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modern_analog
Joined: 11 Jul 2004
Posts: 9
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 11 Jul 2004 22:04 L effect on mismatch |
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This might sound very basic but here goes
The mismatch depends on WL, or more accurately 1/sqrt(WL). Then why do we need large L. It seems we can get away with small L and large W.
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bastos4321
Joined: 01 Jan 1970
Posts: 334
Helped: 24
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| 11 Jul 2004 23:59 Re: L effect on mismatch |
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The problem is that if you have a large W you will have a large parasitic capacitance to substrate. At the same time with a lower L the output resistance will be lower. Also a high L reduce the fliker noise.
Bastos
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guamak_menanak
Joined: 13 Apr 2004
Posts: 139
Location: malaysia
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| 12 Jul 2004 3:44 Re: L effect on mismatch |
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Lower L tends to have problem in circuit realibility!
If you are using 0.5um technology...
Try to have bigeer L such as 2(at)3 times higher that 0.5um
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kyrandia
Joined: 23 Jun 2004
Posts: 34
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| 13 Jul 2004 3:56 Re: L effect on mismatch |
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| 1/sqrt(WL) is the mismatch of Vt. If your L is too small, then short channel effect will play a significant role. The Ids will largely depend on Vds.
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xinsu
Joined: 08 May 2004
Posts: 60
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| 13 Jul 2004 8:26 L effect on mismatch |
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| L affect several parameters for a transistor,you must trade off to chose a good one
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hanjiemy
Joined: 11 Jun 2004
Posts: 54
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| 14 Jul 2004 6:01 L effect on mismatch |
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u can increase your L, but keeping W/L = constant .
it will be beneficial to your matching & low noise.(eg, noise which comes from substrate)
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