issued X cycles after the READ command where X equals the
desired data-out element pairs.
CK
CK
Command
Address
READ
BST
NOP
NOP
NOP
NOP
BA,Col n
CL=2
DQS
DQ
CL=3
DQS
DQ
= Don't Care
1) DO n = Data Out from column n
2) BA, Col n = Bank A, Column n
3) Cases shown are bursts of 4, 8 or 16 terminated after 2 data elements.
4) Shown with nominal tAC, tDQSCK and tDQSQ
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 32 -
W94AD6KB / W94AD2KB
8.5.9 Read to Write
Data from READ burst must be completed or truncated before a subsequent WRITE command can be
issued. If truncation is necessary, the BURST TERMINATE command must be used, as shown in
following figure for the case of nominal tDQSS.
CK
CK
Command
Address
READ
BST
NOP
BA,Col n
WRITE
NOP
NOP
WRITE
NOP
BA,Col b
tDQSS
CL=2
DQS
DO n
DQ
DM
Command
Address
READ
BST
NOP
NOP
BA,Col n
BA,Col b
CL=3
DQS
DO n
DQ
DM
= Don't Care
1) DO n = Data Out from column n; DI b= Data In to column b
2) Burst length = 4, 8 or 16 in the cases shown; If the burst length is 2, the BST command can be omitted
3) Shown with nominal tAC, tDQSCK and tDQSQ
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 33 -
W94AD6KB / W94AD2KB
8.5.10 Read to Precharge
A Read burst may be followed by or truncated with a PRECHARGE command to the same bank
(provided Auto Precharge was not activated). The PRECHARGE command should be issued X cycles
after the READ command, where X equal the number of desired data-out element pairs. This is shown
in following figure. Following the PRECHARGE command, a subsequent command to the same bank
cannot be issued until tRP is met. Note that part of the row precharge time is hidden during the access
of the last data-out elements.
In the case of a Read being executed to completion, a PRECHARGE command issued at the optimum
time (as described above) provides the same operation that would result from Read burst with Auto
Precharge enabled. The disadvantage of the PRECHARGE command is that it requires that the
command and address buses be available at the appropriate time to issue the command. The
advantage of the PRECHARGE command is that it can be used to truncate bursts.
CK
CK
Command
Address
READ
NOP
PRE
NOP
NOP
Bank
(a or all)
BA,Col n
ACT
BA,Row
tRP
CL=2
DQS
DQ
DO n
CL=3
DQS
DQ
DO n
= Don't Care
1) DO n = Data Out from column n
2) Cases shown are either uninterrupted of 4, or interrupted bursts of 8 or 16
3) Shown with nominal tAC,tDQSCK and tDQSQ
4) Precharge may be applied at (BL/2) tCK after the READ command.
5) Note that Precharge may not be issued before tRAS ns after the ACTIVE command for applicable banks.
6) The ACTIVE command may be applied if tRC has been met.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 34 -
W94AD6KB / W94AD2KB
8.5.11 Burst Terminate of Read
The BURST TERMINATE command is used to truncate read bursts (with Auto Precharge disabled).
The most recently registered READ command prior to the BURST TERMINATE command will be
truncated. Note that the BURST TERMINATE command is not bank specific.
This command should not be used to terminate write bursts.
CK
CK
CKE
(High)
CS
RAS
CAS
WE
A0-An
BA0,BA1
= Don't Care
8.6
Write
The WRITE command is used to initiate a burst write access to an active row, with a burst length as
set in the Mode Register. BA0 and BA1 select the bank, and the address inputs select the starting
column location. The value of A10 determines whether or not Auto Precharge is used. If Auto
Precharge is selected, the row being accessed will be precharged at the end of the write burst; if Auto
Precharge is not selected, the row will remain open for subsequent accesses.
8.6.1
Write Command
CK
CK
CKE
(High)
CS
RAS
CAS
WE
Address
CA
Enable AP
A10
AP
Disable AP
BA0,BA1
BA
= Don't Care
BA = Bank Address
CA = Column Address
AP = Auto Precharge
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 35 -
W94AD6KB / W94AD2KB
8.6.2 Basic Write Timing Parameters
Basic Write timing parameters for DQs are shown in below figure; they apply to all Write operations.
Input data appearing on the data bus, is written to the memory array subject to the DM input logic level
appearing coincident with the data. If a given DM signal is registered Low, the corresponding data will
be written to the memory; if the DM signal is registered High, the corresponding data inputs will be
ignored, and a write will not be executed to that byte / column location.
tCK
tCH
tCL
CK
CK
tDQSS
Case 1:
tDQSS = min
tDSH
tDQSH
tDSH
tWPST
DQS
tWPRES
tWPRE
tDH
tDS
DQ, DM
Case 2:
tDQSS = max
tDQSL
DI n
tDQSH
tDQSS
tDSS
tWPST
DQS
tWPRES
DQ, DM
tDSS
tWPRE
tDS
tDH
tDQSL
DI n
= Don't Care
1) DI n = Data In for column n
2) 3 subsequent elements of Data In are applied in the programmed order following DI n.
3) tDQSS: each rising edge of DQS must fall within the +/-25% window of the corresponding positive clock edge.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 36 -
W94AD6KB / W94AD2KB
8.6.3 Write Burst (min. and max. tDQSS)
During Write bursts, the first valid data-in element will be registered on the first rising edge of DQS
following the WRITE command, and the subsequent data elements will be registered on successive
edges of DQS. The Low state of DQS between the WRITE command and the first rising edge is called
the write preamble, and the Low state on DQS following the last data-in element is called the write
postamble.
The time between the WRITE command and the first corresponding rising edge of DQS (tDQSS) is
specified with a relatively wide range - from 75% to 125% of a clock cycle. Following figure shows the
two extremes of tDQSS for a burst of 4. Upon completion of a burst, assuming no other commands
have been initiated, the DQs will remain high-Z and any additional input data will be ignored.
CK
CK
Command
WRITE
Address
BA,Col b
NOP
NOP
NOP
NOP
NOP
tDQSSmin
DQS
DQ
DI b
DM
tDQSSmax
DQS
DQ
DI b
DM
= Don't Care
1) DI b = Data In to column b.
2) 3 subsequent elements of Data In are applied in the programmed order following DI b.
