Assignment #3
1-33. Design an inverting amplifier with voltage gain ≈ -5.6 and an input resistance ≈ 10 kΩ
using an OP27 OpAmp. The OP27 has the following typical performance parameters:
Input resistance -- 2 GΩ
Voltage gain -- 1.5 MV/V
Output resistance -- 70 Ω
Determine the variation from the ideal design goals due to the non-ideal properties of the
OP27 OpAmp.
Solution: MathCAD
%
variation_percent 0.00044−=variation_percent 5.6−vo_vi()−
5.6−100⋅:=
vo_vi 5.60002−=v1_vi 3.73802−10 6−
×=
vo_vi a1
:=v1_vi a0
:=a Find v1_vi vo_vi,():=
0 v1_vi A
Ro
1
Rf
−
⎛
⎜
⎝
⎞
⎠
⋅vo_vi 1
Rf
1
Ro
+
⎛
⎜
⎝
⎞
⎠
⋅−
1
RS v1_vi 1
RS
1
Rf
+1
Ri
+
⎛
⎜
⎝
⎞
⎠
⋅vo_vi 1
Rf
⎛
⎜
⎝
⎞
⎠
⋅−
Given vo_vi 1−:=v1_vi 1:=
Guess A 1.5 106
⋅:=Ro 70:=Ri 2 109
⋅:=RS 10000:=Rf 56000:=
#1-33
1-40. For the amplifier shown below, determine the values of the load resistor, RL, that will
lead to gain that deviates from the ideal value by -0.01%. Assume the OpAmp has the
following properties:
A
v = 500,000
R
i = 1 MΩ
R
o = 75Ω
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