LA75520K

No.A0648-9/12

Continued from preceding page.

Pin No.

Pin name

Function

Equivalent Circuit

7

9

SIF SYSTEM SW A

SIF system selection switch pins. Combining the

settings of these two pins supports four systems.

In M/N mode, the audio output level is increased by

6dB.

The internal trap is also linked to these switches.

The truth-values are as follows.

Pin7

Pin9

MODE

H

H

B/G

H

L

I

L

H

D/K

L

L

M/N

7

9

8

APC FILTER

PLL APC filter connection pin. The APC count is

switched internally in the IC.

The VCO is normally controlled by route A.

When unlocked and during weak field reception, the

VCO is controlled by route B and the loop gain is

increased.

For this APC filter we recommend a resistor of 51

Ω

and capacitor of 0.47

μF.

The buzz characteristics can be improved by

connecting a capacitor of 100pF or so between pins

5 and 8.

8

1k

Ω 1kΩ

from

APC

DET

A

B

10

VIF FREQUENCY

SW

Switch pin for selecting the IF frequency

When this pin is open, 1/2VCC exists.

VCC : 39.5MHz

Open : 38.9MHz

GND : 38.0MHz

10

11k

Ω

50k

Ω

50k

Ω

11

REFERENCE CP

INPUT

Reference signal input pin necessary for adjusting

the internal sound carrier trap, AFT, etc.

Either 4.0 or 4.43 MHz can be selected. Use the

configuration shown in example 1 when using

4.43MHz and configuration shown in example 2

when using 4.0MHz.

Since no oscillator can be configured simply by

connecting the X’tal resonator to pin 11, input the

reference signal from an external source without

fail.

11

1000pF

4.43MHz

Example 1

Example 2

11

1000pF

4.0MHz

270k

Ω

11

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