PDF: 09005aef8085081a/Source: 09005aef806e129d Micron Technology, Inc., reserves the right to change products or specifications without notice.
DD4C16_32x64A.fm - Rev. E 11/08 EN
4 ©2003 Micron Technology, Inc. All rights reserved.
128MB, 256MB (x64, SR) 184-Pin DDR SDRAM UDIMM
Pin Assignments and Descriptions
Table 6: Pin Descriptions
Symbol Type Description
A0–A12 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 device bank. A10
sampled during a PRECHARGE command determines whether the PRECHARGE
applies to one device bank (A10 LOW, device bank selected by BA0, BA1) or all
device banks (A10 HIGH). The address inputs also provide the op-code during a
MODE REGISTER SET command. BA0 and BA1 define which mode register
(mode register or extended mode register) is loaded during the LOAD MODE
REGISTER command.
BA0, BA1 Input
Bank address: BA0 and BA1 define the device bank to which an ACTIVE,
READ, WRITE, or PRECHARGE command is being applied.
CK1, CK1#,
CK2, CK2#
Input
Clock: CK and CK# are differential clock inputs. All address and control input
signals are sampled on the crossing of the positive edge of CK and the
negative edge of CK#. Output data (DQ and DQS) is referenced to the
crossings of CK and CK#.
CKE0 Input
Clock enable: CKE (registered HIGH) activates and CKE (registered LOW)
deactivates the internal clock, input buffers, and output drivers.
DM0–DM7 Input
Input data mask: DM is an input mask signal for write data. Input data is
masked when DM is sampled HIGH, along with that input data, during a write
access. DM is sampled on both edges of DQS. Although DM pins are input-only,
the DM loading is designed to match that of DQ and DQS pins.
RAS#, CAS#, WE# Input
Command inputs: RAS#, CAS#, and WE# (along with S#) define the command
being entered.
S0# Input
Chip selects: S# enables (registered LOW) and disables (registered HIGH) the
command decoder.
SA0–SA2 Input
Presence-detect address inputs: These pins are used to configure the SPD
EEPROM address range on the I
2
C bus
SCL Input
Serial clock for SPD EEPROM: SCL is used to synchronize the presence-detect
data transfer to and from the module.
DQ0–DQ63 I/O
Data input/output: Data bus.
DQS0–DQS7 I/O
Data strobe: Output with read data, input with write data. DQS is edge-
aligned with read data, center-aligned with write data. Used to capture data.
SDA I/O
Serial data: SDA is a bidirectional pin used to transfer addresses and data into
and out of the presence-detect portion of the module.
Vdd/Vddq Supply
Power supply: +2.5V ±0.2V (-40B: +2.6V ±0.1V).
VddSPD Supply
Serial EEPROM positive power supply: +2.3V to +3.6V.
Vref Supply
SSTL_2 reference voltage (Vdd/2).
Vss Supply
Ground.
NC –
No connect: These pins are not connected on the module.
NF –
No function: Connected within the module but provides no functionality.
