BA3842 Просмотр технического описания (PDF) - ROHM Semiconductor
Номер в каталоге
Компоненты Описание
производитель
BA3842 Datasheet PDF : 13 Pages
| |||
Audio ICs
BA3842F
(6) Filter for preset equalizer
(1) Low band
The low cutoff frequency fc of each mode is given by the
following equation :
fc = 1 / 2πCR = 1 / (2π C 15.6kΩ)
When C = 0.22µF,
fc 46 (Hz)
The fc value can be changed to make slight changes in
the boost and cutoff gain of each mode.
(2) High band
The high cutoff frequencies fc of each mode are given by
the following equation :
fc = 1 / 2πCR
When C = 2200pF,
ROCK : R = 8.0kΩ
fc 9.0 (kHz)
JAZZ : R = 10.7kΩ
fc 6.8 (kHz)
CLASSIC : R = 14.9kΩ fc 4.8 (kHz)
BGM. POP : R = 17.4kΩ fc 4.2 (kHz)
The fc values can be changed to make slight changes in
the boost and cutoff gain of each mode.
Note:
If a high or low fc value is changed, the gains of all modes
will change. The gain cannot be changed for only one
mode.
(7) ALC
The band of ALC detection can be changed with the val-
ue of C4. It must be adjusted appropriately for the dynam-
ic bass boost fO. In the example application circuit C4 =
0.1µF, thus fc = 1 / 2πC4 (R5 / / R6 / / R7)
160 (Hz)
The detection wave is dually rectified. In the example ap-
plication circuit, it is 1.3Vrms, but if the resistors R8 and R9
are connected as shown below, it will lower the ALC level.
Adjust the ALC level as needed. The detection band at
this time is :
fc = 1 / 2πC4 (R5 / / R6 / / R7 / / R8 / / / R9)
(8) Attack time and release time
Adjust the attack and release times with the resistors and
capacitors connected to the ALCC pin. The attack time
is determined by R10 (1kΩ) and C5, and the release time
is determined by R11 and C5. If the value set for C5 is below
4.7µF, the ALC level may become unstable.
573
Share Link: 