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previous: Jimi I got a reply from Jack to my email... -- 9/11/1999 8:42 PM view thread

Re:Minibooster Operation

9/16/1999 8:46 PM
John Greene
Re:Minibooster Operation
It's interesting in the ap note that they use a FET with higher gain/higher cutoff voltage on top and a lower gain/lower cutoff voltage FET on the bottom. The top device has a VGSoff of -2 min whereas the bottom device has a VGSoff of -.6 min. The gain is roughly a 2 to 1 relationship.  
 
 
 
It also states that the lower the drain current the higher the gain however you sacrifice input dynamic ranger with increasing gain. Sounds like you could incorporate some sort of 'sag' mechanism using this characteristic.  
 
 
 
Says that it's sometimes called the "JFET u amp" because the voltage gain is dependent on the u of the bottom JFET (roughly half). u of a JFET increases as current decreases therefore the gain of the minibooster increases.  
 
 
 
FWIW,  
 
 
 
--johng  
 
 
 
 
 

 
Replies:
Fuzzman >It also states that the lower the ... -- 9/16/1999 9:18 PM