????????? Introduction to Operational Amplifiers

1
????????? Introduction to Operational
Amplifiers ????????????IC,???????????????????????
1.1 ????? Difference Amplifier 1.2 ???????? Ideal
Operational Amplifiers 1.3 ????????? 1.4 ?????????
????? 1.5 ?????????? 1.6 ?????---??????
2
????? Difference Amplifier
??(single-ended)???(double-ended)???
?????????????
????? (single-ended source)
?????????????
? a
Ra
?
??(???)??? (double-ended or balanced source)
? b
Rb
?-
?out
RL
?out????-??????
3
?
???? difference-mode signal
???? common-mode signal
???? difference-mode gain
???? common-mode gain
4
???????difference amplifier??
?
Ad?d
?out
?-
Ac?c
???Ac?Ad?
?????????
?Ac?,?
,?
?Ad?,?
,?
5
????? common-mode rejection ratio (CMRR)
??????(?????????),?????? - ?- (??d
)????,???c????,????AdgtgtAc?????Ad/Ac??????????
??
Ad100, Ac0.50
??????????CMRR??90dB???