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Written by Robo
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Sunday, 01 June 2008 15:50 |
VIA's VT82C686A is a chip used in motherboard chipsets. The chipset's job is to guide all the traffic inside a PC, between the processor, memory and peripherals. Nowadays they usually consist of two chips: the Northbridge which does all the high-speed stuff (CPU, RAM, and fast buses) and the Southbridge which handles the slower things. The VT82C686A is a Southbridge used in several of VIA's chipsets, roughly between 1999 and 2002.
Here is the chip sitting on its motherboard. This chip was manufactured by National Semiconductor (the curly 'N' before VIA's logo), because VIA doesn't have their own IC fabs.
This is what it looks like inside. There are a few areas with varied structures like this, but most of the chip area is taken up by a dense mesh of wires. This tells us that this chip was made in a semi-custom process: the transistors are placed on the chip by the foundry, and the designer connects them using wires, without moving the transistors. This allows a reduction in development cost, but it also has a performance penalty when compared to a full-custom design.
The bond wires are made of gold, and there are an awful lot of them! Two layers thick around the whole chip makes for quite a shiny forest.
This is the stuff that does all the work. At this level of magnification it's not possible to tell the transistors apart, or even the top-level wires. I guess it's time for me to invest in a more powerful microscope...
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