AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Revision History
1G (64M x 16 and 32M x 32) Low Power DDR2 SDRAM 134ball FBGA Package
AS4C64M16MD2A-25BIN/AS4C32M32MD2A-25BIN
Revision
Rev 1.0
Details
Preliminary datasheet
Date
Jan 2018
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
Confidential
- 1 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
DDR Sync DRAM Features
• Functionality
• Configuration
- VDD2 = 1.14–1.30V
- 64 Meg X 16 (8 Meg X 16 X 8 Banks).
- VDDCA/VDDQ = 1.14–1.30V
- 32 Meg X 32 (4 Meg X 32 X 8 Banks).
• Low Power Features
- VDD1 = 1.70–1.95V
- Interface : HSUL_12
- Low voltage power supply.
- Data width : x16 / x32
- Clock frequency range : 400 MHz
- Auto TCSR (Temperature Compensated Self
Refresh).
- Four-bit pre-fetch DDR architecture
- PASR (Partial Array Self Refresh) power-saving mode.
- Eight internal banks for concurrent operation
- DPD (Deep Power Down) Mode.
- Multiplexed, double data rate, command/address inputs;
- DS (Driver Strength) Control.
• Timing – Cycle Time
commands entered on every CK edge
- Bidirectional/differential data strobe per byte of
data(DQS/DQS#).
- DM masks write date at the both rising and falling edge of
- 2.5ns
@ RL = 6
- 3.0ns
@ RL = 5
• Operating Temperature Ranges
- Industrial
the data strobe
(-40℃ to +85℃).
• Package
- Programmable READ and WRITE latencies (RL/WL)
- 134-Ball FBGA(10.0mm x 11.5mm x 1.0mm)
- Programmable burst lengths: 4, 8, or 16
- Auto refresh and self refresh supported
- All bank auto refresh and per bank auto refresh supported
- Clock stop capability
Table 1. Ordering Information
Product Part No.
Org.
Temperature
Max Clock (MHz)
Package
AS4C64M16MD2A-25BIN
64M x 16
-40°C to 85°C
400
134-ball FBGA
AS4C32M32MD2A-25BIN
32M x 32
-40°C to 85°C
400
134-ball FBGA
Table 2. Speed Grade Information
Speed Grade
DDR2L-800
Confidential
Clock Frequency
RL
WL
400 MHz
6
3
- 2 of 125 -
tRCD (ns)
18
tRP (ns)
18
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Logic Block Diagram
Mode
Registe
r
Row Address
R Latch & decoders
R Latch & decoders
RLatch & decoders
R Latch & decoders
R Latch & decoders
RLatch & decoders
RLatch & decoders
Latch & decoders
Bank7
Bank6
Bank5
Control
Logic
Command / Address
Multiplex and
Decode
CK #
CK
CKE
CS#
CA0
CA1
CA2
CA3
CA4
CA5
CA6
CA7
CA8
CA9
x
Refresh
Counter
Row
Address
Mux
Bank4
Bank3
Bank2
Bank1
Bank0
4n
n
DRVRS
DATA
x
DQS
Generator
DQ0 – DQn-1
DQS , /DQS
Sense amp
Bank
Control
Logic
I/O gating
DM mask logic
Write
FIFO
And
Drivers
4n
4n
Bank
Control
Logic
Mux
Memory
Array
3
3
Read
Latch
`
CK, CK# CK out
CK in
Column Decoder
8
Mask
4n
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
DQS , DQS#
RCVRS
DM
`
Confidential
- 3 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
General Description
The 1Gb Mobile Low-Power DDR2 SDRAM (LPDDR2) is a high-speed CMOS, dynamic random-access memory containing
1,073,741,824 bits. The LPDDR2-S4 device is internally configured as an eight-bank DRAM. Each of the x16’s 134,217,728
-bit banks is organized as 8,192 rows by 1024 columns by 16 bits. Each of the x32’s 134,217,728-bit banks is organized as
8,192 rows by 512 columns by 32 bits.
Simplified Bus Interface State Diagram
Confidential
- 4 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Address Table
Parameter
64Mb X 16
32Mb X 32
Configuration
8Mb x 8banks x 16
4Mb x 8banks x 32
Bank Address
BA0 ~ BA2
BA0 ~ BA2
Row Address
R0 ~ R12
R0 ~ R12
Column Address
C0 ~ C9
C0 ~ C8
Note : 1. The least-significant column address CA0 is not transmitted on the CA bus, and is implied to be zero.
Pin Description(X16)
Symbol
Type
Description
CK, CK#
Input
Clock : CK and CK# are differential clock inputs.
All CA inputs are sampled on both rising and falling edges of CK. CS and CKE inputs
are sampled at the rising edge of CK. AC timings are referenced to clock.
CKE
Input
Clock enable : CKE HIGH activates and CKE LOW deactivates the internal clock
signals, input buffers, and output drivers. Power-saving modes are entered and exited
via CKE transitions. CKE is considered part of the command code. CKE is sampled at
the rising edge of CK.
CS#
Input
Chip select : CS# is considered part of the command code and is sampled at the
rising edge of CK.
DM0–DM1
Input
Input data mask : DM is an input mask signal for WRITE data. Although DM balls
are input-only, the DM loading is designed to match that of DQ and DQS balls.
DM[1:0] is DM for each of the two data bytes, respectively.
DQ0 – DQ15
Input
Data input/output : Bidirectional data bus.
Data strobe : The data strobe is bidirectional (used for read and write data) and complementary (DQS and DQS#). It is edge-aligned output with read data and centered
input with write data. DQS[1:0]/DQS[1:0]# is DQS for each of the two data bytes, respectively.
DQS0 – DQS1
DQS0# – DQS1#
I/O
CA0 – CA9
Input
VDDQ
VSSQ
VDDCA
VSSCA
VDD1
VDD2
VSS
VREFCA,
VREFDQ
Supply
Supply
Supply
Supply
Supply
Supply
Supply
DQ Power : Provide isolated power to DQs for improved noise immunity.
DQ Ground : Provide isolated ground to DQs for improved noise immunity.
Command/address power supply : Command/address power supply.
Command/address ground : Isolated on the die for improved noise immunity.
Core power : Supply 1.
Core power : Supply 2.
Common ground
Supply
Reference voltage : VREFCA is reference for command/address input buffers,
VREFDQ is reference for DQ input buffers.
ZQ
Reference
DNU
NC
–
–
Do not use : Must be grounded or left floating.
No connect : Not internally connected.
(NC)
–
No connect : Balls indicated as (NC) are no connects, however, they could be
connected together internally.
Confidential
Command/address inputs: Provide the command and address inputs according to
the command truth table.
External impedance (240 ohm) : This signal is used to calibrate the device output
impedance for S4 devices. For S2 devices, ZQ should be tied to VDDCA.
- 5 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Address Table
Parameter
64Mb X 16
32Mb X 32
Configuration
8Mb x 8banks x 16
4Mb x 8banks x 32
Bank Address
BA0 ~ BA2
BA0 ~ BA2
Row Address
R0 ~ R12
R0 ~ R12
Column Address
C0 ~ C9
C0 ~ C8
Note : 1. The least-significant column address CA0 is not transmitted on the CA bus, and is implied to be zero.
Pin Description(X32)
Symbol
Type
Description
CK, CK#
Input
Clock : CK and CK# are differential clock inputs.
All CA inputs are sampled on both rising and falling edges of CK. CS and CKE inputs
are sampled at the rising edge of CK. AC timings are referenced to clock.
CKE
Input
Clock enable : CKE HIGH activates and CKE LOW deactivates the internal clock
signals, input buffers, and output drivers. Power-saving modes are entered and exited
via CKE transitions. CKE is considered part of the command code. CKE is sampled at
the rising edge of CK.
CS#
Input
Chip select : CS# is considered part of the command code and is sampled at the
rising edge of CK.
DM0–DM3
Input
Input data mask : DM is an input mask signal for WRITE data. Although DM balls
are input-only, the DM loading is designed to match that of DQ and DQS balls.
DM[3:0] is DM for each of the four data bytes, respectively.
DQ0 – DQ31
Input
Data input/output : Bidirectional data bus.
Data strobe : The data strobe is bidirectional (used for read and write data) and complementary (DQS and DQS#). It is edge-aligned output with read data and centered
input with write data. DQS[3:0]/DQS[3:0]# is DQS for each of the four data bytes, respectively.
DQS0 – DQS3
DQS0# – DQS3#
I/O
CA0 – CA9
Input
VDDQ
VSSQ
VDDCA
VSSCA
VDD1
VDD2
VSS
VREFCA,
VREFDQ
Supply
Supply
Supply
Supply
Supply
Supply
Supply
DQ Power : Provide isolated power to DQs for improved noise immunity.
DQ Ground : Provide isolated ground to DQs for improved noise immunity.
Command/address power supply : Command/address power supply.
Command/address ground : Isolated on the die for improved noise immunity.
Core power : Supply 1.
Core power : Supply 2.
Common ground
Supply
Reference voltage : VREFCA is reference for command/address input buffers,
VREFDQ is reference for DQ input buffers.
ZQ
Reference
DNU
NC
–
–
Do not use : Must be grounded or left floating.
No connect : Not internally connected.
(NC)
–
No connect : Balls indicated as (NC) are no connects, however, they could be
connected together internally.
Confidential
Command/address inputs: Provide the command and address inputs according to
the command truth table.
External impedance (240 ohm) : This signal is used to calibrate the device output
impedance for S4 devices. For S2 devices, ZQ should be tied to VDDCA.
- 6 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Functional Description
Mobile LPDDR2 is a high-speed SDRAM internally configured as a 8-bank memory device. LPDDR2 devices use a double data rate
architecture on the command/address (CA) bus to reduce the number of input pins in the system.
The 10-bit CA bus is used to transmit command, address, and bank information. Each command uses one clock cycle, during which
command information is transferred on both the rising and falling edges of the clock.
LPDDR2-S4 devices use a double data rate architecture on the DQ pins to achieve high-speed operation. The double data rate architecture is essentially a 4n pre-fetch architecture with an interface designed to transfer two data bits per DQ every clock cycle at the
I/O pins. A single read or WRITE access for the LPDDR2-S4 effectively consists of a single 4n-bit-wide, one-clock-cycle data transfer
at
the internal SDRAM core and four corresponding n-bit-wide, one-half-clock-cycle data transfers at the I/O pins.
Read and write accesses 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 ACTIVATE command followed by a READ or WRITE command. The address and BA bits
registered coincident with the ACTIVATE command are used to select the row and bank 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.
Confidential
- 7 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Power-Up
The following sequence must be used to power up the device. Unless specified otherwise, this procedure is mandatory (see Figure1).
Power-up and initialization by means other than those specified will result in undefined operation.
1. Voltage Ramp
While applying power (after Ta), CKE must be held LOW (≤0.2 ×VDDCA), and all other inputs must be between VILMIN and VIHMAX.
The device outputs remain at High-Z while CKE is held LOW. On or before the completion of the voltage ramp (Tb), CKE must
be held LOW. DQ, DM, DQS, and DQS# voltage levels must be Between VSSQ and VDDQ during voltage ramp to avoid latch-up.
CK, CK#, CS#, and CA input levels must be between VSSCA and VDDCA during voltage ramp to avoid latch up.
The following conditions apply for voltage ramp :
• Ta is the point when any power supply first reaches 300mV.
• Noted conditions apply betweenTa and power-down (controlled or uncontrolled).
• Tb is the point at which all supply and reference voltages are within their defined operating ranges.
• Power ramp duration tINIT0 (Tb -Ta) must not exceed 20ms.
• For supply and reference voltage operating conditions, see the Recommended DC Operating Conditions table.
• The voltage difference between any ofVSS,VSSQ, andVSSCA pins must not exceed 100mV.
Voltage Ramp Completion.
After Ta is reached :
• VDD1 must be greater than VDD2 - 200mV
• VDD1 and VDD2 must be greater than VDDCAㅡ200mV
• VDD1 and VDD2 must be greater than VDDQㅡ200mV
• VREF must always be less than all other supply voltages
Beginning at Tb, CKE must remain LOW for at least tINIT1=100ns, after which CKE can be asserted HIGH. The clock must be stable
at least tINIT2 = 5 × tCK prior to the first CKE LOW-to-HIGH transition (Tc). CKE, CS#, and CA inputs must observe setup and hold
requirements (tIS, tIH) with respect to the first rising clock edge (and to subsequent falling and rising edges). If any MRRs are issued,
the clock period must be within the range defined for tCKb(18ns to 100ns). MRWs can be issued at normal clock frequencies as long
as all AC timings are met. Some AC parameters (for example, tDQSCK) could have relaxed timings (such as tDQSCKb) before the
system is appropriately configured. While keeping CKE HIGH, NOP commands must be issued for at least tINIT3=200μs (Td).
2. RESET Command
After tINIT3 is satisfied, the MRW RESET command must be issued (Td). An optional PRECHARGE ALL command can be issued
prior to the MRW RESET command. Wait at least tINIT4 while keeping CKE asserted and issuing NOP commands.
3.MRRs and Device Auto Initialization (DAI) Polling
After tINIT4 is satisfied (Te), only MRR commands and power-down entry/exit commands are supported. After Te, CKE can go LOW
in alignment with power-down entry and exit specifications (see Power-Down (page 53)).
The MRR command can be used to poll the DAI bit, which indicates when device auto initialization is complete; otherwise, the controller must wait a minimum of tINIT5, or until the DAI bit is set, before proceeding. Because the memory output buffers are not properly configured by Te, some AC parameters must use relaxed timing specifications before the system is appropriately configured.
After the DAI bit (MR0, DAI) is set to zero by the memory device (DAI complete), the device is in the idle state (Tf). DAI status can be
determined by issuing the MRR command to MR0. The device sets the DAI bit no later than tINIT5 after the RESET command.
The controller must wait at least tINIT5 or until the DAI bit is set before proceeding.
Confidential
- 8 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
4.ZQ Calibration
After tINIT5 (Tf), the MRW initialization calibration (ZQ calibration) command can be issued to the memory (MR10).
This command is used to calibrate output impedance over process, voltage, and temperature. In systems where more than one
Mobile LPDDR2 device exists on the same bus, the controller must not overlap MRW ZQ calibration commands.
The device is ready for normal operation after tZQINIT.
5.Normal Operation
After (Tg), MRW commands must be used to properly configure the memory (output buffer drive strength, latencies, etc.).
Specifically, MR1, MR2, and MR3 must be set to configure the memory for the target frequency and memory configuration. After the
initialization sequence is complete, the device is ready for any valid command. After Tg, the clock frequency can be changed using
the procedure described in Input Clock Frequency Changes and Clock Stop with CKE HIGH (page 62).
Figure 1 : Voltage Ramp and Initialization Sequence
Note : 1. High-Z on the CA bus indicates valid NOP.
