TABLE OF CONTENTS
1. GENERAL DESCRIPTION ................................................................................................... 4
2. FEATURES ........................................................................................................................... 4
3. PIN DESCRIPTION ............................................................................................................... 5
3.1 Signal Descriptions .......................................................................................................................... 6
4. BLOCK DIAGRAM ............................................................................................................... 8
4.1 Block Diagram .................................................................................................................................8
4.2 Simplified State Diagram ................................................................................................................. 9
5. FUNCTION DESCRIPTION .................................................................................................10
5.1 Initialization ....................................................................................................................................11
5.1.1 Initialization Flow Diagram ................................................................................................................. 12
5.2 Register Definition .........................................................................................................................13
5.2.1 Mode Register ............................................................................................................................ 13
5.3 Burst Definition .............................................................................................................................. 13
5.2.1.2 Burst Type ............................................................................................................................... 14
5.2.2 Extended Mode Register ............................................................................................................ 14
5.2.2.1 Partial Array Self Refresh ....................................................................................................... 15
5.2.2.2 Temperature Compensated Self Refresh ............................................................................... 15
5.2.2.3 Output Drive Strength ............................................................................................................. 15
6.COMMANDS .................................................................................................................... 16
7. OPERATION ........................................................................................................................ 21
7.1. Deselect ........................................................................................................................................ 21
7.2. No Operation ................................................................................................................................ 21
7.4. Active ............................................................................................................................................ 22
7.5. Read ............................................................................................................................................. 23
7.5.1 Read to Read ...................................................................................................................................... 25
6.5.11 Burst Terminate ................................................................................................................................. 30
7.6 Write .............................................................................................................................................. 30
7.6.1 Write to Write ..................................................................................................................................... 32
7.7 Precharge ...................................................................................................................................... 36
7.8 Auto Precharge ............................................................................................................................. 37
7.9 Refresh Requirements .................................................................................................................. 37
7.10 Auto Refresh ............................................................................................................................... 37
7.11 Self Referesh ............................................................................................................................... 37
7.12 Power Down ................................................................................................................................ 39
7.13 Deep Power Down ...................................................................................................................... 41
7.14 Clock Stop ................................................................................................................................... 42
8. ELECTRICAL CHARACTERISTIC ......................................................................................43
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8.1 Absolute Maximum Ratings .......................................................................................................... 43
8.2 Input/Output Capacitance ............................................................................................................. 43
8.3 Electrical Characteristics and AC/DC Operating Conditions ........................................................ 44
8.3.1 Electrical Characteristics and AC/DC Operating Conditions ............................................................... 44
8.4 IDD Specification Parameters and Test Conditions ..................................................................... 45
8.4.1 IDD Specification Parameters and Test Conditions ............................................................................ 45
8.5 AC Timings .................................................................................................................................... 47
8.5.2 Output Slew Rate Characteristics ....................................................................................................... 51
7.5.3 AC Overshoot/Undershoot Specification ............................................................................................. 51
8.5.4 AC Overshoot and Undershoot Definition ........................................................................................... 52
9. PACKAGE DIMENSION ..................................................................................................... 53
10. ORDERING INFORMATION ............................................................................................. 54
11. REVISION HISTORY ........................................................................................................ 55
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Revision History 256M
AS4C16M16MD1- 60-ball FPBGA PACKAGE
Revision Details Date
Rev 1.0 Preliminary datasheet Mar 28, 2013
AS4C16M16MD1
256Mb MOBILE DDR SDRAM
Rev 1.1 Temperature Changed from -25 to -30°C to +85°C Oct 24, 2015
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Alliance Memory Inc. 511 Taylor Way, San Carlos, CA 94070 TEL: (650) 610-6800 FAX: (650) 620-9211
Alliance Memory Inc. reserves the right to change products or specification without notice
1. GENERAL DESCRIPTION
This AS4C16M16MD1 is 268,435,456 bits synchronous double data rate Dynamic RAM. Each 67,108,864 bits bank is organized
as 8,192 rows by 512 columns by 16 bits, fabricated with Alliance Memory's high performance CMOS technology. This device uses a
double data rate architecture to achieve high- speed operation. The double data rate architecture is essentially a 2n-prefetch
architecture with an interface designed to transfer two data words per clock cycle at the I/O balls. Range of operating
frequencies, programmable burst lengths and programmable latencies allow the same device to be useful for a variety of high
bandwidth and high performance memory system applications.
