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CS209A Proximity Detector
The CS209A is a bipolar monolithic integrated circuit for use in metal detection/proximity sensing applications.
The IC (see Figure 1) contains two on−chip current
regulators, oscillator and low−level feedback circuitry, peak detection/demodulation circuit, a comparator and two complementary output stages.
The oscillator, along with an external LC network, provides controlled oscillations where amplitude is highly dependent on the Q of the LC tank.
During low Q conditions, a variable low−level feedback circuit provides drive to maintain oscillation.
The peak demodulator senses the negative portion of the oscillator envelope and provides a demodu...