BH3854AFS View Datasheet(PDF) - ROHM Semiconductor

Part Name

Description

Manufacturer

BH3854AFS

Serial sound control IC

ROHM Semiconductor 

Audio ICs

FOperation notes

(1) Operating power supply voltage range

As long as the operating power supply voltage and ambi-

ent temperature are kept within the specified range, the

basic circuits are guaranteed to function, but be sure to

check the constants as well as the element settings, volt-

age settings, and temperature settings. Also, please take

into consideration internal IC resistance dispersion

(approx. "20%) and temperature fluctuation when mak-

ing settings for IC internal resistance, attachment resis-

tance, capacitor gain, or frequency.

(2) Primary amp

(1) The input impedance is 47kΩ.

(2) A buffer if R and C1 are not present.

(3) The gain can be set by R and the 20kΩ.

GVC = (R + 20kΩ) / R

Note: Set C2 (input coupling) and C1 (used to set the gain) depending on

the frequency band used.

(3) Bass filter

BH3854AS / BH3854AFS

(1) The BPF is composed of a multifeedback active filter.

fo can be varied according to the value of C.

(theoretical equation)

1

fO =

2π

1

1

2

R1R2C1C2

R2

G=

5kΩ

*1

C1

1)

C2

(When R1 = 11.5kΩ, R2 = 85kΩ, C1 = C2 = C)

5.1 10 –6

fO =

Q 1.36 G 8.5

C

Q

R1

1

*1

2

(C1 ) C2)

R2C1C2

Note: Filter gain is calculated using the equation above. Total output

gain is the sum of the gain for each of the internal circuits.

(4) Treble filter

644

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