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nxing
Joined: 10 May 2004
Posts: 446
Helped: 12
Location: China
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 13 Dec 2004 15:50 process variarion |
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Hello everyone,
I am design a circuit with Jazz_semiconductor's PDK. during the extreme condition simulation, eg, power supply variarion, temperature and process variation, I found that the circuit has quite different performance. I just wondering whether or not there are some related documents talking about how to compensation this kinds of variarion?
Thanks
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shutter_man
Joined: 05 Dec 2004
Posts: 13
Helped: 3
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| 16 Dec 2004 13:17 process variarion |
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Do you mean the PCB itself - or electrical design?
For each there are nomber of compensation schemes and design rools (for example - if you need strong independence on variance of passive elements in Filters - than some active solutions are better than others, and Bessel - will be better than Cheb. or Butt. ) Other time teransistors are used, again on other times reflect - diode and transistors are good also - current sources have strong stability over temperature ets...
If you have a specific issue - post it and I'll try to help.
Shutter_man
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serdes
Joined: 18 Nov 2004
Posts: 10
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| 17 Dec 2004 8:56 Re: process variarion |
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| You should have some margin with your design.
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lakeoffire
Joined: 10 Dec 2002
Posts: 54
Helped: 2
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| 20 Dec 2004 6:42 process variarion |
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The best is that you design a circuit that is insensitive to the PVT variation.
For a commercial design, you need to meet the specs at all the design corners.
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bear7679
Joined: 18 May 2004
Posts: 135
Helped: 21
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| 21 Dec 2004 1:35 Re: process variarion |
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There are some circuits not sensitive with power supply, some circuits not sensitive with temperature. You can find it in razavi's book or P.R. Gray's book.
If you still have problem, you can post it to tell us.
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CDRCDR
Joined: 15 Feb 2004
Posts: 82
Helped: 2
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| 23 Dec 2004 4:47 process variarion |
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For process variation, you need to make some margin.
For power supply variation,you could always use bandgap reference on your IC.
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nxing
Joined: 10 May 2004
Posts: 446
Helped: 12
Location: China
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| 23 Dec 2004 15:07 process variarion |
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| Hi Guys, thanks for your reply. What I am looking for are some common circuits that people usually use to compensate this PVT variation if the robustness is not enough to meet all the extremes.
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selvaraja
Joined: 01 Jun 2004
Posts: 220
Helped: 3
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| 26 Dec 2004 14:40 Re: process variarion |
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| what type circuit you designing ......... give more details plz....
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Mazz
Joined: 03 Nov 2001
Posts: 493
Helped: 57
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| 26 Dec 2004 17:26 Re: process variarion |
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I think it cannot exist such a general ans so specific document. It depends strictly on your design. For example if you're doing a gain such a gm/R you have to bias the transistor with PTAT current, but your design can be very complex and so it depends on it.
Usually the designer has some design equations and from these equations it's clear what are the parameters to compensate.
I hope it can help
Mazz
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yaxazaa
Joined: 13 Nov 2004
Posts: 119
Helped: 3
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| 27 Dec 2004 5:40 Re: process variarion |
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| PVT is the way to make sure your design. Some SPEC is worst case spec, so when you design in nominal, you spec has to be better than SPEC. If nominal design, then 15% +/- is good enough for some design depending on company.
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