re: EV-100 power on board

[Bob Wing <bobwing@nbn.com>]

>I don't have much to say on the matter, but..  There are reasons to
>group all of the power pins together.  First, if you use single or
>double sided boards (not ground planes) then grouping them together
>allows you to filter them properly and simply with capacitors.  Second,
>routing, say power on one end and ground on the other, forces the power
>currents to form a loop which increases EMI and noise over having them
>close.  I would also recommend grouping pins across from each other as
>the same voltage, it simplifies the backplane design.  Four pins mught
>be better for ground, too.
>
>Jim
>
>Prof Bill Neill wrote:
>>
>> EV-100 Board Power STANDARD
>> Everybody join in and help us decide which pins will provide power and
>> common on the EV-100
>> SYSTEM BUS.
>> Below is a S-100 card from the old computer. We can change the size
>> and
>> shape of our EV-100
>> cards, still using the 100 pin connector. If we stay with a STANDARD
>> SIZE everything will cost
>> less.
>>
>> <----------10 inches------------------------------------------------->
>> +--------------------------------------------------------------------+
>> |       EV-100 board layout for +12 Volt Power and Common            |
>> |       STANDARDIZES EV-100-PINS 10 AND 40                           |
>> |                                                                    |
>> |                  ______________________________                    |
>> |                 |                             |                    |
>> |                 |       POWER LOOP            |                    |
>> |                 |                             |                    |
>> |                 |                             |                    |
>> |                 |                             |                    |
>> |                 |                             |                    |
>> |                 |                             |                    |
>> |                 |                             |                    |
>> |                 |                             |                    |
>> +--------         1         2         3         4         5----------+
>>          12345678901234567890123456789012345678901234567890
>>          ||||||||||||||||||||||||||||||||||||||||||||||||||
>> Connector is 5.5 inches----------------------------------->
>> Card is 6.5 inches tall.
>>
>> Place power on pins 10 and 40.
>>


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