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richloo
Joined: 24 Aug 2004
Posts: 103
Helped: 5
Location: Isolated Island
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 18 Oct 2004 8:29 NMOS microcircuits |
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| Anyone who know or have some example of NMOS analog microcircuit? What is the advantage of NMOS only microcircuit compare to CMOS microcircuit? Thanks in advance.
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Fom
Joined: 10 Mar 2004
Posts: 759
Helped: 56
Location: Taiwan
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| 18 Oct 2004 10:34 Re: NMOS microcircuits |
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| The only advantage is manufacturing cost. Pure NMOS needs less mask number. No well, no P implant. But this introduce a lot of problems for designer. I think it is obsolete technique.
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richloo
Joined: 24 Aug 2004
Posts: 103
Helped: 5
Location: Isolated Island
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| 18 Oct 2004 12:00 NMOS microcircuits |
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| I've read Ken Martin book said that NMOS reduce parasitic capacitance. Is it due to the large area of PMOS or anything else? I just curious how actually such circuit looks like... any comment?
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Teddy
Joined: 15 Sep 2004
Posts: 281
Helped: 38
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| 19 Oct 2004 2:17 Re: NMOS microcircuits |
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If you mean by microcircuit IC then the answer is - speed. NMOS has higher ft over PMOS.
Any differential gate is created from NMOSes only.
Example could be any 2.5GHz PLL
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radiohead
Joined: 13 May 2004
Posts: 331
Helped: 22
Location: Heart of Europe
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| 22 Oct 2004 12:12 Re: NMOS microcircuits |
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| Drawback is that you can no longer rely on certain circuits as high side curernt mirrors, active loads, .... any circuit that consists of pmos devices. They are slower, but the performance still might be okay for some applications. So this is why we always want them around. Use you nmos devices for fast amplifiers, comparators, .... everything that needs to go fast. You can use pmos for the rest if needed.
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cetc1525
Joined: 08 Oct 2004
Posts: 177
Helped: 3
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| 22 Oct 2004 12:30 Re: NMOS microcircuits |
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| the speed of NMOS is faster than PMOS because of the movement of electron is just 2-3 faster than hole.
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