TDA7000 FM radio receiver 88-108 MHz circuit + LM386. Simple circuit of easy-to-assemble home-built DIY FM radio receiver with TDA7000 dedicated circuit and amplifier for Lm386 CI, although it is a relatively old chip with mono reception. Assembling an FM radio is always something interesting to the electronics enthusiast. In the circuit includes the part of the receiver based on the chip tda7000 and amplifier for CI LM386n, soon we will have our radio receiver of FM using few components. The tuning is done by varicap, simply by activating a potentiometer to tune the stations, not requiring complex circuits with coils and capacitors.

The new circuit is the TDA7000 which integrates a mono FM radio all the way from the aerial input to the audio output. External to the IC are only one tunable LC circuit for the local oscillator, a few inexpensive ceramic plate capacitors and one resistor. The TDA7000 dramatically reduces assembly and post-production alignment costs because only the oscillator circuit needs adjustment during manufacture to set the limits of the tuned frequency band. The complete FM radio can be made small enough to fit inside a
calculator, cigarette lighter, key-ring fob or even a slim watch. The TDA7000 can also be used as receiver in equipment such as cordless telephones, CB radios, radio-controlled models, paging systems, the sound channel of a TV set or other FM demodulating systems.

Schematic of the TDA7000 FM radio receiver 88-108 MHz circuit diagram

Until now, the almost total integration of an FM radio has been prevented by the need for LC tuned circuits in the RF, IF, local oscillator and demodulator stages. An obvious way to eliminate the coils in the IF and demodulator stages is to reduce the normally used intermediate frequency of 10.7MHz to a frequency that can be tuned by active RC filters, the op amps and resistors of which can be integrated. An IF of zero deems to be ideal because it eliminates spurious signals such as repeat spots and image response, but it would not allow the IF signal to be limited prior to demodulation, resulting in poor signal-to-noise ratio and no AM suppression. With an IF of 70kHz, these problems are overcome and the image
frequency occurs about halfway between the desired signal and the center of the adjacent channel. However, the IF image signal must be suppressed and, in common with conventional FM radios, there is also a need to suppress interstation noise and noise when tuned
to a weak signal. Spurious responses above and below the center frequency of the desired station (side tunings), and harmonic distortion in the event of very inaccurate tuning must also be eliminated.
We have now developed a mono FM reception system which is suitable for almost total integration. It uses an active 70kHz IF filter and a unique correlation muting circuit for suppressing spurious signals such as side responses caused by the flanks of the
demodulator S-curve. With such a low IF, distortion would occur with the ±75kHz IF swing due to received signals with maximum modulation. The maximum IF swing is therefore compressed to ±15kHz by controlling the local oscillator in a frequency-locked loop
(FLL). The combined action of the muting circuit and the FLL also suppresses image response.

Printed Circuit Board Suggestion for FM Radio Receiver lm386 tda7000

Download files
Datasheet  TDA7000

Download files of the PCB in PDF and PNG beyond the Gerber files for making the Board.

Mirror

Includes 2 versions, one with double-sided PCB and RF amplifier and one with single-sided PCB.