Jun 17, 2014 #1 M ms_90 Member level 2 Joined Apr 9, 2014 Messages 46 Helped 1 Reputation 2 Reaction score 1 Trophy points 8 Activity points 275 when i was reading some docs about matching,it has been mentioned that while doing transistor matching in diff pair we need to consider the direction of current flow. why this is important? can someone please explain it in detail?
when i was reading some docs about matching,it has been mentioned that while doing transistor matching in diff pair we need to consider the direction of current flow. why this is important? can someone please explain it in detail?
Jun 18, 2014 #2 D.A.(Tony)Stewart Advanced Member level 7 Joined Sep 26, 2007 Messages 9,004 Helped 1,823 Reputation 3,645 Reaction score 2,197 Trophy points 1,413 Location Richmond Hill, ON, Canada Activity points 59,562 If the current gain is not equal, a differential output voltage will exist for an equal input current. This is even more important if only a single ended output is used and current mirrors are used with a different Vbe characteristic. Some more info here https://en.wikipedia.org/wiki/Differential_amplifier#Emitter_constant_current_source Matching on the same chip gives much better results than using discrete parts.
If the current gain is not equal, a differential output voltage will exist for an equal input current. This is even more important if only a single ended output is used and current mirrors are used with a different Vbe characteristic. Some more info here https://en.wikipedia.org/wiki/Differential_amplifier#Emitter_constant_current_source Matching on the same chip gives much better results than using discrete parts.
Jun 18, 2014 #3 crutschow Advanced Member level 6 Joined Feb 22, 2012 Messages 4,458 Helped 998 Reputation 1,994 Reaction score 1,123 Trophy points 1,393 Location Colorado USA Zulu -7 Activity points 25,270 Is this taking about the layout of matched transistors in an analog IC chip design? Last edited: Jun 18, 2014