Table1 : Initialization Timing Parameters
Parameter
Value
Min
Max
tINIT0
-
20
Unit
ms
Comment
Maximum voltage ramp time
tINIT1
100
-
ns
tINIT2
5
-
tCK
Minimum stable clock before first CKE HIGH
Minimum CKE LOW time after completion of voltage ramp
tINIT3
200
-
μs
Minimum idle time after first CKE assertion
tINIT4
1
-
μs
Minimum idle time after RESET command
tINIT5
-
10
μs
Maximum duration of device auto initialization
tZQINIT
1
-
μs
ZQ initial calibration (S4 devices only)
tCKb
18
-
μs
Clock cycle time during boot
Confidential
- 9 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Initialization After RESET (Without Voltage Ramp)
If the RESET command is issued before or after the power-up initialization sequence, the reinitialization procedure must begin at Td.
Power-Off
While powering off, CKE must be held LOW (≤0.2 ×VDDCA); all other inputs must be between VILMIN and VIHMAX.
The device outputs remain at High-Z while CKE is held LOW. DQ, DM, DQS, and DQS# voltage levels must be between VSSQ and
VDDQ during the power-off sequence to avoid latch-up. CK, CK#, CS#, and CA input levels must be between VSSCA and VDDCA
during the power-off sequence to avoid latch-up.
Tx is the point where any power supply drops below the minimum value specified in the Recommended DC Operating
Conditions table. Tz is the point where all power supplies are below 300mV. After Tz, the device is powered off.
Required Power Supply Conditions Between Tx and Tz:
• VDD1 must be greater than VDD2 - 200mV.
• VDD1 must be greater than VDDCA - 200mV.
• VDD1 must be greater than VDDQ - 200mV.
• VREF must always be less than all other supply voltages.
The voltage difference between VSS,VSSQ, and VSSCA must not exceed 100mV.
For supply and reference voltage operating conditions, see Recommended DC Operating Conditions table.
Uncontrolled Power-Off
When an uncontrolled power-off occurs, the following conditions must be met:
• At Tx, when the power supply drops below the minimum values specified in the Recommended DC Operating Conditions table, all power
supplies must be turned off and all power-supply current capacity must be at zero, except for any static charge remaining in the system.
• After Tz (the point at which all power supplies first reach 300mV), the device must power off.
The time between Tx and Tz must not exceed tPOFF. During this period, the relative voltage between power supplies is uncontrolled.
VDD1 andVDD2 must decrease with a slope lower than 0.5V/μs between Tx and Tz.
An uncontrolled power-off sequence can occur a maximum of 400 times over the life of the device.
Table2 : Power-Off Timing
Parameter
Symbol
Min
Max
Maximum power-off ramp time
tPOFF
-
2
Confidential
- 10 of 125 -
Unit
Sec
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Mode Register Definition
LPDDR2 devices contain a set of mode registers used for programming device operating parameters, reading device information and
status, and for initiating special operations such as DQ calibration, ZQ calibration, and device reset.
Mode Register Assignments and Definitions
The MRR command is used to read from a register.The MRW command is used to write to a register. An “R” in the access column of
the mode register assignment table indicates read-only; a “W” indicates write-only; “R/W” indicates read or WRITE capable or enabled.
Table3 : Mode Register Assignments
MR #
MA [7:0]
0
00h
Device info
Function
Access
R
OP7
OP6
RFU
OP5
OP4
OP3
1
01h
Device feature 1
W
nWR (for AP)
2
02h
Device feature 2
W
3
03h
I/O config-1
W
4
04h
SDRAM refresh rate
R
5
05h
Basic config-1
R
LPDDR2 Manufacturer ID
go to MR5
6
06h
Basic config-2
R
Revision ID1
go to MR6
7
07h
Basic config-3
R
Revision ID2
go to MR7
8
08h
Basic config-4
R
9
09h
Test mode
W
Vendor-specific test mode
I/O calibration
W
Calibration code
go to MR10
-
RFU
go to MR11
RZQI
WC
OP2
RFU
I/O width
OP0
DI
DAI
BT
RFU
TUF
OP1
DNVI
RFU
BL
Link
go to MR0
go to MR1
RL and WL
go to MR2
DS
go to MR3
Refresh rate
Density
Type
go to MR4
go to MR8
go to MR9
10
0Ah
11-15
0Bh≈0Fh
16
10h
PASR_Bank
W
Bank mask
go to MR16
17
11h
PASR_Seg
W
Segment mask
go to MR17
-
RFU
Reserved
18-19
12h–13h
Reserved
20-31
14h–1Fh
32
20h
33-39
21h–27h
40
28h
41-47
29h–2Fh
Reserved for NVM
DQ calibration
pattern A
Do not use
DQ calibration
pattern B
Do not use
48-62
30h–3Eh
63
3Fh
64-126
40h–7Eh
Reserved
127
7Fh
Do not use
128-190
80h–BEh
191
BFh
192-254
C0h–FEh
255
FFh
Reserved
RESET
go to MR18
go to MR30
R
See Table 28
go to MR32
go to MR33
R
See Table 28
go to MR40
go to MR41
-
RFU
go to MR48
W
X
go to MR63
-
RFU
go to MR64
go to MR127
Reserved for vendor use
RVU
go to MR128
RVU
go to MR192
Do not use
go to MR191
Reserved for vendor use
Do not use
go to MR255
Notes : 1. RFU bits must be set to 0 during MRW.
2. RFU bits must be read as 0 during MRR.
3. For READs to a write-only or RFU register, DQS will be toggled and undefined data is returned.
4. RFU mode registers must not be written.
5. WRITEs to read-only registers must have no impact on the functionality of the device.
Confidential
- 11 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table4 : MR0 Device information
OP7
OP6
OP5
OP4
OP3
RFU
RZQI
OP2
OP1
DNVI
DI
OP0
DAI
DAI (Device Auto-Initialization Status)
Read–only
OP0
0b : DAI complete
1b : DAI still in progress
DI (Device Information)
Read–only
OP1
0b : SDRAM
1b : NVM
DNVI (Data Not Valid Information)
Read–only
OP2
LPDDR2 SDRAM will not implement DNV functionality
RZQI(Built in Self Test for RZQ Information)
00b : RZQ self test not executed
01b : ZQ-pin may connect to VDDCA or float
Read–only OP[4:3] 10b : ZQ-pin may short to GND
11b : ZQ-pin self test completed, no error condition detected
(ZQ-pin may not connect to VDDCA or float nor short to GND)
Notes : 1. If RZQI is supported, it will be set upon completion of the MRW ZQ initialization calibration.
2. If ZQ is connected to VDDCA to set default calibration, OP[4:3] must be set to 01. If ZQ is not connected to VDDCA, either
OP[4:3]=01 or OP[4:3]=10 could indicate a ZQ-pin assembly error. It is recommended that the assembly error be corrected.
3. In the case of a possible assembly error(either OP[4:3]=01 or OP[4:3]=10, as defined above), the device will default to factory trim settings for RON and will ignore ZQ calibration commands. In either case, the system might not function as Intended.
4. If a ZQ self test returns a value of 11b, this indicates that the device has detected a resistor connection to the ZQ pin. Note
that this result cannot be used to validate the ZQ resistor value, nor does it indicate that the ZQ resistor tolerance meets
the specified limits (240 ohms ±1%).
Table5 : MR1 Device Feature 1 (MA[7:0] = 01h)
OP7
OP6
OP5
nWR (for AP)
OP4
OP3
WC
BT
OP2
OP1
OP0
BL
010b : BL4 (default)
011b : BL8
100b : BL16
All others : reserved
BL
Write - only
OP[2:0]
BT
Write - only
OP3
0b : Sequential (default)
1b : Interleaved
WC
Write – only
OP4
0b : Wrap (default)
1b : No wrap (allowed for SDRAM BL4 only)
nWR
Write – only
OP[7:5]
001b : nWR = 3 (default)
010b : nWR = 4
011b : nWR = 5
100b : nWR = 6
101b : nWR = 7
110b : nWR = 8
All others : reserved
Note : 1. Programmed value in nWR register is the number of clock cycles which determines when to start internal precharge
operation for a write burst with AP enabled. It is determined by RU(tWR / tCK).
Confidential
- 12 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table6 : Burst Sequence by Burst Length(BL), Burst Type(BT), and Wrap Control(WC)
BL
BT
Any
4
Any
Seq
8
Int
Any
Seq
16
Int
Any
C3
C2
C1
C0
X
X
0b
0b
X
X
1b
0b
WC
Wrap
Burst Cycle Number and Burst Address Sequence
1
2
3
4
0
1
2
3
5
6
7
8
2
3
0
1
y
y+
y+
y+
0
1
1
2
2
3
3
4
5
6
7
X
X
X
X
0b
0b
No
0b
Wrap
0b
X
0b
1b
0b
2
3
4
5
6
7
0
1
X
1b
0b
0b
4
5
6
7
0
1
2
3
X
1b
1b
0b
6
7
0
1
2
3
4
5
X
0b
0b
0b
0
1
2
3
4
5
6
7
X
0b
1b
0b
2
3
0
1
6
7
4
5
X
1b
0b
0b
4
5
6
7
0
1
2
3
X
1b
1b
0b
6
7
4
5
2
3
0
1
Wrap
9
10
11
12
13
14
15
46
X
X
X
0b
0b
0b
No
0b
Wrap
0b
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
0b
0b
1b
0b
2
3
4
5
6
7
8
9
A
B
C
D
E
F
0
1
0b
1b
0b
0b
4
5
6
7
8
9
A
B
C
D
E
F
0
1
2
3
0b
1b
1b
0b
6
7
8
9
A
B
C
D
E
F
0
1
2
3
4
5
1b
0b
0b
0b Wrap
8
9
A
B
C
D
E
F
0
1
2
3
4
5
6
7
1b
0b
1b
0b
A
B
C
D
E
F
0
1
2
3
4
5
6
7
8
9
1b
1b
0b
0b
C
D
E
F
0
1
2
3
4
5
6
7
8
9
A
B
1b
1b
1b
0b
E
F
0
1
2
3
4
5
6
7
8
9
A
B
C
D
X
X
X
0b
X
No
0b
Wrap
X
X
illegal (not supported)
illegal (not supported)
illegal (not supported)
Notes : 1. C0 input is not present on CA bus. It is implied zero.
2. For BL = 4, the burst address represents C[1:0].
3. For BL = 8, the burst address represents C[2:0].
4. For BL = 16, the burst address represents C[3:0].
5. For no-wrap, BL4, the burst must not cross the page boundary or the sub-page boundary.
The variable y can start at any address with C0 equal to 0, but must not start at any address shown in the following table.
Confidential
- 13 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table7 : No – Wrap Restrictions
Bus Width
1Gb
Not across full page boundary
X 16
3FE, 3FF, 000, 001
X 32
1FE, 1FF, 000, 001
Not across full page boundary
X 16
1FE, 1FF, 200, 201
X 32
None
Note : 1. No-wrap BL = 4 data orders shown are prohibited.
Table8 : MR2 Device Feature 2 (MA[7:0] = 02h)
OP7
OP6
OP5
OP4
OP3
OP2
RFU
OP1
OP0
OP1
OP0
RL and WL
0001b : RL=3 / WL=1 (default)
0010b : RL=4 / WL=2
0011b : RL=5 / WL=2
RL and WL
Write - only
OP [3:0]
0100b : RL=6 / WL=3
0101b : RL=7 / WL=4
0110b : RL=8 / WL=4
All others : reserved
Table9 : MR3 I/O Configuration 1 (MA [7:0] =03h)
OP7
OP6
OP5
OP4
OP3
OP2
RFU
DS
0000b : reserved
0001b : 34.3 ohm typical
0010b : 40 ohm typical
0011b : 48 ohm typical
DS
Write - only
OP [3:0]
0100b : 60 ohm typical
0101b : reserved for 68.6 ohm typical
0110b : 80 ohm typical
0111b : 120 ohm typical
All others : reserved
Table10 : MR4 Device Temperature (MA [7:0] =04h)
OP7
OP6
OP5
TUF
OP4
OP3
OP2
RFU
OP1
OP0
SDRAM Refresh Rate
000b : SDRAM Low temperature operating limit exceeded.
SDRAM
Refresh rate
001b : 4x tREF, 4x tREFlpb, 4x tREFW.
Read - only
OP [2:0]
010b : 2x tREF, 2x tREFlpb, 2x tREFW.
011b : 1x tREF, 1x tREFlpb, 1x tREFW ( tCK
Figure 7 : Burst READ – RL = 3, BL = 8, tDQSCK < tCK
Confidential
- 21 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 8 : tDQSCKDL Timing
Notes : 1. tDQSCKDL = (tDQSCKn - tDQSCKm).
2. tDQSCKDL (MAX) is defined as the maximum of ABS (tDQSCKn - tDQSCKm) for any (tDQSCKn, tDQSCKm) pair within
any 32ms rolling window.
Confidential
- 22 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 9 : tDQSCKDM Timing
Notes : 1. tDQSCKDM = (tDQSCKn - tDQSCKm).
2. tDQSCKDM (MAX) is defined as the maximum of ABS (tDQSCKn - tDQSCKm) for any (tDQSCKn, tDQSCKm) pair within
any 1.6μs rolling window.
Confidential
- 23 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 10 : tDQSCKDS Timing
Notes : 1. tDQSCKDS = (tDQSCKn - tDQSCKm).
2. tDQSCKDS (MAX) is defined as the maximum of ABS (tDQSCKn - tDQSCKm) for any (tDQSCKn, tDQSCKm) pair for
READs within a consecutive burst, within any 160ns rolling window.
Confidential
- 24 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 11: Burst READ Followed by Burst WRITE – RL = 3, WL = 1, BL = 4
The minimum time from the burst READ command to the burstWRITE command is defined by the read latency (RL) and
the burst length (BL). Minimum READ-to-WRITE latency is RL + RU(tDQSCK(MAX)/tCK) + BL/2 + 1 -WL clock cycles.
Note that if a READ burst is truncated with a burstTERMINATE (BST) command, the effective burst length of the truncated
READ burst should be used for BL when calculating the minimum READ-to-WRITE delay.
Figure 12: Seamless Burst READ – RL = 3, BL = 4, CCD = 2
t
A seamless burst READ operation is supported by enabling a READ command at every other clock cycle for BL = 4
operation, every fourth clock cycle for BL = 8 operation, and every eighth clock cycle for BL = 16 operation.
This operation is supported as long as the banks are activated, whether the accesses read the same or different banks.
Confidential
- 25 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
READs Interrupted by a READ
A burst READ can be interrupted by another READ with a 4-bit burst boundary, provided that tCCD is met.
A burst READ can be interrupted by other READs on any subsequent clock, provided that tCCD is met.
Figure 13: READ Burst Interrupt Example – RL = 3, BL = 8, tCCD = 2
Note : 1. READs can only be interrupted by other READs or the BST command.
Burst WRITE Command
The burstWRITE command is initiated with CS# LOW, CA0 HIGH, CA1 LOW, and CA2 LOW at the rising edge of the clock.
The command address bus inputs, CA5r–CA6r and CA1f–CA9f, determine the starting column address for the burst.
Write latency (WL) is defined from the rising edge of the clock on which theWRITE command is issued to the rising edge of the clock
from which the tDQSS delay is measured.The first valid data must be drivenWL × tCK + tDQSS from the rising edge of the clock from
which the WRITE command is issued.The data strobe signal (DQS) must be driven LOW tWPRE prior to data input.
The burst cycle data bits must be applied to the DQ pins tDS prior to the associated edge of the DQS and held valid until tDH after that
edge. Burst data is sampled on successive edges of the DQS until the 4-, 8-, or 16-bit burst length is completed.
