A1425 AC couplingHall-effect sensorsICs are monolithic integrated circuits that switch in response to a rotating ring magnet and the changing differential magnetic field that occurs when a ferrous target is coupled to the magnet. The device is a true zero crossover detector: the output is precisely switched when the difference in magnetic field strength between the two Hall elements is zero. The unique dual comparator scheme provides accurate switching of the differential signal at the positive and negative zero crossing in the two regions while using hysteresis to prevent false switching. The zero-cross feature provides perfect repeatability and accuracy for spindle applications.
Changes in magnetic field strength on the device surface caused by moving targets can be sensed by two integrated Hall sensors. The sensor generates a signal that can be differentially amplified by the chip electronics. The differential design is resistant to radial vibration by rejecting this common-mode signal within the operating air gap range of the A1425. Steady-state magnets and system offsets can be eliminated using chip differential band-pass filters. The filter also provides relative protection against interference from electromagnetic sources.
The device utilizes the high-pass filter's advanced temperature compensation, sensitivity, and Schmitt trigger switch to ensure optimal operation at low frequencies over a wide air gap and temperature range.
Each Hall-effect digital integrated circuit includes a voltage regulator, two Hall-effect sensing elements, temperature compensation circuitry, a low-level amplifier, band-pass filter, Schmitt trigger, and output driver (pull-up resistors required). The board regulator allows operation from a supply voltage of 4.0 to 26.5 V. The output stage can be easily turned on to 20 mA within the full frequency response range of the device and is compatible with TTL and CMOS logic.
The device is available in a 4-pin plastic single in-line package (SIP). The packages are lead-free and feature 100% matte tin plating.
- Sensing motion of a ring magnet or ferrous target
- Integrated filter capacitors
- Wide operating temperature range
- Operates at magnetic input signal frequencies of 20 kHz to 20 kHz
- Immunity to electromagnetic interference (EMI)
- Large effective air gap
- 4.0 to 26.5 V supply voltage range
- Output compatible with both TTL and CMOS logic families
- Reverse battery protection
- Resistant to mechanical and thermal stress
- Precise true zero crosswise switching point
//www.chip100.com/