Audio ICs
FAttached components
(1) Input buffer
(2) Bass filter
BH3857AFV
S The input impedance is 47kΩ.
S A buffer if R and C1 are not present.
S 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.
S A band-pass filter is constructed using a multiple-feedback type active filter.
f0 can be changed using the C valve.
(Theoretical formula)
674