BH3868BFS-E2 Rohm Semiconductor, BH3868BFS-E2 Datasheet - Page 20

• Manufacturer Part Number: BH3868BFS-E2
• Description: IC AUD SOUND PROCESS SSOP-A32 TR
• Manufacturer: Rohm Semiconductor
• Type: Volume Controlr

Specifications of BH3868BFS-E2

• Applications: Automotive Audio
• Mounting Type: Surface Mount
• Package / Case: 32-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Audio ICs
(2) Setting of Phase Shifter
This IC contains two stages of phase shifters. If none of two stages of phase shifters are not used, the pseudo-stereo
function is also unavailable. If only one of these phase shifters is used, the normal of pseudo stereo may be spoiled.
(3) Surround and Pseudo-Stereo Operation
∆
P
E : Surround effect
1) Surround
2) Pseudo stereo
The above-mentioned figures show the block diagram of surround and pseudo stereo ICs. The characteristics of
surround and pseudo stereo can be varied by changing the effect. Moreover, the number of states of phase shifters can
be increased by turning on a switch of loop. However, an operation becomes unstable if the gain of effect is increased
while the switch of loop remains turning on. Therefore, the effect should be approximately 6 dB. Upon switching the
surround and pseudo stereo to each other, be sure to turn on a switch at the stereo surround side of SSTE to prevent a
shock sound.
t
1
1
∆
P
t
2
2
: Time delayed by a phase shifter
: Attenuation made by a phase shifter
Rch
Lch
28
5
Rch
Lch
2 (L+R)
28
5
L−R
R
R
2
1
Configured
externally
B, P, F
18k
18k
C
1
Phase shifter
29
∆ t
1
× P
R
0.1µ
Phase shifter
1
3
+
−
∆ t
1
18k
× P
Phase shifter
1
∆ t
2
× P
Phase shifter
2
∆ t
2
× P
Effect control
2
R
R
2
1
× E
18k
18k
C
Effect control
1
30
× E
0.1µ
R
3
−
+
LPF
18k
LPF
+
+
+
+
+
−
+
+
+
+
21
12
Resistance in IC is 18kΩ (Typ.).
φ = −2tan
+
−
L
R
OUT
OUT
21
12
− 1
= L + ∆ t
= R − ∆ t
( 2πfR
L
R
OUT
OUT
1
1
C
= L + ∆ t
= R − ∆ t
1
∆ t
1
∆ t
)
2
P
2
BH3868BFS
P
1
P
1
P
2
1
2
1
∆ t
(L−R) E
∆ t
(L−R) E
2
P
2
P
1
P
1
P
2
2
(L+R) E
(L+R) E
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