2. FEATURES
•AS4C16M16MD1
• CAS Latency: 2 and 3
VDD/VDDQ = 1.7~1.95V
•Burst Length: 2, 4, 8 and 16
• Data width: x16
• Burst Type: Sequential or Interleave
• Clock rate: 200MHz,166MHz , 133MHz
• 64 ms Refresh period
• Partial Array Self-Refresh(PASR)
• Interface: LVCMOS
•Auto Temperature Compensated Self-Refresh(ATCSR)
• Operating Temperature Range
• Power Down Mode
• Deep Power Down Mode (DPD Mode)
Extended (-30℃ to + 85 ℃)
• Programmable output buffer driver strength
•Four internal banks for concurrent operation
• Data mask (DM) for write data
• Clock Stop capability during idle periods
• Auto Pre-charge option for each burst access
• Double data rate for data output
•Differential clock inputs (CK and CK )
• Bidirectional, data strobe (DQS)
Table 1. Ordering Information
B: indicates BGA package
C: indicates Extended temp
I: indicates Industrial temp (to follow at a later date)
N: Indicates lead free and ROHS compliant
Part Number
Clock
rate
Package
Temperature
Temp Range
AS4C16M16MD1-6BCN
166MHz
60-ball FPBGA
(8.0X9.0 mm)
Extended
-30°C to +85°C
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3. PIN DESCRIPTION
60- Ball FPBGA Assignment
TOP VIEW
1 2 3 4 5
6
7 8 9
A
VSS DQ15 VSSQ
B
VDDQ DQ13 DQ14
C
VSSQ DQ11 DQ12
D
VDDQ DQ9 DQ10
E
VSSQ UDQS DQ8
F
VSS UDM NC
G
CKE CK /CK
H
A9 A11 A12
VDDQ DQ0 VDD
DQ1 DQ2 VSSQ
DQ3 DQ4 VDDQ
DQ5 DQ6 VSSQ
DQ7 LDQS VDDQ
NC LDM VDD
/WE /CAS /RAS
/CS BA0 BA1
J
A6 A7 A8 A10/AP A0 A1
K
VSS A4 A5 A2 A3 VDD
Figure 1 — PIN DESCRIPTION
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3.1 Signal Descriptions
SIGNAL NAME TYPE DESCRIPTION
CK,/CK Input
Clock: 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.
CKE Input
Clock Enable: 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 POWERDOWN (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.
/CS Input
Chip Select: CS enables (registered LOW) and disables (registered
HIGH) the command decoder. All commands are 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.
/RAS,/CAS,/WE
Input
Command Inputs: RAS, CAS and WE (along with CS) define the
command being entered.
LDM,UDM Input
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. For
x16 devices, LDM corresponds to the data on DQ0-DQ7, UDM
corresponds to the data on DQ8-DQ15.
BA0,BA1
Input
Bank Address Inputs: BA0 and BA1 define to which bank an ACTIVE,
READ, WRITE or PRECHARGE command is being applied.
A [n : 0]
Input
Address Inputs: 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.
DQ0-DQ15 I/O
Data Bus: Input / Output
LDQS,UDQS I/O
Data Strobe: Output with read data, input with write data. Edge-aligned
with read data, centered with write data. Used to capture write data.
LDQS corresponds to the data on DQ0-DQ7, UDQS corresponds to the
data on DQ8-DQ15.
NC - No Connect: No internal electrical connection is presen
VDDQ Supply I/O Power Supply
VSSQ Supply I/O Ground
VDD Supply Power Supply
VSS Supply Ground
Table 1 — Signal Descriptions
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3.2 Mobile DDR SDRAM Addressing Table
ITEM
256 Mb
Number of banks
4
Bank address pins
BA0,BA1
Auto precharge pin
A10/AP
X16
Row addresses
A0-A12
Column addresses
A0-A8
tREFI(µs)
7.8
Table 2 — Addressing Table
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4. BLOCK DIAGRAM
4.1 Block Diagram
Figure.2 — Block Diagram
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4.2 Simplified State Diagram
Figure.3 — State Diagram
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5. FUNCTION DESCRIPTION
The LPDDR SDRAM is a high speed CMOS, dynamic random-access memory internally configured as a quad-bank
DRAM. These devices contain the following number of bits: 256 Mb has 268,435,456 bits The LPDDR SDRAM uses a double
data rate architecture to achieve high speed operation. The double data rate architecture is essentially a 2n prefetch architecture
with an interface designed to transfer two data words per clock cycle at the I/O pins. A single read or write access for the LPDDR
SDRAM effectively consists of a single 2n-bit wide, one clock cycle data transfer at the internal DRAM core and two
corresponding n-bit wide, one-half-clockcycle data transfers at the I/O pins.
Read and write accesses to the LPDDR SDRAM are burst oriented; accesses start at a selected location and continue for a
programmed number of locations in a programmed sequence. Accesses begin with the registration of an ACTIVE command,
which is then followed by a READ or WRITE command. The address bits registered coincident with the ACTIVE command are
used to select the bank and the row to be accessed. The address bits registered coincident with the READ or WRITE command
are used to select the bank and the starting column location for the burst access.
Prior to normal operation, the LPDDR SDRAM must be initialized. The following section provides detailed information covering
device initialization, register definition, command description and device operation.
5.1 Initialization
LPDDR SDRAMs 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 Initialization Flow diagram is shown in Figure 4, and the
Initialization Flow sequence in Figure 5. 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 Steps 1 through 11.