3) A non-interrupted burst of 4 is shown.
4) A10 is LOW with the WRITE command (Auto Precharge is disabled)
8.6.4 Write to Write
Data for any WRITE burst may be concatenated with or truncated with a subsequent WRITE
command. In either case, a continuous flow of input data, can be maintained. The new WRITE
command can be issued on any positive edge of the clock following the previous WRITE command.
The first data-in element from the new burst is applied after either the last element of a completed
burst or the last desired data element of a longer burst which is being truncated. The new WRITE
command should be issued X cycles after the first WRITE command, where X equals the number of
desired data-in element pairs.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 37 -
W94AD6KB / W94AD2KB
8.6.5 Concatenated Write Bursts
An example of concatenated write bursts is shown in below figure.
CK
CK
Command
Address
WRITE
NOP
WRITE
BA,Col b
NOP
NOP
NOP
BA,Col n
tDQSSmin
DQS
DI b
DQ
DI n
DM
tDQSSmax
DQS
DI b
DQ
DI n
DM
= Don't Care
1) DI b (n) = Data in to column b (column n)
2) 3 subsequent elements of Data In are applied in the programmed order following DI b.
3 subsequent elements of Data In are applied in the programmed order following DI n.
3) Non-interrupted bursts of 4 are shown.
4) Each WRITE command may be to any active bank
8.6.6 Non-Concatenated Write Bursts
An example of non-concatenated write bursts is shown in below figure.
CK
CK
Command
Address
WRITE
NOP
NOP
BA,Col b
WRITE
NOP
NOP
BA,Col n
tDQSSmax
DQS
DQ
DI b
DI n
DM
= Don't Care
1) Dl b (n) = Data in to column b (or column n)
2) 3 subsequent elements of Data In are applied in the programmed order following DI b.
3 subsequent elements of Data In are applied in the programmed order following DI n.
3) Non-interrupted bursts of 4 are shown.
4) Each WRITE command may be to any active bank and may be to the same or different devices.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 38 -
W94AD6KB / W94AD2KB
8.6.7 Random Write Cycles
Full-speed random write accesses within a page or pages can be performed as shown in below figure.
CK
CK
Command
Address
WRITE
WRITE
WRITE
WRITE
WRITE
BA,Col b
BA,Col x
BA,Col n
BA,Col a
BA,Col g
NOP
tDQSSmax
DQS
DQ
DI b
DI b'
DI x
DI x'
DI n
DI n'
DI a
DI a'
DM
= Don't Care
1) Dl b etc. = Data in to column b, etc.;
b', etc. = the next Data In following Dl b, etc. according to the programmed burst order
2) Programmed burst length = 2, 4, 8 or 16 in cases shown. If burst of 4, 8 or 16, burst would be truncated
3) Each WRITE command may be to any active bank and may be to the same or different devices.
8.6.8 Write to Read
Data for any Write burst may be followed by a subsequent READ command.
8.6.9 Non-Interrupting Write to Read
To follow a Write without truncating the write burst, tWTR should be met as shown in the figure below.
CK
CK
Command
WRITE
Address
BA,Col b
NOP
NOP
NOP
READ
NOP
NOP
BA,Col n
tDQSSmax
tWTR
CL=3
DQS
DQ
DI b
DM
= Don't Care
1) Dl b = Data in to column b
3 subsequent elements of Data In are applied in the programmed order following DI b.
2) A non-interrupted burst of 4 is shown.
3) tWTR is referenced from the positive clock edge after the last Data In pair.
4) A10 is LOW with the WRITE command (Auto Precharge is disabled)
5) The READ and WRITE commands are to the same device but not necessarily to the same bank.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 39 -
W94AD6KB / W94AD2KB
8.6.10 Interrupting Write to Read
Data for any Write burst may be truncated by a subsequent READ command as shown in the figure
below. Note that the only data-in pairs that are registered prior to the tWTR period are written to the
internal array, and any subsequent data-in must be masked with DM.
CK
CK
Command
WRITE
NOP
NOP
READ
BA,Col b
Address
NOP
NOP
NOP
BA,Col n
tDQSSmax
tWTR
CL=3
DQS
DO n
DI b
DQ
DM
= Don't Care
1) Dl b = Data in to column b. DO n = Data out from column n.
2) An interrupted burst of 4 is shown, 2 data elements are written.
3 subsequent elements of Data In are applied in the programmed order following DI b.
3) tWTR is referenced from the positive clock edge after the last Data In pair.
4) A10 is LOW with the WRITE command (Auto Precharge is disabled)
5) The READ and WRITE commands are to the same device but not necessarily to the same bank.
8.6.11 Write to Precharge
Data for any WRITE burst may be followed by a subsequent PRECHARGE command to the same
bank (provided Auto Precharge was not activated). To follow a WRITE without truncating the WRITE
burst, tWR should be met as shown in the figure below.
8.6.12 Non-Interrupting Write to Precharge
CK
CK
Command
Address
WRITE
NOP
NOP
NOP
NOP
BA,Col b
PRE
BA a (or all)
tDQSSmax
tWR
DQS
DQ
DI b
DM
= Don't Care
1) Dl b = Data in to column b
3 subsequent elements of Data In are applied in the programmed order following DI b.
2) A non-interrupted burst of 4 is shown.
3) tWR is referenced from the positive clock edge after the last Data In pair.
4) A10 is LOW with the WRITE command (Auto Precharge is disabled)
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 40 -
W94AD6KB / W94AD2KB
8.6.13 Interrupting Write to Precharge
Data for any WRITE burst may be truncated by a subsequent PRECHARGE command as shown in
below figure. Note that only data-in pairs that are registered prior to the tWR period are written to the
internal array, and any subsequent data-in should be masked with DM, as shown in below figure.
Following the PRECHARGE command, a subsequent command to the same bank cannot be issued
until tRP is met.
CK
CK
Command
Address
WRITE
NOP
NOP
NOP
PRE
BA,Col b
BA a (or all)
tWR
tDQSSmax
*2
DQS
DQ
NOP
DI b
DM
*1
*1
*1
*1
= Don't Care
1) Dl b = Data in to column b.
2) An interrupted burst of 4, 8 or 16 is shown, 2 data elements are written.
