Copyright: 1996 - 2024
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while tying up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
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and text used on the RF Cafe website are hereby acknowledged.
My Hobby Website:
Substrate contact - RF Cafe Forums
RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media
platforms dominating public commenting venues. RF Cafe Forums began sometime around
August of 2003 and was quite well-attended for many years. By 2010, Facebook and
Twitter were overwhelmingly dominating online personal interaction, and RF Cafe
Forums activity dropped off precipitously. If the folks at
phpBB would release a version with integrated
sign-in from the major social media platforms, I would resurrect the RF Cafe Forums,
but until then it is probably not worth the effort. Regardless, there are still
lots of great posts in the archive that ware worth looking at.
Below are the old forum threads, including responses to the original posts.
|-- Amateur Radio
Gripes & Humor
-- CAE, CAD, &
Test & Measurement
Post subject: Substrate contact Posted: Mon Dec 11, 2006 11:03
Joined: Tue Nov 14, 2006 7:21 pm
In CMOS ckt, there is one extra terminal
for substrate contact to each component.
Can you tell me the
significance of this terminal in CMOS?
what should be the effect
if we avoid this terminal?
Posted: Fri Jan 26, 2007 2:53 am
Fri Jan 26, 2007 2:40 am
Can you tell me the significance
of this terminal in CMOS?
You don't actually have to ground the
terminal but it should at least be tied to the CMOS Source termainal.
The difference in connecting the sub-tie to ground vs. tying it to the
Source would be a slight difference in the threshold voltage.
Of course if we are talking about a PMOS device then the tie would
be connected to either the Source or the positive supply.
should be the effect if we avoid this terminal?
won't work properly.
subject: Posted: Wed Jan 31, 2007 2:22 am
Wed Jun 21, 2006 8:33 pm
Location: Queen Creek, Arizona
In some process technologies, it is possible to avoid connecting
the body, namely specific SOI (Silicon-on-insulator). Here it can also
matter if you are depleted or fully depleted, either way it is defined
by your process.
Generally (especially in a bulk CMOS process),
Jom's statement is correct. If you do not connect it the device will
not function properly.
CMOS RF and Analog