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 LV-CMOS logic high level
2. Once the system has established consistent device power and CKE is driven high, it is safe to apply stable clock
3. There must be at least 200 μs 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.
4. Issue a PRECHARGE ALL command.
5. Provide NOPs or DESELECT commands for at least tRP time.
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.
7. Using the MRS command, load the base mode register. Set the desired operating modes.
8. Provide NOPs or DESELECT commands for at least tMRD time.
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 programming is not important.
10. Provide NOP or DESELCT commands for at least tMRD time.
11. The DRAM has been properly initialized and is ready for any valid command.
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5.1.1 Initialization Flow Diagram
Figure.4 — Flow Diagram
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Figure 5 — Initialization Waveform Sequence
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5.2 Register Definition
5.2.1 Mode Register
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 below table.
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), A4-A6 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.
Mode BA1 BA0 A[n]~A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
Standard
MRS 0 0 Reserved
CAS Latency
010b: 2
011b: 3
Burst Type
0:Sequential
1:Interleave
Burst Length
001b : 2
010b : 4
011b : 8
100b : 16
Reserved 0 1 Reserved
Extended
MRS 1 0 Reserved
Drive Strength
000b: Full
Strength Driver
001b: Half
Strength Driver
010b:Quarter
Strength Driver
011b:Octant
Strength Driver
100b:ThreeQuarters
Strength Driver
Reserved
PASR
000b : All banks
001b : 1/2 array(BA1=0)
010b : ¼ array(BA1=BA0=0)
101b : 1/8 array
(BA1 = BA0 = Row Addr MSB = 0)
110b : 1/16 array
(BA1=BA0 = Row Addr 2 MSB = 0)
5.2.1.1 Burst Length
Table 3 – Mode Register Table
Read and write accesses to the LPDDR SDRAM are burst oriented, with the burst length being set as in Table 6, and the burst
order as in Table 4.
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. A burst
length of 16 is optional and some vendors may choose to implement it.
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5.3 Burst Definition
BURST
LENGTH
STARTING COLUMN
ADDRESS
ORDER OF ACCESSES WITHIN A BURST
(HEXADECIMAL NOTATION)
A3
A2
A1
A0
SEQUENTIAL
INTERLEAVED
2
0
0 – 1
0 – 1
1
1 – 0
1 – 0
4
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
8
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
16
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
1
1
1
1
0
1
1
1
0
1
D-E-F-0-1-2-3-4-5-6-7-8-9-A-B-C
E-F-0-1-2-3-4-5-6-7-8-9-A-B-C-D
F-0-1-2-3-4-5-6-7-8-9-A-B-C-D-E
D-C-F-E-9-8-B-A-5-4-7-6-1-0-3-2
E-F-C-D-A-B-8-9-6-7-4-5-2-3-0-1
F-E-D-C-B-A-9-8-7-6-5-4-3-2-1-0
Table 4 – Burst Definition
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Notes:
1.
16-word burst length is optional.
2.
For a burst length of two, A1-An selects the two data element block; A0 selects the first access within the block.
3.
For a burst length of four, A2-An selects the four data element block; A0-A1 selects the first access within the block.
4.
For a burst length of eight, A3-An selects the eight data element block; A0-A2 selects the first access within the block.
5.
For the optional burst length of sixteen, A4-An selects the sixteen data element block; A0-A3 selects the first access within the block.
6.
Whenever a boundary of the block is reached within a given sequence, the following access wraps within the block
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 and A4-An when the burst length is set to 16 (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.
5.2.1.2 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 Table 4.
5.2.1.3 Read Latency
The READ latency, or 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 3 clocks. Some vendors may offer additional options of 2 clocks and/or 4
clocks.
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 + 2tCK +
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. Lastly, if a READ command is registered at a clock edge n and the latency is 4 clocks, the first data element will be valid
at n + 3tCK + tAC.
5.2.2 Extended Mode Register
The Extended Mode Register controls functions beyond those controlled by the Mode Register; these additional functions
include output drive strength selection, Temperature Compensated Self Refresh (TCSR) and Partial Array Self Refresh (PASR),
as shown in Figure 7. The TCSR and PASR functions are optional and some vendors may choose not to implement them. Both
TCSR and PASR are effective is 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, A3-A4 the TCSR, A5-A6 the Drive 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.
Address bits A0-A2 specify PASR, A3-A4 the TCSR, A5-A7 the Drive Strength.
A logic 0 should be programmed to all the undefined address bits to ensure future compatibility.
Reserved states should not be used, as unknown operation or incompatibility with future versions may result.
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BA1 BA0 A[n]~A8 A7 A6 A5 A4 A3 A2 A1 A0
1 0 Reserved
Drive Strength
000b: Full
Strength Driver
001b: Half
Strength Driver
010b:Quarter
Strength Driver
011b:Octant
Strength Driver
100b:ThreeQuarters
Strength Driver
Reserved
PASR
000b : All banks
001b : 1/2 array(BA1=0)
010b : ¼ array(BA1=BA0=0)
101b : 1/8 array
(BA1 = BA0 = Row Addr MSB = 0)
110b : 1/16 array
(BA1=BA0 = Row Addr 2 MSB = 0)
5.2.2.1 Partial Array Self Refresh
Partial Array Self Refresh (PASR) is an optional feature. With 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. Some vendors may have additional options of
1/8 and 1/16 array refreshed as well. Data outside the defined area will be lost. Address bits A0 to A2 are used to set PASR.