3) tWR is referenced from the positive clock edge after the last desired Data In pair.
4) A10 is LOW with the WRITE command (Auto Precharge is disabled)
5) *1 = can be Don't Care for programmed burst length of 4
6) *2 = for programmed burst length of 4, DQS becomes Don't Care at this point
8.7
Precharge
The PRECHARGE command is used to deactivate the open row in a particular bank or the open row
in all banks. The bank(s) will be available for a subsequent row access a specified time (tRP) after the
PRECHARGE command is issued.
Input A10 determines whether one or all banks are to be precharged. In case where only one bank is
to be precharged, inputs BA0, BA1 select the bank. Otherwise BA0, BA1 are treated as “Don’t Care”.
Once a bank has been precharged, it is in the idle state and must be activated prior to any READ or
WRITE command being issued. A PRECHARGE command will be treated as a NOP if there is no
open row in that bank, or if the previously open row is already in the process of precharging.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 41 -
W94AD6KB / W94AD2KB
8.7.1
Precharge Command
CK
CK
CKE
(High)
CS
RAS
CAS
WE
Address
All Banks
A10
One Bank
BA0,BA1
BA
= Don't Care
BA = Bank Address
(if A10 = L, otherwise Don't Care)
8.8
Auto Precharge
Auto Precharge is a feature which performs the same individual bank precharge function as described
above, but without requiring an explicit command. This is accomplished by using A10 (A10 = High), to
enable Auto Precharge in conjunction with a specific READ or WRITE command. A precharge of the
bank/row that is addressed with the READ or WRITE command is automatically performed upon
completion of the read or write burst. Auto Precharge is non persistent in that it is either enabled or
disabled for each individual READ or WRITE command.
Auto Precharge ensures that a precharge is initiated at the earliest valid stage within a burst. The user
must not issue another command to the same bank until the precharing time (tRP) is completed. This
is determined as if an explicit PRECHARGE command was issued at the earliest possible time, as
described for each burst type in the Operation section of this specification.
8.9
Refresh Requirements
LPDDR SDRAM devices require a refresh of all rows in any rolling 64mS interval. Each refresh is
generated in one of two ways: by an explicit AUTO REFRESH command, or by an internally timed
event in SELF REFRESH mode. Dividing the number of device rows into the rolling 64mS interval
defines the average refresh interval (tREFI), which is a guideline to controllers for distributed refresh
timing.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 42 -
W94AD6KB / W94AD2KB
8.10 Auto Refresh
AUTO REFRESH command is used during normal operation of the LPDDR SDRAM. This command is
non persistent, so it must be issued each time a refresh is required.
The refresh addressing is generated by the internal refresh controller. The LPDDR SDRAM requires
AUTO REFRESH commands at an average periodic interval of tREFI.
8.10.1 Auto Refresh Command
CK
CK
CKE
(High)
CS
RAS
CAS
WE
A0-An
BA0,BA1
= Don't Care
8.10.2 Auto Refresh Cycles Back-to-Back
An Auto Refresh cycle timing diagram is shown in below.
CK
CK
tRP
Command
PRE
NOP
tRFC
ARF
NOP
NOP
DQ
ARF
NOP
NOP
ACT
Ba,A
Row n
Address
A10 (AP)
tRFC
Pre All
Row n
High-z
= Don't Care
Ba A, Row n = Bank A, Row n
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 43 -
W94AD6KB / W94AD2KB
8.11 Self Refresh
The SELF REFRESH command can be used to retain data in the LPDDR SDRAM, even if the rest of
the system is powered down. When in the Self Refresh mode, the LPDDR SDRAM retains data
without external clocking. The LPDDR SDRAM device has a built-in timer to accommodate Self
Refresh operation. The SELF REFRESH command is initiated like an AUTO REFRESH command
except CKE is LOW. Input signals except CKE are “Don’t Care” during Self Refresh. The user may
halt the external clock one clock after the SELF REFRESH command is registered.
Once the command is registered, CKE must be held low to keep the device in Self Refresh mode. The
clock is internally disabled during Self Refresh operation to save power. The minimum time that the
device must remain in Self Refresh mode is tRFC.
The procedure for exiting Self Refresh requires a sequence of commands. First, the clock must be
stable prior to CKE going back High. Once Self Refresh Exit is registered, a delay of at least t XSR must
be satisfied before a valid command can be issued to the device to allow for completion of any internal
refresh in progress.
The use of Self Refresh mode introduces the possibility that an internally timed refresh event can be
missed when CKE is raised for exit from Self Refresh mode. Upon exit from Self Refresh an extra
AUTO REFRESH command is recommended.
In the Self Refresh mode, Partial Array Self Refresh (PASR) function is described in the Extended
Mode Register section.
8.11.1 Self Refresh Command
CK
CK
CKE
CS
RAS
CAS
WE
A0-An
BA0,BA1
= Don't Care
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 44 -
W94AD6KB / W94AD2KB
8.11.2 Self Refresh Entry and Exit
A Self Refresh entry and exit timing diagram is shown in below.
CK
CK
tXSR
>tRFC
tRP
tRFC
CKE
Command
NOP
PRE
ARF
NOP
NOP
ARF
DQ
ACT
Ba A,
Row n
Address
A10 (AP)
NOP
Row n
Pre All
High-z
= Don't Care
Enter
Self Refresh
Mode
Exit from
Self Refresh
Mode
Any Command
(Auto Refresh
Recommened)
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 45 -
W94AD6KB / W94AD2KB
8.12 Power Down
Power-down is entered when CKE is registered Low (no accesses can be in progress). If power-down
occurs when all banks are idle, this mode is referred to as precharge power-down; if power-down
occurs when there is a row active in any bank, this mode is referred to as active power-down.
Entering power-down deactivates the input and output buffers, excluding CK, CK and CKE. In
power-down mode, CKE Low must be maintained, and all other input signals are “Don’t Care”. The
minimum power-down duration is specified by tCKE. However, power-down duration is limited by the
refresh requirements of the device.
The power-down state is synchronously exited when CKE is registered High (along with a NOP or
DESELECT command). A valid command may be applied tXP after exit from power-down.
For Clock Stop during Power-Down mode, please refer to the Clock Stop subsection in this
specification.
