mt18htf25672fdy-80e Micron Semiconductor Products, mt18htf25672fdy-80e Datasheet - Page 7

• Manufacturer Part Number: mt18htf25672fdy-80e
• Description: 1gb, 2gb X72, Dr 240-pin Ddr2 Sdram Fbdimm Dr, Fb, X72
• Manufacturer: Micron Semiconductor Products

General Description
Advanced Memory Buffer
PDF: 09005aef81a2f237/Source: 09005aef81a2f25b
HTF18C128_256x72FD.fm - Rev. C 9/07 EN
The Micron
FBDIMMs. The following specifications contain detailed information on FBDIMM
design, interfaces, and theory of operation and are listed here for the system designers
convenience. Refer to the JEDEC Web site for available specifications.
• FBDIMM Design Specification – pending JEDEC approval
• FBDIMM: Architecture and Protocol – JESD206
• FBDIMM: Advanced Memory Buffer (AMB) Specification – JESD82-20
• Design for Test, Design for Validation (DFx) Specification
• Serial Presence-Detect (SPD) for Fully Buffered DIMM – JEDEC Standard No. 21-C
The MT18HTF12872FD and MT18HTF25672FD DDR2 SDRAM modules are a high-
bandwidth, large-capacity channel solution that have a narrow host interface.
FBDIMMs use DDR2 SDRAM devices isolated from the channel behind an advanced
memory buffer (AMB) on the FBDIMM. Memory-device capacity remains high and total
memory capacity scales with DDR2 SDRAM bit density.
As shown in Figure 2 on page 5, the FBDIMM channel provides a communication path
from a host controller to an array of DDR2 SDRAM devices, with the DDR2 SDRAM
devices buffered behind an AMB device. The physical isolation of the DDR2 SDRAM
devices from the channel enables the flexibility to enhance the communication path to
significantly increase reliability and availability of the memory subsystem.
The AMB isolates the DDR2 SDRAM devices from the channel. This single-chip AMB
component, located in the center of each FBDIMM, acts as a repeater and buffer for all
signals and commands exchanged between the host controller and DDR2 SDRAM
devices, including data input and output. The AMB communicates with the host
controller and adjacent FBDIMMs on a system board using an industry-standard, high-
speed, differential, point-to-point interface at 1.5V. The AMB also allows buffering of
memory traffic to support large memory capacities. Refer to the JEDEC AMB FBDIMM:
JESD82-20 specification for further information.
page 4.1.2.7-1
®
FBDIMM adheres to the currently-proposed industry specifications for
1GB, 2GB (x72, DR) 240-Pin DDR2 SDRAM FBDIMM
7
Micron Technology, Inc., reserves the right to change products or specifications without notice.
General Description
©2005 Micron Technology, Inc. All rights reserved.