5.2.2.2 Temperature Compensated Self Refresh
This function can be used in the LPDDR SDRAM to set refresh rates based on case temperature.This allows the system to
control power as a function of temperature. Address bits A3 and A4 are used to set TCSR.
Some vendors may choose to have Internal Temperature Compensated Self Refresh feature, which should automatically adjust
the refresh rate based on the device temperature without any register update needed. To maintain backward compatibility,
devices having internal TCSR, ignore (don’t care) the inputs to address bits A3 and A4 during EMRS programming.
5.2.2.3 Output Drive Strength
The drive strength could be set to full or half or three-quarters strength via address bits A5 and A6 and A7. The I-V curves for
the full drive strength and half drive strength and three-quarters drive strength are included in this document (cf. Table 17 and
Table 18, Figure 45 and Figure 46 and Figure 47).
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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). Figure 6 shows basic timing parameters for all commands.
Table 5, Table 6 and Table 7 provide a quick reference of available commands.
Table 8 and Table 9 provide the current state / next state information. This is followed by a verbal description of each command.
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
3
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 or enter DEEP POWER DOWN L H H L X X X 4, 5,12
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 10
Table 5 – Truth Table -Commands
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 Autoprecharge 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.
FUNCTION DM DQ NOTES
Write Enable L Valid 1
Write Inhibit H X 1
Notes: Table 6 –Truth Table – DM operations
1. Used to mask write data, provided coincident with the corresponding data.
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CKEn-1 CKEn CURRENT STATE COMMANDn ACTIONn 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:
Table 7 – Truth Table - CKE [Notes 1 - 10]
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 Mobile DDR SDRAM immediately prior to clock edge n.
3. COMMANDn is the command registered at clock edge n, and ACTIONn is the result of COMMANDn.
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.
Basic Timing Parameters for Commands
Figure.6 — Basic Timing Parameters
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CURRENT STATE CS RAS CAS
WE
COMMAND ACTION NOTES
Any
H X X X DESELECT NOP or Continue previous operation
L H H H No Operation NOP or Continue previous operation
Idle
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
Row Active
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
Read (Auto precharge
Disabled)
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
Write (Auto precharge
Disabled)
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
Notes: Table 8 – Current State BANK n- Command to BANK n
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 Prechrge 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 tRCD 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.
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 tRFC is met. Once tRFC is met, the
Mobile DDR SDRAM will be in an ‘all banks idle’ state.
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Accessing Mode Register: Starts with registration of a MODE REGISTER SET command and ends when tMRD has been
met. Once tMRD is met, the Mobile DDR SDRAM 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.
CURRENT
STATE
CS RAS CAS WE COMMAND ACTION NOTES
Any
H X X X DESELECT NOP or Continue previous Operation
L H H H NOP NOP or Continue previous Operation
Idle X X X X ANY Any command allowed to bank m
Row Activating,
Active, or
Precharging
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
Read with Auto
Precharge
disabled
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
Write with Auto
Precharge
disabled
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
Read with Auto
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
Write with Auto
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
Table 9 – Current State BANK n- Command to BANK m
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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.
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7.OPERATION
7.1. Deselect
The DESELECT function (/CS HIGH) prevents new commands from being executed by the Mobile DDR SDRAM. The Mobile
DDR SDRAM is effectively deselected. Operations already in progress are not affected.
7.2. No Operation
The NO OPERATION (NOP) command is used to instruct the selected DDR SDRAM to perform a NOP (/CS = LOW, / RAS =
/CAS = /WE = HIGH). This prevents unwanted commands from being registered during idle or wait states. Operations already in
progress are not affected.
CK
CK
CKE
CS
RAS
CAS
WE
A0-An
BA0,BA1
(High)
= Don't Care
Figure 7 — NOP Command
7.3 MODE REGISTER
The Mode Register and the Extended Mode Register are loaded via the address inputs. See Mode Register and the Extended
Mode Register descriptions for further details.
The MODE REGISTER SET command (see Figure 8) 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 (see Figure 9) is met.The values of the mode register and
extended mode register will be retained even when exiting deep power-down.
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Figure 8 — Mode Register Set Command
Figure 9 — Mode Register Set Command Timing
7.4. 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 (see Figure 10): 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. Figure 11 shows the tRCD and tRRD definition.
The row remains active until a PRECHARGE command (or READ or WRITE command with Auto Precharge) is
issued to the bank.
A PRECHARGE command (or READ or WRITE command with Auto Precharge) must be issued before opening a different row in the same
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bank
Figure 10 — Active Command
Figure 11 — Bank Activation Command Cycle
7.5. Read
The READ command (see Figure 12) 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.
