[SOLVED] Resistor "not qualified".

[palmeiras]

Hi guys,

What does it mean when the design manual of some CMOS Process technology informs that a certain device (for instance, Resistor) is "not qualified yet"?
Can I trust in the electrical models of this device?

Thanks!

 

[dick_freebird]

There are all kinds of resistors that you can make but not all of them are
chosen to be controlled for tolerance, tempco, etc. They may just not
think them worth modeling. Especially true if you're using a flow that the
foundry thinks is "digital". You may be lucky to have a model at all.

In such cases it's basically a matter of luck with no guarantees, that
the resistor characteristics come out as advertised (although odds
are against anyone screwing up an implant too badly without it also
bothering the MOS enough to reject).

Things like undoped unsilicided poly are another matter, that can be
all over the road and no other device uses it so all bets are off if it
is not a dispositionable WAT param. And even then the model may
be unsupported.

You should get the foundry in question to declare their meaning,
as well as whether they will even accept designs using unsupported
devices or under what kind of conditions.

 

[palmeiras]

Thanks freebird for your reply.
Yes…. The foundry supports the fabrication of this resistor. And the weird fact is that the manual informs that this “not qualified” resistor has better tolerance compared to other type of resistors. So I was tempted to use it.
By the way, this CMOS process is for RF circuits (not digital).

 

[leo_o2]

Not qualified devices might be referred to the device without test-key monitoring.