AS4C64M32MD2-25BCNTR

AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN Revision History AS4C64M16MD2-25BCN / AS4C32M32MD2-25BCN 134 ball FBGA PACKAGE Revision Rev 1.0 Details Preliminary datasheet Date July. 2016 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 - 1/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN KEY FEATURE • Double-data rate architecture; two data transfers per clock cycle • Bidirectional data strobes (DQS, DQS#), These are transmitted/received with data to be used in capturing data at the receiver • Differential clock inputs (CK and CK#) • Differential data strobes (DQS and DQS#) • Commands & addresses entered on both positive and negative CK edges; data and data mask referenced to both edges of DQS • 8 internal banks for concurrent operation • Data mask (DM) for write data • Burst Length: 4 (default), 8 or 16 • Burst Type: Sequential or Interleave • Read & Write latency : Refer to Table 47 • Auto Precharge option for each burst access • Configurable Drive Strength • Auto Refresh and Self Refresh Modes • Partial Array Self Refresh and Temperature Compensated Self Refresh • Deep Power Down Mode • HSUL_12 compatible inputs • VDD1/VDD2/VDDQ : 1.8V/1.2V/1.2V • No DLL : CK to DQS is not synchronized • Edge aligned data output, center aligned data input • Auto refresh duty cycle : - 7.8us for -30 to 85 °C Table 1. Ordering Information Part Number Org Temperature MaxClock (MHz) Package AS4C64M16MD2-25BCN 64Mx16 Commercial -30°C to +85°C 400 134-ball FBGA AS4C32M32MD2-25BCN 32Mx32 Commercial -30°C to +85°C 400 134-ball FBGA Table 2. Speed Grade Information Speed Grade Clock Frequency DDR2L-800 Confidential 400MHz RL WL 6 3 - 2/129 - tRCD (ns) 18 tRP (ns) 18 Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN 1. Functional Block Diagrams Control logic Command / Address Multiplex & Decode CKE CK CK# CS# CA0 CA1 CA2 CA3 CA4 CA5 CA6 CA7 CA8 CA9 Refresh Counter X X ROW address MUX Mode registers Bank7 Bank6 Bank7 Bank5 Bank6 Bank4 Bank5 Bank3 Bank4 Bank2 Bank3 Bank1 Bank2 Bank0 Bank1 Sense amplifier Bank0 Sense amplifier Sense amplifier Row Mem array amplifier Sense Address Sense amplifier latch Sense amplifier n & Sense amplifier n decoder Sense amplifier Read n latch n 4n 3 Column address Counter /latch Confidential Column decoder DQS,DQS# CK, CK# 4 4 WRITE 8 4 4 FIFO Mask & 4n 4 drivers 4 n n 4n n n CK OUT Data n n n n CK IN 1 DQ0 DQn-1 INPUT registers I/O gating DM mask logic y-1 n MUX DATA DRVRS DQS generator 3 Bank Control logic COL0 4 DQS, DQS# 4 4 n RCVRS COL0 DM - 3/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! 2. Ball Descriptions 2-1. Pad Definition and Description CK, CK# Name Type Input CKE Input CS# Input CA0 - CA9 Input DQ0 - DQ15 (x16) DQ0 - DQ31 (x32) DQS0, DQS0#, DQS1, DQS1# (x16) DQS0 DQS3, DQS0# DQS3 (x32) DM0-DM1 (x16) DM0 - DM3 (x32) I/O VDD1 VDD2 VDDQ VREF(CA) Supply Supply Supply Supply VREF(DQ) VSS VSSQ ZQ Supply Supply Supply I/O I/O Input Description Clock: CK and CK# are differential clock inputs. All Double Data Rate (DDR) CA inputs are sampled on both positive and negative edge of CK. Single Data Rate (SDR) inputs, CS# and CKE, are sampled at the positive Clock edge. Clock is defined as the differential pair, CK and CK#. The positive Clock edge is defined by the crosspoint of a rising CK and a falling CK#. The negative Clock edge is defined by the crosspoint of a falling CK and a rising CK#. Clock Enable: CKE HIGH activates and CKE LOW deactivates internal clock signals and therefore device input buffers and output drivers. Power savings modes are entered and exited through CKE transitions. CKE is considered part of the command code. See Command Truth Table for command code descriptions. CKE is sampled at the positive Clock edge. Chip Select: CS# is considered part of the command code. See Command Truth Table for command code descriptions. CS# is sampled at the positive Clock edge. DDR Command/Address Inputs: Uni-directional command/address bus inputs. CA is considered part of the command code. See Command Truth Table for command code descriptions. Data Inputs/Output: Bi-directional data bus Data Strobe (Bi-directional, Differential): The data strobe is bi-directional (used for read and write data) and differential (DQS and DQS#). It is output with read data and input with write data. DQS is edge-aligned to read data and centered with write data. For x16, DQS0 and DQS0# correspond to the data on DQ0 - DQ7; DQS1 and DQS1# to the data on DQ8 - DQ15. For x32 DQS0 and DQS0# correspond to the data on DQ0 - DQ7, DQS1 and DQS1# to the data on DQ8 - DQ15, DQS2 and DQS2# to the data on DQ16 - DQ23, DQS3 and DQS3# to the data on DQ24 - DQ31. Input Data Mask: For LPDDR2 devices that do not support the DNV feature, DM is the input mask signal for write data. Input data is masked when DM is sampled HIGH coincident with that input data during a Write access. DM is sampled on both edges of DQS. Although DM is for input only, the DM loading shall match the DQ and DQS (or DQS#). DM0 is the input data mask signal for the data on DQ0-7. For x16 and x32 devices, DM1 is the input data mask signal for the data on DQ8-15. For x32 devices, DM2 is the input data mask signal for the data on DQ16-23 and DM3 is the input data mask signal for the data on DQ24-31. Core Power Supply 1: Core power supply Core Power Supply 2: Core power supply I/O Power Supply: Power supply for Data input/output buffers. Reference Voltage for CA Command and Control Input Receiver: Reference voltage for all CA0-9, CKE, CS#, CK, and CK# input buffers. Reference Voltage for DQ Input Receiver: Reference voltage for all Data input buffers Ground I/O Ground Reference Pin for Output Drive Strength Calibration NOTE : Data includes DQ and DM Confidential - 4/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN LPDDR2 SDRAM Addressing Number of banks Bank address pins Auto precharge pin X16 X32 ITEM Row addresses Column addresses tREFI(µs) Row addresses Column addresses tREFI(µs) 1Gb 8 BA0~BA2 A10/AP R0-R12 C0-C9 7.8 R0-R12 C0-C8 7.8 NOTE 1. The least-significant column address C0 is not transmitted on the CA bus, and is implied to be zero. NOTE 2. tREFI values for all bank refresh is Tc = -25~85℃, Tc means Operating Case Temperature. NOTE 3. Row and Column Address values on the CA bus that are not used are “don’t care.” Confidential - 5/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN 2-2. Package Dimension : 134-Ball FBGA – 10mm x 11.5mm x 1.0mm (max) Confidential - 6/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN 2-3. Package Ballout 134Ball FBGA 1 2 3 4 5 6 7 8 9 10 A DNU DNU NB NB NB NB NB NB DNU DNU B DNU NC NC NB VDD2 VDD1 DQ31 NC DQ29 NC DQ26 NC DNU C VDD1 VSS NC NB VSS VSSQ VDDQ DQ25 NC VSSQ VDDQ D VSS VDD2 ZQ0 NB VDDQ DQ30 NC DQ27 NC DQS3 NC DQS3# NC VSSQ E VSS CA9 CA8 NB DQ28 NC DQ24 NC DM3 NC DQ15 VDDQ VSSQ F NC CA6 CA7 NB VSSQ DQ11 DQ13 DQ14 DQ12 VDDQ G VDD2 CA5 Vref(CA) NB DQS1# DQS1 DQ10 DQ9 DQ8 VSSQ H NC VSS CK# NB DM1 VDDQ NB NB NB NB J VSS NC CK NB VSSQ VDDQ VDD2 VSS Vref(DQ) NB K CKE NC NC NB DM0 VDDQ NB NB NB NB L CS# NC NC NB DQS0# DQS0 DQ5 DQ6 DQ7 VSSQ M CA4 CA3 CA2 NB VSSQ DQ4 DQ2 DQ1 DQ3 VDDQ N VSS NC CA1 NB DQ19 NC DQ23 NC DM2 NC DQ0 VDDQ VSSQ P VSS VDD2 CA0 NB VDDQ DQ17 NC DQ20 NC DQS2 NC DQS2# NC VSSQ R VDD1 VSS NC NB VSS VSSQ VDDQ DQ22 NC VSSQ VDDQ T DNU NC NC NB VDD2 VDD1 DQ16 NC DQ18 NC DQ21 NC DNU U DNU DNU NB NB NB NB NB NB DNU DNU [Top View] 1st Row 2nd Row x32 Device x16 Device Power ZQ Ground NC/DNU NB Confidential - 7/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN 3. Functional Description LPDDR2 is a high-speed SDRAM device internally configured as a 8-Bank memory. These devices contain the following number of bits: 1 Gb has 1,073,741,824 bits LPDDR2-S4 uses 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 contains command, address, and Bank information. Each command uses one clock cycle, during which command information is transferred on both the positive and negative edge of the clock. LPDDR2-S4 uses a double data rate architecture on the DQ pins to achieve high speed operation. The double data rate architecture is essentially a 4n prefetch 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-halfclock-cycle