TDA7000 FM Radio Receiver Circuit Using Tuning Capacitor
GENERAL DESCRIPTION The TDA7000 is a monolithic integrated circuit for mono FM portable radios or receivers where a minimum on peripheral components is important (small dimensions and low costs).
The IC has an FLL (Frequency-Locked-Loop) system with an intermediate frequency of 70 kHz. The i.f. selectivity is obtained by active RC filters. The only function which needs alignment is the resonant circuit for the oscillator, thus selecting the reception frequency. Spurious reception is avoided by means of a mute circuit, which also eliminates too noisy input signals. Special precautions are taken to meet the radiation requirements.
The TDA7000 includes the following functions:
· R.F. input stage
· Local oscillator
· I.F. amplifier/limiter
· Phase demodulator
· Mute detector
· Mute switch
This circuit is typical using with a LM386 for the audio power amplifier.
With a minimum on peripheral components we can build a high performance and small FM radio receiver .
FM Tuning Capacitor (15-30pF)
5¾ (5.75) Turns of 23 swg enamelled copper wire close-wound on a 3mm diameter. (≈78nH)
4¾ (4.75) Turns of 23 swg enamelled copper wire close-wound on a 3mm diameter. (≈70nH)
Telescopic antenna or 1m wire
Mute Switch (mute is disabled when switch is on.)
TDA7000 FM Receiver Coils
L1:Tuning Coil, 5¾ (5.75) Turns of 23 swg enamelled copper wire close-wound on a 3mm diameter.
L2: Antenna Coil, 4¾ (4.75) Turns of 23 swg enamelled copper wire close-wound on a 3mm diameter.
TDA7000 QUICK REFERENCE DATA
Supply voltage range (pin 5)
2.7 to 10 V
Supply current at VP = 4.5 V
typ. 8 mA
R.F. input frequency range
1.5 to 110 MHz
Sensitivity for -3 dB limiting
(source impedance: 75 Ω; mute disabled)
typ. 1.5 mV
Signal handling (e.m.f. voltage)
(source impedance: 75 Ω)
typ. 200 mV
A.F. output voltage at RL = 22 kΩ
typ. 75 mV
TDA7000 FM Radio Using Tuning Capacitor