PRECAUTION FOR USE AND APPLICATION
1) Input Stage
The input stage of power amplifier (Equivalent circuit)
is comprised of a PNP differential pair (Q2 and Q3) pre-
ceded by a PNP emitter follower (Ql) which allows DC
referencing of the source signal to ground.
This eliminates the need for an input coupling capacitor.
However, in case the brush noise of volume becomes
a problem, provide serially a coupling capacitor to the
2) Adjustment of Voltage Gain
The voltage gain is fixed at Gv=40dB by
the resistors (R4 and R5) in IC, however, its
reduction is possible through adding Rf as
shown in Fig 2. In this case, the voltage
gain is obtained by the following Equation.
R5 + R4 +
R4 + Rf
It is recommended to use this IC with the voltage
gain of Gv=28dB or over.
3) Ripple Rejection Ratio
Adding CRIP, to terminasl 2 as shown Fig 3,
the Ripple Rejection ratio is improved from
-25dB Typ. to -45dB Typ.. (in case of CRIP=100//F).
Refer to R.R. vs. f characteristics.
R5 FROM PIN 7
Q2 Q3 I—f-^VNA/
1999. 1. 11
Revision No : 1