data transfers at the I/O pins. Read and write accesses to the LPDDR2 are burst oriented; accesses start at a selected location and continue for a programmed number of locations in a programmed sequence. For LPDDR2-S4 devices, accesses begin with the registration of an Activate command, which is then 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 the 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.Prior to normal operation, the LPDDR2 must be initialized.. Confidential - 8/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN 3.1 Simplified LPDDR2 Bus Interface State Diagram The simplified LPDDR2 bus interface state diagram provides a simplified illustration of allowed state transitions and the related commands to control them. For a complete definition of the device behavior, the information provided by the state diagram should be integrated with the truth tables and timing specification. The truth tables provide complementary information to the state diagram, they clarify the device behavior and the applied restrictions when considering the actual state of all the banks. For the command definition, see “LPDDR2 Command Definitions and Timing Diagrams” Confidential - 9/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN Simplified LPDDR2 Bus Interface State Diagram Figure 3.1 LPDDR2 : Simplified Bus Interface State Diagram NOTE 1 These transitions apply for LPDDR2-SX devices only. NOTE 2 For LPDDR2-SDRAM in the Idle state, all banks are precharged. NOTE 3 Use caution with this diagram. It is intented to provide a floorplan of the possible state transitions and commands to control them, not all details. In particular, situations involving more than one Bank/Row Confidential - 10/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! 3.2 Power-up, Initialization, and Power-Off LPDDR2 Devices must be powered up and initialized in a predefined manner. Operational procedures other than those specified may result in undefined operation 3.2.1 Power Ramp and Device Initialization The following sequence shall be used to power up an LPDDR2 device. 1. Power Ramp While applying power (after Ta), CKE shall be held at a logic low level (=< 0.2 x VDD2), all other inputs shall be between VILmin and VIHmax. The LPDDR2 device will only guarantee that outputs are in a high impedance state while CKE is held low. On or before the completion of the power 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 VDD2 during voltage ramp to avoid latch-up. The following conditions apply: Ta is the point where any power supply first reaches 300 mV. After Ta is reached, VDD1 must be greater than VDD2 - 200 mV. After Ta is reached, VDD1 and VDD2 must be greater than VDD2 - 200 mV. After Ta is reached, VDD1 and VDD2 must be greater than VDDQ - 200 mV. After Ta is reached, VREF must always be less than all other supply voltages. The voltage difference between any of VSS, VSSQ, and VSSCA pins may not exceed 100 mV. The above conditions apply between Ta and power-off (controlled or uncontrolled). Tb is the point when all supply voltages are within their respective min/max operating conditions. Reference voltages shall be within their respective min/max operating conditions a minimum of 5 clocks before CKE goes high. Power ramp duration tINIT0 (Tb - Ta) must be no greater than 20 ms. NOTE VDD2 is not present in some systems. Rules related to VDD2 in those cases do not apply. 2. CKE and clock: Beginning at Tb, CKE must remain low for at least tINIT1 = 100 ns, after which it may be asserted high. Clock must be stable at least tINIT2 = 5 x tCK prior to the first low to high transition of CKE (Tc). CKE, CS# and CA inputs must observe setup and hold time (tIS, tIH) requirements with respect to the first rising clock edge (as well as to the subsequent falling and rising edges). The clock period shall be within the range defined for t CKb (18 ns to 100 ns), if any Mode Register Reads are performed. Mode Register Writes can be sent at normal clock operating frequencies so long as all AC Timings are met. Furthermore, some AC parameters (e.g. tDQSCK) may have relaxed timings (e.g. t DQSCKb) before the system is appropriately configured. While keeping CKE high, issue NOP commands for at least tINIT3 = 200 us. (Td). 3. Reset command: After tINIT3 is satisfied, a MRW(Reset) command shall be issued (Td). The memory controller may optionally issue a Precharge-All command (for LPDDR2-SX) to the MRW Reset command. Wait for at least tINIT4 = 1us while keeping CKE asserted and issuing NOP commands. 4. Mode Registers Reads and Device Auto-Initialization (DAI) polling: After tINIT4 is satisfied (Te) only MRR commands and power-down entry/exit commands are allowed. Therefore, after Te, CKE may go low in accordance to Power-Down entry and exit specification (see “Powerdown” ). The MRR command may be used to poll the DAI-bit to acknowledge when Device Auto-Initialization is complete or the memory controller shall wait a minimum of tINIT5 before proceeding. As the memory output buffers are not properly configured yet, some AC parameters may have relaxed timings before the system is appropriately configured. After the DAI-bit (MR0, “DAI”) is set to zero “DAI complete“ by the memory device, the device is in idle state (Tf). The state of the DAI status bit can be determined by an MRR command to MR0. All SDRAM devices will set the DAI-bit no later than tINIT5 (10 us) after the Reset command. The memory controller shall wait a minimum of tINIT5 or until the DAI-bit is set before proceeding. After the DAI-Bit is set, it is recommended to determine the device type and other device characteristics by issuing MRR commands (MR0 “Device Information” etc.). 5. ZQ Calibration: After tINIT5 (Tf), an MRW ZQ Initialization Calibration command may be issued to the memory (MR10). For Confidential - 11/129 - Rev.1.0 July 2016 ! ! AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN LPDDR2 devices which do not support the ZQ Calibration command, this command shall be ignored. This command is used to calibrate the LPDDR2 output drivers (RON) over process, voltage, and temperature. Optionally, the MRW ZQ Initialization Calibration command will update MR0 to indicate RZQ pin connection. In systems in which more than one LPDDR2 device exists on the same bus, the controller must not overlap ZQ Calibration commands. The device is ready for normal operation after tZQINIT. 6. Normal Operation: After tZQINIT (Tg), MRW commands shall be used to properly configure the memory, for example the output buffer driver strength, latencies etc. Specifically, MR1, MR2, and MR3 shall be set to configure the memory for the target frequency and memory configuration. The LPDDR2 device will now be in IDLE state and ready for any valid command. After Tg, the clock frequency may be changed according to the clock frequency change procedure described in section “Input clock stop and frequency change” of this specification. Table 1 – Timing Parameters for initialization Symbol Value min Unit max tINIT0 20 Comment ms Maximum Power Ramp Time Minimum CKE low time after completion of power ramp tINIT1 100 ns tINIT2 5 tCK Minimum stable clock before first CKE high tINIT3 200 us Minimum Idle time after first CKE assertion tINIT4 1 us Minimum Idle time after Reset command us Maximum duration of Device Auto-Initialization us ZQ Initial Calibration for LPDDR2-S4 devices ns Clock cycle time during boot tINIT5 10 tZQINIT 1 tCKb 18 100 Ta Tb t INIT2 Tc Td Te Tf Tg CK/CK# t INIT0 Supplies t t INIT1 INIT3 CKE t ISCKE t t INIT4 ZQINIT t INIT5 CA RESET MRR MRW ZQCAL Valid RTT DQ Figure 3.2 Power Ramp and Initialization Sequence 3.2.2 Initialization after Reset (without Power ramp): If the RESET command is issued outside the power up initialization sequence, the reinitialization procedure shall begin with step 3 (Td). 