BD3870FS ROHM Co. Ltd., BD3870FS Datasheet - Page 10

• Manufacturer Part Number: BD3870FS
• Description: Audio Sound Processor For Home Audio
• Manufacturer: ROHM Co. Ltd.

●Description of operations
1)
Bass filter
Using external components, center frequencies and Q factors of the bass characteristics are flexible
Standard values of R3, R4 (reference)
（R1=5.6kΩ, R2=390kΩ, C1=C2=0.1µF）
IN
* The actual boost cut amount may deviate from the standard
Bass Boost Cut Amount
values in some degree.
C1
R3
Fig.5
10dB
12dB
14dB
R2
0dB
2dB
4dB
6dB
8dB
R1
+
-
R4
C2
Resistance (kΩ) * Typ.
77.64
58.90
44.02
32.20
22.82
15.36
9.44
4.78
R3
10/16
18.73
33.60
45.42
54.80
62.26
68.18
72.84
R4
0
f
Q
G(boost)
G(cut)
0
=
=
2π
R1R2R4C1C2
R1
R2
=
(
R1R2
C1
20log
+
=
G
R3
20log
+
R2
C2
(
+
R3
R1
R1
+
1
R4
)
R3
R1
R1
(
R2
(
+
R2
R2
Fig.6
R4
R2
(
(
+
(
R2
R2
ｆo
R2R3
R3
+
+
R4
)
(
C1C2
R2R3
R3
R3
R3
+
+
+
R3
R3
R4)
+
+
+
R4
R4
R4
+
+
(Hz)
R4
R4
)
)
)
+
+
)
)
G
G
C2
C2
+
+
C1
C1
ｆ
C2
C2
C1
C1
+
+
1
1
+
+
(dB)
1
1
(dB)