After a burstWRITE operation, tWR must be satisfied before a PRECHARGE command to the same bank can be issued.
Pin input timings are measured relative to the crosspoint of DQS and its complement, DQS#.
Confidential
- 26 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 14 : Data Input (WRITE) Timing
Figure 15 : Burst WRITE – WL = 1, BL = 4
Confidential
- 27 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 16: Burst WRITE Followed by Burst READ – RL = 3, WL = 1, BL = 4
Notes : 1.The minimum number of clock cycles from the burst WRITE command to the burst READ command for any bank is
[WL + 1 + BL/2 + RU(tWTR / tCK)].
2. tWTR starts at the rising edge of the clock after the last valid input data.
3. If a WRITE burst is truncated with a BST command, the effective burst length of the truncated WRITE burst should be used
as BL to calculate the minimum WRITE-to-READ delay.
Figure 17 : Seamless Burst WRITE – WL = 1, BL = 4, tCCD = 2
Note : 1. The seamless burst WRITE operation is supported by enabling a WRITE command every other clock for BL = 4 operation,
every four clocks for BL = 8 operation, or every eight clocks for BL = 16 operation.
This operation is supported for any activated bank.
Confidential
- 28 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
WRITEs Interrupted by a WRITE
A burstWRITE can only be interrupted by anotherWRITE with a 4-bit burst boundary, provided that tCCD (MIN) is met.
AWRITE burst interrupt can occur on even clock cycles after the initial WRITE command, provided that tCCD (MIN) is met.
Figure 18: WRITE Burst Interrupt Timing – WL = 1, BL = 8, tCCD = 2
Notes : 1. WRITEs can only be interrupted by other WRITEs or the BST command.
2. The effective burst length of the first WRITE equals two times the number of clock cycles between the first
WRITE and the interrupting WRITE.
BURST TERMINATE Command
The BURSTTERMINATE (BST) command is initiated with CS# LOW, CA0 HIGH, CA1 HIGH, CA2 LOW, and CA3 LOW at the rising
edge of the clock. A BST command can only be issued to terminate an active READ or WRITE burst.
Therefore, a BST command can only be issued up to and including BL/2 - 1 clock cycles after a READ or WRITE command.
The effective burst length of a READ or WRITE command truncated by a BST command is as follows :
• Effective burst length = 2 × (number of clock cycles from the READ or WRITE command to the BST command).
• If a READ or WRITE burst is truncated with a BST command, the effective burst length of the truncated burst should be used for BL when calculating the minimum READ-to-WRITE or WRITE-to-READ delay.
• The BST command only affects the most recent READ or WRITE command.
The BST command truncates an ongoing READ burst RL × tCK + tDQSCK + tDQSQ after the rising edge of the clock where the BST command
is issued.
The BST command truncates an on going WRITE burst WL X tCK + tDQSS after the rising edge of the clock where the BST command is issued.
• The 4-bit prefetch architecture enables BST command assertion on even clock cycles following a WRITE or READ command.
The effective burst length of a READ or WRITE command truncated by a BST command is thus an integer multiple of four.
Confidential
- 29 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 19 : Burst WRITE Truncated by BST – WL = 1, BL = 16
Notes : 1. The BST command truncates an ongoing WRITE burst WL × tCK + tDQSS after the rising edge of the clock where the BST
command is issued.
2. BST can only be issued an even number of clock cycles after the WRITE command.
3. Additional BST commands are not supported after T4 and must not be issued until after the next READ or WRITE command.
Figure 20: Burst READ Truncated by BST – RL = 3, BL = 16
Notes : 1. The BST command truncates an ongoing READ burst (RL × tCK + tDQSCK + tDQSQ) after the rising edge of the clock
where the BST command is issued.
2. BST can only be issued an even number of clock cycles after the READ command.
3. Additional BST commands are not supported after T4 and must not be issued until after the next READ or WRITE command.
Confidential
- 30 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Write Data Mask
On LPDDR2 devices, one write data mask (DM) pin for each data byte (DQ) is supported, consistent with the implementation on
LPDDR SDRAM. Each DM can mask its respective DQ for any given cycle of the burst. Data mask timings match data bit timing,
but are inputs only. Internal data mask loading is identical to data bit loading to ensure matched system timing.
Figure 21: Data Mask Timing
Figure 22: Write Data Mask – Second Data Bit Masked
Note : 1. For the data mask function, WL = 2, BL = 4 is shown; the second data bit is masked.
Confidential
- 31 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
PRECHARGE Command
The PRECHARGE command is used to precharge or close a bank that has been activated.
The PRECHARGE command is initiated with CS# LOW, CA0 HIGH, CA1 HIGH, CA2 LOW, and CA3 HIGH at the rising edge of the
clock. The PRECHARGE command can be used to precharge each bank independently or all banks simultaneously. For 4-bank
devices, the AB flag and bank address bits BA0 and BA1 are used to determine which bank(s) to precharge.
For 8-bank devices, the AB flag and the bank address bits BA0, BA1, and BA2 are used to determine which bank(s) to precharge.
The precharged bank(s) will be available for subsequent row access tRPab after an all bank PRECHARGE command is issued, or
tRPpb after a single-bank PRECHARGE command is issued.
To ensure that 8-bank devices can meet the instantaneous current demand required to operate, the row precharge time (tRP) for an
all bank PRECHARGE in 8-bank devices (tRPab) will be longer than the row precharge time for a single-bank PRECHARGE (tRPpb).
ACTIVATE to PRECHARGE timing is shown in ACTIVATE Command (page 17).
Table 22: Bank Selection for PRECHARGE by Address Bits
AB(CA4r)
BA2
(CA9r)
BA1
(CA8r)
BA0
(CA7r)
Precharged Bank(s)
8-Bank Device
0
0
0
0
Bank 0 only
0
0
0
1
Bank 1 only
0
0
1
0
Bank 2 only
0
0
1
1
Bank 3 only
0
1
0
0
Bank 4 only
0
1
0
1
Bank 5 only
0
1
1
0
Bank 6 only
0
1
1
1
Bank 7 only
1
Don’t Care
Don’t Care
Don’t Care
All Banks
READ Burst Followed by PRECHARGE
For the earliest possible precharge, the PRECHARGE command can be issued BL/2 clock cycles after a READ command.
A new bank ACTIVATE command can be issued to the same bank after the row precharge time (tRP) has elapsed.
A PRECHARGE command cannot be issued until after tRAS is satisfied.
The minimum READ-to-PRECHARGE time (tRTP) must also satisfy a minimum analog time from the rising clock edge that
initiates the last 4-bit prefetch of a READ command. tRTP begins BL/2 - 2 clock cycles after the READ command.
If the burst is truncated by a BST command, the effective BL value is used to calculate when tRTP begins.
Confidential
- 32 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 23: READ Burst Followed by PRECHARGE – RL = 3, BL = 8, RU(tRTP(MIN)/tCK) = 2
Figure 24: READ Burst Followed by PRECHARGE – RL = 3, BL = 4, RU(tRTP(MIN)/tCK) = 3
WRITE Burst Followed by PRECHARGE
For WRITE cycles, a WRITE recovery time (tWR) must be provided before a PRECHARGE command can be issued.
tWR delay is referenced from the completion of the burst WRITE. The PRECHARGE command must not be issued prior to
the tWR delay. For WRITE-to-PRECHARGE timings see Table 23. These devices write data to the array in prefetch quadruples (prefetch
= 4). An internal WRITE operation can only begin after a
prefetch group has been completely latched. The minimum WRITE-to-PRECHARGE time for commands to the same bank is WL
+ BL/2 + 1 + RU(tWR/tCK) clock cycles. For untruncated bursts, BL is the value set in the mode register. For truncated bursts,
BL is the effective burst length.
Confidential
- 33 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 25 : WRITE Burst Followed by PRECHARGE – WL = 1, BL = 4
Auto Precharge
Before a new row can be opened in an active bank, the active bank must be precharged using either the PRECHARGE command or
the auto precharge function.When a READ or WRITE command is issued to the device, the auto precharge bit (AP) can be set to
enable the active bank to automatically begin precharge at the earliest possible moment during the burst READ or WRITE cycle.
If AP is LOW when the READ or WRITE command is issued, then normal READ or WRITE burst operation is executed and the bank
remains active at the completion of the burst.
If AP is HIGH when the READ or WRITE command is issued, the auto precharge function is engaged. This feature enables the
PRECHARGE operation to be partially or completely hidden during burst READ cycles (dependent upon READ or WRITE latency),
thus improving system performance for random data access.
READ Burst with Auto Precharge
If AP (CA0f) is HIGH when a READ command is issued, the READ with auto precharge function is engaged.
These devices start an auto precharge on the rising edge of the clock BL/2 or BL/2 - 2 + RU(tRTP/tCK) clock cycles later than the
READ with auto precharge command, whichever is greater. For auto precharge calculations see Table 23 . Following an auto precharge
operation, an ACTIVATE command can be issued to the same bank if the following two conditions are satisfied simultaneously:
• The RAS precharge time (tRP) has been satisfied from the clock at which the auto precharge begins.
• The RAS cycle time (tRC) from the previous bank activation has been satisfied.
Confidential
- 34 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 26 : READ Burst with Auto Precharge – RL = 3, BL = 4, RU(tRTP(MIN)/tCK) = 2
WRITE Burst with Auto Precharge
If AP (CA0f) is HIGH when aWRITE command is issued, theWRITE with auto precharge function is engaged.
The device starts an auto precharge at the clock rising edge tWR cycles after the completion of the burst WRITE. Following a WRITE
with auto precharge, an ACTIVATE command can be issued to the same bank if the following two conditions are met:
• The RAS precharge time (tRP) has been satisfied from the clock at which the auto precharge begins.
• The RAS cycle time (tRC) from the previous bank activation has been satisfied.
Figure 27 : Write Burst with Auto Precharge – WL=1, BL=4
Confidential
- 35 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table23 : Precharge and Auto Precharge Clarification
From Command
READ
BST
READ w/AP
WRITE
BST
WRITE w/AP
Precharge
Precharge all
To Command
Precharge to same bank as read
Minimum Delay Between Commands
BL/2 + MAX(2, RU(tRTP/tCK)) - 2
Unit
Notes
CLK
1
Precharge all
BL/2 + MAX(2, RU(tRTP/tCK)) - 2
CLK
1
Precharge to same bank as read
1
CLK
1
Precharge all
1
CLK
1
Precharge to same bank as read w/AP
BL/2 + MAX(2, RU(tRTP/tCK)) - 2
CLK
1, 2
Precharge all
BL/2 + MAX(2, RU(tRTP/tCK)) - 2
CLK
1
Activate to same bank as read w/AP
BL/2 + MAX(2, RU(tRTP/tCK)) - 2 + RU(tRPpb/tCK)
CLK
1
Write or WRITE w/AP (same bank)
Illegal
CLK
3
Write or WRITE w/AP (different bank)
RL + BL/2 + RU(tDQSCKmax/tCK) - WL + 1
CLK
3
Read or read w/AP (same bank)
Illegal
CLK
3
Write or WRITE w/AP (different bank)
BL/2
CLK
3
Precharge to same bank as write
WL + BL/2 + RU(tWR/tCK) + 1
CLK
1
Precharge all
WL + BL/2 + RU(tWR/tCK) + 1
CLK
1
Precharge to same bank as write
Precharge all
Precharge to same bank as WRITE
w/AP
Precharge all
Activate to same bank as write w/AP
Write or WRITE w/ap (same bank)
Write or WRITE w/ap (different bank)
Read or read w/ap (same bank)
Read or read w/ap (different bank)
Precharge to same bank as precharge
Precharge all
Precharge
Precharge all
WL + RU(tWR/tCK) + 1
WL + RU(tWR/tCK) + 1
CLK
CLK
1
1
WL + BL/2 + RU(tWR/tCK) + 1
CLK
1, 2
WL + BL/2 + RU(tWR/tCK) + 1
WL + BL/2 + RU(tWR/tCK) + 1 + RU(tRPpb/tCK)
Illegal
BL/2
Illegal
WL + BL/2 + RU(tWTR/tCK) + 1
1
1
1
1
CLK
CLK
CLK
CLK
CLK
CLK
CLK
CLK
CLK
CLK
1
1
3
3
3
3
1
1
1
1
Notes : 1. For a given bank, the PRECHARGE period should be counted from the latest PRECHARGE command either a one-bank
RECHARGE or PRECHARGE ALL issued to that bank.
The PRECHARGE period is satisfied after tRP, depending on the latest PRECHARGE command issued to that bank.
2. Any command issued during the specified minimum delay time is illegal.
3. After READ with auto precharge, seamless READ operations to different banks are supported. After WRITE with auto
precharge, seamless WRITE operations to different banks are supported. READ with auto precharge and WRITE with auto
precharge must not be interrupted or truncated.
Confidential
- 36 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
REFRESH Command
The REFRESH command is initiated with CS# LOW, CA0 LOW, CA1 LOW, and CA2 HIGH at the rising edge of the clock.
Per-bank REFRESH is initiated with CA3 LOW at the rising edge of the clock. All-bank REFRESH is initiated with CA3 HIGH at the
rising edge of the clock. Per-bank REFRESH is only supported in devices with eight banks.
A per-bank REFRESH command (REFpb) performs a per-bank REFRESH operation to the bank scheduled by the bank counter in
the memory device.The bank sequence for per-bank REFRESH is fixed to be a sequential round-robin :
0-1-2-3-4-5-6-7-0-1-.... The bank count is synchronized between the controller and the SDRAM by resetting the bank count to zero.
Synchronization can occur upon issuing a RESET command or at every exit from self refresh.
Bank addressing for the per-bank REFRESH count is the same as established for the single-bank PRECHARGE command (see Table
22). A bank must be idle before it can be refreshed. The controller must track the bank being refreshed by the per-bank REFRESH
command. The REFpb command must not be issued to the device until the following conditions have been met:
• tRFCab has been satisfied after the prior REFab command.
• tRFCpb has been satisfied after the prior REFpb command.
• tRP has been satisfied after the prior PRECHARGE command to that bank .
• tRRD has been satisfied after the prior ACTIVATE command (if applicable, for example after activating a row in a different bank than the one
affected by the REFpb command).
The target bank is inaccessible during per-bank REFRESH cycle time (tRFCpb), however, other banks within the device are accessible
and can be addressed during the cycle.
During the REFpb operation, any of the banks other than the one being refreshed can be maintained in an active state or accessed by a
READ or WRITE command. When the per-bank REFRESH cycle has completed, the affected bank will be in the idle state.
After issuing REFpb, the following conditions must be met:
• tRFCpb must be satisfied before issuing a REFab command.
• tRFCpb must be satisfied before issuing an ACTIVATE command to the same bank.
• tRRD must be satisfied before issuing an ACTIVATE command to a different bank.
• tRFCpb must be satisfied before issuing another REFpb command.
An all-bank REFRESH command (REFab) issues a REFRESH command to all banks.
All banks must be idle when REFab is issued (for instance, by issuing a PRECHARGE ALL command prior to issuing an all-bank
REFRESH command). REFab also synchronizes the bank count between the controller and the SDRAM to zero.
