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Author Topic: Where to buy a 68882 40MHz PLCC?  (Read 1852 times)

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Offline Kin-Hell

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Re: Where to buy a 68882 40MHz PLCC?
« on: November 05, 2008, 10:04:32 PM »
I've never seen one of these cards for the 1200. However, I must ask what socket you have available for the FPU as there are 2 packages available!
One is PLCC & one is PGA.
Now the interesting factor here is, PLCC is the type that fits in a socket. Afaik, these never went ANY faster than 33mhz. They have contact pins around the edge of the Chip that interface with the socket sides that they fit into.
40Mhz & 50Mhz FPU's were only available in the PGA package. These PGA's are usually a light plum colour like an 040/060 CPU with a brass Core Centre within the Ceramic top surface area. They have pins on the backside just like 040/060 CPU's & just push into a PGA flat & level faced socket.

Some accelerator cards have provision for both types of FPU & the better accelerators had the provision for setting jumpers to make the FPU use its own Osc. Crystal & not the one used by the CPU. You could use a CPU @ say 25Mhz & an FPU @ 33Mhz, but each one using it's own Crystal.

Most 25Mhz FPU's should do 33mhz but 40 is pushing it for that package! It really is on the edge stuff just because of heat within the package itself! hence the Ceramic ones with brass topped cores!  ;-)

Looking at the BBoAH, your FPU is going to have to be a good example to do 40Mhz without issues!
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