Datasheet

LM358, LM258, LM2904, LM2904V
6
MOTOROLA ANALOG IC DEVICE DATA
2
1
V
ref
=V
CC
1
2
Figure 12. Function Generator Figure 13. Multiple Feedback Bandpass Filter
For less than 10% error from operational amplifier.
If source impedance varies, filter may be preceded with voltage
follower buffer to stabilize filter parameters.
Where f
o
and BW are expressed in Hz.
Q
o
f
o
BW
< 0.1
Given: f
o
= center frequency
A(f
o
) = gain at center frequency
Choose value f
o
, C
Then: R3 =
Q
π f
o
C
R3
R1 =
2 A(f
o
)
R1 R3
4Q
2
R1 –R3
R2 =
+
–
+
–
–
+
V
ref
=V
CC
V
ref
f =
R1 + R
C
4 CR
f
R1
R3 =
R2 R1
R2 + R1
R2
300 k
75 k
R3
R1
C
Triangle Wave
Output
Square
Wave
Output
V
CC
R3
R1
R2
V
ref
V
in
C
C
V
O
CO
CO = 10 C
R
f
if,
1/2
LM358
V
ref
1/2
LM358
1/2
LM358
100 k