Datasheet

ADA4665-2
Rev. 0 | Page 16 of 20
ADA4665-2
07650-057
1/2
+V
SY
–V
SY
R1
22.5kΩ
R2
22.5kΩ
C1
1nF
C2
0.5nF
V
OUT
V
IN
Figure 57. Two-Pole Low-Pass Filter
When R1 = R2 and C1 = 2C2, the values of Q and the cutoff
frequency are calculated as follows:
)( R2R1C2 +
C2C1R2R1
Q =
2R1 R2 C1 C
f
c
π
=
2
1
10
0
–10
–20
–30
–40
–50
–60
100 1k 10k 100k 1M
FREQUENCY (Hz)
GAIN (dB)
07650-058
Figure 58. Low-Pass Filter: Gain vs. Frequency
Figure 59 shows a two-pole high-pass filter, with cutoff frequency
at 10 kHz and quality factor, Q, of 1/√2.
ADA4665-2
07650-059
1/2
+V
SY
–V
SY
R1
22.5kΩ
R2
45kΩ
C1
0.5nF
C2
0.5nF
V
OUT
V
IN
Figure 59. Two-Pole High-Pass Filter
When R2 = 2R1 and C1 = C2, the values of Q and the cutoff
frequency are calculated as follows:
)( C2C1R1
C2C1R2R1
Q
+
=
C2C1R2R1
f
c
π
=
2
1
0
–10
10
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
–120
GAIN (dB)
07650-060
10 100 1k 10k 100k 1M
FREQUENCY (Hz)
Figure 60. High-Pass Filter: Gain vs. Frequency