LA1143 Sanyo Semiconductor Corporation, LA1143 Datasheet

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... Ordering number : EN1140D Overview The LA1143 system IC designed for FM car stereo receivers. It features versatile muting characteristics and allows receiver designers to realize the muting performance according to their design concept. Since the muting characteristics can be varied with a switch or a semi-fixed resistor, DX-Local switching will be accomplished with ease ...

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... Signal meter output (4) V 15-100 AGC output (1) V 16-0 AGC output (2) V 16-100 Offset voltage (1) V 7-13 Offset voltage (2) V 8-13 LA1143 Conditions max Pin 12 max Pin 12 Ta=25°C Ta=70°C Pin Pin 2 Pin 3 Pin 6 Pin 5 Pin 13 Pin 14 Pin 15 Pin 16 ...

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... AC Test Circuit Muting Characteristic The muting operation in the LA1143 is performed preamplifier, the gain of which varies continuously with control current, and a muting drive circuit which supplies the control current. The gain preamplifier decreases with increasing gain control current applied to pin 6. However, the gain does not decrease further when the control current reaches approximately 120µ ...

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... These characteristics investigated by using an actual receiver are shown on the curves below. The general method to adjust the muting circuit of the LA1143 set the signal input level required to actuate the muting circuit with the adjust the slope of the curve for the muting attenuation vs. antenna signal input with the R ...

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... Muting by varying R 14-6 Proper cares in using LA1143 1. The detector transformers should be designed to develop a quadrature signal (pin 11) of higher than 175mVrms (about 105dBµ) under high antenna signal input. If the quadrature signal strength is less than 125mVrms, the muting drive output can not decrease to zero even in a strong signal strength. Furthermore, when the quadrature signal strength lies between 125mV and 175mV, the muting drive output may move from zero to plus under high temperature conditions ...