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Amplifiers
A.3.7
Noninverting Op Amp with Inverting Negative Reference
The transfer equation takes the form of Y = mX + b and is given in Equation A–7.
R
V OUT
V F
R G
R
IN
V F
R REF
G
R G
A–7
The transfer function slope is positive, and the dc intercept is positive. This is the minimum
component count configuration for this transfer function. The reference termination resistor
is connected to a virtual ground, so R G is the load across V REF . R F and R G are contained
in both halves of the equation. Thus it is hard to obtain the desired slope and dc
intercept without modifying V REF or placing an attenuator in series with V IN .
+ 5 V
R F
V REF
R G
V IN
– 5 V
+V CC
_
+
V OUT
V OUT — 1 V/Div
– 5 V
V IN — 1 V/Div
+ 5 V
V IN = 10 Vp-p
V REF = –1 V
V CC = 5 V R G = R F = 10 k
Op Amp = TLV247x
Figure A–11. Noninverting Op Amp with Inverting Positive Reference
Single-Supply Circuit Collection
A-11