The basic Read timing parameters for DQs are shown in Figure 13; they apply to all Read operations.
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 Figure 14 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.
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Figure 12 — Read Command
Figure 13 — Basic Read Timing Parameters
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Figure 14 — Read Burst Showing CAS Latency
7.5.1 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 Figure 15.
A READ command can be initiated on any clock cycle following a previous READ command. Non-consecutive Reads are shown
in Figure 16.
Full-speed random read accesses within a page or pages can be performed as shown in Figure 17.
7.5.2 Read Burst Terminate
Data from any READ burst may be truncated with a BURST TERMINATE command, as shown in Figure 18. TheBURST
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.
7.5.3 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 Figure 19 for the case of nominal tDQSS .
5.5.4 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 Figure 20. 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.
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Figure 15 — Consecutive Read Bursts
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CK
CK
Command READ NOP NOP READ NOP NOP
Address
DQS
DQ
DQS
DQ
BA,Col n
CL=2
DO n
CL=3
BA,Col b
DO n
DO b
1) DO n (or b) =Data Out from column n (or column b)
2) BA,Col n (or b) =Bank A,Column n (or column b)
= Don't Care
3) Burst Length=4; 3 subsequent elements of Data Out appear in the programmed order following DO n (or b)
4) Shown with nominal tAC, tDQSCK and tDQSQ
Figure 16 — Non-Consecutive Read Bursts
Figure 17 — Random Read Bursts
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.
Figure 18 — Terminating a Read Burst
Figure 19 — Read To Write
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Figure 20 — Read To Precharge
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6.5.11 Burst Terminate
The BURST TERMINATE command is used to truncate read bursts (with Auto Pre-charge 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.
Figure 21 — Burst Terminate Command
7.6 Write
The WRITE command (see Figure 22) 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.
Basic Write timing parameters for DQs are shown in Figure 23; 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.
Figure 22 — Write Command
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Figure 23 — Basic Write Timing Parameters
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. Figure 24 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.
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Figure 24 — Write Burst (min. and max. tDQSS)
7.6.1 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.
Figure 25 shows concatenated write burst of 4. An example of non-consecutive write bursts is shown in Figure 26. Full-
speed random write accesses within a page or pages can be performed as shown in Figure 27.
7.6.2 Write to Read
Data for any Write burst may be followed by a subsequent READ command. To follow a Write without truncating the write burst,
tWTR should be met as shown in Figure 28.
Data for any Write burst may be truncated by a subsequent READ command as shown in Figure 29. 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.
7.6.3 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 Figure 30.
Data for any WRITE burst may be truncated by a subsequent PRECHARGE command as shown in Figure 31. 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 Figure 31. Following the PRECHARGE command, a subsequent command to the same bank cannot be
issued until tRP is met
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Figure 25 — Concatenated Write Bursts
Figure 26 — Non-Consecutive Write Bursts
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Figure 27 — Random Write Cycles
Figure 28 — Non-Interrupting Write to Read
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Figure 29 — Interrupting Write to Read
Figure 30 — Non-Interrupting Write to Precharge
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CK
CK
Command WRITE
NOP NOP
NOP
PRE NOP
Address
BA,Col b
BA,Col n BA
a(or
all)
DQS
DQ
tDQSSmax tWR
*2
DI b
DM
1) Dl b = Data in to column b.
*1 *1
*1
*1
= Don't Care
2) An interrupted burst of 4, 8 or 16 is shown, 2 data elements are written.
3) t
WR
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
Figure 31 — Interrupting Write to Precharge
7.7 Precharge
The PRECHARGE command (see Figure 32) 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.
CK
CK
CKE
CS
RAS
CAS
WE
Address
A10
BA0,BA1
(High)
All Banks
One Bank
BA
= Don't Care
BA=BANK Address
(if A10 = L,otherwise Don't Care)
Figure 32 — Precharge command
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.
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7.8 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 precharging time (tRP) is completed. This is determined as if an xplicit PRECHARGE
command was issued at the earliest possible time, as described for each burst type in the Operation section of this specification.
7.9 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.
7.10 Auto Refresh
AUTO REFRESH command (see Figure 33) 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.
CK
CK
CKE
CS
RAS
CAS
WE
A0-An
BA0,BA1
(High)
= Don't Care
Figure 33 — Auto Refresh Command
7.11 Self Referesh
The SELF REFRESH command (see Figure 34) 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 tXS 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.
Figure 36 shows Self Refresh entry and exit.
In the Self Refresh mode, two additional power-saving options exist: Temperature Compensated Self Refresh (TCSR) and
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Partial Array Self Refresh (PASR); they are described in the Extended Mode Register section .
Figure 34 — Self Refresh command
Figure 35 — Auto Refresh Cycles Back-to-Back
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7.12 Power Down
Figure 36 — Self Refresh Entry and Exit
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.
Figure 37 shows Power-down entry and exit.