8.12.1 Power-Down Entry and Exit
CK
CK
tRP
tXP
tCKE
CKE
Command
PRE
NOP
NOP
NOP
Address
A10 (AP)
DQ
NOP
NOP
Valid
Valid
Valid
Pre All
High-z
Power Down
Entry
Exit from
Power Down
Precharge Power-Down mode shown; all banks are idle and tRP
is met when Power-down Entry command is issued
Any
Command
= Don't Care
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 46 -
W94AD6KB / W94AD2KB
8.13 Deep Power Down
The Deep Power-Down (DPD) mode enables very low standby currents. All internal voltage
generators inside the LPDDR SDRAM are stopped and all memory data is lost in this mode. All the
information in the Mode Register and the Extended Mode Register is lost.
Deep Power-Down is entered using the BURST TERMINATE command except that CKE is registered
Low. All banks must be in idle state with no activity on the data bus prior to entering the DPD mode.
While in this state, CKE must be held in a constant Low state.
To exit the DPD mode, CKE is taken high after the clock is stable and NOP commands must be
maintained for at least 200μs. After 200μs a complete re-initialization is required following steps 4
through 11 as defined for the initialization sequence.
8.13.1 Deep Power-Down Entry and Exit
T0
T1
Ta0
NOP
DPD
Ta1
Ta2
NOP
Valid
CK
CK
CKE
Command
Address
Valid
DQS
DQ
DM
tRP
T = 200 µs
Enter DPD Mode
Exit DPD Mode
= Don't Care
1) Clock must be stable before exiting Deep Power-Down mode. That is, the clock must be cycling
within specifications by Ta0
2) Device must be in the all banks idle state prior to entering Deep Power-Down mode
3) 200µs is required before any command can be applied upon exiting Deep Power-Down mode
4) Upon exiting Deep Power-Down mode a PRECHARGE ALL command must be issued, followed
by two AUTO REFRESH commands and a load mode register sequence
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 47 -
W94AD6KB / W94AD2KB
8.14 Clock Stop
Stopping a clock during idle periods is an effective method of reducing power consumption.
The LPDDR SDRAM supports clock stop under the following conditions:
 the last command (ACTIVE, READ, WRITE, PRECHARGE, AUTO REFRESH or MODE
REGISTER SET) has executed to completion, including any data-out during read bursts; the
number of clock pulses per access command depends on the device’s AC timing parameters and
the clock frequency;
 the related timing conditions (tRCD, tWR, tRP, tRFC, tMRD) has been met;
 CKE is held High
When all conditions have been met, the device is either in “idle state” or “row active state” and clock
stop mode may be entered with CK held Low and CK held High.
Clock stop mode is exited by restarting the clock. At least one NOP command has to be issued
before the next access command may be applied. Additional clock pulses might be required
depending on the system characteristics.
The following Figure shows clock stop mode entry and exit
 Initially the device is in clock stop mode
 The clock is restarted with the rising edge of T0 and a NOP on the command inputs
 With T1 a valid access command is latched; this command is followed by NOP commands in
order to allow for clock stop as soon as this access command is completed
 Tn is the last clock pulse required by the access command latched with T1
 The clock can be stopped after Tn
8.14.1 Clock Stop Mode Entry and Exit
T0
T1
T2
Tn
CK
CK
CKE
Timing Condition
NOP
Command
CMD
NOP
NOP
NOP
Valid
Address
(High-Z)
DQ, DQS
Clock
Stopped
Exit
Clock
Stop
Mode
Valid
Command
Enter
Clock
Stop
Mode
= Don't Care
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 48 -
W94AD6KB / W94AD2KB
9. ELECTRICAL CHARACTERISTICS
9.1 Absolute Maximum Ratings
PARAMETER
SYMBOL
VALUES
UNITS
MIN.
MAX.
VDD
-0.5
2.3
V
VDDQ
-0.5
2.3
V
VIN, VOUT
-0.5
2.3
V
Operating Temperature (for 5E/6E grades)
TCASE
-25
85
°C
Operating Temperature (for 5I/6I grades)
TCASE
-40
85
°C
Storage Temperature
TSTG
-55
150
°C
Short Circuit Output Current
IOUT
±50
mA
PD
1.0
W
Voltage on VDD relative to VSS
Voltage on VDDQ relative to VSS
Voltage on any pin relative to VSS
Power Dissipation
Note:
Stresses greater than those listed in “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.
9.2
Input / Output Capacitance
PARAMETER
SYMBOL
MIN.
MAX.
UNITS
Input Capacitance CK, CK
CCK
1.5
3.0
pF
Input Capacitance delta CK, CK
CDCK
0.25
pF
3.0
pF
0.5
pF
5.0
pF
3
0.5
pF
3
Input capacitance, all other input-only pins
CI
Input capacitance delta, all other input-only pins
CDI
Input/ output capacitance, DQ,DM,DQS
CIO
Input/output capacitance delta, DQ, DM, DQS
CDIO
1.5
3.0
NOTES
Notes
1. These values are guaranteed by design and are tested on a sample base only.
2. These capacitance values are for single monolithic devices only. Multiple die packages will have parallel capacitive loads.
3. Although DM is an input-only pin, the input capacitance of this pin must model the input capacitance of the DQ and DQS
pins. This is required to match signal propagation times of DQ, DQS and DM in the system.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 49 -
W94AD6KB / W94AD2KB
9.3
Electrical Characteristics and AC/DC Operating Conditions
All values are recommended operating conditions unless otherwise noted.
9.3.1
Electrical Characteristics and AC/DC Operating Conditions
PARAMETER/CONDITION
Supply Voltage
I/O Supply Voltage
SYMBOL
MIN.
MAX.
