Video ICs
Pin No.
Pin name, function and remarks
Voltage
〈PRE GND〉
• GND for the HEAD AMP.
19
• Use this terminal for the pin 17 to pin 21 GND
connections to improve the noise characteristics.
• Connect this pin to the main GND (pin 16).
GND
〈PRE IN ch2〉
• Inputl for the playback amplifier (ch2).
The low-frequency cutoff characteristics can be
adjusted with the value of the input coupling
REC: 0V
20
capacitor.
PB: 0.7V
• The frequency characteristics can be adjusted so
that it is flat with the L value of the rotary
transformer, and the external capacitor C (100pF
etc.).
〈PRE AC-FB ch2〉
21
• AC feedback for the playback amplifier (ch2).
• The high-frequency characteristics of the playback
REC: 0V
PB: 0.8V
amplifier can be adjusted with the R value.
BA7746S / BA7746FS
Circuit diagram
—
4k
21
13k
20
〈N.C.〉
22
• Unused.
—
—
• Connect to 〈MAIN GND〉 to improve the
interchannel matching.
〈REC + B ch2〉
• REC + B (ch2).
23
• Open emitter output circuit.
REC: 4.1V
PB: 0V
• Turns on and off in accordance with the REC / PB
control signal.
〈REC + B ch1〉
• REC + B (ch1).
24
• Open emitter output circuit.
REC: 4.1V
PB: 0V
• Turns on and off in accordance with the REC / PB
control signal.
∗ The values given above are design values, they are not ratings and are not guaranteed.
6