CGaAs FXU (PowerPC Integer Processor)

Tuesday, March 24, 2009

CGaAs FXU (PowerPC Integer Processor)

Abstract:

The primary focus of this project is the development of a radiation-hard complementary GaAs (CGaAs), PowerPC microprocessor with flip-chip, area I/O packaging. This processor, called PUMA, is ideally suited to space applications because of its low power-delay product and excellent radiation hardness. We have partially tested a CMOS prototype of the PUMA architecture, and are ready to begin testing the CGaAs processor. We have analyzed the CGaAs technology to determine the most cost-effective scaling factor for each design rule; in this effort, we have developed a methodology and tools to help engineers also scale CMOS processes non-linearly.

We have developed and tested low-jitter PLL clock generators, current-mode I/O, and CAD tools for better leaf-cell design, logic synthesis, and minimization of cross-talk. We have developed new packaging capabilities, including a gold bumping process which produces bumps with pitches as small as 50 mm. Assembly of MCMs has begun at 3-M. The remainder of this project and an accompanying AASERT will complete the system design and demonstrate the prototype in a desktop computer.

This project is supported by the Advanced Research Projects Agency under ARPA/ARO Contract Number DAAH04-94-G-0327.

Microprocessor

The microprocessor is the center of your computer. It processes instructions and communicates with outside devices, controlling most of the operation of the computer. The microprocessor usually has a large heat sink attached to it. Some microprocessors come in a package with a heat sink and a fan included as a part of the package. Other microprocessors require you to install the heat sink and fan separately. This is not a difficult problem, but can be a bit daunting when the buyer wants to make sure they get the correct parts to fit their microprocessor. Also the buyer needs to make sure they will get the motherboard that their microprocessor will work with. This section will explain some of the differences in microprocessors and ways to be sure your parts match.

Microprocessors and Mounting

The mounting method refers to the type of connection the microprocessor makes with the motherboard. The following table lists the various mounting packages and some of the well known microprocessors that are mounted for that package.

  • Socket 7 - AMD K5, K6, Intel Pentium 75-200Mhz, IBM
  • Socket 370 - Some Intel Celerons
  • Slot 1 - Intel Pentium II, Pentium III, Some Celeron 266-533
  • Slot II - Intel Xeon
  • Slot A - AMD Athlon

The Socket 7 processors are becoming less popular. We recommend socket 370, through slot A microprocessors at the current time. The prices on Socket 370 microprocessors are currently very low considering the performance of the systems. I recently bought a Celeron 500Mhz microprocessor with 66Mhz sidebus for under $120 with a motherboard for $84. When buying a microprocessor, make sure you get the type of socket you think since some processors are made for different sockets such as the Celeron. Be sure of one of the following.

  1. The socket type is stated at the vendors website.
  2. There is a microprocessor part number stated at the vendors website that can be traced to the manufacturers website which specifies the mounting package you want.

It would be no fun to get a Slot 1 motherboard and a socket 370 Microprocessor.

Microprocessor heat sinks and fans.

Being sure you get the correct heat sink and fan for your microprocessor can be a bit daunting. Who wants to get a $300 microprocessor, and risk it with an incorrect mounting of a heatsink or fan? Who wants to find out that they have purchased the wrong heatsink for their processor and spend days or weeks trying to sort it out? My solution is to purchase the microprocessor with the heatsink in the same package. Usually you get a better warranty and return policy this way and you don't need to worry about whether the two are compatible. I do not believe you can save enough money buying the heatsink and fan from anyone other then the vendor selling the microprocessor because of the time it takes for the additional research required and the potential trouble. The best solution to this problem is simply to buy a slot1, slot II or slot A microprocessor with the package that includes the fan and heatsink. These would be one of the Pentium II, Pentium III, Athlon, or Xeon packages. All that is required in this case is to slide the microprocessor carefully into its slot. With the exception of processors such as the Athlon which have a larger heat sink, requiring an extra plastic clip mechanism to help stabilize the heatsink, it is easier to install one of these processors than it is to install the computer's RAM memory or a hard drive