3.2.3 Power-off Sequence The following sequence shall be used to power off the LPDDR2 device. Unless specified otherwise, these steps are mandatory and apply to S4 devices. While removing power, CKE shall be held at a logic low level (=< 0.2 x VDD2), all other inputs shall be between VILmin and VIHmax. The LPDDR2 device will only guarantee that outputs are in a high impedance state while CKE is held low. DQ, DM, DQS, and DQS# voltage levels must be between VSSQ and VDDQ during power off sequence to avoid latch-up. CK, CK#, CS#, and CA input levels must be between VSSCA and VDD2 during power off sequence to avoid latch-up. Confidential - 12/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN Tx is the point where any power supply decreases under its minimum value specified in the DC operating condition table. Tz is the point where all power supplies are below 300 mV. After Tz, the device is powered off. The time between Tx and Tz (tPOFF) shall be less than 2s. The following conditions apply: Between Tx and Tz, VDD1 must be greater than VDD2 - 200 mV. Between Tx and Tz, VDD1 and VDD2 must be greater than VDD2 - 200 mV. Between Tx and Tz, VDD1 and VDD2 must be greater than VDDQ - 200 mV. Between Tx and Tz, VREF must always be less than all other supply voltages. The voltage difference between any of VSS, VSSQ, and VSSCA pins may not exceed 100 mV. Table 2 – Timing Parameters Power-Off Symbol tPOFF Value min max - 2 Unit s Comment Maximum Power-Off ramp time 3.2.4 Uncontrolled Power-Off Sequence The following sequence shall be used to power off the LPDDR2 device under uncontrolled condition. Tx is the point where any power supply decreases under its minimum value specified in the DC operating condition table. After turning off all power supplies, any power supply current capacity must be zero, except for any static charge remaining in the system. Tz is the point where all power supply first reaches 300 mV. After Tz, the device is powered off. The time between Tx and Tz (tPOFF) shall be less than 2s. The relative level between supply voltages are uncontrolled during this period. VDD1 and VDD2 shall decrease with a slope lower than 0.5 V/usec between Tx and Tz. Uncontrolled power off sequence can be applied only up to 400 times in the life of the device. Confidential - 13/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN 3.3 Mode Register Definition 3.3.1 Mode Register Assignment and Definition in LPDDR2 SDRAM Table 3 shows the 16 common mode registers for LPDDR2 SDRAM Table 4 shows only LPDDR2 SDRAM mode registers. Additionally Table 5 shows RFU mode registers and Reset Command. Each register is denoted as “R” if it can be read but not written, “W” if it can be written but not read, and “R/W” if it can be read and written. Mode Register Read command shall be used to read a register. Mode Register Write command shall be used to write a register. Table 3 – Mode Register Assignment in LPDDR2 SDRAM MR# MA Function Access OP7 OP6 0 00h Device Info. R (RFU) 1 01h Device Feature 1 W nWR(for AP) 2 02h Device Feature 2 W (RFU) RL & WL 3 03h I/O Config-1 W (RFU) DS 4 04h Refresh Rate R 5 05h Basic Config-1 R LPDDR2 Manufacturer ID 6 06h Basic Config-2 R Revision ID1 7 07h Basic Config-3 R Revision ID2 8 08h Basic Config-4 R 9 09h Test Mode W Vendor-Specific Test Mode 10 0Ah IO Calibration W Calibration Code 11:15 0Bh~0Fh (reserved) TUF OP5 OP4 OP3 RZQI WC OP2 OP1 OP0 (RFU) DI DAI BT (RFU) I/O width BL Refresh Rate Density Type (RFU) Table 4 — Mode Register Assignment in LPDDR2 SDRAM MR# MA Function Access OP7 OP6 OP5 OP4 OP3 16 10h PASR_Bank (S4) W Bank Mask 17 11h PASR_Seg W Segment Mask 18:19 12h:13h (Reserved) OP2 OP1 OP0 OP1 OP0 (RFU) Mode Register Assignment in LPDDR2 SDRAM (NVM Part) MR# MA Function 20:31 14h~1Fh (Do Not Use) Confidential Access OP7 OP6 - 14/129 - OP5 OP4 OP3 OP2 Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN Table 5 – Mode Register Assignment in LPDDR2 SDRAM MR# MA Function 32 20h 33:39 21h:27h 40 28h 41:47:00 29h:2Fh (Do Not Use) 48:62 30h~3Eh (Reserved) 63 3Fh Reset 64:126 40h:7Eh (Reserved) 127 7Fh (Do Not Use) 128:190 80h: BEh 191 BFh 192:254 C0h:FEh 255 FFh DQ Calibration Pattern A Access OP7 OP6 OP5 OP4 OP3 OP2 R See " DQ Calibration: R See " DQ Calibration: OP1 OP0 (Do Not Use) DQ Calibration Pattern B (RFU) W X (RFU) Reserved for (RFU) Vendor Use) (Do Not Use) Reserved for (RFU) Vendor Use) (Do Not Use) The following notes apply to Tables 3-5: NOTE 1 RFU bits shall be set to ‘0’ during Mode Register writes. NOTE 2 RFU bits shall be read as ‘0’ during Mode Register reads. NOTE 3 All Mode Registers that are specified as RFU or write-only shall return undefined data when read and DQS,DQS# shall be toggled. NOTE 4 All Mode Registers that are specified as RFU shall not be written. NOTE 5 Writes to read-only registers shall have no impact on the functionality of the device. Confidential - 15/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN MR0 Device Information (MA =00H) : OP7 OP6 OP5 OP4 OP3 RZQI (Optional) RFU DAI(Device Auto-Initialization Status) Read-only OP0 DI (Device Information) Read-only OP1 RZQI ( Built in Self Test for RZQ Information) Read -only OP4:OP3 OP2 OP1 OP0 RFU DI DAI 0B: DAI complete 1B: DAI still in progress 0B: S4 SDRAM 1B: Do Not Use 00B : RZQ self test not supported) 01B : ZQ-pin may connect to VDD2 or float 10B : ZQ-pin may short to GND 11B : ZQ-pin self test completed, no error condition detected (ZQ-pin may not connect to VDD2 or float nor short to GND) 1 NOTE 1 RZQI, if supported, will be set upon completion of the MRW ZQ Initialization Calibration command. NOTE 2 If ZQ is connected to VDD2 to set default calibration, OP[4:3] shall be set to 01. If ZQ is not connected to VDD2, either OP[4:3]=01 or OP[4:3]=10 might indicate a ZQ-pin assembly error. It is recommended that the assembly error is corrected. NOTE 3 In the case of possible assembly error (either OP[4:3]=01 or OP[4:3]=10 per NOTE 4), the LPDDR2 device will default to factory trim settings for RON, and will ignore ZQ calibration commands. In either case, the system may not function as intended. NOTE 4 In the case of the ZQ self-test returning a value of 11b, this result indicates that the device has detected a resistor connection to the ZQ pin. However, this result cannot be used to validate the ZQ resistor value or that the ZQ resistor tolerance meets the specified limits (i.e., 240-ohm +/-1%). Confidential - 16/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN MR1 Device Feature 1 (MA =01H) : OP7 OP6 OP5 nWR (for AP) OP4 WC OP3 BT OP2 OP1 BL OP0 010B: BL4 (default) BL Write-only OP 011B: BL8 110B: BL16 All others : reserved BT Write-only OP WC Write-only OP nWR Write-only OP 0B: Sequential (default) 1 1B: Interleaved 0B: Wrap (default) 1B: No wrap (allowed for SDRAM BL4 only) 001B: nWR =3(default) 010B: nWR =4 011B: nWR =5 100B: nWR =6 101B: nWR =7 110B :nWR =8 All others : reserved 2 NOTE 1 BL 16, interleaved is not an official combination to be supported. NOTE 2 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 - 17/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN Table 6 - Burst Sequence by BL,BT, and WC W/C BT C2 C1 C0 X X 0B 0B X X 1B 0B X X X 0B X 0B 0B 0B X 0B 1B 0B X 1B 0B 0B X 1B 1B 0B X 0B 0B 0B X 0B 1B 0B X 1B 0B 0B X 1B 1B 0B X X X 0B 0B 0B 0B 0B 0 1 2 3 4 5 6 7 8 0B 0B 1B 0B 2 3 4 5 6 7 8 9 0B 1B 0B 0B 4 5 6 7 8 9 A 0B 1B 1B 0B 6 7 8 9 A B 1B 0B 0B 0B 8 9 A B C D 1B 0B 1B 0B A B C D E 1B 1B 0B 0B C D E F 1B 1B 1B 0B E F 0 1 X X X 0B X X X 0B wrap any nw any BL Burst Cycle Number are Burst Address Sequence C3 4 seq wrap 8 int nw wrap 2 3 4 0 1 2 3 5 6 7 8 2 3 0 1 y y+1 y+2 y+3 0 1 2 2 3 4 11 12 13 14 15 16 3 4 5 6 7 4 5 6 7 0 1 5 6 7 0 1 2 3 6 7 0 1 2 3 4 5 0 1 2 3 4 5 6 7 2 3 0 1 6 7 4 5 4 5 6 7 0 1 2 3 6 7 4 5 2 3 0 1 9 10 9 A B C D E F A B C D E F 0 1 B C D E F 0 1 2 3 C D E F 0 1 2 3 4 5 E F 0 1 2 3 4 5 6 7 F 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 A B 2 3 4 5 6 7 8 9 A B C D illegal (not allowed) any seq 16 nw 1 int illegal (not allowed) any illegal (not allowed) 1. C0 input is not present on CA bus. It is implied zero. 2. For BL=4, the burst address represents C1 - C0. 3. For BL=8, the burst address represents C2 - C0. 4. For BL=16, the burst address represents C3 - C0. 