The Mobile Intel^® 945GMS Express Chipset, a member of the Mobile Intel^® 945 Express Chipset family, is a specially designed Graphics and Memory Controller Hub (GMCH) targeted for use with small form factor (SFF) platforms. The package and features of the Mobile Intel 945GMS Express Chipset are optimized for size, power, and performance to best suit SFF applications.

The feature set of the Mobile Intel 945GMS Express Chipset makes it a compelling product in mini- and sub-notebook segments for the following features.

• The Intel^® Core™ Duo and Core Solo processor Low Voltage (LV)/Ultra Low Voltage (ULV) support with a Front Side Bus (FSB) speed of 667 MHz and 533 MHz, respectively.
• DDR2 533 MHz single channel memory interface. The maximum memory supported is 2 GB.
• Integrated Graphics with a 166 MHz pixel clock. Integrated graphics supports CRT, TV, dual channel Low Voltage Differential Signaling (LVDS), and Serial Digital Video Output (SDVO) interfaces.

The Intel Core Duo LV and Core Solo low-voltage ULV processors are high-performance, low-power, mobile processors with several micro-architectural enhancements over existing Intel^® mobile processors. The ULV Intel^® Celeron^® M processor is a low-power mobile processor with good performance targeted towards value products.

The Mobile Intel 945GM Express Chipset family optimized for SFF-based designs contains two core chipsets: the Mobile Intel 945GMS Express Chipset and the ICH7M (I/O Controller Hub). The Mobile Intel 945GMS Express Chipset provides the host interface controller, System Memory Interface (SDRAM), Direct Media Interface (DMI), and an integrated graphics engine with display output ports.

The ICH7M integrates a number of I/O device controllers and interfaces for legacy and high-speed devices to provide system design flexibility. The DMI, the chipset component interconnect, is designed into the chipset to provide an efficient high-bandwidth communication channel between the GMCH and the ICH7M. The ICH7M also supports PCI Express* x1 I/O ports, next-generation Serial ATA (AT Attachment), and Hi-Speed USB* 2.0 connectivity. An Advanced Configuration and Power Interface (ACPI)-compliant Mobile Intel 945GMS chipset platform can support the Full-On (S0), Suspend to RAM, Suspend to Disk (S4), and Soft-Off (S5) power management states, processor C states, and PCIe-based power management. Through the use of an appropriate LAN device, the chipset also supports wake-on LAN for remote administration and troubleshooting.

Figure 1: Intel Centrino Duo mobile technology-based SFF platform
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In this paper, we discuss the benefits of the Mobile Intel 945GMS chipset over the Mobile Intel 915GMS chipset [2] in terms of the features supported, the challenges in the Intel 945GMS Ball Grid Array (BGA) breakout, motherboard routing, and manufacturability. In comparison to the Mobile Intel^® 915GMS, the Mobile Intel 945GMS had an additional 27 signals to be routed on the package. Also, the Intel 945GMCH die size is bigger than that of the Intel 915 GMCH by about 15 mils on one side and 22 mils on the other side. The development efforts to deliver the smallest package, meeting all the electrical, layout, and manufacturing requirements are key to Intel’s competitive advantage, while pushing the design envelope for thinner, lighter notebooks.

The platform signal and power integrity analysis to enable the DDR2-533 MHz SODIMM with onboard memory and decoupling methodology are discussed in detail. As real estate and BOM costs are key factors in SFF platforms, we describe the platform power delivery with a steeper load line technique and the motherboard decoupling for the Intel Core Solo ULV processors. A steeper load line implementation results in a 50% reduction in the processor decoupling BOM cost compared to the previous-generation SFF platform. Despite the significant improvement in performance in terms of FSB-667 and DDR2-533, the advanced platform power-management features enable lower platform power, compared to previous platforms. The power-management innovation in the Mobile Intel 945GMS Chipset and ICH7M are also discussed in greater detail. Lastly, we discuss the rising challenges foreseen in power management, packaging, design, routing, and electricals.