For Clock Stop during Power-Down mode, please refer to the Clock Stop subsection in this specification
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Figure 37 — Power-Down Entry and Exit
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7.13 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 (see Figure 21) 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 200 ȝs.
After 200 ȝs a complete re-initialization is required following steps 4 through 11 as defined for the initialization sequence.
Deep Power-Down entry and exit is shown in Figure 38.
Figure 38 — Deep Power-Down Entry and Exit
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7.14 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.
Figure 39 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
Figure 39 — Clock Stop Mode Entry and Exit
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8. ELECTRICAL CHARACTERISTIC
8.1 Absolute Maximum Ratings
PARAMETER SYMBOL VALUES UNITS
MIN MAX
Vol
tage on VDD relative to VSS VDD −0.3 2.7 V
Vol
tage on VDDQ relative to VSS VDDQ −0.3 2.7 V
Vol
tage on any pin relative to VSS VIN, VOUT −0.3 2.7 V
O
perating temperature : Tj -30
-40
85
85
°C
Storag
e Temperature TSTG −55 150 °C
Short
Circuit Output Current IOUT ±50 mA
Po
wer Dissipation PD 1.0 W
8.2 Input/Output Capacitance
[Notes 1-3]
PARAMETER SYMBOL MIN MAX UNITS NOTES
I
nput capacitance, CK, CK CCK 1.5 3.0 pF
I
nput capacitance delta, CK, CK CDCK 0.25 pF
I
nput capacitance, all other input-only pins CI 1.5 3.0 pF
I
nput capacitance delta, all other input-only pins CDI 0.5 pF
I
nput/ output capacitance, DQ,DM,DQS CIO 3.0 5.0 pF 4
I
nput/output capacitance delta, DQ, DM, DQS CDIO 0.50 pF 4
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.
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8.3 Electrical Characteristics and AC/DC Operating Conditions
All values are recommended operating conditions unless otherwise noted.
8.3.1 Electrical Characteristics and AC/DC Operating Conditions
(VDD/VDDQ: 1.7~1.95V)
PARAMETER/CONDITION SYMBOL MIN MAX UNITS NOTES
Supply Voltage
VDD
1.70
1.95
V
I/O Supply Voltage
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
CLOCK INPUTS (CK, CK )
DC Input Voltage
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
AC Differential Crossing Voltage
VIX
0.4*VDDQ
0.6*VDDQ
V
3
DATA INPUTS (DQ, DM, DQS)
DC Input High Voltage
VIHD (DC)
0.7*VDDQ
VDDQ + 0.3
V
DC Input Low Voltage
VILD (DC)
−0.3
0.3*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
Control OUTPUT(TQ)
Output High Voltage (IoH=-0.1mA)
VoH
0.9*VDDQ
V
Output Low Voltage (IoL=+0.1mA)
VoL
0.1*VDDQ
V
DATA OUTPUTS (DQ, DQS)
DC Output High Voltage (IOH=−0.1mA)
VOH
0.9*VDDQ
-
V
DC Output Low Voltage (IOL=0.1mA)
VOL
-
0.1*VDDQ
V
Leakage Current
Input Leakage Current5
liL
-1
1
uA
Output Leakage Current
loL
-5
5
uA
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 CK .
3. The value of VIX is expected to be 0.5*VDDQ and must track variations in the DC level of the same.
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8.4 IDD Specification Parameters and Test Conditions
8.4.1 IDD Specification Parameters and Test Conditions
[Recommended Operating Conditions; Notes 1-3]
(256Mb, X16)
PARAMETER
SYMBOL
TEST CONDITION
-5
- 6
- 75
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
40 38 35 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
0.4 0.4 0.4 mA
Precharge power-
down standby
current with clock
stop
IDD2PS
all banks idle, CKE is LOW; CS is HIGH, CK = LOW,
CK = HIGH; address and control inputs are
SWITCHING; data bus inputs are STABLE
0.4 0.4 0.4 mA
Precharge non
power-down
standby current
IDD2N
all banks idle, CKE is HIGH; CS is HIGH, tCK = tCKmin;
address and control inputs are SWITCHING; data bus
inputs are STABLE
10 10 10 mA
Precharge non
power-down
standby current
with clock stop
IDD2NS
all banks idle, CKE is HIGH; CS is HIGH, CK =
LOW, CK = HIGH; address and control inputs are
SWITCHING; data bus inputs are STABLE
3 3 3 mA
Active power-
down standby
current
IDD3P
one bank active, CKE is LOW; CS is HIGH, tCK =
tCKmin;address and control inputs are SWITCHING; data
bus inputs are STABLE
3 3 3 mA
Active power-
down standby
current with clock
stop
IDD3PS
one bank active, CKE is LOW; CS is HIGH, CK = LOW,
CK = HIGH; address and control inputs are
SWITCHING; data bus inputs are STABLE
3 3 3 mA
Active non power-
down standby
current
IDD3N
one bank active, CKE is HIGH; CS is HIGH, tCK =
tCKmin; address and control inputs are SWITCHING; data
bus inputs are STABLE
25 20 20 mA
Active non power-
down standby
current with clock
stop
IDD3NS
one bank active, CKE is HIGH; CS is HIGH, CK = LOW,
CK = HIGH; address and control inputs are
SWITCHING; data bus inputs are STABLE
15 12 12 mA
Operating burst
read current IDD4R
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
75 70 70 mA
Operating burst
write current IDD4W
one bank active; BL = 4; tCK = tCKmin ; continuous write
bursts; address inputs are SWITCHING; 50% data change
each burst transfer
55 50 50 mA
Auto-Refresh
Current IDD5
tRC = tRFCmin ; tCK = tCKmin ; burst refresh; CKE is
HIGH; address and control inputs are SWITCHING; data
bus inputs are STABLE
50 50 50 mA
Deep Power-
Down current
IDD8(4)
Address and control inputs are STABLE; data bus inputs
are STABLE
10 10 10 uA
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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 V
IN
≤
0.1 * V
DDQ
;
HIGH is defined as V
IN
≥ 0.9 * V
DDQ
;
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 a typical value at 25
℃.