5. For no-wrap (nw), BL4, the burst shall not cross the page boundary and shall not cross sub-page boundary. The variable y may start at any address with C0 equal to 0 and may not start at any address in Table 7 for the respective density and bus width combinations. Confidential - 18/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN Table 7 – LPDDR2- SX Non Wrap Restrictions 1Gb x16 x32 x16 x32 Not across full page boundary 3FE, 3FF, 000, 001 1FE, 1FF, 000, 001 Not across sub page boundary 1FE, 1FF, 200, 201 None NOTE 1 Non - wrap BL =4 data-orders shown above are prohibited MR2 Device Feature 2 (MA =02H) : OP7 OP6 OP5 (RFU) RL & WL Writeonly OP4 OP MR3 I/O Configuration 1 (MA =03H) : OP7 OP6 OP5 (RFU) DS Writeonly OP3 MR4 Device Temperature (MA =04H) : OP7 OP6 OP5 OP4 TUF (RFU) OP0 0001B: RL =3 /WL=1(default) 0010B: RL =4 /WL=2 0011B: RL =5 /WL=2 0100B: RL =6 /WL=3 0101B: RL =7 /WL=4 0110B :RL =8 /WL=4 All others : reserved OP4 OP3 OP OP2 OP1 RL & WL OP2 DS OP1 OP0 0000B: reserved 0001B: 34.3-ohm typical 0010B: 40-ohm typical (default) 0011B: 48-ohm typical 0100B: 60-ohm typical 0101B: reserved for 68.6-ohm typical 0110B :80-ohm typical 0111B :120-ohm typical (optional) All others : reserved OP3 OP2 OP1 OP0 SDRAM Refresh Rate 000B: SDRAM Low temperature operating limit exceeded 001B: 4X tREF, 4x tREFlqb, 4x tREFW 010B: 2X tREF, 2x tREFlqb, 2x tREFW SDRAM Refresh Rate Readonly OP Temperature Update Flag (TUF) Readonly OP 011B: 1X tREF, 1x tREFlqb, 1x tREFW (≤85℃) 100B: Reserved 101B: 0.25X tREF, 0.25x tREFlqb, 0.25x tREFW , do not de-rate SDRAM AC timing 110B :0.25X tREF, 0.25x tREFlqb, 0.25x tREFW , de-rate SDRAM AC timing 111B :SDRAM High temperature operating limit exceeded 0B: OP value has not changed since last read of MR4 1B: OP value has changed since last read of MR4 NOTE 1 A Mode Register Read from MR4 will reset OP7 to ‘0’. NOTE 2 OP7 is reset to ‘0’ at power-up. OP bits are undefined after power-up. Confidential - 19/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN NOTE 3 If OP2 equals ‘1’, the device temperature is greater than 85℃ NOTE 4 OP7 is set to ‘1’ if OP2:OP0 has changed at any time since the last read of MR4. NOTE 5 LPDDR2 might not operate properly when OP[2:0] = 000B or 111B. NOTE 6 LPDDR2-SX devices shall be de-rated by adding 1.875 ns to the following core timing parameters: tRCD, tRC, tRAS, tRP, and tRRD. tDQSCK shall be de-rated according to the tDQSCK de-rating in Table 52. Prevailing clock frequency spec and related setup and hold timings shall remain unchanged. NOTE 8 See “Temperature Sensor” for information on the recommended frequency of reading MR4. MR5 Basic Configuration 1 (MA =05H) : OP7 OP6 OP5 OP4 OP3 LPDDR2 Manufacture ID LPDDR2 Manufacture ID Readonly MR6_Basic Configuration 2 (MA = 06H): OP7 OP6 OP5 Revision ID1 NOTE 1 MR6 is Vendor Specific Confidential Readonly OP OP1 OP0 OP1 OP0 0000 0000B : Reserved 0000 0001B : Samsung 0000 0010B : Qimonda 0000 0011B : Elpida 0000 0100B : Etron 0000 0101B : Nanya 0000 0111B : Mosel 0000 1000B : Winbond 0000 1001B : ESMT 0000 1010B : Reserved 0000 1011B : Spansion 0000 1100B : SST 0000 1101B : ZMOS 0000 1110B : Intel 0001 1100B : Alliance 1111 1110B : Numonyx 1111 1111B : Micron All Others : Reserved OP4 OP3 Revision ID1 OP OP2 OP2 0001 0001B: Q-version - 20/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN MR7 Basic Configuration 3 (MA =07H) : OP7 OP6 Revision ID2 NOTE 1 MR7 is Vendor Specific OP5 OP4 OP3 Revision ID2 Readonly MR8_Basic Configuration 4 (MA = 08B H): OP7 OP6 OP5 I/O width OP OP2 OP1 OP0 OP1 OP0 0000 0000B: A-version OP4 OP3 Density OP2 Type 00B: S4 SDRAM Type Readonly OP 01B: Reserved 10B: Do Not Use 11B: Reserved Density Readonly OP 0000B: 64Mb 0001B: 128Mb 0010B: 256Mb 0011B: 512Mb 0100B: 1Gb 0101B: 2Gb 0110B: 4Gb 0111B 8Gb 1000B: 16Gb 1001B: 32Gb All others : reserved 00B: x32 I/O Width MR9_Test Mode (MA = 09H): OP7 OP6 MR10_Calibration (MA = 0AH): OP7 OP6 Readonly OP5 OP 01B: x16 10B: x8 11B: not used OP4 OP3 Vendor-specific Test Mode OP5 OP4 OP2 OP1 OP3 OP2 Calibration Code OP1 OP0 OP0 0xFFB: Calibration command after initialization Calibration Code Writeonly 0xABB: Long calibration OP 0x56B: Short calibration 0xC3B: ZQ Reset Others : Reserved NOTE 1 Host processor shall not write MR10 with “Reserved” values NOTE 2 LPDDR2 devices shall ignore calibration command when a “Reserved” value is written into MR10. NOTE 3 See AC timing table for the calibration latency. NOTE 4 If ZQ is connected to VSSCA through RZQ, either the ZQ calibration function (see “Mode Register Write ZQ Calibration Command” ) or default calibration (through the ZQreset command) is supported. If ZQ is connected to VDD2, the device operates with default calibration, and ZQ calibration commands are ignored. In both cases, the ZQ connection shall not change after power is applied to the Confidential - 21/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! device. NOTE 5 LPDDR2 devices that do not support calibration shall ignore the ZQ Calibration command. NOTE 6 Optionally, the MRW ZQ Initialization Calibration command will update MR0 to indicate RZQ pin connection. MR11:15_(Reserved) (MA = 0B H-0FH): MR16_PASR_Bank Mask (MA = 010 H): S2 and S4 SDRAM only OP7 OP6 OP5 OP4 OP3 OP2 S4 SDRAM Bank Mask (4-bank or 8 bank) OP1 OP0 S4 SDRAM : 0B: refresh enable to the bank (=unmasked, OP default) 1B: refresh blocked (=masked) For 4-bank S4 SDRAM, only are used. 4-Bank S4 SDRAM OP Bank Mask 8-Bank S4 SDRAM 0 XXXX XXX1 Bank 0 Bank 0 1 XXXX XX1X Bank 1 Bank 1 2 XXXX X1XX Bank 2 Bank 2 3 XXXX 1XXX Bank 3 Bank 3 4 XXX1 XXXX Bank 4 5 XX1X XXXX Bank 5 6 X1XX XXXX Bank 6 7 1XXX XXXX Bank 7 Writeonly Bank Mask 1. MR17_PASR_Segment Mask (MA = 011 H): 1Gb ~ 8Gb S4 SDRAM only OP7 OP6 OP5 OP4 OP3 OP2 Segment Mask Segment Mask Writeonly OP OP1 1 OP0 0B: refresh enable to the segment (=unmasked, default) 1B: refresh blocked (=masked) 1Gb R12 : 10 2Gb, 4Gb R13 : 11 Segment OP Segment Mask 0 0 XXXX XXX1 000B 1 2 3 4 5 6 7 1 2 3 4 5 6 7 XXXX XX1X XXXX X1XX XXXX 1XXX XXX1 XXXX XX1X XXXX X1XX XXXX 1XXX XXXX 001B 010B 011B 100B 101B 110B 111B 8Gb R14 : 12 NOTE This table indicates the range of row addresses in each masked segment X is do not care for a particular segment MR18-19_Reserved (MA = 012H - 013H): MR20-31_Do Not Use, NVM only MR32_DQ Calibration Pattern A (MA = 20 H): Reads to MR32 return DQ Calibration Pattern “A”. See “DQ Calibration”. MR33:39_(Do Not Use) (MA = 21 H-27H): MR40_DQ Calibration Pattern B (MA = 28 H): Reads to MR40 return DQ Calibration Pattern “B”. See “DQ Calibration”. Confidential - 22/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! MR41:47_(Do Not Use) (MA = 29H-2FH): MR48:62_(Reserved) (MA = 30H-3EH): MR63_Reset (MA = 3FH): MRW only OP7 OP6 OP5 OP4 X OP3 OP2 OP1 OP0 NOTE1 For additional information on MRW RESET see " Mode Register Write Command " MR64:126_(Reserved) (MA = 40H-7EH): MR127_(Do Not Use) (MA = 7FH): MR128:190_(Reserved for Vendor Use) (MA = 80H-BEH): MR191_(Do Not Use) (MA = BFH): MR192:254_(Reserved for Vendor Use) (MA = C0 H-FEH): MR255_(Do Not Use) (MA = FFH): Confidential - 23/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! 4. LPDDR2 Command Definitions and Timing Diagrams 4.1 Active Command 4.1.1 LPDDR2-SX: Activate Command The SDRAM Activate command is issued by holding CS# LOW, CA0 LOW, and CA1 HIGH at the rising edge of the clock. The bank addresses BA0 - BA2 are used to select the desired bank. The row address R0 through R14 is used to determine which row to activate in the selected bank. The Activate command must be applied before any Read or Write operation can be executed. The LPDDR2 SDRAM can accept a read or write command at time tRCD after the activate command is sent. Once a bank has been activated it must be precharged before another Activate command can be applied to the same bank. The bank active and precharge times are defined as tRAS and tRP, respectively. The minimum time interval between successive Activate commands to the same bank is determined by the RAS cycle time of the device (tRC). The minimum time interval between Activate commands to different banks is tRRD. Certain restrictions on operation of the 8-bank devices must be observed. There are two rules. One for restricting the number of sequential Activate commands that can be issued and another for allowing more time for RAS precharge for a Precharge All command. The rules are