LA4500 Просмотр технического описания (PDF) - SANYO -> Panasonic
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LA4500 Datasheet PDF : 12 Pages
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LA4500
Description of External Parts
C1 (C1) Feedback capacitors
Related to low roll-off frequency fL for –3dB (100µF, fL=60Hz).
A capacitance value of 47µF to 100µF is recommended. Increasing the capacitance value makes the
starting time (ts) later. Decreasing the capacitance value makes the starting time (ts) earlier.
C3 (C4) Bootstrap capacitors
Decreasing the capacitance value lowers output at low frequencies. A capacitance value of 47µF to
100µF is recommended.
C5 (C6) Oscillation blocking capacitors
Polyester film capacitor, being excellent in temperature characteristic, frequency characteristics, is
recommended.
C7 (C8) Output capacitors
Related to low roll-off frequency and output at low frequencies. BTL applications normally require
output capacitors.
C9 (C10) Switching distortion compensating capacitors
Compensates switching distortion which occurs at a high frequency of 10kHz. Ceramic capacitor of
0.01µF is recommended. If no problem arises in terms of radio-casette recorder design or tone, it is
unnecessary to use these capacitors.
C11
Filter capacitor (A)
Ripple filter circuit provided in power supply line. A capacitance value of 220µF is recommended.
Ripple rejection SVRR starts to be saturated at 47µF. The starting time and pop noise generated at the
time of power supply ON must be considered when fixing the capacitance value. A capacitance value of
100µF to 220µF is usable.
C12
Filter capacitor (B)
Ripple filter circuit provided in bias circuit. A capacitance value of 100µF is recommended. 3V suffices
the breakdown voltage of this capacitor. This capacitor is for ripple rejection at transient state and rejects
noise “buzz” generated when the above-mentioned filter circuit provided in power supply line is satu-
rated due to large ripple and supply voltage drop induced at the time of start of the motor connected to
power supply line. If the motor is satisfactory in performance and the power supply regulation including
ripple is 500mVrms or less, it is unnecessary to use this capacitor. If noise “buzz” is not offensive to the
ear, it is unnecessary to use this capacitor. In this case, other basic performances are not affected ad-
versely.
Feaures of IC Contents and Functions of Other Pins
(a) Since the input circuit uses PNP transistors and the bias voltage is set nearly equal to 0, no input coupling
capacitor is required, thereby enabling direct coupling. However, if slider contact noise of the variable resistor
presents any problem, connect a capacitor in series with input.
(b) Various ideas embodied in the idling circuit enable reduced ICCO and prolonged battery life. Since the non-
operating level of the idling circuit is made equal to that of the amplifier, crossover distortion does not worsen at
the time of reduced voltage.
(c) The open loop voltage gain is lowered and the negative feedback amount is made small to assure stable opera-
tion. Radiation to the radio-frequency stage is made less by soft clipping.
(d) Capacitors for oscillation compensation are contained as a means of reducing the number of external parts.
10pF×2 and 2pF×2 are used. Hig roll-off frequency fH (–3dB point) depends on these capacitance values.
(fH=28kHz)
(e) A thermal shutdown (THD) circuit is contained to prevent the IC from being destroyed by abromal heat genera-
tion attributable to insufficient heat dissipation. Pin (11) is used as THD control pin. Biasing pin (11) externally
makes the operating temperature lower ; and connecting a resister across pin (11) and (10) makes the operating
temperature higher. If pin (11) is connected to GND, the thermal shutdown circuit stops operating.
(f) The pin assignment is carefully considered so that no destruction takes place even if power supply is applied at a
state where adjacent pins are shorted by solder bridge, etc. Even 180°C-rotated insertion causes no destruction.
(g) Collector pins (5), (16) and base pins (6), (15) for predrive can be conveniently used in applications. For oscilla-
tion compensation occuring when operated at a lowered gain, connect a capacitor across the pins (4) and (6) and
a capacitor across pins (15) and (16). For fH compensation occuring when operated at a lowered gain, connect a
capacitor across pins (4) and (6) and a capacitor across pins (17) and (15). Further soft clippling and prevention
of waveform distortion at high frequencies are attained by connecting a series circuit of diode (DS442) and
resistor (10kΩ) across pin (6) and GND and the same across pin (15) and GND.
Continued on next page.
No.1164–4/12
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