TDA4362X

The TDA4362X includes a 2-Pin oscillator (1.LO) with sym. input, buffered output and a double balanced mixer with symmetrical input. This stage converts the AM-Inputsignal to a 1. IF, which is much higher (~10 MHz) than the input frequencies. The 1. LO operates as a LC-varactor tuned oscillator in the same 100 MHz range like the FM-Tuner oscillator ( e.g. TUA 4310 X) . So the same peripherial elements can be used.Depending on the signal strength the prestage AGC controls a MOSFET-prestage amplifier.

The 1. IF passes an external selectivity and is then converted in a symmetrical double balanced mixer to the 2. IF.

The 2. LO operates as an amplifier for an external forcing signal.

The 2. IF signal passes an automatic gain controlled IF amplifier and is then demodulated to the AF in a quasisynchronous-demodulator.

For AM-Stereo application a gain controlled output of the 2. IF is available.

The TDA4362X is prepared to work with a PLL in the 100MHz range. When applied with a standard AM-PLL the oscillator frequency divided by 6 or 10 has to be used. In this case a higher phase noise is to be expected.