node "w_44_71#" in magic layout tool

[020170]

I used maigc layout tool to design "p & n mos inverter".

last night I extracted inverter layout into spice model.

**broken link removed**
_____________________________________________________

* SPICE3 file created from inverter2.ext - technology: scmos

M0 a_63_30# a_59_49# a_53_72# Vdd pfet w=8u l=1u
+ ad=0p pd=0u as=0p ps=0u
M1 a_63_30# a_59_49# a_52_30# Gnd nfet w=4u l=1u
+ ad=0p pd=0u as=0p ps=0u
C0 a_52_30# GND 7.1fF
C1 a_63_30# GND 7.2fF
C2 a_53_72# GND 11.0fF
C3 a_59_49# GND 5.3fF
C4 w_44_71# GND 34.9fF **FLOATING

I didn't understand what did C4 mean.

node of C4, "w_44_71#", is not connected anything.

where do I connect it with? and what did it mean?

besides, I didn't understand "**floating "

even though it is not important, I feel like knowing it.

I'll appreciate if you help me

ps. floating capacitor only happened when I set a lambda =0.5.

but why?

magic tool is so tutorial tool so that I cannot help using minimum

lambda size = 0.5 ,

magic is not allowed the lower minimum lambda value than 0.5

 

[Vamsi Mocherla]

I really do not understand why the tool is calling the capacitor as floating when it has shown two nodes for the capacitor w_44_71# and GND. Well, FLOATING means that one of the terminals of any device is not connected anywhere. May be that is the reason why your tool has connected it to default GND net.

 

[srivatsan]

Why dont u attach the magic layout in the form of a picture.. it may be really help. Recently I had lots of these problems, so I could help you.
srivats

 

[flyankh]

Hi,020170

Although I can't answer your question,I haved found out one of your mistake.The diffusion contact must in the active area,right?It dosn't make sense in my eyes.

Regards

flyankh

Added after 26 minutes:

Now I think I found the point:
Did your Nwell connected to VDD too?I guess you haven't ,so the Nwell is floating.....
Now can you guess what the C4 is and where is the floating point?
It is very important,man.The mosfet is the 4 pin device ,you have let its back-gate floating.

Regards

flyankh

Added after 5 minutes:

And another point:
Have you seen the GND-GND cap?In fact ,it tells you that your GND is no connected to Psub,and the Psub is the really(or physical) GND,so the N-type mosfet's back-gate is floating too

Regards

flyankh

 

[020170]

thanks, flyankh

but I wish someone tell me in detail about floating cap

I'll be waiting for someone to reply my question in a week.

if not, I'll recommend you.

 

[flyankh]

Hi,020170

It doesn't matter.I think my answer can be trusted and is clearly.If you have any questions about it,you can write it out.Let us discuss it,OK?Time is money ,man

Regards

flyankh