as follows: • 8-bank device Sequential Bank Activation Restriction : No more than 4 banks may be activated (or refreshed, in the case of REFpb) in a rolling tFAW window. Converting to clocks is done by dividing tFAW[ns] by tCK[ns], and rounding up to next integer value. As an example of the rolling window, if RU{ (tFAW / tCK) } is 10 clocks, and an activate command is issued in clock N, no more than three further activate commands may be issued at or between clock N+1 and N+9. REFpb also counts as bank-activation for the purposes of tFAW. • 8-bank device Precharge All Allowance : tRP for a Precharge All command for an 8-bank device shall equal tRPab, which is greater than tRPpb. T0 T1 T2 T3 Tn Tn+1 Tn+2 Tn+3 CK# CK# CA[9:0] Bank n addr Bank m addr Row addr Row Bank n col addr Bank n row addr Bank n Col addr Row addr t RRD t RCD t t RAS RP t RC CMD ACTIVATE NOP ACTIVATE READ PRECHARGE NOP NOP ACTIVATE Figure 4.1 — LPDDR2-SX: Activate command cycle: tRCD = 3, tRP = 3, tRRD = 2 NOTE 1 A Precharge-All command uses tRPab timing, while a Single Bank Precharge command uses tRPpb timing. In this figure, tRP is used to denote either an All-bank Precharge or a Single Bank Precharge. Tn Tn+ Tm Tm+ Tx Tx+ Ty Ty+1 Ty+2 Tz Tz+1 Tz+2 CK# CK# CA[9:0] Bank A Bank A Bank B Bank B t ACTIVATE NOP Bank C t RRD CMD Bank C NOP Bank D Bank E Bank E t RRD ACTIVATE Bank D RRD ACTIVATE NOP ACTIVATE NOP NOP NOP ACTIVATE NOP t FAW Figure 4.2 — LPDDR2-SX: tFAW timing NOTE 1: For 8-bank devices only. Confidential - 24/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! 4.2 LPDDR2 Command Input Signal Timing Definition 4.2.1 LPDDR2 Command Input Setup and Hold Timing T1 T0 T2 T3 CK# CK# t IS tIH t IS tIH VIH(DC) CS# VIL(AC) CA[9:0] CMD CA rise CA fall NOP t IS tIH CA rise VIL(DC) CA fall Command VIH(AC) t IS tIH CA rise CA fall NOP CA rise CA fall Command Transitioning data Don’t Care NOTE : Setup and hold conditions also apply to the CKE pin. See section related to power down for timing diagrams related to the CKE pin. Figure 4.3 — LPDDR2: Command Input Setup and Hold Timing Confidential - 25/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN 4.3 Read and Write access modes 4.3.1 LPDDR2-SX: Read and Write access modes After a bank has been activated, a read or write cycle can be executed. This is accomplished by setting CS# LOW, CA0 HIGH, and CA1 LOW at the rising edge of the clock. CA2 must also be defined at this time to determine whether the access cycle is a read operation (CA2 HIGH) or a write operation (CA2 LOW). The LPDDR2 SDRAM provides a fast column access operation. A single Read or Write Command will initiate a burst read or write operation on successive clock cycles. For LPDDR2-S4 devices, a new burst access must not interrupt the previous 4-bit burst operation in case of BL = 4 setting. In case of BL = 8 and BL = 16 settings, Reads may be interrupted by Reads and Writes may be interrupted by Writes provided that this occurs on even clock cycles after the Read or Write command and tCCD is met. Confidential - 26/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! 4.4 Burst Read Command The Burst Read command is initiated by having CS# LOW, CA0 HIGH, CA1 LOW and CA2 HIGH 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. The Read Latency (RL) is defined from the rising edge of the clock on which the Read Command is issued to the rising edge of the clock from which the tDQSCK delay is measured. The first valid datum is available RL * tCK + tDQSCK + tDQSQ after the rising edge of the clock where the Read Command is issued. The data strobe output is driven LOW tRPRE before the first rising valid strobe edge. The first bit of the burst is synchronized with the first rising edge of the data strobe. Each subsequent data-out appears on each DQ pin edge aligned with the data strobe. The RL is programmed in the mode registers. Timings for the data strobe are measured relative to the crosspoint of DQS and its complement, DQS#. RL-1 RL t RL+BL/2 t CH CL CK# CK# t t DQSCKmax t HZ(DQS) t LZ(DQS) t RPRE RPST DQS# DQS# t t QH QH t t DQSQmax DQSQmax DQ DOUT DOUT DOUT t DOUT t LZ(DQ) HZ(DQ) Transitioning data Figure 4.4 — Data output (read) timing (tDQSCKmax) NOTE 1 tDQSCK may span multiple clock periods. NOTE 2 An effective Burst Length of 4 is shown. RL-1 RL CK# CK# t RL+BL/2 t CH CL t t DQSCKmin t LZ(DQS) HZ(DQS) t t RPRE RPST DQS# DQS# t t QH QH t t DQSQmax DQSQmax DQ DOUT DOUT t DOUT DOUT t LZ(DQ) HZ(DQ) Transitioning data Figure 4.5 — Data output (read) timing (tDQSCKmin) NOTE 1 An effective Burst Length of 4 is shown. Confidential - 27/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! T0 T1 T2 T3 T4 T5 T6 T7 T8 CK# CK# RL = 5 CA[9:0] Bank n col addr CMD Col Addr READ NOP NOP NOP NOP NOP NOP NOP NOP t DQSCK DQS# DQS# DOUT A0 DQ DOUT A1 DOUT A2 DOUT A3 Transitioning data Figure 4.6 — LPDDR2-SX: Burst read: RL = 5, BL = 4, tDQSCK > tCK T0 T1 T2 T3 T4 T5 T6 T7 T8 CK# CK# RL = 3 CA[9:0] CMD Bank n col addr Col Addr READ NOP NOP NOP NOP NOP NOP NOP NOP t DQSCK DQS# DQS# DQ DOUT A0 DOUT A1 DOUT A2 DOUT A3 DOUT A4 DOUT A5 DOUT A6 DOUT A7 Transitioning data Figure 4.7 — LPDDR2-SX: Burst read: RL = 3, BL = 8, tDQSCK < tCK Confidential - 28/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! Tn Tn+1 Tn+2 Tn+3 Tn+4 Tn+5 Tn+6 Tn+7 Tn+8 CK# CK# RL = 5 CA[9:0] Bank n col addr CMD Col Addr READ NOP NOP NOP NOP NOP NOP NOP NOP t DQSCKn DQS# DQS# DOUT A0 DQ DOUT A1 DOUT A2 DOUT A3 32ms maximum... 1 Tm Tm+1 Tm+2 Tm+3 Tm+4 Tm+5 Tm+6 Tm+7 Tm+8 CK# CK# RL = 5 Bank n col addr CA[9:0] CMD Col Addr READ NOP NOP NOP NOP NOP NOP NOP NOP t DQSCKm DQS# DQS# DOUT A0 DQ DOUT A1 DOUT A2 DOUT A3 ...32ms maximum Transitioning data 1 Figure 4.8 — LPDDR2: tDQSCKDL timing NOTE 1 tDQSCKDLmax is defined as the maximum of ABS(tDQSCKn - tDQSCKm) for any {tDQSCKn ,tDQSCKm} pair within any 32ms rolling window. Confidential - 29/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! Tn Tn+1 Tn+2 Tn+3 Tn+4 Tn+5 Tn+6 Tn+7 Tn+8 CK# CK# RL = 5 CA[9:0] Bank n col addr CMD Col Addr READ NOP NOP NOP NOP NOP NOP NOP NOP t DQSCKn DQS# DQS# DOUT A0 DQ DOUT A1 DOUT A2 DOUT A3 1.6us maximum... 1 Tm Tm+1 Tm+2 Tm+3 Tm+4 Tm+5 Tm+6 Tm+7 Tm+8 CK# CK# RL = 5 Bank n col addr CA[9:0] CMD Col Addr READ NOP NOP NOP NOP NOP NOP NOP NOP t DQSCKm DQS# DQS# DOUT A0 DQ DOUT A1 DOUT A2 DOUT A3 ...1.6us maximum Transitioning data 1 Figure 4.9 — LPDDR2: tDQSCKDM timing NOTE 1 tDQSCKDMmax is defined as the maximum of ABS(tDQSCKn - tDQSCKm) for any {tDQSCKn,tDQSCKm} pair within any 1.6us rolling window Confidential - 30/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! Tn Tn+1 Tn+2 Tn+3 Tn+4 Tn+5 Tn+6 Tn+7 Tn+8 CK# CK# RL = 5 CA[9:0] Bank n col addr CMD Col Addr READ NOP NOP NOP NOP NOP NOP NOP NOP t DQSCKn DQS# DQS# DOUT A0 DQ DOUT A1 DOUT A2 DOUT A3 DOU A 160ns maximum... 1 Tm Tm+1 Tm+2 Tm+3 Tm+4 Tm+5 Tm+6 Tm+7 Tm+8 CK# CK# RL = 5 Bank n col addr CA[9:0] CMD Col Addr READ NOP NOP NOP NOP NOP NOP NOP NOP t DQSCKm DQS# DQS# DQ DOUT A2 DOUT A3 DOUT A0 DOUT A1 DOUT A2 DOUT A3 DOUT A0 DOUT A1 DOUT A2 DOUT A3 DOUT A0 DOUT A1 DOUT A2 DOUT A3 DOUT A0 DOUT A1 DOUT A2 DOUT A3 ...160ns maximum 1 Transitioning data Figure 4.10 — LPDDR2: tDQSCKDS timing NOTE 1 tDQSCKDSmax 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. T0 T1 T2 T3 T4 T5 T6 T7 T8 CK# CK# WL = 1 RL = 3 CA[9:0] CMD Bank n col addr Bank n col addr Col addr READ NOP NOP NOP NOP t NOP WRITE NOP NOP t DQSSmin BL/2 DQSCK Col addr DQS# DQS# DQ DOUT A0 DOUT A1 DOUT A2 DOUT A3 DIN A0 DIN A1 D Transitioning data Figure 4.11 — LPDDR2-SX: Burst read followed by burst write: RL = 3, WL = 1, BL = 4 The minimum time from the burst read command to the burst write command is defined by the Read Latency (RL) Confidential - 31/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! and the Burst Length (BL). Minimum read to write latency is RL + RU(tDQSCKmax/tCK) + BL/2 + 1 - WL clock cycles. Note that if a read burst is truncated with a Burst Terminate (BST) command, the effective burst length of the truncated read burst should be used as “BL” to calculate the minimum read to write delay. T0 T1 T2 T3 T4 T5 T6 T7 T8 CK# CK# RL = 3 CA[9:0] Bank n Col Addr a Col addr a Bank n Col Addr b Col addr b t CCD = 2 CMD READ NOP READ NOP NOP NOP NOP NOP NOP DQS# DQS# DOUT A0 DQ DOUT A1 DOUT A2 DOUT A3 DOUT B0 DOUT B1 DOUT B2 DOUT B3 Transitioning data Figure 4.12 — LPDDR2-SX: Seamless burst read: RL = 3, BL = 4, tCCD = 2 The seamless burst read operation is supported by enabling a read command at every other clock for BL = 4 operation, every 4 clocks for BL = 8 operation, and every 8 clocks for BL=16 operation. For LPDDR2-SDRAM, this operation is allowed regardless of whether the accesses read the same or different banks as long as the banks are activated. 