The REFab command must not be issued to the device until the following conditions have been met:
• tRFCab has been satisfied following the prior REFab command.
• tRFCpb has been satisfied following the prior REFpb command.
• tRP has been satisfied following the prior PRECHARGE commands.
After an all-bank REFRESH cycle has completed, all banks will be idle. After issuing REFab:
• tRFCab latency must be satisfied before issuing an ACTIVATE command.
• tRFCab latency must be satisfied before issuing a REFab or REFpb command.
Confidential
- 37 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table24 : Refresh Command Scheduling Separation Requirements
Symbol
Minimum delay From
To
Notes
REFab
tRFCab
REFab
ACTIVATE command to any bank
REFpb
REFab
tRFCpb
REFpb
ACTIVATE command to same bank as REFpb
REFpb
REFpb
tRRD
ACTIVATE
ACTIVATE command to a different bank than REFpb
REFpb
1
ACTIVATE command to a different bank than the prior ACTIVATE command
Note : 1. A bank must be in the idle state before it is refreshed, so REFab is prohibited following an ACTIVATE command.
REFpb is supported only if it affects a bank that is in the idle state.
Mobile LPDDR2 devices provide significant flexibility in scheduling REFRESH commands as long as the required boundary conditions
are met (see Figure 32).
In the most straightforward implementations, a REFRESH command should be scheduled every tREFI. In this case, self refresh can
be entered at any time. Users may choose to deviate from this regular refresh pattern, for instance, to enable a period in which no refresh is required. As an example, using a 1Gb LPDDR2 device, the user can choose to issue a refresh burst of 4096 REFRESH comands at the maximum supported rate (limited by tREFBW), followed by an extended period without issuing any REFRESH commands,
until the refresh window is complete. The maximum supported time without REFRESH commands is calculated as follows :
tREFW - (R/8) × tREFBW = tREFW - R × 4 × tRFCab.
For example, a 1Gb device atTC ≤ 85˚C can be operated without a refresh for up to 32ms - 4096 × 4 × 130ns ≈ 30ms.
Both the regular and the burst/pause patterns can satisfy refresh requirements if they are repeated in every 32ms window. It is critical
to satisfy the refresh requirement in every rolling refresh window during refresh pattern transitions.
The supported transition from a burst pattern to a regular distributed pattern is shown in Figure 28. If this transition occurs immediately
after the burst refresh phase, all rolling tREFW intervals will meet the minimum required number of REFRESH commands.
A nonsupported transition is shown in Figure 55. In this example, the regular refresh pattern starts after the completion of the pause
phase of the burst/pause refresh pattern. For several rolling tREFW intervals, the minimum number of REFRESH commands is not
satisfied.
Understanding this pattern transition is extremely important, even when only one pattern is employed. In self refresh mode, a regular
distributed refresh pattern must be assumed. Alliance Memory recommends entering self refresh mode immediately following the burst
phase of a burst/pause refresh pattern; upon exiting self refresh, begin with the burst phase (see Figure 31).
Confidential
- 38 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure29 : Regular Distributed Refresh Pattern
Notes : 1. Compared to repetitive burst REFRESH with subsequent REFRESH pause.
2. As an example, in a 1Gb LPDDR2 device at TC ≤ 85˚C, the distributed refresh pattern has one REFRESH command per
7.8μs; the burst refresh pattern has one REFRESH command per 0.52μs, followed by ≈ 30ms without any REFRESH
command.
Confidential
- 39 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure28 : Supported Transition from Repetitive REFRESH Burst
Notes : 1. Shown with subsequent REFRESH pause to regular distributed refresh pattern.
2. As an example, in a 1Gb LPDDR2 device at TC ≤ 85˚C, the distributed refresh pattern has one REFRESH command per
7.8μs; the burst refresh pattern has one REFRESH command per 0.52μs, followed by ≈ 30ms without any REFRESH
command.
Confidential
- 40 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure30 : Nonsupported Transition from Repetitive REFRESH Burst
Notes : 1. Shown with subsequent REFRESH pause to regular distributed refresh pattern.
2. There are only ≈ 2048 REFRESH commands in the indicated tREFW window. This does not provide the required minimum
number of REFRESH commands (R). PDF:
Confidential
- 41 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure31 : Recommended Self Refresh Entry and Exit
Note : 1. In conjunction with a burst/pause refresh pattern.
REFRESH Requirements
1. Minimum Number of REFRESH Commands
Mobile LPDDR2 requires a minimum number, R, of REFRESH (REFab) commands within any rolling refresh window (tREFW =
32 ms @ MR4[2:0] = 011 orTC ≤ 85˚C). For actual values per density and the resulting average refresh interval (tREFI), (see Table
75).
For tREFW and tREFI refresh multipliers at different MR4 settings, see the MR4 Device Temperature (MA[7:0] = 04h) table.
For devices supporting per-bank REFRESH, a REFab command can be replaced by a full cycle of eight REFpb commands.
2. Burst REFRESH Limitation
To limit current consumption, a maximum of eight REFab commands can be issued in any rolling tREFBW (tREFBW = 4 × 8 ×
tRFCab). This condition does not apply if REFpb commands are used.
3. REFRESH Requirements and Self Refresh
If any time within a refresh window is spent in self refresh mode, the number of required REFRESH commands in that window is
reduced to the following:
R´ = RU tSRF = R - RU R × tSRF
tREFW
tREFI
Where RU represents the round-up function.
Confidential
- 42 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 32: tSRF Definition
Notes : 1. Time in self refresh mode is fully enclosed in the refresh window (tREFW).
2. At self refresh entry.
3. At self refresh exit.
4. Several intervals in self refresh during one tREFW interval. In this example, tSRF = tSRF1 + tSRF2.
Figure 33 All-Bank REFRESH Operation
Figure 34 Per-Bank REFRESH Operation
Notes : 1. Prior to T0, the REFpb bank counter points to bank 0.
2. Operations to banks other than the bank being refreshed are supported during the tRFCpb period.
Confidential
- 43 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
SELF REFRESH Operation
The SELF REFRESH command can be used to retain data in the array, even if the rest of the system is powered down. When in the
self refresh mode, the device retains data without external clocking. The device has a built-in timer to accommodate SELF REFRESH
operation. The SELF REFRESH command is executed by taking CKE LOW, CS# LOW, CA0 LOW, CA1 LOW, and CA2 HIGH at the
rising edge of the clock.
CKE must be HIGH during the clock cycle preceding a SELF REFRESH command. A NOP command must be driven in the clock cycle
following the SELF REFRESH command. After the power-down command is registered, CKE must be held LOW to keep the device in
self refresh mode.
Mobile LPDDR2 devices can operate in self refresh mode in both the standard and extended temperature ranges. These devices also
manage self refresh power consumption when the operating temperature changes, resulting in the lowest possible power consumption
across the operating temperature range. See Table 59 for details.
After the device has entered self refresh mode, all external signals other than CKE are “Don’t Care.” For proper self refresh operation,
power supply pins (VDD1, VDD2, VDDQ, and VDDCA) must be at valid levels. VDDQ can be turned off during self refresh. If VDDQ is
turned off, VREFDQ must also be turned off. Prior to exiting self refresh, both VDDQ and VREFDQ must be within their respective
minimum/maximum operating ranges (see the Single-Ended AC and DC Input Levels for DQ and DM table). VREFDQ can be at any
level between 0 and VDDQ; VREFCA can be at any level between 0 and VDDCA during self refresh.
Before exiting self refresh, VREFDQ and VREFCA must be within specified limits (see AC and DC Logic Input Measurement Levels
for Single-Ended Signals (page 78)). After entering self refresh mode, the device initiates at least one all-bank REFRESH command
internally during tCKESR. The clock is internally disabled during SELF REFRESH operation to save power. The device must remain in
self refresh mode for at least tCKESR. The user can change the external clock frequency or halt the external clock one clock after
self refresh entry is registered; however, the clock must be restarted and stable before the device can exit SELF REFRESH operation.
Exiting self refresh requires a series of commands. First, the clock must be stable prior to CKE returning HIGH. After the self refresh
exit is registered, a minimum delay, at least equal to the self refresh exit interval (tXSR), must be satisfied before a valid command
can be issued to the device. This provides completion time for any internal refresh in progress. For proper operation, CKE must remain
HIGH throughout tXSR, except during self refresh re-entry. NOP commands must be registered on each rising clock edge during
tXSR.
Using self refresh mode introduces the possibility that an internally timed refresh event could be missed when CKE is driven HIGH for
exit from self refresh mode. Upon exiting self refresh, at least one REFRESH command (one all-bank command or eight per-bank
commands) must be issued before issuing a subsequent SELF REFRESH command.
Confidential
- 44 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 35: SELF REFRESH Operation
Notes : 1. Input clock frequency can be changed or stopped during self refresh, provided that upon exiting self-refresh, a minimum of
two cycles of stable clocks are provided, and the clock frequency is between the minimum and maximum frequencies for
the particular speed grade.
2. The device must be in the all banks idle state prior to entering self refresh mode.
3. tXSR begins at the rising edge of the clock after CKE is driven HIGH.
4. A valid command can be issued only after tXSR is satisfied. NOPs must be issued during tXSR.
Partial-Array Self Refresh – Bank Masking
Devices in densities of 64Mb–512Mb are comprised of four banks; densities of 1Gb and higher are comprised of eight banks. Each
bank can be configured independently whether or not a SELF REFRESH operation will occur in that bank. One 8-bit mode register
(accessible via the MRW command) is assigned to program the bank-masking status of each bank up to eight banks.
For bank masking bit assignments, see the MR16 PASR Bank Mask (MA[7:0] = 010h) and MR16 Op-Code Bit Definitions tables.
The mask bit to the bank enables or disables a refresh operation of the entire memory space within the bank.
If a bank is masked using the bank mask register, a REFRESH operation to the entire bank is blocked and bank data
retention is not guaranteed in self refresh mode.To enable a REFRESH operation to a bank, the corresponding bank mask
bit must be programmed as “unmasked.”When a bank mask bit is unmasked, the array space being refreshed within that
bank is determined by the programmed status of the segment mask bits.
Partial-Array Self Refresh – Segment Masking
Programming segment mask bits is similar to programming bank mask bits. For densities 1Gb and higher, eight segments are used for
masking (see the MR17 PASR Segment Mask (MA[7:0] = 011h) and MR17 PASR Segment Mask Definitions tables). A mode register is
used for programming segment mask bits up to eight bits. For densities less than 1Gb, segment masking is not supported.
When the mask bit to an address range (represented as a segment) is programmed as “masked,” a REFRESH operation to that segment is blocked. Conversely, when a segment mask bit to an address range is unmasked, refresh to that segment is enabled.
A segment masking scheme can be used in place of or in combination with a bank masking scheme. Each segment mask bit setting is
applied across all banks. For segment masking bit assignments, see the tables noted above.
Confidential
- 45 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table26 : Bank and Segment Masking Example
Segment Mask(MR17)
Bank0
Bank Mask(MR16)
Bank1
Bank2
Bank3
Bank4
Bank5
Bank6
Bank7
0
1
0
0
0
0
0
1
Segment 0
0
-
M
-
-
-
-
-
M
Segment 1
0
-
M
-
-
-
-
-
M
Segment 2
1
M
M
M
M
M
M
M
M
Segment 3
0
-
M
-
-
-
-
-
M
Segment 4
0
-
M
-
-
-
-
-
M
Segment 5
0
-
M
-
-
-
-
-
M
Segment 6
0
-
M
-
-
-
-
-
M
Segment 7
1
M
M
M
M
M
M
M
M
Note : 1. This table provides values for an 8-bank device with REFRESH operations masked to banks 1 and 7, and segments 2 and 7.
MODE REGISTER READ
The MODE REGISTER READ (MRR) command is used to read configuration and status data from SDRAM mode registers.
The MRR command is initiated with CS# LOW, CA0 LOW, CA1 LOW, CA2 LOW, and CA3 HIGH at the rising edge of the clock.
The mode register is selected by CA1f–CA0f and CA9r–CA4r.The mode register contents are available on the first data beat of DQ[7:0]
after RL × tCK + tDQSCK + tDQSQ and following the rising edge of the clock where MRR is issued. Subsequent data beats contain
valid but undefined content, except in the case of the DQ calibration function, where subsequent data beats contain valid content as
described in Table 28. All DQS are toggled for the duration of the mode register READ burst.
The MRR command has a burst length of four. MRR operation (consisting of the MRR command and the corresponding data traffic)
must not be interrupted.The MRR command period (tMRR) is two clock cycles.
Figure 36: MRR Timing – RL = 3, tMRR = 2
Notes : 1. MRRs to DQ calibration registers MR32 and MR40 are described in DQ Calibration (page 48).
Confidential
- 46 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Notes : 1. MRRs to DQ calibration registers MR32 and MR40 are described in DQ Calibration (page 48).
2. Only the NOP command is supported during tMRR.
3. Mode register data is valid only on DQ[7:0] on the first beat. Subsequent beats contain valid but undefined data.
DQ[MAX:8] contain valid but undefined data for the duration of the MRR burst.
4. Minimum MRR to write latency is RL + RU(tDQSCKmax/tCK) + 4/2 + 1 - WL clock cycles.
5. Minimum MRR to MRW latency is RL + RU(tDQSCKmax/tCK) + 4/2 + 1 clock cycles.
READ bursts andWRITE bursts cannot be truncated by MRR. Following a READ command, the MRR command must not be issued
before BL/2 clock cycles have completed. Following A WRITE command, the MRR command must not be issued before WL + 1 +
BL/2 + RU(tWTR/tCK) clock cycles have completed. If a READ or WRITE burst is truncated with a BST command, the effective burst
length of the truncated burst should be used for the BL value.
Figure 37: READ to MRR Timing – RL = 3, tMRR = 2
Notes : 1. The minimum number of clock cycles from the burst READ command to the MRR command is BL/2.
2. Only the NOP command is supported during tMRR.
Confidential
- 47 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 38: Burst WRITE Followed by MRR – RL = 3, WL = 1, BL = 4
Notes : 1. The minimum number of clock cycles from the burst WRITE command to the MRR command is [WL+1+BL/2+ RU(tWTR/tCK)].
2. Only the NOP command is supported during tMRR.
Temperature Sensor
Mobile LPDDR2 devices feature a temperature sensor whose status can be read from MR4.
This sensor can be used to determine an appropriate refresh rate, determine whether AC timing derating is required in the extended
temperature range, and/or monitor the operating temperature. Either the temperature sensor or the device operating temperature can
be used to determine whether operating temperature requirements are being met (see Operating Temperature Range table).
Temperature sensor data can be read from MR4 using the mode register read protocol. Upon exiting self-refresh or power-down, the
device temperature status bits will be no older than tTSI.
When using the temperature sensor, the actual device case temperature may be higher than the operating temperature specification
that applies for the standard or extended temperature ranges (see table noted above).
For example,TCASE could be above 85˚C when MR4[2:0] equals 011b. To ensure proper operation using the temperature sensor,
applications must accommodate the parameters in the temperature sensor definitions table.
