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bluestatic
Joined: 04 Aug 2004
Posts: 28
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 13 Aug 2004 10:53 In IO pad, why do we need a floating Well? |
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A lot of IO design use floating Nwell on the PMOS output transistors. For input IO cell, I guess this is to do with 5V tolerance. But why do we need a floating Nwell in output cells.
Any one got a clear picture on this issue?
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Colbhaidh
Joined: 10 Aug 2004
Posts: 151
Helped: 16
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| 15 Aug 2004 16:47 Re: In IO pad, why do we need a floating Well? |
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| For 3.3Volt logic IO,s that need to be 5Volt tolerant, a way of ensuring that the PMOS gate oxide never sees 5.5Volts across it is to use floating wells.
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sunking
Joined: 25 May 2004
Posts: 914
Helped: 46
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| 16 Aug 2004 4:30 Re: In IO pad, why do we need a floating Well? |
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| http://patimg1.uspto.gov/.piw?docid=US006545506&PageNum=2&IDKey=53466D63A704&HomeUrl=http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2%2526Sect2=HITOFF%2526p=1%2526u=/netahtml/search-bool.html%2526r=1%2526f=G%2526l=50%2526co1=AND%2526d=ptxt%2526s1=6545506%2526OS=6545506%2526RS=6545506
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rambus_ddr
Joined: 26 Jun 2001
Posts: 119
Helped: 4
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| 16 Aug 2004 5:44 Re: In IO pad, why do we need a floating Well? |
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| For protecting the bonding wire connected with sub when bonding
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