LA3160 View Datasheet(PDF) - SANYO -> Panasonic

Part Name

Description

Manufacturer

LA3160

2-Channel Preamplifier For Car Stereo

SANYO -> Panasonic 

LA3161

Sample Application Circuit 1 : Preamplifier for Car Stereo

Function of External Parts

C2, C4 are input coupling capacitors. In NAB equalizer amplifier, the gain at low frequencies is high and 1/f noise

inside the IC is emphasized as output noise. Therefore, if the reactance of capacitor at low frequencies is increased,

the dependence of 1/f noise on the signal source resistance causes the output noise voltage to deteriorate, and the

value of reactance must be made small enough as compared with the signal source resistance. C2, C4 also influence

the operation start time and the adequate value of these capacitors is 10µF. (Since C2, C4 of less than 4.7µF make the

operation start time longer, use C2, C4, of 4.7µF or more).

C5, C11 are NF capacitors. The lower cut-off frequency depends on the value of these capacitors.

If the lower cut-off frequency is taken as fL :

C5 (C11) = 1/2π · fL · R2 (R7)

If the value of this capacitor is made larger, the operation start time of amplifier is more delayed. The adequate value

of capacitor is 47µF.

The frequency characteristic of the equalizer amplifier depends on C6 and R4, R3 (C10 and R5, R6).

The time constants to obtain the standard NAB characteristic are as shown below.

Tape speed

C6 (R3 + R4)

R3 C6

9.5cm/s

3180µs

90µs

4.75cm/s

1590µs

120µs

C8 is bias capacitor for the power line. C8 of 47µF is inserted at a point as close to the power supply pin (pin 4) as

possible.

C1, C3 are for preventing radio interference in the strong electric field, interference attributable to engine noise, and

blocking oscillation at the time of large amplitude operation. The adequate value of C1, C3 is approximately 1000pF.

C7, C9 are output coupling capacitors. The adequate value of C7, C9 is 10µF.

No.573–3/7

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