la4820m Sanyo Semiconductor Corporation, la4820m Datasheet - Page 13

• Manufacturer Part Number: la4820m
• Description: Monaural Speaker/stereo Headphone Power Amplifier
• Manufacturer: Sanyo Semiconductor Corporation

c C8 (0.33 µF to 0.1 µF):
c C9 (0.1 µF to 0.01 µF):
c C10 (0.47 µF to 2.2 µF):
c C11 (22 µF to 47 µF):
c C12 (220 µF to 10 µF):
Description of Each System
1. Ripple filter
c Used when the ripple level on the power line is high and a high ripple rejection ratio is needed in the amplifier block. When not
c When using a ripple filter, the output Tr V
2. MONO amplifier block
c Adds the channel 1 and channel 2 inputs and outputs the addition in single-channel BTL operation.
c Non-clipping and output limiter circuits are built in as output control functions.
1)
2)
3. HzP amplifier block
c Pin 11 (PWRC CONT) can be used to create a common amplifierless configuration. (This configuration is recommended when
c The output control function PVSS (Peak Volume Select System) controls the output level by means of ALC configuration
Descriptional of Each Block Switching
1. Power mute switch
c When an application set is microcomputer controlled, the power supply must be turned on/off with mute turned on in order to
needed, pins 1, 23 and 24 must be left open. (Refer to Sample Application Circuit 2.)
be adjusted according to the power supply ripple level.
Power supply
there is a possibility that the jack common pin may be shorted with GND in an application set.)
(keeping user-friendly volume level, etc.); the level can be varied by an external resistor.
prevent shock noise. Even if an application set is not microcomputer controlled, the mute-on time for power-on can be set by
the capacitance of the external capacitor on pin 2.
The output limiter detects the output level from the pin 20 detection input and controls the output level by means of ALC
configuration. Adjust the level according to the speaker impedance, the power dissipation capability of the power supply, etc.
If not needed, the pin 20 detection input must be left open.
The non-clipping circuit prevents large input-caused output clipping (degradation in sound quality). The detection input is
connected internally, while the output level depends on the V
Mute-on condition
Mute-on time 6
VS
2
% 0.1 V
Capacitance
The V
Coupling capacitor for PVSS detection input and HzP power output.
Not needed when PVSS is not used.
Capacitor for SP/HzP switching smoothing (charging/discharging).
Capacitor for blocking common amplifier oscillation.
Polyester film or ceramic capacitor (of which capacitance specified must be independent of
temperature changes) is recommended. Not needed when common amplifier is turned off.
Ripple filter output capacitor. Also functions as oscillation blocking capacitor.
Power supply capacitor.
* Use of a Tantalum capacitor is recommended for C11 and C12, because electrolytic
capacitors cause the high-region impedance to increase at low temperatures.
1.5 µA
CE
CE
voltage and the pin 1 C1 capacitance (LPF capacitor for the reference bias) must
voltage must be adjusted to be ripple bottom peak voltage +0.1 V or more.
0.75 V
LA4820M
CC
2 voltage and is controlled by means of ALC configuration.
Mute time
Pin 2 charging
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