Table 27: Temperature Sensor Definitions and Operating Conditions
Parameter
Description
Symbol
System
Maximum temperature gradient experienced by the memory
TempGradient
Temperature Gradient device at the temperature of interest over a range of 2˚C
MR4 READ interval
Time period between MR4 READs from the System
Temperature
Sensor interval
Maximum delay between internal updates of MR4
System
response delay
Maximum response time from an MR4 READ to the
system response
Device
temperature margin
Confidential
Margin above maximum temperature to support controller
response
- 48 of 125 -
Min/Max
MAX
Value
Unit
System
dependent
System
dependent
˚C/s
ReadInterval
MAX
tTSI
MAX
32
ms
SysRespDelay
MAX
System
dependent
ms
TempMargin
MAX
2
˚C
Rev.1.0
ms
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Mobile LPDDR2 devices accommodate the temperature margin between the point at which the device temperature enters the extended temperature range and the point at which the controller reconfigures the system accordingly. To determine the required MR4
polling frequency, the system must use the maximum TempGradient and the maximum response time of the system according to the
following equation:
TempGradient × (ReadInterval + tTSI + SysRespDelay) ≤ 2°C
For example, ifTempGradient is 10˚C/s and the SysRespDelay is 1ms:
10°C/s X (ReadInterval + 32ms +1ms) ≤ 2°C
In this case, ReadInterval must not exceed 167ms.
Figure 39: Temperature Sensor Timing
DQ Calibration
Mobile LPDDR2 devices feature a DQ calibration function that outputs one of two predefined system timing calibration patterns.
For x16 devices, pattern A (MRR to MRR32), and pattern B (MRR to MRR40), will return the specified pattern on DQ0 and DQ8; x32
devices return the specified pattern on DQ0, DQ8, DQ16, and DQ24.
For x16 devices, DQ[7:1] and DQ[15:9] drive the same information as DQ0 during the MRR burst. For x32 devices, DQ[7:1], DQ[15:9],
DQ[23:17], and DQ[31:25] drive the same information as DQ0 during the MRR burst. MRR DQ calibration commands can occur only
in the idle state.
Confidential
- 49 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 40: MR32 and MR40 DQ Calibration Timing – RL = 3, tMRR = 2
Note : 1. Only the NOP command is supported during tMRR.
Table28 : Data Calibration Pattern Description
Pattern
MR#
Bit Time 0 Bit Time 1 Bit Time 2 Bit Time 3
Description
Pattern A
MR32
1
0
1
0
Reads to MR32 return DQ calibration pattern A
Pattern B
MR40
0
0
1
1
Reads to MR40 return DQ calibration pattern B
Confidential
- 50 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
MODE REGISTER WRITE Command
The MODE REGISTER WRITE (MRW) command is used to write configuration data to the mode registers.
The MRW command is initiated with CS# LOW, CA0 LOW, CA1 LOW, CA2 LOW, and CA3 LOW at the rising edge of the clock.
The mode register is selected by CA1f–CA0f, CA9r–CA4r.The data to be written to the mode register is contained in CA9f–CA2f.
The MRW command period is defined by tMRW. MRWs to read-only registers have no impact on the functionality of the device.
MRW can only be issued when all banks are in the idle precharge state. One method of ensuring that the banks are in this state
is to issue a PRECHARGE ALL command.
Figure 41: MODE REGISTER WRITE Timing – RL = 3, tMRW = 5
Notes : 1. At time Ty, the device is in the idle state.
2. Only the NOP command is supported during tMRW.
Table29 : Truth Table for MRR and MRW
Current State
All banks idle
Bank(s) active
Command
MRR
MRW
MRW (RESET)
MRR
MRW
MRW (RESET)
Intermediate State
Reading mode register, all banks idle
Writing mode register, all banks idle
Resetting, device auto initialization
Reading mode register, bank(s) idle
Not allowed
Not allowed
Next State
All banks idle
All banks idle
All banks idle
Bank(s) active
Not allowed
Not allowed
MRW RESET Command
The MRW RESET command brings the device to the device auto initialization (resetting) state in the power-on initialization sequence
(see 2. RESET Command under Power-Up (page 7)).
The MRW RESET command can be issued from the idle state. This command resets all mode registers to their default values.
Only the NOP command is supported during tINIT4.
After MRW RESET, boot timings must be observed until the device initialization sequence is complete and the device is in the idle
state. Array data is undefined after the MRW RESET command has completed. For MRW RESET timing, see Figure 1.
Confidential
- 51 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
MRW ZQ Calibration Commands
The MRW command is used to initiate a ZQ calibration command that calibrates output driver impedance across process, temperature, and voltage. LPDDR2-S4 devices support ZQ calibration.To achieve tighter tolerances, proper ZQ calibration must be performed.
There are four ZQ calibration commands and related timings: tZQINIT, tZQRESET, tZQCL, and tZQCS. tZQINIT is used for initialization
calibration; tZQRESET is used for resetting ZQ to the default output impedance; tZQCL is used for long calibration(s); and tZQCS is
used for short calibration(s). See the MR10 Calibration (MA[7:0] = 0Ah) table for ZQ calibration command code definitions.
ZQINIT must be performed for LPDDR2 devices. ZQINIT provides an output impedance accuracy of ±15%.
After initialization, the ZQ calibration long (ZQCL) can be used to recalibrate the system to an output impedance accuracy of ±15%.
A ZQ calibration short (ZQCS) can be used periodically to compensate for temperature and voltage drift in the system.
ZQRESET resets the output impedance calibration to a default accuracy of ±30% across process, voltage, and temperature.
This command is used to ensure output impedance accuracy to ±30% when ZQCS and ZQCL commands are not used.
One ZQCS command can effectively correct at least 1.5% (ZQ correction) of output impedance errors within tZQCS for all speed bins,
assuming the maximum sensitivities specified in Table 68 and Table 69 are met.The appropriate interval between ZQCS
commands can be determined using these tables and system-specific parameters.
Mobile LPDDR2 devices are subject to temperature drift rate (Tdriftrate) and voltage drift rate (Vdriftrate) in various applications.
To accommodate drift rates and calculate the necessary interval between ZQCS commands, apply the following formula:
ZQcorrection
(Tsens× Tdriftrate) + (Vsens×Vdriftrate)
Where Tsens = MAX (dRONdT) andVsens = MAX (dRONdV) define temperature and voltage sensitivities.
For example, ifTsens = 0.75%/˚C,Vsens= 0.20%/mV,Tdriftrate = 1˚C/sec, and Vdriftrate = 15 mV/sec, then the interval between
ZQCS commands is calculated as:
1.5
= 0.4s
(0.75 × 1) + (0.20 × 15)
A ZQ calibration command can only be issued when the device is in the idle state with all banks precharged.
No other activities can be performed on the data bus during calibration periods (tZQINIT, tZQCL, or tZQCS).
The quiet time on the data bus helps to accurately calibrate output impedance.
There is no required quiet time after the ZQRESET command. If multiple devices share a single ZQ resistor, only one device can
be calibrating at any given time. After calibration is complete, the ZQ ball circuitry is disabled to reduce power consumption.
In systems sharing a ZQ resistor between devices, the controller must prevent tZQINIT, tZQCS, and tZQCL overlap between the
devices. ZQRESET overlap is acceptable. If the ZQ resistor is absent from the system, ZQ must be connected to VDDCA.
In this situation, the device must ignore ZQ calibration commands and the device will use the default calibration settings.
Confidential
- 52 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 42: ZQ Timings
Notes : 1. Only the NOP command is supported during ZQ calibrations.
2. CKE must be registered HIGH continuously during the calibration period.
3. All devices connected to the DQ bus should be High-Z during the calibration process.
ZQ External Resistor Value, Tolerance, and Capacitive Loading
To use the ZQ calibration function, a 240 ohm (±1% tolerance) external resistor must be connected between the ZQ pin
And ground. A single resistor can be used for each device or one resistor can be shared between multiple devices if the
ZQ calibration timings for each device do not overlap.The total capacitive loading on the ZQ pin must be limited
(see the Input/Output Capacitance table).
Confidential
- 53 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Power-Down
Power-down is entered synchronously when CKE is registered LOW and CS# is HIGH at the rising edge of clock. A NOP command
must be driven in the clock cycle following power-down entry. CKE must not go LOW while MRR, MRW, READ, or WRITE operations
are in progress. CKE can go LOW while any other operations such as ACTIVATE, PRECHARGE, auto precharge, or REFRESH are in
progress, but the power-down IDD specification will not be applied until such operations are complete.
If power-down occurs when all banks are idle, this mode is referred to as idle 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 must be held
LOW; all other input signals are “Don’t Care.” CKE LOW must be maintained until tCKE is satisfied.VREFCA must be Maintained at a
valid level during power-down. VDDQ can be turned off during power-down. IfVDDQ is turned off,VREFDQ must also be turned off.
Prior to exiting power-down, bothVDDQ andVREFDQ must be within their respective minimum/maximum operating ranges (see AC
and DC Operating Conditions).
No refresh operations are performed in power-down mode.The maximum duration in power-down mode is only limited by the refresh
requirements outlined in REFRESH Command. The power-down state is exited when CKE is registered HIGH.
The controller must drive CS# HIGH in conjunction with CKE HIGH when exiting the power-down state. CKE HIGH must be maintained
until tCKE is satisfied. A valid, executable command can be applied with power-down exit latency tXP after CKE goes HIGH. Powerdown exit latency is defined in the ACTiming section.
Confidential
- 54 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 43: Power-Down Entry and Exit Timing
Note : 1. Input clock frequency can be changed or the input clock stopped during power-down, provided that the clock frequency is
between the minimum and maximum specified frequencies for the speed grade in use, and that prior to power-down exit,
a minimum of two stable clocks complete.
Figure 44: CKE Intensive Environment
Figure 45: REFRESH-to-REFRESH Timing in CKE Intensive Environments
Note : 1. The pattern shown can repeat over an extended period of time. With this pattern, all AC and DC timing and voltage
specifications with temperature and voltage drift are ensured.
Confidential
- 55 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 46: READ to Power-Down Entry
Notes : 1. CKE must be held HIGH until the end of the burst operation.
2. CKE can be registered LOW at (RL + RU(tDQSCK(MAX)/tCK) + BL/2 + 1) clock cycles after the clock on which the READ
command is registered.
Confidential
- 56 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 47: READ with Auto Precharge to Power-Down Entry
Notes : 1. CKE must be held HIGH until the end of the burst operation.
2. CKE can be registered LOW at (RL + RU(tDQSCK/tCK)+ BL/2 + 1) clock cycles after the clock on which the READ
command is registered.
3. BL/2 with tRTP = 7.5ns and tRAS (MIN) is satisfied.
4. Start internal PRECHARGE.
Confidential
- 57 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 48: WRITE to Power-Down Entry
Note : 1. CKE can be registered LOW at (WL + 1 + BL/2 + RU(tWR/tCK)) clock cycles after the clock on which the WRITE command
is registered.
Confidential
- 58 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 49: WRITE with Auto Precharge to Power-Down Entry
Notes : 1. CKE can be registered LOW at (WL + 1 + BL/2 + RU(tWR/tCK + 1) clock cycles after the WRITE command is registered.
2. Start internal PRECHARGE.
Confidential
- 59 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 50: REFRESH Command to Power-Down Entry
Note : 1. CKE can go LOW tIHCKE after the clock on which the REFRESH command is registered.
Figure 51: ACTIVATE Command to Power-Down Entry
Note : 1. CKE can go LOW at tIHCKE after the clock on which the ACTIVATE command is registered.
Figure 52: PRECHARGE Command to Power-Down Entry
Note : 1. CKE can go LOW tIHCKE after the clock on which the PRECHARGE command is registered.
Confidential
- 60 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 53: MRR Command to Power-Down Entry
Note : 1. CKE can be registered LOW at (RL + RU(tDQSCK/tCK)+ BL/2 + 1) clock cycles after the clock on which the MRR command
is registered.
Figure 54: MRW Command to Power-Down Entry
Note : 1. CKE can be registered LOW tMRW after the clock on which the MRW command is registered.
Deep Power-Down
Deep power-down (DPD) is entered when CKE is registered LOW with CS# LOW, CA0 HIGH, CA1 HIGH, and CA2 LOW at the rising
edge of the clock.The NOP command must be driven in the clock cycle following power-down entry. CKE must not go LOW while MRR
or MRW operations are in progress. CKE can go LOW while other operations such as ACTIVATE, auto precharge, PRECHARGE, or
REFRESH are in progress, however, deep power-down IDD specifications will not be applied until those operations complete.
The contents of the array will be lost upon entering DPD mode.
In DPD mode, all input buffers except CKE, all output buffers, and the power supply to internal circuitry are disabled within the
device.VREFDQ can be at any level between 0 and VDDQ, andVREFCA can be at any level between 0 andVDDCA during DPD.
All power supplies (including VREF) must be within the specified limits prior to exiting DPD (see AC and DC Operating Conditions).
To exit DPD, CKE must be HIGH, tISCKE must be complete, and the clock must be stable. To resume operation, the device must be
fully reinitialized using the power-up initialization sequence.
Confidential
- 61 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 55: Deep Power-Down Entry and Exit Timing
Notes : 1. The initialization sequence can start at any time after Tx + 1.
2. tINIT3 and Tx + 1 refer to timings in the initialization sequence. For details, see Mode Register Definition.
Input Clock Frequency Changes and Stop Events
Input Clock Frequency Changes and Clock Stop with CKE LOW
During CKE LOW, Mobile LPDDR2 devices support input clock frequency changes and clock stop under the following conditions:
• Refresh requirements are met
• Only REFab or REFpb commands can be in process
• Any ACTIVATE or PRECHARGE commands have completed prior to changing the frequency
• Related timing conditions,tRCD and tRP, have been met prior to changing the frequency
• The initial clock frequency must be maintained for a minimum of two clock cycles after CKE goes LOW
• The clock satisfies tCH(abs) and tCL(abs) for a minimum of two clock cycles prior to CKE going HIGH
For input clock frequency changes, tCK(MIN) and tCK(MAX) must be met for each clock cycle.
After the input clock frequency is changed and CKE is held HIGH, additional MRW commands may be required to set theWR, RL, etc.
These settings may require adjustment to meet minimum timing requirements at the target clock frequency.
For clock stop, CK is held LOW and CK# is held HIGH.
Confidential
- 62 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Input Clock Frequency Changes and Clock Stop with CKE HIGH
During CKE HIGH, LPDDR2 devices support input clock frequency changes and clock stop under the following conditions:
• REFRESH requirements are met.
• Any ACTIVATE, READ, WRITE, PRECHARGE, MRW, or MRR commands must have completed, including any associated data bursts, prior to
changing the frequency.
• Related timing conditions, tRCD, tWR, tWRA, tRP, tMRW, and tMRR, etc., are met
• CS# must be held HIGH
• Only REFab or REFpb commands can be in process
The device is ready for normal operation after the clock satisfies tCH(abs) and tCL(abs) for a minimum of 2 × tCK + tXP.
For input clock frequency changes, tCK(MIN) and tCK(MAX) must be met for each clock cycle.
After the input clock frequency is changed, additional MRW commands may be required to set the WR, RL, etc. These settings
may
require adjustment to meet minimum timing requirements at the target clock frequency.
For clock stop, CK is held LOW and CK# is held HIGH.