UNIT
NOTES
VDD
1.70
1.95
V
-
VDDQ
1.70
1.95
V
-
Address and Command Inputs (A0~An, BA0, BA1, CKE, CS , RAS , CAS , WE )
Input High Voltage
VIH
0.8 * VDDQ
VDDQ + 0.3
V
-
Input Low Voltage
VIL
-0.3
0.2 * VDDQ
V
-
VIN
-0.3
VDDQ + 0.3
V
-
DC Input Differential Voltage
VID(DC)
0.4 * VDDQ
VDDQ + 0.6
V
2
AC Input Differential Voltage
VID(AC)
0.6 * VDDQ
VDDQ + 0.6
V
2
VIX
0.4 * VDDQ
0.6 x VDDQ
V
3
DC Input High Voltage
VIHD(DC)
0.7 * VDDQ
VDDQ + 0.3
V
-
DC Input Low Voltage
VILD(DC)
-0.3
0.3 x VDDQ
V
-
AC Input High Voltage
VIHD(AC)
0.8 * VDDQ
VDDQ + 0.3
V
-
AC Input Low Voltage
VILD(AC)
-0.3
0.2 * VDDQ
V
-
DC Output High Voltage (IOH = -0.1mA)
VOH
0.9 * VDDQ
-
V
-
DC Output Low Voltage (IOL = 0.1mA)
VOL
-
0.1 * VDDQ
V
-
Input Leakage Current
IiL
-1
1
µA
4
Output Leakage Current
IoL
-5
5
µA
5
Clock Inputs (CK, CK )
DC Input Voltage
AC Differential Cross Point Voltage
Data Inputs (DQ, DM, DQS)
Data Outputs (DQ, DQS)
Leakage Current
Notes
1. All voltages referenced to VSS and VSSQ must be same potential.
2. VID(DC) and VID(AC) are the magnitude of the difference between the input level on CK and the input level on CK .
3. The value of VIX is expected to be 0.5 * VDDQ and must track variations in the DC level of the same.
4. Any input 0V ≤ VIN ≤ VDD. All other pins are not tested under VIN = 0V.
5. Any output 0V ≤ VOUT ≤ VDDQ. DOUT is disabled.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 50 -
W94AD6KB / W94AD2KB
9.4
DC Characteristics
9.4.1
IDD Specification and Test Conditions (x16)
[Recommended Operating Conditions; Note 1-4]
PARAMETER
SYMBOL
TEST CONDITION
-5
-6
UNIT
Operating one bank
active-precharge current
IDD0
tRC = tRCmin; tCK = tCKmin; CKE is HIGH; CS is
HIGH between valid commands; address inputs
are SWITCHING; data bus inputs are STABLE
70
60
mA
Precharge power-down
standby current
IDD2P
all banks idle, CKE is LOW; CS is HIGH, tCK
= tCKmin; address and control inputs are
SWITCHING; data bus inputs are STABLE
0.6
0.6
mA
Precharge power-down
standby current with
clock stop
IDD2PS
0.6
0.6
mA
Precharge non powerdown standby current
IDD2N
15
15
mA
8
8
mA
3.6
3.6
mA
3.6
3.6
mA
15
15
mA
8
8
mA
115
105
mA
115
105
mA
95
95
mA
10
10
µA
all banks idle, CKE is LOW; CS is HIGH, CK =
LOW, CK = HIGH; address and control inputs
are SWITCHING; data bus inputs are STABLE
all banks idle, CKE is HIGH; CS is HIGH, tCK
= tCKmin; address and control inputs are
SWITCHING; data bus inputs are STABLE
all banks idle, CKE is HIGH; CS is HIGH, CK
Precharge non powerdown standby current
with clock stop
IDD2NS
Active power-down
standby current
IDD3P
Active power-down
standby current with
clock stop
IDD3PS
Active non power-down
standby current
IDD3N
= LOW, CK = HIGH; address and control
inputs are SWITCHING; data bus inputs are
STABLE
one bank active, CKE is LOW; CS is HIGH,
tCK = tCKmin; address and control inputs are
SWITCHING; data bus inputs are STABLE
one bank active, CKE is LOW; CS is HIGH, CK
= LOW, CK = HIGH; address and control inputs
are SWITCHING; data bus inputs are STABLE
one bank active, CKE is HIGH; CS is HIGH,
tCK = tCKmin; address and control inputs are
SWITCHING; data bus inputs are STABLE
one bank active, CKE is HIGH; CS is HIGH,
Active non power-down
standby current with
clock stop
IDD3NS
Operating burst read
current
IDD4R
Operating burst write
current
IDD4W
Auto-Refresh Current
IDD5
Deep Power-Down
current
IDD8*4
CK = LOW, CK = HIGH; address and control
inputs are SWITCHING; data bus inputs are
STABLE
one bank active; BL = 4; CL = 3; tCK = tCKmin;
continuous read bursts; IOUT = 0 mA; address
inputs are SWITCHING; 50% data change each
burst transfer
one bank active; BL = 4; tCK = tCKmin;
continuous write bursts; address inputs are
SWITCHING; 50% data change each burst
transfer
tRC = tRFCmin; tCK = tCKmin ; burst refresh;
CKE is HIGH; address and control inputs are
SWITCHING; data bus inputs are STABLE
Address and control inputs are STABLE; data
bus inputs are STABLE
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 51 -
W94AD6KB / W94AD2KB
9.4.2
IDD Specification and Test Conditions (x32)
[Recommended Operating Conditions; Note 1-4]
PARAMETER
SYMBOL
TEST CONDITION
-5
-6
UNIT
Operating one bank
active-precharge current
IDD0
tRC = tRCmin; tCK = tCKmin; CKE is HIGH; CS is
HIGH between valid commands; address inputs
are SWITCHING; data bus inputs are STABLE
70
60
mA
Precharge power-down
standby current
IDD2P
all banks idle, CKE is LOW; CS is HIGH, tCK
= tCKmin; address and control inputs are
SWITCHING; data bus inputs are STABLE
0.6
0.6
mA
Precharge power-down
standby current with
clock stop
IDD2PS
0.6
0.6
mA
Precharge non powerdown standby current
IDD2N
15
15
mA
8
8
mA
3.6
3.6
mA
3.6
3.6
mA
15
15
mA
8
8
mA
115
105
mA
115
105
mA
95
95
mA
10
10
µA
all banks idle, CKE is LOW; CS is HIGH, CK =
LOW, CK = HIGH; address and control inputs
are SWITCHING; data bus inputs are STABLE
all banks idle, CKE is HIGH; CS is HIGH, tCK
= tCKmin; address and control inputs are
SWITCHING; data bus inputs are STABLE
all banks idle, CKE is HIGH; CS is HIGH, CK
Precharge non powerdown standby current
with clock stop
IDD2NS
Active power-down
standby current
IDD3P
Active power-down
standby current with
clock stop
IDD3PS
Active non power-down
standby current
IDD3N
= LOW, CK = HIGH; address and control
inputs are SWITCHING; data bus inputs are
STABLE
one bank active, CKE is LOW; CS is HIGH,
tCK = tCKmin; address and control inputs are
SWITCHING; data bus inputs are STABLE
one bank active, CKE is LOW; CS is HIGH, CK
= LOW, CK = HIGH; address and control inputs
are SWITCHING; data bus inputs are STABLE
one bank active, CKE is HIGH; CS is HIGH,
tCK = tCKmin; address and control inputs are
SWITCHING; data bus inputs are STABLE
one bank active, CKE is HIGH; CS is HIGH,
Active non power-down
standby current with
clock stop
IDD3NS
Operating burst read
current
IDD4R
Operating burst write
current
IDD4W
Auto-Refresh Current
IDD5
Deep Power-Down
current
IDD8*4
CK = LOW, CK = HIGH; address and control
inputs are SWITCHING; data bus inputs are
STABLE
one bank active; BL = 4; CL = 3; tCK = tCKmin;
continuous read bursts; IOUT = 0 mA; address
inputs are SWITCHING; 50% data change each
burst transfer
one bank active; BL = 4; tCK = tCKmin;
continuous write bursts; address inputs are
SWITCHING; 50% data change each burst
transfer
tRC = tRFCmin; tCK = tCKmin ; burst refresh;
CKE is HIGH; address and control inputs are
SWITCHING; data bus inputs are STABLE
Address and control inputs are STABLE; data
bus inputs are STABLE
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 52 -
W94AD6KB / W94AD2KB
IDD6 Conditions:
PARAMETER
Self Refresh
Current
SYM.