4.4.1 Reads interrupted by a read For LPDDR2-S4 burst read can be interrupted by another read on even clock cycles after the Read command, provided that tCCD is met T0 T1 T2 T3 T4 T5 T6 T7 T8 CK# CK# RL = 3 CA[9:0] Bank n Col Addr a Col addr a Bank n Col Addr b Col addr b t CCD = 2 CMD READ NOP READ NOP NOP NOP NOP NOP NOP DQS# DQS# DQ DOUT A0 DOUT A1 DOUT A2 DOUT A3 DOUT B0 DOUT B1 DOUT B2 DOUT B3 DOUT B4 DOUT B5 Transitioning data Figure 4.13 — LPDDR2-SX: Read burst interrupt example: RL = 3, BL = 8, tCCD = 2 NOTE 1 For LPDDR2-S4 devices, read burst interrupt function is only allowed on burst of 8 and burst of 16. NOTE 2 For LPDDR2-S4 devices, read burst interrupt may only occur on even clock cycles after the previous commands, provided that tCCD is met. NOTE 3 Reads can only be interrupted by other reads or the BST command. NOTE 4 Read burst interruption is allowed to any bank inside DRAM. NOTE 5 Read burst with Auto-Precharge is not allowed to be interrupted NOTE 6 The effective burst length of the first read equals two times the number of clock cycles between the first read and the interrupting read. Confidential - 32/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! 4.5 Burst Write Operation The Burst Write command is initiated by having 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. The Write Latency (WL) is defined from the rising edge of the clock on which the Write Command is issued to the rising edge of the clock from which the tDQSS delay is measured. The first valid datum shall be driven WL * tCK + tDQSS from the rising edge of the clock from which the Write command is issued. The data strobe signal (DQS) should be driven LOW tWPRE prior to the data input. The data bits of the burst cycle must be applied to the DQ pins tDS prior to the respective edge of the DQS, DQS# and held valid until tDH after that edge. The burst data are sampled on successive edges of the DQS, DQS# until the burst length is completed, which is 4, 8, or 16 bit burst. For LPDDR2-SDRAM devices, tWR must be satisfied before a precharge command to the same bank may be issued after a burst write operation. Input timings are measured relative to the crosspoint of DQS and its complement, DQS#. t t WPRE DQS# DQS# DQSH t VIH(DC) VIH(AC) t DQSL WPST DQS# DQS VIH(AC) DQ DIN VIL(AC) t DS VIH(DC) DIN VIL(DC) tDS t DH DIN DH VIL(AC) t t DS DIN t DH VIL(DC) tDS t DH VIH(AC) VIH(DC) VIH(AC) VIH(DC) VIL(AC) VIL(DC) VIL(AC) VIL(DC) DM Don’t Care Figure 4.14: Data Input (WRITE) Timing T0 T1 T2 T3 T4 Tx Tx+1 Ty Ty+1 CK# CK# WL = 1 Bank n col addr CA[9:0] CMD Col addr Bank n row addr Bank n WRITE NOP t Case 1: DQSSmax NOP NOP t t t DSS DQSSmax NOP DSS PRECHARGE NOP Row addr ACTIVATE NOP Completion of burst WRITE DQS# DQS# t WR DIN A0 DQ Case 2: tDQSSmin DIN A1 DSH DSH DQSSmin DIN A3 t t t DIN A2 t RP DQS# DQS# t WR DQ DIN A0 DIN A1 DIN A2 DIN A3 Transitioning data Figure 4.15 — LPDDR2-SX: Burst write : WL = 1, BL = 4 Confidential - 33/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! T0 T1 T2 T3 T4 T5 T6 T7 T8 CK# CK# WL = 1 CA[9:0] Bank m col addr a RL = 3 Bank n col addr b Col addr a Col addr b t WTR CMD WRITE NOP NOP NOP NOP NOP READ NOP NOP DQS# DQS# DIN A0 DQ DIN A1 DIN A2 DIN A3 Transitioning data Figure 4.16 — LPDDR2-SX: Burst write followed by burst read: RL=3, WL = 1, BL = 4 NOTE 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)]. NOTE 2 tWTR starts at the rising edge of the clock after the last valid input datum. NOTE 3 If a write burst is truncated with a Burst Terminate (BST) command, the effective burst length of the truncated write burst should be used as “BL” to calculate the minimum write to read delay. 4.5.1 Writes interrupted by a write For LPDDR2-S4 devices, burst write can only be interrupted by another write on even clock cycles after the Write command, provided that tCCD(min) is met. T0 T1 T2 T3 T4 T5 T6 T7 T8 CK# CK# WL = 1 CA[9:0] Bank m col addr a Bank n col addr b Col addr a Col addr b t CCD = 2 CMD WRITE NOP WRITE NOP NOP NOP NOP NOP NOP DQS# DQS# DQ DIN A0 DIN A1 DIN A2 DIN A3 DIN B0 DIN B1 DIN B2 DIN B3 DIN B4 DIN B5 DIN B6 DIN B7 Transitioning data Figure 4.17 — LPDDR2-SX: Write burst interrupt timing: WL = 1, BL = 8, t CCD = 2 NOTE 1 For LPDDR2-S4 devices, write burst interrupt function is only allowed on burst of 8 and burst of 16. NOTE 2 For LPDDR2-S4 devices, write burst interrupt may only occur on even clock cycles after the previous write commands, provided that tCCD(min) is met. NOTE 3 Writes can only be interrupted by other writes or the BST command. NOTE 4 Write burst interruption is allowed to any bank inside DRAM. NOTE 5 Write burst with Auto-Precharge is not allowed to be interrupted NOTE 6 The effective burst length of the first write equals two times the number of clock cycles between the first write and the interrupting write. Confidential - 34/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! 4.6 Burst Terminate The Burst Terminate (BST) command is initiated by having CS# LOW, CA0 HIGH, CA1 HIGH, CA2 LOW, and CA3 LOW at the rising edge of clock. A Burst Teminate command may only be issued to terminate an active Read or Write burst. Therefore, a Burst Terminate command may 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 x {Number of clock cycles from the Read or Write Command to the BST command} Note that if a read or write burst is truncated with a Burst Terminate (BST) command, the effective burst length of the truncated burst should be used as “BL” to calculate 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 Burst Terminate command is issued. The BST command truncates an ongoing write burst WL * tCK + tDQSS after the rising edge of the clock where the Burst Terminate command is issued. For LPDDR2-S4 devices, the 4-bit prefetch architecture allows the BST command to be issued on an even number of clock cycles after a Write or Read command. Therefore, the effective burst length of Read or Write command truncated by a BST command is an integer multiple of 4. T0 T1 T2 T3 T4 T5 T6 T7 T8 CK# CK# WL = 1 CA[9:0] CMD Bank m col addr a Col addr a WRITE NOP NOP NOP BST NOP NOP NOP NOP WL x tCK + tDQSS DQS# DQS# DQ DIN A0 DIN A1 DIN A2 DIN A3 DIN A4 DIN A5 DIN A6 DIN A7 BST prohibited Transitioning data Figure 4.18 — LPDDR2-S4: Burst Write truncated by BST: WL = 1, BL = 16 NOTE 1 The BST command truncates an ongoing write burst WL * tCK + tDQSS after the rising edge of the clock where the Burst Terminate command is issued. NOTE 2 For LPDDR2-S4 devices, BST can only be issued an even number of clock cycles after the Write command. NOTE 3 Additional BST commands are not allowed after T4 and may not be issued until after the next Read or Write command. Confidential - 35/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! T0 T1 T2 T3 T4 T5 T6 T7 T8 CK# CK# BL = 3 CA[9:0] CMD Bank n col addr a Col addr a READ NOP NOP NOP BST NOP NOP NOP NOP RL x tCK + tDQSCK + tDQSQ DQS# DQS# DQ DOUT A0 DOUT A1 DOUT A2 DOUT A3 DOUT A4 DOUT A5 DOUT A6 BST prohibited DOUT A7 Transitioning data Figure 4.19 — LPDDR2-S4: Burst Read truncated by BST: RL=3, BL = 16 NOTE 1 The BST command truncates an ongoing read burst RL * tCK + tDQSCK + tDQSQ after the rising edge of the clock where the Burst Terminate command is issued. NOTE 2 For LPDDR2-S4 devices, BST can only be issued an even number of clock cycles after the Read command. NOTE 3 Additional BST commands are not allowed after T4 and may not be issued until after the next Read or Write command. Confidential - 36/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! 