NO OPERATION Command
The NO OPERATION (NOP) command prevents the device from registering any unwanted commands issued between
operations. A NOP command can only be issued at clock cycle N when the CKE level is constant for clock cycle N-1 and clock
cycle N. The NOP command has tw possible encodings: CS# HIGH at the clock rising edge N; and CS# LOW with CA0,
CA1, CA2 HIGH at the clock rising edge N.
The NOP command will not terminate a previous operation that is still in process, such as a READ burst or WRITE burst cycle.
Simplified Bus Interface State Diagram
The state diagram provides a simplified illustration of the bus interface, supported state transitions, and the commands that control
them. For a complete description of device behavior, use the information provided in the state diagram with the truth tables and
timing specifications.
The truth tables describe device behavior and applicable restrictions when considering the actual state of all banks.
Truth Tables
Truth tables provide complementary information to the state diagram.They also clarify device behavior and applicable restrictions
when
considering the actual state of the banks. Unspecified operations and timings are illegal.To ensure proper operation after an illegal
event, the
device must be powered down and then restarted using the specified initialization sequence before normal operation can
continue.
Confidential
- 63 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table30 : Command Truth table
Notes 1–11 apply to all parameters conditions
Command Pins
Command
CKE
CK(n-1) CK(n)
CA Pins
/CS
CA0
CA1
CA2
CA3
CA4
CA5
CA6
CA7
CA8
CA9
H
H
L
L
L
L
L
MA0
MA1
MA2
MA3
MA4
MA5
H
H
X
MA6
MA7
OP0
OP1
OP2
OP3
OP4
OP5
OP6
OP7
H
H
L
L
L
L
H
MA0
MA1
MA2
MA3
MA4
MA5
H
H
X
MA6
MA7
REFRESH
(per bank)
H
H
L
L
L
H
L
H
H
X
REFRESH
(all banks)
H
H
L
L
L
H
H
H
H
X
Enter self
refresh
H
L
L
L
L
H
X
L
X
ACTIVATE
(bank)
H
H
L
L
H
R8
BA0
BA1
BA2
H
H
X
R0
R1
R2
H
H
L
H
L
L
H
H
X
AP
C3
C4
H
H
L
H
L
H
H
X
AP
C3
H
H
L
H
H
L
H
H
X
H
H
L
H
H
X
H
L
L
X
L
X
MRW
MRR
WRITE(bank)
READ bank)
PRECHARGE
(bank)
BST
Enter DPD
NOP
Maintain PD,
SREF, DPD,
(NOP)
NOP
Maintain PD,
SREF, DPD,
(NOP)
Enter
power-down
Exit PD, SREF,
DPD
CK
Edge
X
X
X
X
X
X
X
R9
R10
R11
R12
R3
R4
R5
R6
R7
R13
R14
RFU
RFU
C1
C2
BA0
BA1
BA2
C5
C6
C7
C8
C9
C10
C11
H
RFU
RFU
C1
C2
BA0
BA1
BA2
C4
C5
C6
C7
C8
C9
C10
C11
H
AB
X
X
BA0
BA1
BA2
X
H
H
L
L
X
X
H
H
L
X
X
H
H
L
H
H
X
H
H
H
X
L
L
L
L
L
X
X
H
H
H
X
H
H
X
X
L
L
H
X
L
L
X
X
H
L
H
X
X
H
H
H
X
X
L
X
X
L
H
H
X
X
H
X
X
Notes : 1. All commands are defined by the current state of CS#, CA0, CA1, CA2, CA3, and CKE at the rising edge of the clock.
2. Bank addresses (BA) determine which bank will be operated upon.
3. AP HIGH during a READ or WRITE command indicates that an auto precharge will occur To the bank associated with the
READ or WRITE command.
Confidential
- 64 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
4. X indicates a “Don’t Care” state, with a defined logic level, either HIGH (H) or LOW (L).
5. Self refresh exit and DPD exit are asynchronous.
6. VREF must be between 0 and VDDQ during self refresh and DPD operation.
7. CAxr refers to command/address bit “x” on the rising edge of clock.
8. CAxf refers to command/address bit “x” on the falling edge of clock.
9. CS# and CKE are sampled on the rising edge of the clock.
10. Per-bank refresh is only supported in devices with eight banks.
11. he least-significant column address C0 is not transmitted on the CA bus, and is inferred to be zero.
Table31 : CKE Truth Table
Notes 1–5 apply to all parameters and conditions ; L=LOW , H=HIGH , X=“Don’t Care”
Current State
Active
power-down
Idle power-down
CKEn-1
CKEn
CS#
Command n
Operation n
Next State
L
L
X
X
L
H
H
NOP
L
L
X
X
L
H
H
NOP
L
L
X
X
L
H
H
NOP
Exit resetting power-down
Idle or
resetting
L
L
X
X
Maintain deep power-down
Deep
power-down
L
H
H
NOP
Active
power-down
Maintain active power-down
Exit active power-down
Active
6, ,7
Idle
power-down
Maintain idle power-down
Exit idle power-down
Idle
6, 7
Resetting
power-down
Maintain resetting power-down
Resetting idle
power-down
Deep power-down
Exit deep power-down
6, 7, 8
Power-on
L
L
X
X
L
H
H
NOP
Exit self refresh
H
L
H
NOP
Enter active power-down
Active
power-down
H
L
H
NOP
Enter idle power-down
Idle
power-down
H
L
L
Enter self
refresh
Enter self refresh
Self refresh
H
L
L
DPD
Enter deep power-down
Deep
power-down
Resetting
H
L
H
NOP
Other states
H
H
Self refresh
Bank(s) active
All banks idle
Notes
Maintain self refresh
9
Self refresh
Idle
Enter deep power-down
10, 11
Resetting
power-down
Refer to the command truth table
Notes : 1. Current state = the state of the device immediately prior to the clock rising edge n.
2. All states and sequences not shown are illegal or reserved unless explicitly described elsewhere in this document.
3. CKEn = the logic state of CKE at clock rising edge n; CKEn-1 was the state of CKE at the previous clock edge.
4. CS#= the logic state of CS# at the clock rising edge n.
5. Command n = the command registered at clock edge n, and operation n is a result of command n.
6. Power-down exit time (tXP) must elapse before any command other than NOP is issued.
Confidential
- 65 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
7. The clock must toggle at least twice prior to the tXP period.
8. Upon exiting the resetting power-down state, the device will return to the idle state if tINIT5 has expired.
9. The DPD exit procedure must be followed as described in Deep Power-Down (page 60).
10. Self refresh exit time (tXSR) must elapse before any command other than NOP is issued.
11. The clock must toggle at least twice prior to the tXSR time.
Table32 : Current State Bank n to Command to Bank n Truth Table
Notes 1–5 apply to all parameters and conditions
Current State
Command
Any
NOP
ACTIVATE
Operation
Next State
Continue previous operation
Notes
Current state
Select and activate row
Active
Refresh (per bank)
Begin to refresh
Refreshing (per bank)
6
Refresh (all banks)
Begin to refresh
Refreshing (all banks)
7
MR writing
7
Idle
MRW
Load value to mode register
MRR
Read value from mode register
Idle, MR reading
RESET
Begin device auto initialization
Resetting
7, 8
9, 10
PRECHARGE
Deactivate row(s) in bank or banks
Precharging
READ
Select column and start read burst
Reading
WRITE
Row active
MRR
PRECHARGE
Reading
Writing
Active MR reading
Precharging
9
READ
Select column and start new read burst
Reading
11, 12
WRITE
Select column and start write burst
Writing
11, 12, 13
BST
WRITE
Writing
Select column and start write burst
Read value from mode register
READ
BST
Deactivate row(s) in bank or banks
Read burst terminate
Active
14
Select column and start new write burst
Writing
11, 12
Select column and start read burst
Reading
11, 12, 15
Active
14
7, 9
Write burst terminate
Power-on
MRW RESET
Begin device auto initialization
Resetting
Resetting
MRR
Read value from mode register
Resetting MR reading
Notes : 1. Values in this table apply when both CKEn -1 and CKEn are HIGH, and after tXSR or tXP has been met, if the previous
state was power-down.
2. All states and sequences not shown are illegal or reserved.
3. Current state definitions: Idle: The bank or banks have been precharged, and tRP has been met.
Active : A row in the bank has been activated, and tRCD has been met. No data bursts or accesses and no register accesses are in progress. Reading: A READ burst has been initiated with auto precharge disabled and has not yet terminated
or been terminated. Writing: A WRITE burst has been initiated with auto precharge disabled and has not yet terminated
or been terminated.
4. The states listed below must not be interrupted by a command issued to the same bank.
NOP commands or supported commands to the other bank must be issued on any clock edge occurring during these states.
Supported commands to the other banks are determined by that bank’s current state, and the definitions given in Table 33 .
Confidential
- 66 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Precharge: Starts with registration of a PRECHARGE command and ends when tRP is met. After tRP is met, the bank is
in the idle state.
Row activate: Starts with registration of an ACTIVATE command and ends when tRCD is met. After tRCD is met, the bank
is in the active state. READ with AP enabled: Starts with registration of a READ command with auto precharge enabled
and ends when tRP is met. After tRP is met, the bank is in the idle state.
WRITE with AP enabled: Starts with registration of a WRITE command with auto precharge enabled and ends when tRP
is met. After tRP is met, the bank is in the idle state.
5. The states listed below must not be interrupted by any executable command. NOP commands must be applied to each
rising clock edge during these states. Refresh (per bank): Starts with registration of a REFRESH (per bank) command
and ends when tRFCpb is met. After tRFCpb is met, the bank is in the idle state. Refresh (all banks): Starts with registration of a REFRESH (all banks) command and ends when tRFCab is met. After tRFCab is met, the device is in the all banks
idle state. Idle MR reading: Starts with registration of the MRR command and ends when tMRR is met. After tMRR is met,
the device is in the all banks idle state.
Resetting MR reading: Starts with registration of the MRR command and ends when tMRR is met. After tMRR is met, the
device is in the all banks idle state. Active MR reading: Starts with registration of the MRR command and ends when tMRR
is met. After tMRR is met, the bank is in the active state. MR writing: Starts with registration of the MRW command and
ends when tMRW is met.
After tMRW is met, the device is in the all banks idle state. Precharging all: Starts with registration of a PRECHARGE ALL
command and ends when tRP is met. After tRP is met, the device is in the all banks idle state.
6. Bank-specific; requires that the bank is idle and no bursts are in progress.
7. Not bank-specific; requires that all banks are idle and no bursts are in progress.
8. Not bank-specific.
9. This command may or may not be bank specific. If all banks are being precharged, they must be in a valid state for precharging.
10. If a PRECHARGE command is issued to a bank in the idle state, tRP still applies.
11. A command other than NOP should not be issued to the same bank while a burst READ or burst WRITE with auto precharge is enabled.
12. The new READ or WRITE command could be auto precharge enabled or auto precharge disabled.
13. A WRITE command can be issued after the completion of the READ burst; otherwise, a BST must be issued to end the
READ prior to asserting a WRITE command.
14. Not bank-specific. The BST command affects the most recent READ/WRITE burst started by the most recent READ /
WRITE command, regardless of bank.
15. A READ command can be issued after completion of the WRITE burst; otherwise, a BST must be used to end the WRITE
prior to asserting another READ command.
Confidential
- 67 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table 33: Current State Bank n to Command to Bank m Truth Table
Notes 1–6 apply to all parameters and conditions
Current State of Bank n
Any
Idle
Row activating, active,
or precharging
Reading
(auto precharge disabled)
Writing
(auto precharge disabled)
Reading with
auto precharge
Writing with
auto precharge
Command to Bank m
Operation
Next State for Bank m
NOP
Continue previous operation
Current State of Bank m
notes
Any
Any command supported to Bank m
-
7
ACTIVATE
Select and activate row in bank m
Active
8
READ
Select column and start READ
Burst from bank m
Reading
9
WRITE
Select column and start WRITE
burst to bank m
Writing
9
PRECHARGE
Deactivate row(s) in bank or banks
10
MRR
READ value from mode register
Precharging
Idle MR reading or
Active MR reading
BST
READ or WRITE burst terminates
an ongoing READ/WRITE
from/to bank m
Active
7
READ
Select column and start READ
burst from bank m
Reading
9
WRITE
Select column and start WRITE
burst to bank m
Writing
9,14
11,12,13
ACTIVATE
Select and activate row in bank m
Active
PRECHARGE
Deactivate row(s) in bank or banks
Precharging
10
READ
Select column and start READ
burst from bank m
Reading
9,15
WRITE
Select column and start WRITE
burst to bank m
Writing
9
ACTIVATE
Select and activate row in bank m
Active
PRECHARGE
Deactivate row(s) in bank or banks
Precharging
10
READ
Select column and start READ
burst from bank m
Reading
9,16
WRITE
Select column and start WRITE
burst to bank m
Writing
9,14,16
ACTIVATE
Select and activate row in bank m
Active
PRECHARGE
Deactivate row(s) in bank or banks
Precharging
10
READ
Select column and start READ
burst from bank m
Reading
9,15,16
WRITE
Select column and start WRITE
burst to bank m
Writing
9,16
ACTIVATE
Select and activate row in bank m
Active
PRECHARGE
Deactivate row(s) in bank or banks
Precharging
10
Power-on
MRW RESET
Begin device auto initialization
Resetting
17,18
Resetting
MRR
Read value from mode register
Resetting MR reading
Notes : 1. This table applies when: the previous state was self refresh or power-down ; after tXSR or tXP has been met; and both
CKEn -1 and CKEn are HIGH.
2. All states and sequences not shown are illegal or reserved.
Confidential
- 68 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
3. Current state definitions:
Idle: The bank has been precharged and tRP has been met.
Active: A row in the bank has been activated, tRCD has been met, no data bursts or accesses and no register accesses
are in progress. Read: A READ burst has been initiated with auto precharge disabled and the READ has not yet terminated
or been terminated. Write: A WRITE burst has been initiated with auto precharge disabled and the WRITE has not yet terminated or been terminated.
4. Refresh, self refresh, and MRW commands can only be issued when all banks are idle.
5. A BST command cannot be issued to another bank; it applies only to the bank represented by the current state.
6. The states listed below must not be interrupted by any executable command.
NOP commands must be applied during each clock cycle while in these states:
Idle MRR: Starts with registration of the MRR command and ends when tMRR has been met.
After tMRR is met, the device is in the all banks idle state.
Reset MRR: Starts with registration of the MRR command and ends when tMRR has been met.
After tMRR is met, the device is in the all banks idle state.
Active MRR: Starts with registration of the MRR command and ends when tMRR has been met.
After tMRR is met, the bank is in the active state.
MRW: Starts with registration of the MRW command and ends when tMRW has been met.
After tMRW is met, the device is in the all banks idle state.
7. BST is supported only if a READ or WRITE burst is ongoing.
8. tRRD must be met between the ACTIVATE command to bank n and any subsequent ACTIVATE command to bank m.
9. READs or WRITEs listed in the command column include READs and WRITEs with or without auto precharge enabled.
10. This command may or may not be bank-specific.
If all banks are being precharged, they must be in a valid state for precharging.