IDD6
TEST CONDITION
CKE is LOW; CK = LOW, CK = HIGH;
Extended Mode Register set to all 0’s;
Address and control inputs are STABLE;
Data bus inputs are STABLE
PASR RANGE 45°C
85°C
UNIT
Full array
750
1300
µA
1/2 array
600
1050
µA
1/4 array
500
900
µA
Notes:
1. IDD specifications are tested after the device is properly initialized.
2. Input slew rate is 1V/ns.
3. Definitions for IDD:
LOW is defined as VIN ≤ 0.1 * VDDQ;
HIGH is defined as VIN ≥ 0.9 * VDDQ;
STABLE is defined as inputs stable at a HIGH or LOW level;
SWITCHING is defined as:
- Address and command: inputs changing between HIGH and LOW once per two clock cycles;
- Data bus inputs: DQ changing between HIGH and LOW once per clock cycle; DM and DQS are STABLE.
4. IDD8 is typical values at 25°C.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 53 -
W94AD6KB / W94AD2KB
9.5
AC Characteristics and Operating Condition
[Recommended Operating Conditions: Notes 1-9]
PARAMETER
CL = 3
DQ Output Access Time from CK, CK
CL = 2
CL = 3
DQS Output Access Time from CK, CK
-5
SYM.
CL = 2
tAC
tDQSCK
-6
MIN.
MAX.
MIN.
MAX.
2.0
5.0
2.0
5.0
2.0
6.5
2.0
6.5
2.0
5.0
2.0
5.0
2.0
6.5
2.0
6.5
UNIT
nS
nS
Clock high-level width
tCH
0.45
0.55
0.45
0.55
tCK
Clock low-level width
tCL
0.45
0.55
0.45
0.55
tCK
tHP
Min.
(tCL,tCH)
Clock half period
Clock cycle time
DQ and DM input setup time
DQ and DM input hold time
CL = 3
Address and control input hold time
Min.
(tCL,tCH)
nS
10,11
5
6
nS
12
12
12
nS
12
0.48
0.6
nS
13,14,15
slow
0.58
0.7
nS
13,14,16
fast
0.48
0.6
nS
13,14,15
0.58
0.7
nS
13,14,16
1.4
1.6
nS
17
0.9
1.1
nS
15,18
1.1
1.3
nS
16,18
0.9
1.1
nS
15,18
1.1
1.3
nS
16,18
tIPW
2.3
2.6
nS
17
tLZ
1.0
1.0
nS
19
CL = 2
fast
slow
DQ and DM input pulse width
Address and control input setup time
tCK
tDS
tDH
tDIPW
fast
slow
fast
slow
Address and control input pulse width
Data-out Low-impedance Time from CK, CK
Data-out High-impedance Time from CK,
CL = 3
CK
CL = 2
DQS-DQ skew
tIS
tIH
tHZ
tDQSQ
DQ/DQS output hold time from DQS
tQH
5.0
5.0
6.5
6.5
0.4
tHP tQHS
0.5
tHP tQHS
20
nS
11
11
tQHS
065
nS
tDQSS
0.75
1.25
0.75
1.25
tCK
DQS input high-level width
tDQSH
0.4
0.6
0.4
0.6
tCK
DQS input low-level width
tDQSL
0.4
0.6
0.4
0.6
tCK
DQS falling edge to CK setup time
tDSS
0.2
0.2
tCK
DQS falling edge hold time from CK
tDSH
0.2
0.2
tCK
tCK
tMRD
2
2
tWPRES
0
0
Write postamble
tWPST
0.4
Write preamble
tWPRE
0.25
Write preamble setup time
CL = 3
CL = 2
tRPRE
0.6
0.4
0.6
0.25
19
nS
Write command to 1st DQS latching transition
MODE REGISTER SET command period
0.5
nS
Data hold skew factor
Read preamble
NOTES
nS
21
tCK
22
tCK
0.9
1.1
0.9
1.1
tCK
23
0.5
1.1
0.5
1.1
tCK
23
0.4
0.6
0.4
0.6
tCK
70,000
42
70,000
nS
Read postamble
tRPST
ACTIVE to PRECHARGE command period
tRAS
40
ACTIVE to ACTIVE command period
tRC
tRAS +
tRP
tRAS +
tRP
nS
AUTO REFRESH to ACTIVE/AUTO REFRESH
command period
tRFC
72
72
nS
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 54 -
W94AD6KB / W94AD2KB
-5
-6
PARAMETER
SYM.
