LA4183 View Datasheet(PDF) - SANYO -> Panasonic

Part Name

Description

Manufacturer

LA4183

2.3 W 2-Channel AF Power Amplifier for Radio Cassette Players

SANYO -> Panasonic 

LA4183

Description of External Parts

C1 (C2)

Feedback capacitor

C3 (C4)

C5 (C6)

C7 (C8)

Bootstrap capacitor

Oscillation preventing capacitor

Output capacitor

C9

Decoupling capacitor

C10

Power source capacitor

The low-range cut-off frequency is determined by the following formula:

fL = 1 / (2 π C1vRf), fL: Low-range cut-off frequency

Rf: Feedback resistor

(50 Ω embedded + Rf externally connected)

The frequency, however, affects the starting time in conjuction with

decoupling capacitors. Therefore, it is necessary to determine it after a

full review of the required low-frequency range and other similar

conditions.

The output at low frequencies depends on this capacitor. If the capacity

is decreased, the output at low frequencies goes lower. 47 µF min. is

required.

Use polyester film capacitor which is good in temperature characteristic

and frequency characteristic. Aluminum electrolytic capacitor or

ceramic capacitor causes oscillation at low temperatures.

The low-range cut-off frequency is determined by the following formula.

fL = 1 / (2π C7vRL), fL: Low-range cut-off frequency

RL:Load resistance

When using bridge-connected, double the capacitance to obtain

equivalent low-range frequency characteristics to those in a 2-channel

application.

Used for the ripple filter. Since the rejection effect is saturated at a

certain capacity, it is meaningless to increase the capacity more than

needed.

This capacitor, being also used for the time constant of the muting

circuit, affects the starting time.

Application Circuits

1. Voltage gain adjustment

. Stereo

The voltage gain depends on built-in-resistors R1 (R2), R3 (R4) as follows:

R3 (R4)

VG = 20 log

R1 (R2)

[dB]

If the IC is used at a voltage gain less than this, the following

equation with Rf added applies.

R3 (R4)

VG = 20 log R1 (R2) + Rf [dB]

where R1 (R2) = 50 Ω typ.,

R3 (R4) = 10 kΩ typ.

. Bridge

The following shows the bridge amplifier configuration, where ch1 operates as a non-inverting amplifier and ch2 as an inverting

amplifier.

No.887-4/11

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