mt9jsf12872a Micron Semiconductor Products, mt9jsf12872a Datasheet - Page 7

• Manufacturer Part Number: mt9jsf12872a
• Description: 1gb X72, Ecc, Sr 240-pin Ddr3 Sdram Udimm
• Manufacturer: Micron Semiconductor Products

General Description
Fly-By Topology
Temperature Sensor with Serial Presence-Detect EEPROM
Thermal Sensor Operations
PDF: 09005aef8300b5ee/Source: 09005aef8300b63a
JSF9C128x72A.fm - Rev. A 3/08 EN
The MT9JSF12872A DDR3 SDRAM module is a high-speed, CMOS dynamic random
access 1GB memory module organized in a x72 configuration. This DDR3 SDRAM
module uses internally configured, 8-bank 1Gb DDR3 SDRAM devices.
DDR3 SDRAM modules use double data rate architecture to achieve high-speed opera-
tion. The double data rate architecture is essentially an 8n-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 DDR3 SDRAM module effectively consists of a single
8n-bit-wide, one-clock-cycle data transfer at the internal DRAM core and eight corre-
sponding n-bit-wide, one-half-clock-cycle data transfers at the I/O pins.
The differential data strobe (DQS, DQS#) is transmitted externally, along with data, for
use in data capture at the DDR3 SDRAM input receiver. DQS is center-aligned with data
for WRITEs. The read data is transmitted by the DDR3 SDRAM and edge-aligned to the
data strobes.
DDR3 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.
Control, command, and address 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.
These DDR3 modules use faster clock speeds than earlier DDR technologies, making
signal quality more important than ever. For improved signal quality, the clock, control,
command, and address buses have been routed in a fly-by topology, where each clock,
control, command, and address pin on each DRAM is connected to a single trace and
terminated (rather than a tree structure, where the termination is off the module near
the connector). Inherent to fly-by topology, the timing skew between the clock and DQS
signals can be easily accounted for by using the write-leveling feature of DDR3.
The temperature from the integrated thermal sensor is monitored and converted into a
digital word via the I
to create a custom temperature-sensing solution based on system requirements.
Programming and configuration details comply with JEDEC Standard No. 21-C, page
4.7-1, “Mobile Platform Memory Module Thermal Sensor Component Specification.”
2
C bus. System designers can use the user-programmable registers
1GB (x72, ECC, SR) 240-Pin DDR3 SDRAM UDIMM
7
Micron Technology, Inc., reserves the right to change products or specifications without notice.
General Description
©2008 Micron Technology, Inc. All rights reserved