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ISL55004_06 Datasheet, PDF (10/12 Pages) Intersil Corporation – High Supply Voltage 200MHz Unity-Gain Stable Operational Amplifier | |||
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ISL55004
R1
V1
1kâ¦
C1
1nF
R2
1k⦠C2
1nF
RA
1kâ¦
V2
5V
C5
1nF
+ V+
- V-
RB
1kâ¦
C5
1nF
V3
5V
VOUT
R7
1kâ¦
FIGURE 28. SALLEN KEY LOW PASS FILTER
K = 1+ RB
RA
Vo = K 1 V1
R2C2s + 1
Vo
V1â Vi 1+ K â V1 + Vo â Vi = 0
R1
R2
1
C1s
H(s) =
K
R1C1R2C2s2 + ((1â K)R1C1+ R1C2 + R21C2)s + 1
H(jw) =
1
1â w 2R1C1R2C2 + jw((1â K)R1C1+ R1C2 + R2C2)
Holp = K
wo =
1
R1C1R2C2
Q=
1
(1â K) R1C1 + R1C2 +
R2C2 R2C1
R2C2
R1C1
Holp = K
wo = 1
RC
Q= 1
3âK
Equations simplify if we let all
components be equal R=C
R1
V1
1kâ¦
C1
1nF
R2
1k⦠C2
1nF
RA
1kâ¦
V2
5V
C5
1nF
+ V+
- V-
RB
1kâ¦
C5
1nF
V3
5V
VOUT
R7
1kâ¦
Holp = K
wo =
1
R1C1R2C2
Q=
1
(1â K) R1C1 + R1C2 +
R2C2 R2C1
R2C2
R1C1
Holp = K
4âK
wo = 2
RC
Equations simplify if we let
all components be equal R=C
Q= 2
4âK
FIGURE 29. SALLEN KEY HIGH PASS FILTER
10
FN6219.2
July 27, 2006
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