Centrino

Abstract: The mobile thin and light platform has a limited cooling capability, in part due to a form factor that limits the volume available for the thermal solution. The high performance of the Pentium M processor on 90nm process technology and the Intel 915 Chipset in the second-generation platform built on Intel Centrino mobile technology demands a high electrical power and generates substantial heat, presenting a challenge to the thin and light notebook system designer. In this paper, we addresses two methods of dealing with the thermal challenge. First, we discuss the path-finding effort to improve the thermal interface materials (TIMs) that allow a good thermal contact between processor and thermal solution, minimizing the transistor temperature of the bare-die Pentium M processors. Two tester methodologies are described, and the need to test TIMs under mobile usage conditions is emphasized. We also discuss the reliability test methodology for TIMs with a focus on the effect of mobile usage conditions affecting long-term reliability of the TIM. ® Pentium is a registered trademark of Intel Corporation or its subsidiaries in the United States and other countries. ® Intel is a registered trademark of Intel Corporation or its subsidiaries in the United States and other countries. TM Centrino is a trademark of Intel Corporation or its subsidiaries in the United States and other countries. We then focus on power-based thermal state estimation as a platform thermal management technique. This technique is used to detect and limit the thermal impact of power virus workloads. In the second-generation platforms built on Intel Centrino mobile technology, the Intel 915 Chipset Graphics and Memory Controller Hub (GMCH) is uniquely positioned to understand much of the workload for the platform. The Intel 915 GMCH has implemented filter-based thermal management. Several key usage models for filter-based thermal management are explored in detail: detecting and limiting the impact of power viruses on system memory and detecting and limiting the impact of power viruses on chipset memory controller hubs. INTRODUCTION Notebook system designs vary significantly from designer to designer; however, they are all densely packed with components and devices, which leave the system with little room for cooling. The problem is compounded by the limited room inside a thin and light notebook product, which typically has a one-inch total thickness when folded and a 17 mm inner vertical space in the lower half of the notebook computer. Figure 1 shows a schematic electrical layout of the major components in the second-generation 1 A power virus is an unusually intensive workload that maximizes power consumption. Most useful applications draw only a fraction of the power a power virus consumes. Intel Technology Journal, Volume 9, Issue 1, 2005 Interface Material Selection and a Thermal Management Technique 76 platforms built on Intel Centrino mobile technology. Figure 2 shows a layout of platform-based notebook system that is roughly representative of performance thin and light notebook designs in the industry. In general, the low-profile thin and light form factor limits the flexibility of thermal solution choices for the system components that must be cooled in order to get any appreciable performance. Figure 1: Electrical schematic of the secondgeneration platforms built on Intel Centrino mobile technology Figure 3 shows the use of the remote heat exchange, the predominant method of cooling of high-power components that require dedicated active cooling. In remote heat exchange, the thermal energy is transported to a location, typically via a heat pipe, where a larger fan and heat exchanger can be used. Also shown in Figure 3 are the silicon portion of the hot component (bare die assumed), the attached hardware for coupling the thermal solution to the hot component, and the key temperature monitor points typically used to characterize the performance of the solution. In the first section, we discuss the ability to transfer the thermal energy from the processor to the thermal solution by using thermal interface materials (TIMs). Figure 2: Layout of typical thin and light notebook (base only with top surface removed)