CIRCUIT DESCRIPTION | Appendix |
Linear Audio
1Outline
This audio circuit uses a LA71598SM Super A/V 1 chip IC made by SANYO.
The major features of this IC is that REC/EE mode, PB/EE mode, SP/LP mode and audio input selection are controlled by parallel.
21 pin ( 1~9 pin, 75~80 pin, and 95~100 pin ) are related to Audio circuit.
2Audio IC : name and operation of pins
A. Features
Including PB Amp, Line Amp, REC Amp, ALC circuit, EQ switch and Auto REC bias circuit.
It is equipped with EQ switch operates in SP/LP mode respectively.
ALC level is fixed on 4dBm by values.
B. Function
Pin No. | Name | Function |
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1 | Playback Amp output | |
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2 | Capacitor switch for head resonance: in SP or LP, SW ON | |
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3 | Negative feedback of PB Amp | |
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4 | Input impedance : 120Kohm | |
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5 | Playback equalizer switch : in SLP mode, SW ON | |
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6 | 70KHz signal input for | |
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7 | AUDIO REC OUT | Recording Amp out |
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8 | GND | |
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9 | GND | |
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75 | AUDIO VCC(5V) | Vcc ( 5V ) |
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76 | Audio in | |
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77 | Port for ALC Filter | |
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78 | Audio in | |
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79 | VREF | Vref filter |
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80 | Audio in | |
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95 | GND | |
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96 | Line Amp output | |
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97 | ALC detect | |
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98 | Input to REC Amp | |
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99 | DC control voltage for | |
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100 |
| Line Amp input of PB Amp out |
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