The A1421, A1422, and A1423 are AC-coupledHall-effect sensorsICs, which contain monolithic integrated circuits that switch in response to switching by rotating ring magnets or changing differential magnetic fields generated when ferrite targets are coupled to magnets. The family also includes integrated capacitors that provide high-precision analog sensing without the need for external filter capacitors. This increases the reliability of the sensor's final solution while saving costs and components.
The magnetic field change will affect the two integrated Hall transmitters before differential amplification on the chip. The differential design is resistant to radial vibration by rejecting this common-mode signal variation within the air gap range of the device's operation. Steady-state system offsets can be eliminated using a chip differential band-pass filter with integrated capacitors. The filter also protects against interference from electromagnetic sources. The device utilizes the high-pass filter's advanced temperature compensation, sensitivity, and Schmitt trigger switchpoints to ensure optimal operation at lower frequencies over a wide air gap and temperature range.
Each device consists of one regulator and twoHall sensor, temperature compensation circuitry, a low-level amplifier, band-pass filter, Schmitt trigger, and output driver. The on-board regulator allows operation from a supply voltage of 4.0 to 26.5 V. The output stage can reach 20 mA over the full frequency response of the device and is compatible with CMOS logic.
The devices in this family differ from each other in terms of switchpoint specifications and switch polarity. The A1421 has a slight hysteresis and asymmetrical switchpoint, one of which is at the zero crossing point. The A1422 has a slight hysteresis and symmetrical switchpoints, both close to the zero crossing point. The A1423 is resistant to high vibration by its large hysteresis, which creates a symmetrical switching point away from the zero crossing point. The output polarity is shown in the Product Selection Guide table.
The versatility of options provides more flexibility to provide solutions for a variety of applications, including automotive transmission and axle speed sensing.
The device package has an ambient temperature range of -40°C to 150°C and is available in a 4-pin plastic SIP (Single In-line Package). All packages are Pb-free (suffix, –T) with 100% matte tin leadframe plating.
- Integrated tracking capacitor
- It can sense the motion of ring magnet or ferrite targets
- Wide operating temperature range
- Operates at magnetic input signal frequencies from 20 Hz to 30 kHz
- EMI/ESD resistant
- Large effective air gap
- 4.0 to 26.5 V supply voltage range
- The output is compatible with the CMOS logic family
- Reverse battery protection
- Resistant to mechanical and thermal stress
- Precision true zero-crossing switchpoint (A1421 only)
- High vibration resistance in operating mode (A1423 only)