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bala9383
Joined: 01 Jun 2007
Posts: 30
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 19 Mar 2008 13:36 CMOS |
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If nMOS is connected to Vdd and pMOS is connected to GND. What wud happen ??
Explain plzz
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vlsitechnology
Joined: 01 Nov 2007
Posts: 242
Helped: 6
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| 19 Mar 2008 17:34 CMOS |
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Then it will behave like a weak buffer..that is the reason we will connect nmos to vss and pmos to vdd
Bye take care
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RDRyan
Joined: 24 May 2007
Posts: 134
Helped: 17
Location: China
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| 20 Mar 2008 2:37 CMOS |
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Your question is not very clearly.Maybe your meaning is that the buck (or body) of nMOS connect to Vdd and the buck of pMOS connect to GND. what will happen?
The buck of nMOS is P type, the source and the drain of the nMOS is N type, generally we connect the buck to GND, and the source and the drain connect to a higher voltage than GND. Then the PN junction will be reverse biased, and no current flow.
If we connect the buck of nMOS to VDD, the PN junction between source-to-buck and drain-to-buck will forward biased, and there will be a very large current flow between source to buck and drain to buck, which is not allowed.
The reason for pMOS is the same.
Ryan
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gurpreet.singh
Joined: 10 Mar 2008
Posts: 23
Helped: 1
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| 20 Mar 2008 4:50 Re: CMOS |
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| We connect substrate terminal NMOS to lowest potential and PMOS to highest potential because we need to reverse bias the drian source terminal with respect to channel and substrate and moreover if we do the reverse it will work as week buffer as when Vin =0 nmos will work and gives 1 at output and when Vin=1 then pmos works and vout =0 so it works as a buffer.
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