Input Stage Question

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Hi, I have a question:

Is there a real difference between the input stage A and B?

Input Stage A - from Randy Slone
An externally hosted image should be here but it was not working when we last tested it.


and Input Stage B - from SiliconChip
An externally hosted image should be here but it was not working when we last tested it.


Some interesting links to read more about it?
How is configured the VAS in Input Stage A

sorry for my Englis ;)
 
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Joined 2006
Yes there is a difference, input stage of randy sloan does not work. The vas bias current is not defined and causes output offset to be unstable. The more recent sloan design has changed the current mirror ltp to cascodes which works. Do a search here, of randy sloan, you will find many info about this.
 
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