4.7 Write Data Mask One write data mask (DM) pin for each data byte (DQ) will be supported on LPDDR2 devices, consistent with the implementation on LPDDR SDRAMs. Each data mask (DM) may mask its respective data byte (DQ) for any given cycle of the burst. Data mask has identical timings on write operations as the data bits, though used as input only, is internally loaded identically to data bits to insure matched system timing. Data Mask Timing DQS# DQS# DQ t t DS t DH DS t DH VIH(AC) VIH(DC) VIH(AC) VIH(DC) VIL(AC) VIL(DC) VIL(AC) VIL(DC) CMD Don＇t care Data Mask Function, WL = 2, BL = 4 shown, second DQ masked CK# CK# t WR WL = 2 CMD Case 1: tDQSSmin t WTR WRITE t DQSSmin DQS# DQS# DQ DOUT 0 DOUT 1 DOUT 2 DOUT 3 DM Case 2: tDQSSmax t DQSSmax DQS# DQS# DQ DOUT 0 DOUT 1 DOUT 2 DOUT 3 DM Don＇t care Figure 4.20 — LPDDR2-SX: Write data mask Confidential - 37/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN 4.8 LPDDR2-SX: Precharge operation The Precharge command is used to precharge or close a bank that has been activated. The Precharge command is initiated by having 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 4bank devices, the AB flag, and the 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 bank(s) will be available for a subsequent row access tRPab after an All-Bank Precharge command is issued and tRPpb after a Single-Bank Precharge command is issued. In order to ensure that 8-bank devices do not exceed the instantaneous current supplying capability of 4-bank devices, the Row Precharge time (tRP) for an All-Bank Precharge for 8-bank devices (tRPab) will be longer than the Row Precharge time for a Single-Bank Precharge (tRPpb). For 4-bank devices, the Row Precharge time (tRP) for an All-Bank Precharge (tRPab) is equal to the Row Precharge time for a Single-Bank Precharge (tRPpb). Figure 4-1 shows Activate to Precharge timing. Table 8 – Bank selection for Precharge by address bits AB (CA4r) BA2 (CA9r) BA1 (CA8r) BA0 (CA7r) Precharged Bank(s) 4-bank device Precharged Bank(s) 8-bank device 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 1 1 Don't care 0 0 1 1 0 0 1 1 Don't care 0 1 0 1 0 1 0 1 Don't care Bank 0 only Bank 1 only Bank 2 only Bank 3 only Bank 0 only Bank 1 only Bank 2 only Bank 3 only All Banks Bank 0 only Bank 1 only Bank 2 only Bank 3 only Bank 4 only Bank 5 only Bank 6 only Bank 7 only All Banks 4.8.1 LPDDR2-SX: Burst Read operation followed by Precharge For the earliest possible precharge, the precharge command may be issued BL/2 clock cycles after a Read command. For an untruncated burst, BL is the value from the Mode Register. For a truncated burst, BL is the effective burst length. A new bank active (command) may be issued to the same bank after the Row Precharge time (tRP). A precharge command cannot be issued until after tRAS is satisfied. For LPDDR2-S4 devices, the minimum Read to Precharge spacing has also to satisfy a minimum analog time from the rising clock edge that initiates the last 4-bit prefetch of a Read command. This time is called tRTP (Read to Precharge). For LPDDR2-S4 devices, tRTP begins BL/2 - 2 clock cycles after the Read command. If the burst is truncated by a BST command or a Read command to a different bank, the effective “BL” shall be used to calculate when tRTP begins. See Table 9 for Read to Precharge timings for LPDDR2-S4 Confidential - 38/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! T0 T1 T2 CK# CK# T3 T4 T5 T6 T7 T8 addr RL = 3 BL/2 CA[9:0] Bank m col addr a Bank m row addr Bank m Col addr a t t RTP CMD READ NOP NOP NOP Row RP PRECHARGE NOP NOP ACTIVATE NOP DQS# DQS# DOUT A0 DQ DOUT A1 DOUT A2 DOUT A3 DOUT A4 DOUT A5 DOUT A6 DOUT A7 Transitioning data Figure 4.21 — LPDDR2-S4: Burst read followed by Precharge: RL = 3, BL = 8, RU(tRTP(min)/tCK) = 2 CK# CK# T0 T1 T2 T3 T4 T5 T6 T7 T8 BL/2 RL = 3 CA[9:0] Bank m col addr a Bank m row addr Bank m Col addr a t RTP=3 CMD READ NOP Row addr t RP NOP PRECHARGE NOP NOP ACTIVATE NOP NOP DQS# DQS# DQ DOUT A0 DOUT A1 DOUT A2 DOUT A3 Transitioning data Figure 4.22 — LPDDR2-S4: Burst read followed by Precharge: RL = 3, BL = 4, RU(tRTP(min)/tCK) = 3 4.8.2 LPDDR2-SX: Burst Write followed by Precharge For write cycles, a delay must be satisfied from the time of the last valid burst input data until the Precharge command may be issued. This delay is known as the write recovery time (tWR) referenced from the completion of the burst write to the precharge command. No Precharge command to the same bank should be issued prior to the tWR delay. LPDDR2-S4 devices write data to the array in prefetch quadruples (prefetch = 4). The beginning of an internal write operation may only begin after a prefetch group has been latched completely. Therefore, the write recovery time (tWR) starts at different boundaries for LPDDR2-S4 devices. For LPDDR2-S4 devices, minimum Write to Precharge command spacing to the same bank is WL + BL/2 + 1 + RU(tWR/tCK) clock cycles. For an untruncated burst, BL is the value from the Mode Register. For an truncated burst, BL is the effective burst length. See Table 9 for Write to Precharge timings for LPDDR2-S4 Confidential - 39/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! T0 T1 T2 T3 T4 Tx Tx+1 Ty Ty+1 CK# CK# WL = 1 CA[9:0] Bank m col addr a t WRITE NOP Case 1: tDQSSmax NOP NOP NOP t DQSSmax Row addr t WR CMD Bank n row addr Bank n Col addr ≥ RP PRECHARGE NOP ACTIVATE NOP Completion of burst WRITE DQS# DQS# DQ Case 2: tDQSSmin DOUT A0 DOUT A1 DOUT A2 DOUT A1 DOUT A2 DOUT A3 DOUT A3 t DQSSmin DQS# DQS# DOUT A0 DQ Transitioning data Figure 4.23 — LPDDR2-SX: Burst write followed by precharge: WL = 1, BL = 4 4.8.3 LPDDR2-SX: Auto Precharge operation Before a new row in an active bank can be opened, the active bank must be precharged using either the Precharge command or the auto-precharge function. When a Read or a Write command is given to the LPDDR2 SDRAM, the AP bit (CA0f) may be set to allow 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, then the auto-precharge function is engaged. This feature allows 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. 4.8.3.1 LPDDR2-SX: Burst Read with Auto-Precharge If AP (CA0f) is HIGH when a Read Command is issued, the Read with Auto-Precharge function is engaged. LPDDR2-S4 devices start an Auto-Precharge operation on the rising edge of the clock BL/2 or BL/2 - 2 + RU(tRTP/tCK) clock cycles later than the Read with AP command, whichever is greater. Refer to Table 9 for equations related to Auto-Precharge for LPDDR2-S4. A new bank Activate command may be issued to the same bank if both of 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 - 40/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! CK# CK# T0 T1 T2 T3 T4 T5 T6 T7 T8 BL/2 RL CA[9:0] Bank m col addr a Bank m addr Col addr a t ≥ tRPpb RTP CMD READ w/AP Row addr NOP NOP NOP NOP ACTIVATE NOP NOP NOP DQS# DQS# DQ DOUT A0 DOUT A1 DOUT A2 DOUT A3 Transitioning data Figure 4.24 — LPDDR2-S4: Burst read with Auto-Precharge: RL = 3, BL = 4, RU(tRTP(min)/tCK) = 2 4.8.3.2 LPDDR2-SX: Burst write with Auto-Precharge If AP (CA0f) is HIGH when a Write Command is issued, the Write with Auto-Precharge function is engaged. The LPDDR2 SDRAM starts an Auto Precharge operation on the rising edge which is tWR cycles after the completion of the burst write. A new bank activate (command) may be issued to the same bank if both of the following two conditions are satisfied. 