BA3308F Datasheet, PDF (6/13 Pages) Rohm – Preamps with Built-in ALC

BA3308F,BA3308FV
Technical Note
2. On playback
S. ince amplifier ch1 and ch2 are used as a NAB equalizer
amplifier at playback, a time constant circuit is established in
the NF section (1-11pin, 7-10pin) to obtain NAB
characteristics. The voltage gain at this time is determined by
the following formula:
GV = │R11＋R9/ (│＋jωC9・R9)│/R3
Obtain the necessary gain by regulating the (power-on pop
noise prevention) NAB time constant circuit in the same way
when regulating the gain at recording stage. The operating
point of the output stage (1,7pin) is fixed at 3VF.
Accordingly, even if VCC is raised to 5V or more, as in the
VMAX-VCC characteristic (Fig.13), the maximum output voltage
does not rise above 1.2V (Typ.). 4pin is grounded at playback
since ALC is not needed. For better signal-to-noise ratio
characteristics at playback, don’t use R1 and R2, which are
attached to the input pin (13pin, 9pin).
BA3308
A1
1₂3(₍9₈)₎
C1
(C2)
10μF
111(1(09))
R3
(R4)
39
R11
(R12)
4.3k
C3
(C4)
100μF
R9
(R10)
120k
31 ((77))
C9 _0.027μF
(C10)
45
C5
(C6)
10μF
INPUT
Fig.16
Fig.7
OUTPUT
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2012.06 - Rev.C