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High-quality FM receiver circuit based on CXA1019 integrated circuit

23rd Jan. 2014

As shown in Figure. CXA1019 is a bipolar silicon chip FM / AM radio receiver IC from Sony. Built-in CXA1019 interior design circuits include RF amplifiers, mixers, oscillators, IF amplifier, quadrature detector circuit, adjust the LED drive some electronic volume control, such as FM detector IC is only used in this circuit. The IC can supply anything that can drive an 8 ohm speaker between 3 to 7V DC.

Circuit diagram

1302323O2-0

 CXA1019 FM receiver circuit

Circuit description

Inductor L1, L2 and capacitors C4, C6, C7 of the oscillator circuit forms part of the oscillator built in the IC. If the 15-pin output is grounded through the resistor R1. C1 is R1 AC bypass capacitor. Capacitor C16 is the ripple filter. LED D1 is an indicator. Built-in stage detector output (pin24) plus built-in AF amplifier stage via a capacitor C19, pots R2 and capacitor C18 input (pin 25). R2 can be used as volume control, because it controls the input of audio amplifier stage. Audio output from capacitors couples C15 to C14 and the speaker is a noise bypass capacitor. C5 is just a power supply filter, which couples C20 IC FM radio antenna input (pin13). Use ceramic filters 10MHz FM IF output, 15-pin, for FM IF input pin18. Capacitor C2 is used to bypass the noise audio power amplifier IC internal parts. The output of this amplifier section is about 500MW. Capacitors C1 and transformer T1 are the IC FM discriminator circuit. Resistor R3 is a part of the AGC feedback capacitance.

 

 Tips:

  •  With good quality printed circuit board assembly circuit.
  •   Winding wire For L1, 2.75 22 with a diameter of 5mm plastic.
  •   As L2, 3.75 enameled copper wire wrapped ring 22 5mm plastic.
  •   T1 is an FM IF transformer.
  •   CF1 of the FM 10.7MHz ceramic filters
  •   C4 is a double-gang FM tuner 30pF capacitor.
  •   The circuit can be powered from a 3V to between any 7V DC.
  •   Use battery-powered circuitry to reduce noise and improve performance
  •   If you use a battery eliminator, then it must be well regulated and free from noise.
  •   K1 can be a 3W, 8 ohm speakers.
  •   A1 can be a 100 cm long whip antenna.

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