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super
Joined: 18 Aug 2002
Posts: 84
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 01 Jan 2005 9:37 ABOUT unit gain buffer ... |
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Dear all :
I have question about unit gain buffer.
There are three type op.
1. General 2 to 1 op
2. telescopic op
3. folded cascode op
if I connect these op to unit gain buffer ,
what's the different both of them ?
Thanks ..
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chingtang
Joined: 19 Dec 2004
Posts: 11
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| 01 Jan 2005 18:08 ABOUT unit gain buffer ... |
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| I think the key difference is the output voltage swing. For telescopic op amp, if you connect the input and output to implement a unity-gain buffer, the output swing is Vth4-(Vgs4-Vth2) [Razavi page 299]. But if you are using a folded cascode op amp, the output swing is higher than the telescopic op amp. Hope this will help. Sorry I am not famillier with the 2 to 1 op amp.
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yeechyan
Joined: 14 Jun 2004
Posts: 111
Helped: 1
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| 02 Jan 2005 4:10 ABOUT unit gain buffer ... |
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| Do you mean the 2 to 1 op amp is the differential to single ended configuration?
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super
Joined: 18 Aug 2002
Posts: 84
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| 02 Jan 2005 8:27 Re: ABOUT unit gain buffer ... |
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sorry,,,
the 2 to 1 op amp is the differential to single ended configuration.
How about folded cascode and differential to single(D2S) Opamp ?
because folded cascode only open loop gain and Vomax folded is large than
D2S and Vomin are equal .
I don't know what's different between folded and D2S if connect to
Unit gain buffer?
Thanks .
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