BA7795 データシートの表示（PDF） - ROHM Semiconductor
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BA7795 Datasheet PDF : 12 Pages
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Video ICs
•Operation notes
(1) ALC level
Set the ALC level in the range – 8dBV to 0dBV by
selecting the values of resistors R1 and R2 connected
between BIAS, ALC LEVEL and GND.
The formula for approximating the value of this resistor
is as follows:
VOA =
1
2
=
1
2
•
VCC –
2
0.7
•
R1
R1 + R2
•
R1
R1 +
R2
•
VBIAS
If the ALC level setting is too low, level variation will
increase compared to that of the standerd level (VOA =
– 6dBV), and conversely, if the level is too high, the
level variation will decrease, but distortion will
increase.There is almost no temperature characteristic,
but the ALC level does vary with supply voltage (VCC)
as shown in the formula above. Use care when setting
it.
VBIAS
=
VCC –
2
0.7
R1
R1 + R2
VBIAS
Fig. 6
BIAS
ALC LEVEL
BA7795LS / BA7795FS
(2) Mute signal
Apply the mute signal shown below at power on and
off. If the muting time is short, a pop sound will be audi-
ble, particularly when the power is switched on.
VCC
(H)
(H)
MUTE CTRL
2sec or more
Fig. 7
LINE OUT
Also, be certain to apply the mute signal when switch-
ing between PB / LINE / TU. In the case of LINE / TU
switching, it is possible to suppress switching noise by
applying a time constant to the signal, in which case it
is not necessary to apply the mute signal.
(3) Recording control
Do not switch the PB and REC modes on togther. This
will cause faulty operation.
(4) Line output
The line output can drive a load resistance of up to
2kΩ. Depending on the type of load, it can cause local
oscillation (eg. large capacitive loads that draw large
current), so caution is required. In particular, when
there is a possibility that the line output will be connect-
ed to a shielded cable, or line cable, connect a resistor
of about 1kΩ in series with the output so that the
capacitive load is not directly coupled to the IC output
terminal.
10
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