11. MRR is supported in the row-activating state.
12. MRR is supported in the precharging state.
13. The next state for bank m depends on the current state of bank m (idle, row-activating, precharging, or active).
14. A WRITE command can be issued after the completion of the READ burst;
otherwise a BST must be issued to end the READ prior to asserting a WRITE command.
15. A READ command can be issued after the completion of the WRITE burst;
otherwise, a BST must be issued to end the WRITE prior to asserting another READ command.
16. A READ with auto precharge enabled or a WRITE with auto precharge enabled can be followed by any valid command to
other banks provided that the timing restrictions in the PRECHARGE and Auto Precharge Clarification table are met.
17. Not bank-specific; requires that all banks are idle and no bursts are in progress.
18. RESET command is achieved through MODE REGISTER WRITE command.
Table 34: DM Truth Table
Functional Name
Write enable
DM
DQ
notes
L
Valid
1
Write inhibit
H
X
1
Note : 1. Used to mask write data, and is provided simultaneously with the corresponding input data.
Confidential
- 69 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Electrical Specifications
Absolute Maximum Ratings
Stresses greater than those listed below 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 outside those indicated in the
operational sections of this document is not implied.
Exposure to absolute maximum rating conditions for extended periods may adversely affect reliability.
Table 35: Absolute Maximum DC Ratings
Symbol
Min
Max
Unit
Notes
VDD1 supply voltage relative to VSS
VDD1
–0.4
+2.3
V
1
VDD2 supply voltage relative to VSS
VDD2 (1.2V)
–0.4
+1.6
V
1
Parameter
VDDCA supply voltage relative to VSSCA
VDDQ supply voltage relative to VSSQ
Voltage on any ball relative to VSS
VDDCA
–0.4
+1.6
V
1,2
VDDQ
–0.4
+1.6
V
1,3
VIN, VOUT
–0.4
+1.6
V
TSTG
-55
+125
˚C
Storage temperature
4
Notes : 1. See 1. Voltage Ramp under Power-Up (page 7).
2. VREFCA 0.6 ≤ VDDCA; however, VREFCA may be ≥ VDDCA provided that VREFCA ≤ 300mV.
3. VREFDQ 0.6 ≤ VDDQ; however, VREFDQ may be ≥ VDDQ provided that VREFDQ ≤ 300mV.
4. Storage temperature is the case surface temperature on the center/top side of the device.
For measurement conditions, refer to the JESD51-2 standard.
Input/Output Capacitance
Table 36: Input/Output Capacitance
Note 1 applies to all parameters and conditions
Parameter
Symbol
LPDDR2 800-466
LPDDR2 400-200
Unit
Notes
pF
1
Min
Max
Min
Max
1.0
2.0
1.0
2.0
CDCK
0
0.2
0
0.25
pF
1
CI
1.0
2.0
1.0
2.0
pF
1,2
Input capacitance delta, all other input Only pins
CDI
-0.40
+0.40
-0.50
+0.50
pF
1,3
Input/output capacitance, DQ,DM,DQS, DQS#
CIO
1.25
2.5
1.25
2.5
pF
CDDQS
0
0.25
0
0.30
pF
Input/output capacitance delta, DQ,DM
CDIO
-0.5
+0.5
-0.6
+0.6
pF
Input/output capacitance ZQ
CZQ
0
2.5
0
2.5
pF
Input capacitance, CK and CK#
Input capacitance delta, CK and CK#
Input capacitance, all other input Only pins
Input/output capacitance delta, DQS, DQS#
CCK
4
Notes : 1. TC –40˚C to +105˚C; VDDQ = 1.14–1.3V; VDDCA = 1.14–1.3V; VDD1 = 1.7–1.95V; VDD2 = 1.14–1.3V.
2. This parameter applies to die devices only (does not include package capacitance).
3. This parameter is not subject to production testing. It is verified by design and characterization.
The capacitance is measured according to JEP147 (procedure for measuring input capacitance using a vector network
analyzer), with VDD1, VDD2, VDDQ, VSS, VSSCA, and VSSQ applied; all other pins are left floating.
4. Absolute value of CCK - CCK#.
5. CI applies to CS#, CKE, and CA[9:0].
Confidential
- 70 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
6. CDI = CI - 0.5 × (CCK + CCK#).
7. DM loading matches DQ and DQS.
8. MR3 I/O configuration drive strength OP[3:0] = 0001b (34.3 ohm typical).
9. Absolute value of CDQS and CDQS#.
10. CDIO = CIO - 0.5 × (CDQS + CDQS#) in byte-lane.
11. Maximum external load capacitance on ZQ pin: 5pF.
Electrical Specifications – IDD Specifications and Conditions
The following definitions and conditions are used in the IDD measurement tables unless stated otherwise:
• LOW:VIN ≤VIL(DC)max
• HIGH:VIN ≥VIH(DC)min
• STABLE: Inputs are stable at a HIGH or LOW level
• SWITCHING: See the following three tables
Table 37: Switching for CA Input Signals
Notes 1–3 apply to all parameters and conditions
Parameter
CK Rising/ CK Rising/ CK Rising/ CK Rising/ CK Rising/ CK Rising/
CK# Falling CK# Falling CK# Falling CK# Falling CK# Falling CK# Falling
Cycle
N
CS#
N+1
HIGH
CA0
CK Rising/ CK Rising/
CK# Falling CK# Falling
N+2
HIGH
N+3
HIGH
H
L
L
L
L
CA1
H
H
H
L
L
CA2
H
L
L
L
L
CA3
H
H
H
L
L
CA4
H
L
L
L
L
HIGH
H
H
H
L
L
H
H
H
H
L
L
H
H
H
H
CA5
H
H
H
L
L
L
L
H
CA6
H
L
L
L
L
H
H
H
CA7
H
H
H
L
L
L
L
H
CA8
H
L
L
L
L
H
H
H
CA9
H
H
H
L
L
L
L
H
Notes : 1.
CS# must always be driven HIGH.
2.
For each clock cycle, 50% of the CA bus is changing between HIGH and LOW.
3.
The noted pattern (N, N + 1, N + 2, N + 3...) is used continuously during IDD measurement for IDD values that require switching
on the CA bus.
Confidential
- 71 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table 38: Switching for IDD4R
Clock
CKE
CS#
Clock Cycle
Number
Command
CA[2:0]
CA[9:3]
All DQ
Rising
H
L
N
Read_Rising
HLH
LHLHLHL
L
Falling
H
L
N
Read_Falling
LLL
LLLLLLL
L
Rising
H
H
N+1
NOP
LLL
LLLLLLL
H
Falling
H
H
N+1
NOP
HLH
LHLLHLH
L
Rising
H
L
N+2
Read_Rising
HLH
LHLLHLH
H
Falling
H
L
N+2
Read_Falling
LLL
HHHHHHH
H
Rising
H
H
N+3
NOP
LLL
HHHHHHH
H
Falling
H
H
N+3
NOP
HLH
LHLHLHL
L
Notes : 1. Data strobe (DQS) is changing between HIGH and LOW with every clock cycle.
2. The noted pattern (N, N + 1...) is used continuously during IDD measurement for IDD4R
Table 39: Switching for IDD4W
Clock
CKE
CS#
Clock Cycle
Number
Command
CA[2:0]
CA[9:3]
All DQ
Rising
H
L
N
Write Rising
LLH
LHLHLHL
L
Falling
H
L
N
Write Falling
LLL
LLLLLLL
L
Rising
H
H
N+1
NOP
LLL
LLLLLLL
H
Falling
H
H
N+1
NOP
LLH
LHLLHLH
L
Rising
H
L
N+2
Write Rising
LLH
LHLLHLH
H
Falling
H
L
N+2
Write Falling
LLL
HHHHHHH
H
Rising
H
H
N+3
NOP
LLL
HHHHHHH
H
Falling
H
H
N+3
NOP
LLH
LHLHLHL
L
Notes : 1. Data strobe (DQS) is changing between HIGH and LOW with every clock cycle.
2. Data masking (DM) must always be driven LOW.
3. The noted pattern (N, N + 1...) is used continuously during IDD measurement for IDD4W .
Confidential
- 72 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table 40: IDD Specification and Conditions(X16)
Parameter / Condition
Operating one bank active-precharge current (SDRAM) :
tCK = tCKmin; tRC = tRCmin; CKE is HIGH; CS# is HIGH
between valid commands; CA bus inputs are switching;
Data bus inputs are stable
Idle power-down standby current: tCK = tCKmin; CKE is LOW;
CS# is HIGH; All banks are idle; CA bus inputs are switching;
Data bus inputs are stable
Idle power-down standby current with clock stop: CK = LOW,
CK# = HIGH; CKE is LOW; CS# is HIGH; All banks are idle; CA
bus inputs are stable; Data bus inputs are stable
Idle non-power-down standby current: tCK = tCKmin; CKE is
HIGH; CS# is HIGH; All banks are idle; CA bus inputs are
switching; Data bus inputs are stable
Idle non-power-down standby current with clock stopped: CK =
LOW; CK# = HIGH; CKE is HIGH; CS# is HIGH; All banks are
idle; CA bus inputs are stable; Data bus inputs are stable
Active power-down standby current: tCK = tCKmin; CKE is LOW;
CS# is HIGH; One bank is active; CA bus inputs are switching;
Data bus inputs are stable
Power Supply
IDD01
VDD1
15
IDD02
VDD2
50
IDD0in
VDDCA,VDDQ
6
IDD2P1
VDD1
400
Active non-power-down standby current with clock stopped :
CK = LOW, CK# = HIGH CKE is HIGH; CS# is HIGH; One bank
is active; CA bus inputs are stable; Data bus inputs are stable
Confidential
-25
IDD2P2
VDD2
500
IDD2P,in
VDDCA,VDDQ
40
IDD2PS1
VDD1
400
IDD2PS2
VDD2
500
IDD2PS,in VDDCA,VDDQ
IDD2N1
VDD1
0.6
VDD2
30
IDD2N,in
VDDCA,VDDQ
6
IDD2NS1
VDD1
0.6
IDD2NS2
VDD2
12
IDD2NS,in VDDCA, VDDQ
Unit Notes
mA
4
μA
4
μA
4
40
IDD2N2
mA
4
mA
4
6
IDD3P1
VDD1
500
μA
IDD3P2
VDD2
4
mA
IDD3P,in
VDDCA, VDDQ
40
μA
IDD3PS1
VDD1
500
μA
4
mA
40
μA
Active power-down standby current with clock stop: CK = LOW,
CK# = HIGH; CKE is LOW; CS# is HIGH; One bank is active; CA IDD3PS2
VDD2
bus inputs are stable; Data bus inputs are stable
IDD3PS,in VDDCA, VDDQ
Active non-power-down standby current: tCK = tCKmin; CKE is
HIGH; CS# is HIGH; One bank is active; CA bus inputs are
switching; Data bus inputs are stable
Data Rate
Symbol
IDD3N1
VDD1
2
IDD3N2
VDD2
35
IDD3N,in
VDDCA, VDDQ
6
IDD3NS1
VDD1
2
IDD3NS2
VDD2
10
IDD3NS,in VDDCA, VDDQ
- 73 of 125 -
4
4
mA
4
mA
4
6
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table 41: IDD Specification and Conditions(X16) (continued)
Data Rate
Parameter / Condition
Symbol
Power Supply
Operating burst READ current: tCK = tCKmin;
CS# is HIGH between valid commands; One bank is active;
BL = 4; RL = RL (MIN); CA bus inputs are switching; 50% data
change each burst transfer
Operating burst WRITE current: tCK = tCKmin; CS# is HIGH
between valid commands; One bank is active; BL = 4; WL =
WLmin; CA bus inputs are switching; 50% data change each
burst transfer
IDD4R1
VDD1
5
IDD4R2
VDD2
150
IDD4R,in
VDDCA
6
IDD4W1
VDD1
5
IDD4W2
VDD2
130
All-bank REFRESH burst current: tCK = tCKmin; CKE is HIGH
between valid commands; tRC = tRFCabmin; Burst refresh; CA
bus inputs are switching; Data bus inputs are stable
All-bank REFRESH average current: tCK = tCKmin;
CKE is HIGH between valid commands; tRC = tREFI;
CA bus inputs are switching; Data bus inputs are stable
IDD4W,in VDDCA, VDDQ
VDD1
15
IDD52
VDD2
100
IDD5IN
VDDCA, VDDQ
6
IDD5AB1
VDD1
2
IDD5AB2
VDD2
25
Self refresh current (–25˚C to +85˚C): CK = LOW, CK# = HIGH;
CKE is LOW; CA bus inputs are stable; Data bus inputs are
stable; Maximum 1x self refresh rate
Deep power-down current: CK = LOW, CK# = HIGH;
CKE is LOW; CA bus inputs are stable; Data bus inputs are
stable
mA
mA
4
mA
4
mA
4
6
IDD5PB1
VDD1
2
IDD5PB2
VDD2
25
IDD5PB,in VDDCA, VDDQ
Unit Notes
10
IDD51
IDD5AB,in VDDCA, VDDQ
Per-bank REFRESH average current: tCK = tCKmin;
CKE is HIGH between valid commands; tRC = tREFI/8;
CA bus inputs are switching; Data bus inputs are stable
-25
5
mA
5
6
4, 5
VDD1
500
6
IDD62
VDD2
1000
IDD6IN
VDDCA, VDDQ
30
IDD61
IDD81
VDD1
10
IDD82
VDD2
30
IDD8IN
VDDCA, VDDQ
30
μA
6
4,6
7
μA
7
4, 7
Notes : 1. IDD values are the maximum of the distribution of the arithmetic mean.
2. IDD current specifications are tested after the device is properly initialized.
3. The 1x self refresh rate is the rate at which the device is refreshed internally during self refresh, before going into the
extended temperature range.
