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elone
Joined: 29 Dec 2001
Posts: 111
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 27 Aug 2004 9:55 About fuse trimming ! |
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| tags: fuse trimming resistor |
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I need a accuracy resistor in my design, so i want to use fuse trimming. But how to design this trimming format! Should use metal fuse or poly fuse?
where to find some docs about fuse trimming!
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Colbhaidh
Joined: 10 Aug 2004
Posts: 151
Helped: 16
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| 28 Aug 2004 14:51 Re: About fuse trimming ! |
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| Metal fuses are better for processing on Silicon. These are usually top metal - 1. Most foundries support these in their design rules (TSMC, UMC, Chartered Semi).
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sunking
Joined: 25 May 2004
Posts: 914
Helped: 46
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| 30 Aug 2004 0:53 Re: About fuse trimming ! |
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| Both are ok, it depends on the foundry.
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survivor
Joined: 10 Aug 2004
Posts: 36
Helped: 3
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| 31 Aug 2004 7:03 About fuse trimming ! |
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Hi,
Metal fuse is much better than poly if you try to use laser to cut it. If you try to use current across the fuse to burn it out, poly is the only choice.
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Hughes
Joined: 10 Jun 2003
Posts: 715
Helped: 85
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| 27 Sep 2004 4:24 About fuse trimming ! |
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| Is the fuse poly different from the gate poly?
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frankon_o2
Joined: 07 Sep 2004
Posts: 8
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| 27 Sep 2004 12:25 About fuse trimming ! |
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| how about the temperature coefficient of the resistor? Maybe you could only attain an accurate resistance under typcial temperator if it vary a lot with temperature.
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electronrancher
Joined: 24 Mar 2002
Posts: 479
Helped: 34
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| 27 Sep 2004 19:22 About fuse trimming ! |
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use metal fuses for accuracy - poly *might* work, but putting 100Ohm of poly in parallel with a 1k resistor is going to be pretty crappy. better to use 0.1ohm of metal in parallel with that 1k.
actually, 1k is an easy bit to trim. something below 200Ohm begins to be difficult. i suggest metal.
oh, and metal fuses blow just fine using current - i'm not sure what survivor saw, but most fuses can be blown with 5v, 250-500mA. This is actally pretty easy on prober.
I have only seen poly fuses used for selection (digital), or digital post-package trim, where they again are used for digital selection. They vary too much to be used for anything except 1/0.
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