Sony PCS-1500 Service Manual page 122

3-2. Circuit Description of the Respective Boards
[AUANA block]
The AUANA block consists of the AD/DA-converter (IC600), operational amplifiers (IC601 to IC603),
Audio Selector (IC604), Audio Amplifier (IC605) and mute circuit. (Refer to Fig. 3-19.)
AD/DA Converter(IC600)
\PWDA
from CPU BLOCK
\PWD_AK \PWAD
from VIDDA BLOCK(IC352)
MIC_SEL1,2
from NETIF BLOCK(IC750)
SP_MUTE
OUT_MUTE
The audio signal that is input from the built-in microphone (CN601), MIC1 connector and MIC2 connec-
tor is amplified by the operational amplifier (IC601) and enters the Audio Selector (IC604). (The MIC1
and MIC2 signals are mixed together.) The Audio Selector (IC604) selects the signal in accordance with
the port output from the VIDDA block (IC352). The level of the selected audio signal is adjusted by the
level adjustment circuit consisting of the operational amplifier (IC602), and the signal is converted to a
balanced signal that is suited to the A/D converter (IC600). The level adjusted signal enters the left
channel of the A/D converter (IC600). The audio signal that is input from the AUDIO-IN connector is
converted to a balanced signal having the suitable level by the level adjustment circuit consisting of the
operational amplifier (IC602), and is input to the right channel of the A/D converter (IC600).
The DC power of about 5.4 V is supplied to the built-in microphone (CN601). The DC power of about
3 V is supplied to the MIC1 connector and MIC2 connector as it is plug-in powered on the audio signal.
The output audio signal is output from the left channel of the D/A converter (IC600), amplified by the
operational amplifier consisting of the operational amplifier (IC603), and feeds the AUDIO-OUT connec-
tor. AUDIO-OUT can be muted by the MUTE circuit that is controlled by the port output
"OUT_MUTE" of the NETIF block (IC750).
The audio output signal for the built-in speaker is output from the right channel of the D/A converter
(IC600), amplified by the audio amplifier (IC605) and drives the speaker (CN602). The speaker output
can be muted by the MUTE circuit that is controlled by the port output "SP_MUTE" of the NETIF block
(IC750).
The operating clock signal (4.096 MHz) of the AD/DA converter (IC600) is supplied from the Serial
Timing Generator (IC501). The AD/DA converter (IC600) can be reset by the "PWD_AK" signal that is
supplied from the CPU block.
The AD/DA converter (IC600) operates on the +3.3 V-2 power supply voltage. The other circuit oper-
ates on the +10 V power supply voltage.
3-32
Vcc = +3.3V-2
AK4520
AINL+
LevelAdjuster
AINL-
Op. Amp(IC602)
AINR+
LevelAdjuster
AINR-
Op. Amp(IC603)
AMP
AOUTL
Audio Amp(IC605)
AOUTR
MUTE
2
Fig. 3-19 AUANA Block
Vcc =+10V
Audio Selector(IC604)
NJM2521
Mixer
00
01
1x MIC_DE
from CN902(DE-54)
NotUsed
MUTE
NJM2073
AMP
Power
Supply
AMP MIC1
AMP MIC2
Op. Amp(IC601)
AMP
MIC_IN
Power
MIC_PWR
Supply
AUDIO IN
AUDIO OUT
SPOUT_A,B
from CN600
(Ext. MIC.)
from/to CN601
(MIC. Unit)
from/to CN401
to CN602
PCS-1500/1500P