ACTIVE to READ or WRITE delay
tRCD
15
18
nS
tRP
3
3
tCK
ACTIVE bank A to ACTIVE bank B delay
tRRD
10
12
nS
WRITE recovery time
tWR
15
15
nS
24
Auto precharge write recovery + precharge time
tDAL
-
-
tCK
25
Internal write to Read command delay
tWTR
1
1
tCK
Self Refresh exit to next valid command delay
tXSR
120
120
nS
26
Exit power down to next valid command delay
tXP
2
1
tCK
27
tCKE
1
1
tCK
PRECHARGE command period
CKE min. pulse width (high and low pulse width)
MIN.
MAX.
MIN.
MAX.
UNIT
Refresh Period
tREF
64
64
mS
Average periodic refresh interval
tREFI
7.8
7.8
μS
MRS for SRR to READ
tSRR
2
2
tCK
READ of SRR to next valid command
tSRC
CL+1
CL+1
tCK
NOTES
28,29
Notes:
1. All voltages referenced to VSS.
2. All parameters assume proper device initialization.
3. Tests for AC timing may be conducted at nominal supply voltage levels, but the related specifications and device operation
are guaranteed for the full voltage and temperature range specified.
4. The circuit shown below represents the timing reference load used in defining the relevant timing parameters of the part. It
is not intended to be either a precise representation of the typical system environment nor a depiction of the actual load
presented by a production tester. System designers will use IBIS or other simulation tools to correlate the timing reference
load to system environment. Manufacturers will correlate to their production test conditions (generally a coaxial transmission
line terminated at the tester electronics). For the half strength driver with a nominal 10pF load parameters t AC and tQH are
expected to be in the same range. However, these parameters are not subject to production test but are estimated by
design / characterization. Use of IBIS or other simulation tools for system design validation is suggested.
Full Drive Strength
Half Drive Strength
I/O
I/O
Z0 = 50 Ohms
20 pF
Z0 = 50 Ohms
10 pF
Time Reference Load
5. The CK/ CK input reference voltage level (for timing referenced to CK/ CK ) is the point at which CK and CK cross; the
input reference voltage level for signals other than CK/ CK is VDDQ/2.
6. The timing reference voltage level is VDDQ/2.
7. AC and DC input and output voltage levels are defined in the section for Electrical Characteristics and AC/DC operating
conditions.
8. A CK/ CK differential slew rate of 2.0 V/nS is assumed for all parameters.
9. CAS Latency definition: with CL = 3 the first data element is valid at (2 * tCK + tAC) after the clock at which the READ
command was registered; with CL = 2 the first data element is valid at (tCK + tAC) after the clock at which the READ
command was registered.
10. Min (tCL, tCH) refers to the smaller of the actual clock low time and the actual clock high time as provided to the device (i.e.
this value can be greater than the minimum specification limits of tCL and tCH)
11. tQH = tHP - tQHS, where tHP = minimum half clock period for any given cycle and is defined by clock high or clock low (tCL,
tCH). tQHS accounts for 1) the pulse duration distortion of on-chip clock circuits; and 2) the worst case push-out of DQS on
one transition followed by the worst case pull-in of DQ on the next transition, both of which are, separately, due to data pin
skew and output pattern effects, and p-channel to n-channel variation of the output drivers.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 55 -
W94AD6KB / W94AD2KB
12. The only time that the clock frequency is allowed to change is during clock stop, power-down or self-refresh modes.
13. The transition time for DQ, DM and DQS inputs is measured between VIL(DC) to VIH(AC) for rising input signals, and VIH(DC)
to VIL(AC) for falling input signals.
14. DQS, DM and DQ input slew rate is specified to prevent double clocking of data and preserve setup and hold times. Signal
transitions through the DC region must be monotonic.
15. Input slew rate ≥ 1.0 V/nS.
16. Input slew rate ≥ 0.5 V/nS and < 1.0 V/nS.
17. These parameters guarantee device timing but they are not necessarily tested on each device.
18. The transition time for address and command inputs is measured between VIH and VIL.
19. tHZ and tLZ transitions occur in the same access time windows as valid data transitions. These parameters are not referred
to a specific voltage level, but specify when the device is no longer driving (HZ), or begins driving (LZ).
20. tDQSQ consists of data pin skew and output pattern effects, and p-channel to n-channel variation of the output drivers for
any given cycle.
21. The specific requirement is that DQS be valid (HIGH, LOW, or some point on a valid transition) on or before the corresponding
CK edge. A valid transition is defined as monotonic and meeting the input slew rate specifications of the device. When no
writes were previously in progress on the bus, DQS will be transitioning from Hi-Z to logic LOW. If a previous write was in
progress, DQS could be HIGH, LOW, or transitioning from HIGH to LOW at this time, depending on t DQSS.
22. The maximum limit for this parameter is not a device limit. The device operates with a greater value for this parameter, but
system performance (bus turnaround) will degrade accordingly.
23. A low level on DQS may be maintained during High-Z states (DQS drivers disabled) by adding a weak pull-down element in
the system. It is recommended to turn off the weak pull-down element during read and write bursts (DQS drivers enabled).
24. At least one clock cycle is required during tWR time when in auto precharge mode.
25. tDAL = (tWR/tCK) + (tRP/tCK): for each of the terms, if not already an integer, round to the next higher integer.
26. There must be at least two clock pulses during the tXSR period.
27. There must be at least one clock pulse during the tXP period.
28. tREFI values are dependent on density and bus width.
29. A maximum of 8 Refresh commands can be posted to any given LPDDR, meaning that the maximum absolute interval
between any Refresh command and the next Refresh command is 8*tREFI.
9.5.1
CAS Latency Definition (With CL = 3)
T0
T1
T2
READ
NOP
NOP
T2n
T3
T3n
T4
T4n
T5
T5n
T6
CK
CK
Command
NOP
NOP
NOP
NOP
CL=3
tRPST
tDQSCKmin
tDQSCKmin
tRPRE
DQS
tLZmin
All DQ,
collectively
T2
T2n
T3
T3n
T4
T4n
T5
T5n
tLZmin
1) DQ transitioning after DQS transition define tDQSQ window.
