Manual

DDR2 UDIMM with ECC
Product Specification
Pin Description
Symbol Type Description
Ax Input
Address inputs: Provide the row address for ACTIVE 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 BAx) or all banks (A10 HIGH). The address
inputs also provide the op-code during a LOAD MODE command. See the Pin
Assignments Table for density-specific addressing information.
BAx Input
Bank address inputs: Define the device bank to which an ACTIVE, READ, WRITE,
or PRECHARGE command is being applied. BA define which mode register (MR0,
MR1, MR2, and MR3) is loaded during the LOAD MODE command.
CKx,
CKx#,
Input
Clock: Differential clock inputs. All control, command, and address input signals are
sampled on the crossing of the positive edge of CK and the negative edge of CK#.
CKEx Input
Clock enable: CKE (registered HIGH) activates and CKE (registered LOW)
deactivates clocking circuitry on the DDR2 SDRAM.
DMx I/O
Data input mask (x8 devices only): DM is an input mask signal for write data.
Input data is masked when DM is sampled HIGH, along with that input data, during
a write access. DM is sampled on both edges of DQS. Although DM pins are
input-only, the DM loading is designed to match that of DQ and DQS pins.
ODTx Input
On-die termination: ODT (registered HIGH) enables termination resistance
internal to the DDR2 SDRAM. When enabled, ODT is only applied to the following
pins: DQ, DQS, DQS#, and CB. The ODT input will be ignored if disabled via the
LOAD MODE command.
RAS#, CAS#,
WE#
Input
Command inputs: RAS#, CAS#, and WE# (along with S#) define the command
being entered.
Sx#, Sx# Input
Chip select: Enables (registered LOW) and disables (registered HIGH) the
command decoder.
SAx Input
Serial address inputs: Used to configure the SPD EEPROM address range on the
I
2
C bus.
SCL Input
Serial clock for SPD EEPROM: Used to configure the SPD EEPROM address
range on the I
2
C bus.
SDA I/O
Serial presence-detect data: SDA is a bidirectional pin used to transfer addresses
and data into and out of the presence-detect portion of the module.
DQx I/O Data input/output: Bidirectional data bus.
DQSx,
DQSx#
I/O
Data strobe: Output with read data, input with write data for source synchronous
operation. Edge-aligned with read data, center-aligned with write data. DQS# is only
used when differential data strobe mode is enabled via the LOAD MODE command.
V
DD
/V
DDQ
Supply Power supply: 1.8V ±0.1V.
V
DDSPD
Supply
Serial EEPROM positive power supply: +1.7V to +3.6V.
V
REF
Supply SSTL_18 reference voltage. (VDD/2)
V
SS
Supply Ground.
NC –
No connect: These pins are not connected on the module.
Rev. 1.2 Aug. 2011
4