IDD6 Conditions :
IDD6 Normal Power Units
TCSR Range
45
℃
85
℃
uA
Full Array
250
400
1/2 Array
200
300
1/4 Array
180
250
1/8 Array
150
230
1/16 Array
130
220
Notes:
1.
Measured with outputs open.
2.
Internal TCSR can be supported.
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8.5 AC Timings
[Recommended Operating Conditions: Notes 1-9]
PARAMETER SYMBOL
- 5
- 6
- 75
UNIT NOTES
MIN
MAX
MIN
MAX
MIN
MAX
DQ output access time
from CK/
CK
CL=3
tAC
2.0
5.0
2.0
5.0
2.0
6.0
ns
CL=2
2.0
6.5
2.0
6.5
2.0
6.5
DQS output access time from
CK/
CK
CL=3
tDQSCK
2.0
5.0
2.0
5.0
2.0
6.0
ns
CL=2
2.0
6.5
2.0
6.5
2.0
6.5
Clock high-level width
tCH
0.45
0.55
0.45
0.55
0.45
0.55
tCK
Clock low-level width
tCL
0.45
0.55
0.45
0.55
0.45
0.55
tCK
Clock half period
tHP
Min
(tCL, tCH)
Min
(tCL, tCH)
Min
(tCL, tCH)
ns 10,11
Clock cycle time
CL=3
tCK
5
6
7.5
ns
12
CL=2
12
12
12
ns
12
DQ and DM input setup
time
fast slew rate
tDS
0.48
0.6
0.8
ns
13,14,15
slow slew rate
0.58
0.7
0.9
ns
13,14,16
DQ and DM input hold time
fast slew rate
tDH
0.48
0.6
0.8
ns
13,14,15
slow slew rate
0.58
0.7
0.9
ns
13,14,16
DQ and DM input pulse width
tDIPW
1.6
1.6
1.8
ns
17
Address and control input
setup time
fast slew rate
tIS
0.9
1.1
1.3
ns
15,18
slow slew rate
1.1
1.3
1.5
ns
16,18
Address and control input
hold time
fast slew rate
tIH
0.9
1.1
1.3
ns
15,18
slow slew rate
1.1
1.3
1.5
ns
16,18
Address and control input pulse width
tIPW
2.3
2.6
2.6
ns
17
DQ & DQS low-impedance time from CK/
CK
tLZ 1.0 1.0 1.0 ns 19
DQ & DQS high-impedance
time from CK/
CK
CL=3
tHZ
5.0
5.0
6.0
ns 19
CL=2
6.5
6.5
6.5
DQS-DQ skew
tDQSQ
0.4
0.5
0.6
ns
20
DQ/DQS output hold time from DQS
tQH
tHP-tQHS
tHP-tQHS
tHP-tQHS
ns
11
Data hold skew factor
tQHS
0.5
0.65
0.75
ns
11
Write command to 1st DQS latching
transition
tDQSS 0.75 1.25 0.75 1.25 0.75 1.25 tCK
DQS input high-level width
tDQSH
0.4
0.6
0.4
0.6
0.4
0.6
tCK
DQS input low-level width
tDQSL
0.4
0.6
0.4
0.6
0.4
0.6
tCK
DQS falling edge to CK setup time
tDSS
0.2
0.2
0.2
tCK
DQS falling edge hold time from CK
tDSH
0.2
0.2
0.2
tCK
MODE REGISTER SET command period
tMRD
2
2
2
tCK
Write preamble setup time
tWPRES
0
0
0
ns
21
Write postamble
tWPST
0.4
0.6
0.4
0.6
0.4
0.6
tCK
22
Write preamble
tWPRE
0.25
0.25
0.25
tCK
Read preamble
CL = 3
tRPRE
0.9
1.1
0.9
1.1
0.9
1.1
tCK
23
CL = 2
0.5
1.1
0.5
1.1
0.5
1.1
tCK
23
Read postamble
tRPST
0.4
0.6
0.4
0.6
0.4
0.6
tCK
ACTIVE to PRECHARGE command period
tRAS
40
70,000
42
70,000
45
70,000
ns
ACTIVE to ACTIVE command period
tRC tRAS+
tRP
tRAS+
tRP
tRAS+
tRP
ns
AUTO REFRESH to ACTIVE/AUTO
REFRESH command period
tRFC 72 72 72 ns
ACTIVE to READ or WRITE delay
tRCD
15
18
22.5
ns
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PARAMETER SYMBOL
- 5
- 6
- 75
UNIT NOTES
MIN
MAX
MIN
MAX
MIN
MAX
PRECHARGE command period
tRP
3
3
3
tCK
ACTIVE bank A to ACTIVE bank B delay
tRRD
10
12
15
ns
WRITE recovery time
tWR
15
15
15
ns
24
Auto precharge write recovery + precharge
time
tDAL
- - -
tCK 25
Internal write to Read command delay
tWTR
2
2
1
tCK
Self Refresh exit to next valid command
delay
tXSR 120 120 120 ns 26
Exit power down to next valid command
delay
tXP 2 1 1 tCK 27
CKE min. pulse width (high and low pulse
width)
tCKE 1 1 1 tCK
Refresh Period
tREF
64
64
64
ms
Average periodic refresh interval (x16)
tREFI
7.8
7.8
7.8
ȝs
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
tAC 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.
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
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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.
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
tDQSS.
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. Minimum 3 clocks of tDAL (=tWR + tRP) is required because it need minimum 2 clocks for tWR and minimum 1 clock for
tRP.
