LA1265

No.1820-3/15

How to use the LA1265

1. LED lighting, muting drive output, stop signal (SD).

• For LED lighting, muting drive output, stop signal, the output at

pin 8 is used.

• The voltage on pin 8, when tuned, turns from "H" to "L".

(Active-Low)

• Signal bandwidth at pin 8.

– For AM, the bandwidth depends on the CF (BFU450CN) at

pin 11. If a capacitor is connected in place of the CF, the

bandwidth will get wider.

– For FM, the bandwidth depends on the resistance across pins

9 and 20. If the resistance is increased, the bandwidth will get

narrower. R=15k

Ω makes the bandwidth approximately

120kHz.

• Sensitivity adjustment of LED, muting, stop signal.

– For FM, the semifixed variable resistor across pin 13 and GND is used.

– For AM, the semifixed variable resistor across pins 13 and 14 is used. Be sure to start adjustment for FM, and then

make adjustment for AM. For the stop signal sensitivity and FM stop signal bandwidth, the variations should be

considered and it is recommended to use the semifixed variable resistor for adjustment.

• LED lighting sensitivity setting for AM.

For the LED lighting sensitivity setting for AM, it is desirable that the IC input be 30dBµ (antenna input :

approximately 50dB/m). In this case, the value of VR1 is 30k

Ω.

Equivalent Circuit Block Diagram

Resistance across pins 9 and 20 – k

Ω

LED Lighting Bandwidth – Resistance across pins 9 and 20

S Carve

S meter