3845

3845 AM NOISE BLANKER This noise blanker integrated circuit contains all of the necessary circuitry for adding an extremely efficient (patented) noise-blanking technique to any type of AM tuner or receiver with RF input frequencies (or a first IF) to 30 MHz. The A3845ELW and A3845SLW feature dual audio channels and are intended for AM-stereo or independent sideband applications. A high input impedance, high-gain, broadband RF amplifier permits these devices to be directly connected to the RF stage of a tuner. Internal AGC circuitry ensures that the noise detection threshold remains constant with changes in input signal level. The RF gate response time is sufficiently fast to blank the noise pulse at the output of the mixer before the IF filter. Short blanking times effectively suppress most of the interfering noise. Residual audio noise is removed by an audio sample-and-hold gate. The RF blanking time, audio gate delay time, and audio gate blanking time can all be independently adjusted to suit the particular application. These AM noise blankers are packaged in plastic SOICs and are rated for operation over the a standard temperature range of -20°C to +85°C (suffix ‘SLW’) or an extended temperature range to -40°C (suffix ‘ELW’). Data Sheet 27126B* RF IN RF BYPASS RF BIAS RF AGC AUDIO DELAY AUDIO BLANK TIME (R) NO CONNECT AUDIO BLANK TIME (C) AUDIO OUT1 AUDIO IN 1 1 2 3 4 5 6 7 8 9 10 NC DET VCC NC 20 19 18 17 16 15 SUPPLY NO CONNECT RF GATE LOW RF GATE HIGH GROUND RF B...