4. Measured currents are the sum of VDDQ and VDDCA.
5. Per-bank REFRESH is only applicable for LPDDR2-S4 device densities 1Gb or higher.
6. This is the general definition that applies to full-array self refresh.
7. IDD6ET and IDD8 are typical values, are sampled only, and are not tested.
Confidential
- 74 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table 42: IDD Specification and Conditions(X32)
Parameter / Condition
Operating one bank active-precharge current (SDRAM) :
tCK = tCKmin; tRC = tRCmin; CKE is HIGH; CS# is HIGH
between valid commands; CA bus inputs are switching;
Data bus inputs are stable
Idle power-down standby current: tCK = tCKmin; CKE is LOW;
CS# is HIGH; All banks are idle; CA bus inputs are switching;
Data bus inputs are stable
Idle power-down standby current with clock stop: CK = LOW,
CK# = HIGH; CKE is LOW; CS# is HIGH; All banks are idle; CA
bus inputs are stable; Data bus inputs are stable
Idle non-power-down standby current: tCK = tCKmin; CKE is
HIGH; CS# is HIGH; All banks are idle; CA bus inputs are
switching; Data bus inputs are stable
Idle non-power-down standby current with clock stopped: CK =
LOW; CK# = HIGH; CKE is HIGH; CS# is HIGH; All banks are
idle; CA bus inputs are stable; Data bus inputs are stable
Active power-down standby current: tCK = tCKmin; CKE is LOW;
CS# is HIGH; One bank is active; CA bus inputs are switching;
Data bus inputs are stable
Power Supply
IDD01
VDD1
15
IDD02
VDD2
50
IDD0in
VDDCA,VDDQ
6
IDD2P1
VDD1
400
Active non-power-down standby current with clock stopped :
CK = LOW, CK# = HIGH CKE is HIGH; CS# is HIGH; One bank
is active; CA bus inputs are stable; Data bus inputs are stable
Confidential
-25
IDD2P2
VDD2
500
IDD2P,in
VDDCA,VDDQ
40
IDD2PS1
VDD1
400
IDD2PS2
VDD2
500
IDD2PS,in VDDCA,VDDQ
IDD2N1
VDD1
0.6
VDD2
30
IDD2N,in
VDDCA,VDDQ
6
IDD2NS1
VDD1
0.6
IDD2NS2
VDD2
12
IDD2NS,in VDDCA, VDDQ
Unit Notes
mA
4
μA
4
μA
4
40
IDD2N2
mA
4
mA
4
6
IDD3P1
VDD1
500
μA
IDD3P2
VDD2
4
mA
IDD3P,in
VDDCA, VDDQ
40
μA
IDD3PS1
VDD1
500
μA
4
mA
40
μA
Active power-down standby current with clock stop: CK = LOW,
CK# = HIGH; CKE is LOW; CS# is HIGH; One bank is active; CA IDD3PS2
VDD2
bus inputs are stable; Data bus inputs are stable
IDD3PS,in VDDCA, VDDQ
Active non-power-down standby current: tCK = tCKmin; CKE is
HIGH; CS# is HIGH; One bank is active; CA bus inputs are
switching; Data bus inputs are stable
Data Rate
Symbol
IDD3N1
VDD1
2
IDD3N2
VDD2
35
IDD3N,in
VDDCA, VDDQ
6
IDD3NS1
VDD1
2
IDD3NS2
VDD2
10
IDD3NS,in VDDCA, VDDQ
- 75 of 125 -
4
4
mA
4
mA
4
6
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table 43: IDD Specification and Conditions(X32) (continued)
Data Rate
Parameter / Condition
Symbol
Power Supply
Operating burst READ current: tCK = tCKmin;
CS# is HIGH between valid commands; One bank is active;
BL = 4; RL = RL (MIN); CA bus inputs are switching; 50% data
change each burst transfer
Operating burst WRITE current: tCK = tCKmin; CS# is HIGH
between valid commands; One bank is active; BL = 4; WL =
WLmin; CA bus inputs are switching; 50% data change each
burst transfer
IDD4R1
VDD1
5
IDD4R2
VDD2
150
IDD4R,in
VDDCA
6
IDD4W1
VDD1
5
IDD4W2
VDD2
130
All-bank REFRESH burst current: tCK = tCKmin; CKE is HIGH
between valid commands; tRC = tRFCabmin; Burst refresh; CA
bus inputs are switching; Data bus inputs are stable
All-bank REFRESH average current: tCK = tCKmin;
CKE is HIGH between valid commands; tRC = tREFI;
CA bus inputs are switching; Data bus inputs are stable
IDD4W,in VDDCA, VDDQ
VDD1
15
IDD52
VDD2
100
IDD5IN
VDDCA, VDDQ
6
IDD5AB1
VDD1
2
IDD5AB2
VDD2
25
Self refresh current (–25˚C to +85˚C): CK = LOW, CK# = HIGH;
CKE is LOW; CA bus inputs are stable; Data bus inputs are
stable; Maximum 1x self refresh rate
Deep power-down current: CK = LOW, CK# = HIGH;
CKE is LOW; CA bus inputs are stable; Data bus inputs are
stable
mA
mA
4
mA
4
mA
4
6
IDD5PB1
VDD1
2
IDD5PB2
VDD2
25
IDD5PB,in VDDCA, VDDQ
Unit Notes
10
IDD51
IDD5AB,in VDDCA, VDDQ
Per-bank REFRESH average current: tCK = tCKmin;
CKE is HIGH between valid commands; tRC = tREFI/8;
CA bus inputs are switching; Data bus inputs are stable
-25
5
mA
5
6
4, 5
VDD1
500
6
IDD62
VDD2
1000
IDD6IN
VDDCA, VDDQ
30
IDD61
IDD81
VDD1
10
IDD82
VDD2
30
IDD8IN
VDDCA, VDDQ
30
μA
6
4,6
7
μA
7
4, 7
Notes : 1. IDD values are the maximum of the distribution of the arithmetic mean.
2. IDD current specifications are tested after the device is properly initialized.
3. The 1x self refresh rate is the rate at which the device is refreshed internally during self refresh, before going into the
extended temperature range.
4. Measured currents are the sum of VDDQ and VDDCA.
5. Per-bank REFRESH is only applicable for LPDDR2-S4 device densities 1Gb or higher.
6. This is the general definition that applies to full-array self refresh.
7. IDD6ET and IDD8 are typical values, are sampled only, and are not tested.
Confidential
- 76 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table 44: IDD6 Partial-Array Self Refresh Current
VDD2, VDDQ, VDDCA = 1.14–1.30V; VDD1 = 1.70–1.95V
PASR
Full array
1/2 array
1/4 array
1/8 array
Confidential
Symbol
Power Supply
VDD1
1200
VDD2
2500
VDDi
100
VDD1
1000
VDD2
2000
VDDi
100
VDD1
900
VDD2
1700
VDDi
100
VDD1
900
VDD2
1500
VDDi
100
- 77 of 125 -
Unit
μA
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
AC and DC Operating Conditions
Operation or timing that is not specified is illegal.To ensure proper operation, the device must be initialized properly.
Table 45: Recommended DC Operating Conditions
LPDDR2-S4B
Symbol
Power Supply
Unit
1.95
Core power 1
V
1.30
Core power2
V
Min
Typ
Max
VDD1
1.70
1.80
VDD2
1.14
1.20
VDDCA
1.14
1.20
1.30
Input buffer power
V
VDDQ
1.14
1.20
1.30
I/O buffer power
V
Note : 1. VDD1 uses significantly less power than VDD2.
Table 46: Input Leakage Current
Parameter/Condition
Input leakage current : For CA, CKE, CS#, CK, CK#;
Any input 0V ≤ VIN ≤ VDDCA; (All other pins not under test = 0V)
VREF supply leakage current : VREFDQ=VDDQ/2, or VREFCA=VDDCA/2;
(All other pins not under test = 0V)
Symbol
Min
Max
Unit
Notes
IL
-2
2
uA
1
IVREF
-1
1
uA
2
Note : 1. Although DM is for input only, the DM leakage must match the DQ and DQS/DQS# output leakage specification.
2. The minimum limit requirement is for testing purposes. The leakage current on VREFCA and VREFDQ pins should be minimal.
Table 47: Operating Temperature Range
Parameter/Condition
Symbol
Min
Max
Unit
IT temperature range
TCASE
-40
+85
˚C
Note : 1. Operating temperature is the case surface temperature at the center of the top side of the device.
For measurement conditions, refer to the JESD51-2 standard.
2. Some applications require operation in the maximum case temperature range, between 85˚C and 105˚C. For some LPDDR2
devices, derating may be necessary to operate in this range (see the MR4 Device Temperature (MA[7:0] = 04h) table).
3. Either the device operating temperature or the temperature sensor can be used to set an appropriate refresh rate, determine
the need for AC timing derating, and/or monitor the operating temperature (see Temperature Sensor (page 47)). When using
the temperature sensor, the actual device case temperature may be higher than the TCASE rating that applies for the operating
temperature range. For example, TCASE could be above 85˚C when the temperature sensor indicates a temperature of less
than 85˚C.
Confidential
- 78 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
AC and DC Logic Input Measurement Levels for Single-Ended Signals
Table 48: Single-Ended AC and DC Input Levels for CA and CS# Inputs
Symbol
Parameter
VIHCA(AC)
LPDDR2-800 to LPDDR2-466
LPDDR2-400 to LPDDR2-200
Unit notes
Min
Max
Min
Max
AC input logic HIGH
VREF+0.220
Note 2
VREF+0.300
Note 2
V
1,2
VREF-0.300
V
1,2
VDDCA
V
1
VILCA(AC)
AC input logic LOW
DC input logic HIGH
note 2
VREF+0.130
VREF-0.220
VIHCA(DC)
VDDCA
note 2
VREF+0.200
VILCA(DC)
DC input logic LOW
VSSCA
VREF-0.130
VSSCA
VREF-0.200
V
1
VREFCA(DC)
Reference voltage for
CA and CS# inputs
0.49 × VDDCA
0.51 × VDDCA
0.49 × VDDCA
0.51 × VDDCA
V
3, 4
Note : 1. For CA and CS# input-only pins. VREF = VREFCA(DC).
2. See Figure 65.
3. The AC peak noise on VREFCA could prevent VREFCA from deviating more than ±1% VDDCA from VREFCA(DC)
(for reference, approximately ±12mV).
4. For reference, approximately VDDCA/2 ±12mV.
Table 49: Single-Ended AC and DC Input Levels for CKE
Symbol
VIHCKE
Parameter
Min
Max
Unit
notes
CKE input HIGH level
0.8 X VDDCA
Note 1
V
1
VILCKE
CKE input LOW level
Note 1
0.2 X VDDCA
V
1
Note : 1. See Figure 65.
Table 50: Single-Ended AC and DC Input Levels for DQ and DM
Symbol
Parameter
VIHDQ(AC)
LPDDR2-800 to LPDDR2-466
LPDDR2-400 to LPDDR2-200
Unit notes
Min
Max
Min
Max
AC input logic HIGH
VREF+0.220
Note 2
VREF+0.300
Note 2
V
1,2
VILDQ(AC)
AC input logic LOW
VREF-0.220
V
1,2
DC input logic HIGH
VDDQ
Note 2
VREF+0.200
VREF-0.300
VIHDQ(DC)
note 2
VREF+0.130
VDDQ
V
1
VILDQ(DC)
DC input logic LOW
VSSQ
VREF-0.130
VSSQ
VREF-0.200
V
1
VREFDQ(DC)
Reference voltage for
DQ and DM inputs
0.49 X VDDQ
0.51X VDDQ
0.49 X VDDQ
0.51 X VDDQ
V
3, 4
Note : 1. For DQ input-only pins. VREF = VREFDQ(DC).
2. See Figure 65.
3. The AC peak noise on VREFDQ could prevent VREFDQ from deviating more than ±1% VDDQ from VREFDQ(DC)
(for reference, approximately ±12mV).
4. For reference, approximately. VDDQ/2 ±12mV.
Confidential
- 79 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
VREF Tolerances
The DC tolerance limits and AC noise limits for the reference voltages VREFCA and VREFDQ are illustrated below.
This figure shows a valid reference voltageVREF(t) as a function of time.VDD is used in place ofVDDCA forVREFCA, and VDDQ for
VREFDQ. VREF(DC) is the linear average ofVREF(t) over a very long period of time (for example, 1 second) and is specified as a
fraction of the linear average ofVDDQ orVDDCA, also over a very long period of time (for example, 1 second).This average must meet
the MIN/MAX requirements in Table 48. Additionally,VREF(t) can temporarily deviate from VREF(DC) by no more than ±1%VDD.
VREF(t) cannot track noise onVDDQ orVDDCA if doing so would forceVREF outside these specifications.
Figure 56: VREF DC Tolerance and VREF AC Noise Limits
The voltage levels for setup and hold time measurementsVIH(AC),VIH(DC),VIL(AC), and VIL(DC) are dependent onVREF.
VREF DC variations affect the absolute voltage a signal must reach to achieve a valid HIGH or LOW, as well as the time from which
setup and hold times are measured. When VREF is outside the specified levels, devices will function correctly with appropriate timing
deratings as long as:
• VREF is maintained between 0.44 xVDDQ (orVDDCA) and 0.56 xVDDQ (orVDDCA), and
• the controller achieves the required single-ended AC and DC input levels from instantaneous VREF (see Table).
System timing and voltage budgets must account forVREF deviations outside this range. The setup/hold specification and derating
values must include time and voltage associated withVREF AC noise. Timing and voltage effects due to AC noise onVREF up to the
specified limit (±1%VDD) are included in LPDDR2 timings and their associated deratings.
Confidential
- 80 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Input Signal
Figure 57: LPDDR2-466 to LPDDR2-800 Input Signal
Notes : 1. Numbers reflect typical values.
2. For CA[9:0], CK, CK#, and CS# VDD stands for VDDCA. For DQ, DM, DQS, and DQS#, VDD stands for VDDQ.
3. For CA[9:0], CK, CK#, and CS# VSS stands for VSSCA. For DQ, DM, DQS, and DQS#, VSS stands for VSSQ.
Confidential
- 81 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 58: LPDDR2-200 to LPDDR2-400 Input Signal
Notes : 1. Numbers reflect typical values.
2. For CA[9:0], CK, CK#, and CS# VDD stands for VDDCA. For DQ, DM, DQS, and DQS#, VDD stands for VDDQ.
3. For CA[9:0], CK, CK#, and CS# VSS stands for VSSCA. For DQ, DM, DQS, and DQS#, VSS stands for VSSQ.
Confidential
- 82 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Figure 59: Differential AC Swing Time and tDVAC
Table 51: Differential AC and DC Input Levels
For CK and CK#, VREF = VREFCA(DC); For DQS and DQS# VREF = VREFDQ(DC)
Symbol
Parameter
LPDDR2-800 to LPDDR2-466
Min
VIH,diff(AC)
Differential input HIGH AC 2 × (VIH(AC) - VREF)
VIL,diff(AC)
Differential input LOW AC
VIH,diff(DC)
Differential input HIGH
VIL,diff(DC)
Differential input LOW
LPDDR2-400 to LPDDR2-200
Max
Min
Max
note1
2 × (VIH(AC) - VREF)
note1
note 1
2 × (VIH(AC) – VREF)
note 1
2 × (VREF - VIL(AC))
2 × (VIH(DC) - VREF)
note 1
2 × (VIH(DC) - VREF)
note 1
note1
2 × (VREF - VIL(DC))
note1
2 × (VREF - VIL(DC))
Unit notes
V
2
V
2
V
3
V
3
Notes : 1. These values are not defined, however the single-ended signals CK, CK#, DQS, and DQS# must be within the respective
limits (VIH(DC)max, VIL(DC)min) for single-ended signals and must comply with the specified limitations for overshoot and
undershoot (see Figure 65).
2. For CK and CK#, use VIH/VIL(AC) of CA and VREFCA; for DQS and DQS#, use VIH/VIL(AC) of DQ and VREFDQ. If a reduced AC
HIGH or AC LOW is used for a signal group, the reduced voltage level also applies.
3. Used to define a differential signal slew rate.
Confidential
- 83 of 125 -
Rev.1.0
Jan. 2018
AS4C32M32MD2A-25BIN
AS4C64M16MD2A-25BIN
Table 52: CK/CK# and DQS/DQS# Time Requirements Before Ringback (tDVAC)
Slew Rate (V/ns)
tDVAC(ps) at VIH/VILdiff(AC) = 440mV
tDVAC(ps) at VIH/VILdiff(AC) = 600mV
Min
Min
>4.0
175
75
4.0
170
57
3.0
167
50
2.0
163
38
1.8
162
34
1.6
161
29
1.4
159
22
1.2
155
13
1.0
150
0