GENERAL DESCRIPTION

The TDA1072A integrated AM receiver circuit performs the active and part of the filtering functions of an AM radio receiver. It is intended for use in mains-fed home receivers and car radios. The circuit can be used for oscillator frequencies up to 50 MHz and can handle r.f. signals up to 500 mV. R.F. radiation and sensitivity to interference are minimized by an almost symmetrical design. The voltage-controlled oscillator provides signals with extremely low distortion and high spectral purity over the whole frequency range even when tuning with variable capacitance diodes. If required, band switching diodes can easily be applied. Selectivity is obtained using a block filter before the i.f. amplifier.

Features

• Inputs protected against damage by static discharge

• Gain-controlled r.f. stage

• Double balanced mixer

• Separately buffered, voltage-controlled and temperature-compensated oscillator, designed for simple coils

• Gain-controlled i.f. stage with wide a.g.c. range

• Full-wave, balanced envelope detector

• Internal generation of a.g.c. voltage with possibility of second-order filtering

• Buffered field strength indicator driver with short-circuit protection

• A.F. preamplifier with possibilities for simple a.f. filtering

• Electronic standby switch.