12 Apr
2013
12 Apr
'13
10:18 a.m.
On 04/12/2013 10:09 AM, Dave McGuire wrote:
On 04/12/2013 09:24 AM, David Riley wrote:
I use spice, XFTD, NEC2, and on and on...
They are all nice tools if you keep one thing in mind.
GIGO
For those that have forgotten of never heard that
"Garbage In produces Garbage Out". To avoid that
don't put garbage in. What is garbage? Simulations
with far to many unknown and parasitic items
unaccounted for.
If one takes the time and efffort to correlate and qualify the
results then the answers should be valid and often are.
That means if you use a mbt2222 transistor in spice
the first task is that spice realization a valid one!
Like anything computer simulation and test can be
good or bad and as a designer you can control that.
Allison
Yeah, I can't stress enough that SPICE is NOT
A DESIGN TOOL.
It is a verification tool. People coming out of college in
my generation fail to understand that because even a cheap
PC runs complex SPICE simulations in a fraction of the time
that the original machines did... that, and they're lazy.
The late, great Bob Pease was fond of pointing out that both
SPICE and spreadsheets are great at giving you the answer
you want, not the answer you need (the right one).
And indeed, famously threw a
computer off the roof of the parking garage,
stating that he then knew that THAT computer would never lie to him again.
I'm not certain that this was due to SPICE, but I'd bet it was, given his
overall feelings toward it.
-Dave