PRELIMINARY DATA SHEET
2GB Registered DDR SDRAM DIMM
EBD21RD4ABNA (256M words × 72 bits, 2 Banks)
Description
Features
The EBD21RD4ABNA is a 256M words × 72 bits, 2
bank Double Data Rate (DDR) SDRAM Module,
mounted 36 pieces of DDR SDRAM sealed in TCP
package. Read and write operations are performed at
the cross points of the CK and the /CK. This high-
speed data transfer is realized by the 2-bit prefetch-
pipelined architecture. Data strobe (DQS) both for
read and write are available for high speed and reliable
data bus design. By setting extended mode register,
the on-chip Delay Locked Loop (DLL) can be set
enable or disable. This module provides high density
mounting without utilizing surface mount technology.
Decoupling capacitors are mounted beside each TCP
on the module board.
• 184-pin socket type dual in line memory module
(DIMM)
PCB height: 30.48mm
Lead pitch: 1.27mm
• 2.5V power supply
• Data rate: 266Mbps/200Mbps (max.)
• 2.5 V (SSTL_2 compatible) I/O
• Double Data Rate architecture; two data transfers per
clock cycle
• Bi-directional, data strobe (DQS) is transmitted
/received with data, to be used in capturing data at
the receiver
• Data inputs and outputs are synchronized with DQS
• 4 internal banks for concurrent operation
(Component)
Note: Do not push the cover or drop the modules in
order to avoid mechanical defects, which may
result in electrical defects.
• DQS is edge aligned with data for READs; center
aligned with data for WRITEs
• Differential clock inputs (CK and /CK)
• LL aligns DQ and DQS transitions with CK
transitions
• Commands entered on each positive CK edge; data
referenced to both edges of DQS
• Auto precharge option for each burst access
• Programmable burst length: 2, 4, 8
• Programmable /CAS latency (CL): 2, 2.5
• Refresh cycles: (8192 refresh cycles /64ms)
7.8µs maximum average periodic refresh interval
• 2 variations of refresh
Auto refresh
Self refresh
• 1 piece of PLL clock driver, 1 piece of register driver
and 1 piece of serial EEPROM (2k bits EEPROM) for
Presence Detect (PD)
Document No. E0273E20 (Ver. 2.0)
Date Published Aug 2002 (K) Japan
URL: http://www.elpida.com
Elpida Memory, Inc. 2002
ELPIDA [ ELPIDA MEMORY ]
