Rail-to-Rail Op AmpsAMSC/TAMU
Rail-to-Rail Op Amps
Edgar Sánchez-Sinencio TAMU, AMSC
Thanks to Shouli Yan for his valuable input in helping in generating part of this material 1
Op Amp Configurations
There are the following Op Amp Configurations, (a) inverting configuration, (b) non-inverting configuration, (c) voltage follower ( or voltage buffer, a special case of (b)), (d) fully-differential configuration, (e) fully-differential to single-ended conversion
R2 R1
vI vO
R1 R2
vO
vI
vO
vI
(a)
(b)
R2
(c)
vI+ R1 vI- R1
R2
vOR2
vI- R1
vO
R2
vO+ v I+ R1
(d)
(e)
2
Why Rail-to-Rail Differential Input Stage?
The input and output swing requirements
Configuration Inverting Non-inverting Voltage follower Fully Differential FD to SE Figure (a) (b) (c) (d) (e) Input common mode voltage swing ≈0 R1/(……
