Datasheet LA4160 (Sanyo) - 8

LA4160
b) Power Amplifier
For the oscillation preventing capacitor connected across output pin (1) and ground, it is recommended to use a
polyester film capacitor which is excellent in temperature characteristic and frequency characteristic. It should be
noted, however, that if such a polyester film capacitor as to have a resonance point at a high frequency is used
oscillation may not be prevented.
3. Shock Noise
The shock noise which occurs from the power amplifier at the time of power supply ON/OFF is reduced by means of
the prevention circuit. However, when the starting time of the power amplifier is set earlier than that of the
preamplifier or the power supply is turned ON immediately after turning OFF, it may happen that the shock noise of
the preamplifier cannot be masked. In this case, a germanium diode is connected across pins (7) and (9), and pins (7)
and (12) respectively to make the starting time as early as possible. Even if no germanium diode is connected across
pins (7) and (12), the starting time can be made earlier, but the starting time can be made much earlier by using 2pcs.
of germanium diode.
1S188 (Germanium diode)
12
IN
9
OUT Preamp.
7 Rf [How to make the starting time of the
preamplifier earlier] 4. Power Supply for Radio’s Built-in Capacitor Microphone
Pin (13) is for the low ripple power supply. This pin cannot be used as the power supply for a block, such as radio,
which requires a large amount of current. The reason for this is that if this pin is used for this purpose, the middle
point of the power amplifier shifts, thereby causing the drop in output. However, this pin can be safely used as the
power supply for a built-in capacitor microphne.
5. Recording Muting
The recording muting at the time of recording by use of the built-in microphone is enabled by applying 1 to 5V DC
voltage to feedback pin (3) of the power amplifier. (Power amplifier : Cutoff) 6. In case of using in a radio-cassette recorder, the IC and the bar antenna must be arranged sufficiently distant from each
other to avoid the radiation of higher harmonic component at the time of output saturation of the power amplifier.
7. Pin-to-pin short causes breakdown and deterioration.
8. Load short causes breakdown and deterioration of both preamplifier and power amplifier.
VO -Vi Preamplifier
10 3 Output Voltage, VO -V 100 2 Total Harmonic Distortion, THD -% 5 1.0 clip z 5 0H 3 f= 10 Hz 2 1k Hz k 0.1 10 5
3
2
5 0.1 2 3 5 1.0 2 3 THD -VO Preamplifier
VCC = 6V
RL = 10kΩ
VG = 40dB/1kHz
Playback 5 Input Voltage, Vi -mV 10 2 3 5 VCC = 6V
RL = 10kΩ
VG = 40dB/1kHz
Playback 5
3
2
10
5
3
2
1.0
5
3
2 f = Hz
100 0.1
5
3
2 10k Hz 3 5 7 0.1 2 3 5 1kHz
7 1.0 2 3 5 Output Voltage, VO -V No.870-8/11