1Gb: x4, x8, x16 DDR3 SDRAM
Ball Assignments and Descriptions
Table 5: 96-Ball FBGA – x16 Ball Descriptions
Symbol
Type
Description
A0, A1, A2, A3, A4,
A5, A6, A7, A8, A9,
A10/AP, A11,
Input
Address inputs: Provide the row address for ACTIVATE commands, and the column
address and auto precharge bit (A10) for READ/WRITE commands, to select one
location out of the memory array in the respective bank. A10 sampled during a
PRECHARGE command determines whether the PRECHARGE applies to one bank (A10
LOW, bank selected by BA[2:0]) or all banks (A10 HIGH). The address inputs also pro-
vide the op-code during a LOAD MODE command. Address inputs are referenced to
A12/BC#
VREFCA. A12/BC#: When enabled in the mode register (MR), A12 is sampled during
READ and WRITE commands to determine whether burst chop (on-the-fly) will be
performed (HIGH = BL8 or no burst chop, LOW = BC4). See Table 70 (page 116).
BA0, BA1, BA2
Input
Bank address inputs: BA[2:0] define the bank to which an ACTIVATE, READ, WRITE,
or PRECHARGE command is being applied. BA[2:0] define which mode register (MR0,
MR1, MR2, or MR3) is loaded during the LOAD MODE command. BA[2:0] are
referenced to VREFCA
.
CK, CK#
CKE
Input
Input
Clock: CK and CK# are differential clock inputs. All control and address input signals
are sampled on the crossing of the positive edge of CK and the negative edge of CK#.
Output data strobe (DQS, DQS#) is referenced to the crossings of CK and CK#.
Clock enable: CKE enables (registered HIGH) and disables (registered LOW) internal
circuitry and clocks on the DRAM. The specific circuitry that is enabled/disabled is
dependent upon the DDR3 SDRAM configuration and operating mode. Taking CKE
LOW provides PRECHARGE POWER-DOWN and SELF REFRESH operations (all banks
idle),or active power-down (row active in any bank). CKE is synchronous for
power-down entry and exit and for self refresh entry. CKE is asynchronous for self re-
fresh exit. Input buffers (excluding CK, CK#, CKE, RESET#, and ODT) are disabled dur-
ing POWER-DOWN. Input buffers (excluding CKE and RESET#) are disabled during
SELF REFRESH. CKE is referenced to VREFCA
.
CS#
LDM
ODT
Input
Input
Input
Chip select: CS# enables (registered LOW) and disables (registered HIGH) the
command decoder. All commands are masked when CS# is registered HIGH. CS#
provides for external rank selection on systems with multiple ranks. CS# is considered
part of the command code. CS# is referenced to VREFCA
.
Input data mask: LDM is a lower-byte, input mask signal for write data. Lower-byte
input data is masked when LDM is sampled HIGH along with the input data during a
write access. Although the LDM ball is input-only, the LDM loading is designed to
match that of the DQ and DQS balls. LDM is referenced to VREFDQ
.
On-die termination: ODT enables (registered HIGH) and disables (registered LOW)
termination resistance internal to the DDR3 SDRAM. When enabled in normal
operation, ODT is only applied to each of the following balls: DQ[15:0], LDQS, LDQS#,
UDQS, UDQS#, LDM, and UDM for the x16; DQ0[7:0], DQS, DQS#, DM/TDQS, and
NF/TDQS# (when TDQS is enabled) for the x8; DQ[3:0], DQS, DQS#, and DM for the x4.
The ODT input is ignored if disabled via the LOAD MODE command. ODT is
referenced to VREFCA
Command inputs: RAS#, CAS#, and WE# (along with CS#) define the command
being entered and are referenced to VREFCA
.
RAS#, CAS#, WE#
RESET#
Input
Input
.
Reset: RESET# is an active LOW CMOS input referenced to VSS. The RESET# input
receiver is a CMOS input defined as a rail-to-rail signal with DC HIGH ≥ 0.8 × VDD and
DC LOW ≤ 0.2 × VDDQ. RESET# assertion and desertion are asynchronous.
PDF: 09005aef826aa906
1Gb_DDR3_SDRAM.pdf - Rev. L 03/13 EN
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