EL5252 INTERSIL [Intersil Corporation], EL5252 Datasheet - Page 12

• Manufacturer Part Number: EL5252
• Description: 300MHz Amplifiers
• Manufacturer: INTERSIL [Intersil Corporation]

Application Circuits
Sullen Key Low Pass Filter
A common and easy to implement filter taking advantage of
the wide bandwidth, low offset and low power demands of
the EL5152. A derivation of the transfer function is provided
for convenience. (See Figure 32)
12
EL5152, EL5153, EL5252, EL5455
FIGURE 32. SULLEN KEY LOW PASS FILTER
Sullen Key High Pass Filter
Again this useful filter benefits from the characteristics of the
EL5152. The transfer function is very similar to the low pass
so only the results are presented. (See Figure 33)
K
( H
( H
Holp
Holp
Vo
wo
Q
wo
Q
V
1
=
) s
R
jw
=
=
−
=
=
=
1
1
1 (
3
=
)
Vi
+
K
=
=
RC
=
−
−
1
R
1
K
K
R
R
R
1
R
K
1
K
1
B
A
+
1
2
C
−
C
)
C
1
K
1
1
R
w
1
2
R
R
Vo
R
R
s
−
2
2
2
2
C
1
2
R
+
V
C
C
C
2
1
1
1
2
1
C
2
Equations simplify if we let all
components be equal R=C
s
V
+
2
1
+
R
1
+
Vo
2
1
((
C
C
R
R
1
1
−
1
2
1
2
s
−
C
+
C
Vi
2
K
1
jw
R )
=
+
((
K
0
1
1
C
1
R
−
R
1
2
K
+
1
C
C
R )
R
1
2
1
1
C
C
2
1
+
+
R
R
February 17, 2005
21
1
C
C
2
2
+
s )
FN7385.3
R
+
2
C
1
2
)