2) ALL DQ must transition by tDQSQ after DQS transitions, regardless of tAC
3) tAC is the DQ output window relative to CK,and is the long term component of DQ skew.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 56 -
W94AD6KB / W94AD2KB
9.5.2
Output Slew Rate Characteristics
PARAMETER
MIN
MAX
UNIT
NOTES
Pull-up and Pull-Down Slew Rate for Full Strength Driver
0.7
2.5
V/nS
1,2
Pull-up and Pull-Down Slew Rate for Three-Quarter Strength Driver
0.5
1.75
V/nS
1,2
Pull-up and Pull-Down Slew Rate for Half Strength Driver
0.3
1.0
V/nS
1,2
Output Slew rate Matching ratio (Pull-up to Pull-down)
0.7
1.4
-
3
Notes:
1. Measured with a test load of 20 pF connected to VSSQ.
2. Output slew rate for rising edge is measured between VILD(DC) to VIHD(AC) and for falling edge between VIHD(DC) to
VILD(AC).
3. The ratio of pull-up slew rate to pull-down slew rate is specified for the same temperature and voltage, over the entire
temperature and voltage range. For a given output, it represents the maximum difference between pull-up and pull-down
drivers due to process variation.
9.5.3
AC Overshoot/Undershoot Specification
PARAMETER
SPECIFICATION
Maximum peak amplitude allowed for overshoot
0.5 V
Maximum peak amplitude allowed for undershoot
0.5 V
The area between overshoot signal and VDD must be less than or equal to
3 V-nS
The area between undershoot signal and GND must be less than or equal to
3 V-nS
AC Overshoot and Undershoot Definition
2.5
Overshoot Area
2.0
VDD
1.5
Voltage (V)
9.5.4
1.0
Max Amplitude = 0.5V
Max Area = 3V-nS
0.5
VSS
0
-0.5
Undershoot Area
Time (nS)
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 57 -
W94AD6KB / W94AD2KB
10. PACKAGE DIMENSIONS
10.1 LPDDR x16
Package Outline VFBGA 60 Balls (8x9 mm2, Ball pitch: 0.8mm, Ø =0.42mm)
–A–
D1
aaa
D
PIN #1
e
–B–
K
J
H
G
E
E1
F
E
D
C
Φb
B
A
2
1
2
3
4
5
6
7
8
aaa
9
CAVITY
MIN
NOM
MAX
MIN
NOM
MAX
A
---
---
1.025
---
---
0.040
A1
0.270
0.320
0.370
0.011
0.013
0.015
D
7.90
8.00
8.10
0.311
0.315
0.319
E
8.90
9.00
9.10
0.350
0.354
0.358
D1
---
6.40
---
---
0.252
-----
E1
---
7.20
---
---
0.283
e
---
0.80
---
---
0.031
---
b
0.40
0.45
0.50
0.016
0.018
0.020
aaa
0.15
0.006
bbb
0.20
0.008
ccc
0.12
0.005
A1
Symbol
Dimension in inch
A
//
Dimension in mm
bbb C
–C–
SOLDER BALL
ccc
SEATING PLANE
C
BALL LAND
1
BALL OPENING
Note: 1. Ball land : 0.5mm. Ball opening : 0.4mm. PCB Ball land suggested ≤ 0.4mm
2. Dimensions apply to Solder Balls Post-Reflow. The Pre-Reflow diameter is 0.42 on a 0.4 SMD Ball Pad
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 58 -
W94AD6KB / W94AD2KB
10.2 LPDDR x32
Package Outline VFBGA 90 Balls (8x13 mm2, Ball pitch: 0.8mm, Ø =0.42mm)
–A–
D1
aaa
D
PIN #1
e
–B–
R
P
N
M
L
K
E
E1
J
H
G
F
E
D
C
Φb
B
A
2
1
2
3
4
5
6
7
8
aaa
9
CAVITY
MIN
NOM
MAX
MIN
NOM
MAX
A
---
---
1.025
---
---
0.040
A1
0.270
0.320
0.370
0.011
0.013
0.015
D
7.90
8.00
8.10
0.311
0.315
0.319
E
12.90
13.00
13.10
0.508
0.512
0.516
D1
---
6.40
---
---
0.252
---
E1
---
11.20
---
---
0.441
---
e
---
0.80
---
---
0.031
---
b
0.40
0.45
0.50
0.016
0.018
0.020
aaa
0.15
0.006
bbb
0.20
0.008
ccc
0.12
0.005
bbb C
A1
Symbol
Dimension in inch
A
//
Dimension in mm
–C–
SOLDER BALL
SEATING PLANE
ccc C
BALL LAND
1
BALL OPENING
Note: 1. Ball land : 0.5mm. Ball opening : 0.4mm. PCB Ball land suggested ≤ 0.4mm
2. Dimensions apply to Solder Balls Post-Reflow. The Pre-Reflow diameter is 0.42 on a 0.4 SMD Ball Pad
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 59 -
W94AD6KB / W94AD2KB
11. REVISION HISTORY
VERSION
DATE
PAGE
DESCRIPTION
P01-001
Dec. 19, 2012
All
P01-002
Mar. 25, 2013
50, 51
A01-001
Jul. 01, 2013
All
52
Remove text "Preliminary" & release to active version
Add PASR value
A01-002
Jul. 30, 2013
2
Add 166MHz ordering information
A01-003
Nov. 27, 2013
8
Remove Reduce page
A01-004
Jul. 21, 2014
All
6
58
59
Refine format
Update section 4.2 LPDDR x32 ball assignment figure
Update symbol A1 spec of VFBGA 60 balls package
Update symbol A1 spec of VFBGA 90 balls package
A01-005
Oct. 02, 2014
58
Revise symbol E1 spec typo of VFBGA 60 balls package
First preliminary release
Update IDD3P & IDD3PS value
Important Notice
Winbond products are not designed, intended, authorized or warranted for use as components
in systems or equipment intended for surgical implantation, atomic energy control
instruments, airplane or spaceship instruments, transportation instruments, traffic signal
instruments, combustion control instruments, or for other applications intended to support or
sustain life. Further more, Winbond products are not intended for applications wherein failure
of Winbond products could result or lead to a situation wherein personal injury, death or
severe property or environmental damage could occur.
Winbond customers using or selling these products for use in such applications do so at their
own risk and agree to fully indemnify Winbond for any damages resulting from such improper
use or sales.
Publication Release Date: Oct. 02, 2014
Revision: A01-005
- 60 -