🚀 go-pugleaf

[In the message entitled "pc532 board caps" on May  8, 10:16, Jon Buller writes:]
> Can someone tell me if the caps labeled tantalum on the silk screen
> page really need to be tantalum caps?  Is there some critical reason
> for this or can I use disk caps like I have for everything else?

Yes they do. Tantalum caps have larger values than ceramics or monolithics.
They supply the BULK capacitance for the low frequency currents, the
monolithics supply the high frequency currents. I recommend the use of
monolithic caps (0.3 inch centers, look like little bricks - i.e. the same
as a 2 pin DIP integrated circuit), they have better specs than disc caps.
The tantalums should be around 22uf or so and at least 16V, preferably 25V
or the ones on the +/- 12V rails.

> Also, what positions should J1 and J2 be in?  I assume that J1 should
> be A12 -> 1M4M for 1Mb SIMMs and A23 for 4Mb SIMMs.  (Is that really A23

J1 - berg between center and A12 for 1Mbit drams.
J2 - berg between center and A22 for 1Mbit drams.

> or should it be A13?)  I am also guessing that on J2, A22 -> BANKS is

Yes, it really is A23 - note the schematics are 100% correct, the netlist
represents the PCB!! The scheme for selecting A12 or A23 was chosen to
produce the 1M4M signal so that the page comparator (74ALS6311) would be
correctly wired to make use of the maximum page size of the DRAM device.
1Mbit drams have 1k page sizes, 4Mbit have 2k page sizes.

best regards,

-- 
George Scolaro (gs@vw25.chips.com)	Chips & Technologies
+1 408/434-0600 X4556 work		3050 Zanker Road
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