regarding opto isolator

[prav]

Hi all,

I was studying some board schematics. In this there are some clocks
coming from external world . Before these clocks are connected to the
FPGA pins they pass through an opto isolator.Could any body help me
out why the opto isolators are really required .

rgds,
prav

 

[Jamie]

protection,
and convenience of use over some of the older
methods for controlling high volt functions with low voltage
sensitive components.


prav wrote:

Hi all,

I was studying some board schematics. In this there are some clocks
coming from external world . Before these clocks are connected to the
FPGA pins they pass through an opto isolator.Could any body help me
out why the opto isolators are really required .

rgds,
prav

 

[Chaos Master]

prav called The Usenet Police (tm) of sci.electronics.basics and said to the cops,
at 11 Feb 2004 22:04:41 -0800:

Hi all,

I was studying some board schematics. In this there are some clocks
coming from external world . Before these clocks are connected to the
FPGA pins they pass through an opto isolator.Could any body help me
out why the opto isolators are really required .

For protection. A little spike can turn the FPGA into toast, and replacing it will
be not fun (consider a FPGA of 144 pins).

--
Chaos MasterŽ - Posting from Brazil!
MSN/E-Mail address: wizard_of_yendor-|<|-@hotmail.com-|<|-
Remove the diodes [-|<|-], they're for protection (no pun intended).