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. T0 T1 T2 T3 T4 T5 T6 T7 T8 CK# CK# WL = 1 CA[9:0] Bank n col addr a Bank n row addr Col addr t WR CMD WRITE NOP NOP NOP NOP Row addr t ≥ RPpb NOP NOP ACTIVATE NOP DQS# DQS# DQ DOUT A0 DOUT A1 DOUT A2 DOUT A3 Transitioning data Figure 4.25 — LPDDR2-SX: Burst write w/Auto Precharge: WL = 1, BL = 4 Confidential - 41/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN Table 9 – LPDDR-S4 : Precharge & Auto Precharge Clarification From command To command Minimum Delay between " From Command " to "To Command " unit Notes Precharge (to same Bank as Read) BL/2 + max(2,RU(tRTP/tCK)) - 2 clks 1 Precharge All BL/2 + max(2,RU(tRTP/tCK)) - 2 clks 1 Precharge (to same Bank as Read) Precharge All 1 1 clks clks 1 1 Precharge (to same Bank as Read w/AP) BL/2 + max(2,RU(tRTP/tCK)) - 2 clks 1.2 Precharge All BL/2 + max(2,RU(tRTP/tCK)) - 2 clks 1 Activate (to same Bank as Read w/AP) BL/2 + max(2,RU(tRTP/tCK)) - 2 + RU(tRPpb/tCK) clks 1 Write or Write w/AP (same bank) Illegal clks 3 Write or Write w/AP (different bank) RL+BL/2+RU(tDQSCKmax/tCK) - WL+1 clks 3 Read or Read w/AP (same bank) Read or Read w/AP (different bank) Illegal BL/2 clks clks 3 3 Precharge (to same Bank as Write) WL + BL/2 + RU(tWR/tCK)+1 clks 1 Precharge All WL + BL/2 + RU(tWR/tCK)+1 clks 1 BST Precharge (to same Bank as Write) WL + RU(tWR/tCK)+1 clks 1 (For Writes) Precharge All WL + RU(tWR/tCK)+1 clks 1 Precharge (to same Bank as Write w/AP) WL + BL/2 + RU(tWR/tCK)+1 clks 1 Precharge All WL + BL/2 + RU(tWR/tCK)+1 clks 1 Activate (to same Bank as Write w/AP) WL + BL/2 + RU(tWR/tCK)+1 +RU(tRPpb/tCK) clks 1 Write or Write w/AP (same bank) Write or Write w/AP (different bank) Read or Read w/AP (same bank) Illegal BL/2 Illegal clks clks clks 3 3 3 Read or Read w/AP (different bank) W/L + BL/2 + RU(tWTR/tCK)+1 clks 3 Read BST (For Reads) Read w/AP Write Write w/AP Precharge (to same Bank as Precharge) 1 clks 1 Precharge Precharge All 1 clks 1 Precharge 1 clks 1 Precharge All Precharge All 1 clks 1 NOTE 1 For a given bank, the precharge period should be counted from the latest precharge command, either one bank precharge or precharge all, issued to that bank. The precharge period is satisfied after tRP depending on the latest precharge command issued to that bank, NOTE 2 Any command issued during the minimum delay time as specified in Table 51 is illegal. NOTE 3 After Read With AP, seamless read operations to different banks are supported. After Write with AP, seamless write operation to different banks are supported. Read w/AP and Write w/AP may not be interrupted or truncated. Confidential - 42/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN 4.9 LPDDR2-SX: Refresh command The Refresh command is initiated by having CS# LOW, CA0 LOW, CA1 LOW, and CA2 HIGH at the rising edge of clock. Per Bank Refresh is initiated by having CA3 LOW at the rising edge of clock and All Bank Refresh is initiated by having CA3 HIGH at the rising edge of clock. Per Bank Refresh is only allowed in devices with 8 banks. A Per Bank Refresh command, REFpb performs a refresh operation to the bank which is scheduled by the bank counter in the memory device. The bank sequence of Per Bank Refresh is fixed to be a sequential round-robin: “0-1- 2-3-45-6-7-0-1-...”. The bank count is synchronized between the controller and the SDRAM upon issuing a RESET command or at every exit from self refresh, by resetting bank count to zero. The bank addressing for the Per Bank Refresh count is the same as established in the single-bank Precharge command (see Table 8 , “Bank selection for Precharge by address bits”). A bank must be idle before it can be refreshed. It is the responsibility of the controller to track the bank being refreshed by the Per Bank Refresh command. As shown in Table 10, the REFpb command may not be issued to the memory until the following conditions are met: a) tRFCab has been satisified after the prior REFab command b) tRFCpb has been satisfied after the prior REFpb command c) tRP has been satisified after the prior Precharge command to that given bank tRRD has been satisfied after the prior ACTIVATE command (if applicable, for example after activating a row in a different bank than affected by the REFpb command). The target bank is inaccessable during the Per Bank Refresh cycle time (tRFCpb), however other banks within the device are accessable and may be addressed during the Per Bank Refresh cycle. During the REFpb operation, any of the banks other than the one being refreshed can be maintained in active state or accessed by a read or a write command. When the Per Bank refresh cycle has completed, the affected bank will be in the Idle state. As shown in Table 10, after issuing REFpb: a) tRFCpb must be satisified before issuing a REFab command b) tRFCpb must be satisfied before issuing an ACTIVATE command to the same bank c) tRRD must be satisified before issuing an ACTIVATE command to a different bank d) tRFCpb must be satisified before issuing another REFpb command An All Bank Refresh command, REFab performs a refresh operation to all banks. All banks have to be in Idle state when REFab is issued (for instance, by Precharge all-bank command). REFab also synchronizes the bank count between the controller and the SDRAM to zero. As shown in Table 10, the REFab command may not be issued to the memory until the following conditions have been met: a) tRFCab has been satisified after the prior REFab command b) tRFCpb has been satisified after the prior REFpb command c) tRP has been satisified after prior Precharge commands When the All Bank refresh cycle has completed, all banks will be in the Idle state. As shown in Table 10, after issuing REFab: a) the tRFCab latency must be satisfied before issuing an ACTIVATE command b) the tRFCab latency must be satisfied before issuing a REFab or REFpb command. Confidential - 43/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! ! Table 10 – Command Scheduling Separations related to Refresh Symbol Minimum delay from tRFCab REFab tRFCpb REFpb to REFab Activate cmd to any bank REFpb REFab Activate cmd to same bank as REFpb REFpb Activate cmd to different bank than REFpb REfFpb affecting an idle bank (different bank than Activate) Activate cmd to different bank than prior Activate REFpb tRRD Activate Notes 1 NOTE 1 A bank must be in the Idle state before it is refreshed. Therefore, after Activate, REFab is now allowed and REFpb is allowed only if it affects a bank which is in the Idle state. 4.9.1 LPDDR2 SDRAM Refresh Requirements (1) Minimum number of Refresh commands: The LPDDR2 SDRAM requires a minimum number of R Refresh (REFab) commands within any rolling Refresh 85 °C). See Table 50 for actual numbers per density. Window (tREFW = 32 ms @ MR4[2:0] = “011” or Tcase The resulting average refresh interval (tREFI) is given in Table 50. See Mode Register 4 for tREFW and tREFI refresh multipliers at different MR4 settings. For LPDDR2-SDRAM devices supporting Per-Bank-Refresh, a REFab command may be replaced by a full cycle of eight REFpb commands. (2) Burst Refresh limitation: To limit maximum current consumption, a maximum of 8 REFab commands may be issued in any rolling tREFBW (tREFBW = 4 x 8 x 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 this particular window is reduced to: R* = R - RU{tSRF / tREFI} = R - RU{R * tSRF / tREFW}; where RU stands for the round-up function. Example A t REFW t SRF CKE Enter self refresh mode Example B Exit self refresh mode t REFW t SRF CKE Enter self refresh mode Example C Exit self refresh mode t REFW t SRF CKE Exit self refresh mode Example D t REFW t t SRF1 SRF2 CKE Exit self refresh mode Enter self refresh mode Exit self refresh mode Figure 4.26 — LPDDR2-SX: Definition of tSRF Several examples on how to tSRF is calculated: Confidential - 44/129 - Rev.1.0 July 2016 AS4C64M16MD2-25BCN AS4C32M32MD2-25BCN ! A: with the time spent in Self-Refresh Mode fully enclosed in the Refresh Window (tREFW), B: at Self-Refresh entry C: at Self-Refresh exit D: with several different intervals spent in Self Refresh during one tREFW interval In contrast to JESD79 and JESD79-2 and JESD79-3 compliant SDRAM devices, LPDDR2-SX devices allow significant flexibiliy in scheduling REFRESH commends, as long as the boundary conditions above are met. In the most straight forward case a REFRESH command should be scheduled every tREFI. In this case SelfRefresh may be entered at any time. The users may choose to deviate from this regular refresh pattern e.g., to enable a period where no refreshes are required. In the extreme (e.g., LPDDR2-S4 1Gb) the user may choose to issue a refresh burst of 4096 REFRESH commands with the maximum allowable rate (limited by tREFBW) followed by a long time without any REFRESH commands, until the refresh window is complete, then repeating this sequence. The achieveable time without REFRESH commands is given by tREFW - (R / 8) * tREFBW = tREFW R * 4 * tRFCab. (e.g., for a LPDDR2-S4 1Gb device @ Tcase