The ATS616 gear-tooth sensor is a peak-detecting device that uses automatic gain control and an integrated capacitor to provide extremely accurate gear edge detection down to low operating speeds. Each sensor module consists of a high-temperature plastic shell that holds together a samarium-cobalt magnet, a pole piece, and a differential open-collector Hall IC that has been optimized to the magnetic circuit. This small package can be easily assembled and used in conjunction with a wide variety of gear shapes and sizes. The gear-sensing technology used for this sensor module is Hall-effect based. The sensor incorporates a dual-element Hall IC that switches in response to differential magnetic signals created by ferrous targets. The sophisticated processing circuitry contains an A-to-D converter that self-calibrates (normalizes) the internal gain of the device to minimize the effect of air-gap variations. The patented peakdetecting filter circuit eliminates magnet and system offsets and has the ability to discriminate relatively fast changes such as those caused by tilt, gear wobble, and eccentricities. This easy-to-integrate solution provides first-tooth detection and stable operation to extremely low rpm. The ATS616 can be used as a replacement for the ATS612LSB, eliminating the external peak-holding capacitor needed by the ATS612LSB.