—11—

CXA1538M/N/S

2. MPX circuit

1) MPX load resistance

When power supply voltage is over 3 V, change the MPX load resistor R6, R7 from 3.3 k

Ω to 6.8 kΩ.

In this case, the output level is increased by about 6 dB.

2) Time constant of de-emphasis

Refer to the following table as the time constant is determined at C13, C14, R6 and R7.

3. AFC circuit

1) This IC has a built-in variable capacitances.

Change to the following circuit when designing J band, because the standard circuit is for W band.

2) AFC pull-in range is expanded by increasing the capacitance of standard circuit C7 3 pF.

Adjust the value of capacitance according to the set specification.

4. Auto blend circuit

This IC has a built-in auto blend circuit and a MONO switch is not required as a rule. This circuit controls

the separation in proportion to the signal level and reduces noise automatically for stereo reception below

the mid electric field when the electric field strength reaches lower than about 40 dBµ. When the electric

field strength turns below 10 to 15 dBµ, MONO operation is automatically activated.

To switch MONO mode on externally, ground pin 3 with 33 k

Ω.

50 µs

75 µs

3.3 k

Ω

0.015 µF

0.022 µF

6.8 k

Ω

0.0082 µF

0.012 µF

R6, R7

C13, C14

3pF

1µ

1µ

4.7µ

150k

9

10

22

23

33k

MONO

SW

2

3