tDAL = (tWR/tCK) + (tRP/tCK): for each of the terms above, 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 dependence on density and bus width.
29. A maximum of 8 Refresh commands can be posted to any given M, meaning that the maximum absolute interval
between any Refresh command and the next Refresh command is 8*tREFI.
CAS Latency Definition (With CL=3)
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8.5.2 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 V
SSQ
.
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.
8.5.3 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
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8.5.4 AC Overshoot and Undershoot Definition
Figure 40 — AC Overshoot and Undershoot Definition
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9.PACKAGE DIMENSION
60Ball Fine Pitch BGA (8.0x9.0mm)
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19.REVISION HISTORY
VERSION
DATE
PAGE
DESCRIPTION
0.0 08/14/2012 All Initial draft
0.1 11/22/2012 All Change TYPO & Block Diagram
0.2 12/03/2012 15 EMRS Code
0.3 12/13/2012 53 Package Information
0.4 02/26/2013 Remove AAG
0.5 03/18/2013 46 Change AC Character
1.0 03/28/2013 All Change Company Name & Logo
1.1 4/11/2013 53 Change package type from AS4C16M16MD1 to ‘8x9mm’
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Alliance Memory, Inc.
511 Taylor Way,
San Carlos, CA 94070
Tel: 650-610-6800
Fax: 650-620-9211
www.alliancememory.com
Copyright © Alliance Memory
All Rights Reserved
© Copyright 2007 Alliance Memory, Inc. All rights reserved. Our three-point logo, our name and Intelliwatt are
trademarks or registered trademarks of Alliance. All other brand and product names may be the trademarks of their
respective companies. Alliance reserves the right to make changes to this document and its products at any time
without notice. Alliance assumes no responsibility for any errors that may appear in this document. The data
contained herein represents Alliance's best data and/or estimates at the time of issuance. Alliance reserves the right
to change or correct this data at any time, without notice. If the product described herein is under development,
significant changes to these specifications are possible. The information in this product data sheet is intended to be
general descriptive information for potential customers and users, and is not intended to operate as, or provide, any
guarantee or warrantee to any user or customer. Alliance does not assume any responsibility or liability arising out of
the application or use of any product described herein, and disclaims any express or implied warranties related to the
sale and/or use of Alliance products including liability or warranties related to fitness for a particular purpose,
merchantability, or infringement of any intellectual property rights, except as express agreed to in Alliance's Terms
and Conditions of Sale (which are available from Alliance). All sales of Alliance products are made exclusively
according to Alliance's Terms and Conditions of Sale. The purchase of products from Alliance does not convey a
license under any patent rights, copyrights; mask works rights, trademarks, or any other intellectual property rights of
Alliance or third parties. Alliance does not authorize its products for use as critical components in life-supporting
systems where a malfunction or failure may reasonably be expected to result in significant injury to the user, and the
inclusion of Alliance products in such life-supporting systems implies that the manufacturer assumes all risk of such
use and agrees to indemnify Alliance against all claims arising from such use.
PART NUMBERING SYSTEM
AS4C 16M16MD1 6B CN
DRAM 16M16=16Mx16
MD1=Mobile DDR1 6=166MHz B = FBGA C=Commercial
(-30° C85° C)
Indicates Pb and
Halogen Free
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