MT18HTF25672PDY-80EE1 Micron Technology Inc, MT18HTF25672PDY-80EE1 Datasheet - Page 6

• Manufacturer Part Number: MT18HTF25672PDY-80EE1
• Manufacturer: Micron Technology Inc

Specifications of MT18HTF25672PDY-80EE1

• Main Category: DRAM Module
• Sub-category: DDR2 SDRAM
• Module Type: 240RDIMM
• Device Core Size: 72b
• Organization: 256Mx72
• Total Density: 2GByte
• Chip Density: 1Gb
• Access Time (max): 40ps
• Maximum Clock Rate: 800MHz
• Operating Supply Voltage (typ): 1.8V
• Operating Current: 1.773A
• Number Of Elements: 18
• Operating Supply Voltage (max): 1.9V
• Operating Supply Voltage (min): 1.7V
• Operating Temp Range: 0C to 65C
• Operating Temperature Classification: Commercial
• Pin Count: 240
• Mounting: Socket
• Lead Free Status / RoHS Status: Compliant

General Description
PLL and Register Operation
Serial Presence-Detect Operation
PDF: 09005aef80e935cd/Source: 09005aef80e934a6
HTF18C64_128_256x72D.fm - Rev. D 9/06 EN
The MT18HTF6472(P)D, MT18HTF12872(P)D, and MT18HTF25672(P)D DDR2 SDRAM
modules are high-speed, CMOS, dynamic random-access 512MB, 1GB, and 2GB
memory modules organized in a x72 configuration. These DDR2 SDRAM modules use
internally configured quad-bank (256Mb, 512Mb) or eight-bank (1Gb) DDR2 SDRAM
devices.
DDR2 SDRAM modules use double data rate architecture to achieve high-speed opera-
tion. The double data rate architecture is essentially a 4n-prefetch architecture with an
interface designed to transfer two data words per clock cycle at the I/O pins. A single
read or write access for the DDR2 SDRAM module effectively consists of a single 4n-bit-
wide, one-clock-cycle data transfer at the internal DRAM core and four corresponding
n-bit-wide, one-half-clock-cycle data transfers at the I/O pins.
A bidirectional data strobe (DQS, DQS#) is transmitted externally, along with data, for
use in data capture at the receiver. DQS is a strobe transmitted by the DDR2 SDRAM
device during READs and by the memory controller during WRITEs. DQS is edge-
aligned with data for READs and center-aligned with data for WRITEs.
DDR2 SDRAM modules operate from a differential clock (CK and CK#); the crossing of
CK going HIGH and CK# going LOW will be referred to as the positive edge of CK.
Commands (address and control signals) are registered at every positive edge of CK.
Input data is registered on both edges of DQS, and output data is referenced to both
edges of DQS, as well as to both edges of CK.
DDR2 SDRAM modules operate in registered mode, where the command/address input
signals are latched in the registers on the rising clock edge and sent to the DDR2 SDRAM
devices on the following rising clock edge (data access is delayed by one clock cycle). A
phase-lock loop (PLL) on the module receives and redrives the differential clock signals
(CK, CK#) to the DDR2 SDRAM devices. The registers and PLL minimize system and
clock loading. PLL clock timing is defined by JEDEC specifications and ensured by use of
the JEDEC clock reference board. Registered mode will add one clock cycle to CL.
DDR2 SDRAM modules incorporate serial presence-detect (SPD). The SPD function is
implemented using a 2,048-bit EEPROM. This nonvolatile storage device contains 256
bytes. The first 128 bytes can be programmed by Micron to identify the module type and
various SDRAM organizations and timing parameters. The remaining 128 bytes of
storage are available for use by the customer. System READ/WRITE operations between
the master (system logic) and the slave EEPROM device occur via a standard I
using the DIMM’s SCL (clock) and SDA (data) signals, together with SA (2:0), which
provide eight unique DIMM/EEPROM addresses. Write protect (WP) is tied to ground on
the module, permanently disabling hardware write protect.
512MB, 1GB, 2GB (x72, ECC, DR) 240-Pin DDR2 SDRAM RDIMM
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Micron Technology, Inc., reserves the right to change products or specifications without notice.
General Description
©2006 Micron Technology, Inc. All rights reserved.
2
C bus