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Audio ICs

AM radio / FM IF stereo system IC

BA1442A

The BA1442A is an AM radio and FM IF stereo system IC developed for radio cassette players. The FM circuit is com-

prised of a differential IF amplifier, a double-balance type quadrature detector, and a PLL-type stereo MPX circuit. The

AM circuit is comprised of a local oscillator, a double-balanced mixer, an IF amplifier, a detector, and an AGC circuit.

FApplications

Radio cassette players

FFeatures

1) The “S” curve characteristic of the FM detector can

be used for upper heterodyne (“N” curve) operation.

2) Audio high cut and low cut can be used to improve the

AM fidelity.

3) A reference voltage supply is provided to ensure

good frequency stability in the shortwave bands.

4) Good FM stability.

5) Built-in damping resistor (3.3k

Ω) for the quadrature

coil.

6) The FM MPX uses a Laser Locked Loop, making

adjustment of the VCO and addition of external

components unnecessary.

7) Built-in forced monaural function for the MPX (VCO

stops, LED off).

8) VCO of the MPX is switched off during AM opera-

tion.

9) The stereo indicator pin has a constant drive cur-

rent, and a current limiting resistor is not required.

10) Few external components required.

FAbsolute maximum ratings (Ta = 25_C)

FRecommended operating conditions (Ta = 25_C)