BH3854AS Datasheet, PDF (13/15 Pages) Rohm – Serial sound control IC

Audio ICs
BH3854AS / BH3854AFS
(6) Signal level setting
The following figure represents the standard setting for
the BH3854A.
S Cutoff frequency (fC1) for the bypass filter can be
changed using the attached C1.
1
fC1 =
2π C1 2kΩ
The fC1 for the recommended
constant is approximately
8kHz.
S fC2 is determined by the band of the built-in amp.
fC2 is approximately 100kHz.
The tone control is designed for a fluctuation of "15dB
(Typ.) when the frequency that you want to boost or cut
is a peak or valley of the frequency characteristics for the
filter. So be sure to design the filter while taking into con-
sideration its frequency characteristics.
(5) Tone boost
When volume attenuation increases, tone control width
will change. Reference values are listed below, but be
aware that actual values vary for different products.
(Reference values)
At attenuation of 0dB, tone control width is "15.0dB.
At attenuation of *40dB, tone control width is "13.5dB.
As indicated above, if the front volume and rear volume
input level are set so as not to exceed +6dBV (2 Vrms), the
pre-amp gain setting can be used to improve the S / N ra-
tio.
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