The A1421, A1422, and A1423 are AC-coupled Hall-effect sensor ICs that contain monolithic integrated circuits that switch and switch in response to a changing differential magnetic field generated by rotating a ring magnet or when a ferrite target is coupled to a magnet. The devices also include integrated capacitors that provide high-precision analog sensing without the need for external filtering capacitors. This increases the reliability of the sensor's final solution while also saving costs and components.
The magnetic field change will affect the two integrated Hall transmitters before differential amplification on the chip. The differential design resists radial vibration by rejecting this common-mode signal change within the device's operating air gap. Steady-state system offsets can be eliminated using a chip differential bandpass filter with integrated capacitors. The filter also protects against interference from electromagnetic sources. The device utilizes the advanced temperature compensation capabilities, sensitivity, and Schmitt flip-flop switch points of high-pass filters to ensure optimal operation at lower frequencies over a wide air gap and temperature range.
Each device includes: a voltage regulator, two Hall sensors, temperature compensation circuitry, a low-level amplifier, bandpass filter, Schmitt flip-flops, and output drivers. 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 range of the device and is compatible with CMOS logic circuitry.
The devices in this family differ from each other in terms of switch point specifications and switching polarity. The A1421 has a slight hysteresis and asymmetric switching points, one of which is at the zero crossing point. The A1422 has a slight hysteresis and symmetrical switching points, and both switching points are close to the zero crossing point. The A1423 resists high vibration through its large hysteresis, which establish a symmetrical switching point away from the zero crossing point. The output polarity is shown in the Product Selection Guide table.
The variety of options allows for greater flexibility in providing solutions for a variety of applications, including automotive transmissions and shaft speed sensing.
The device package has an operating ambient temperature range of -40°C to 150°C and is available in a 4-pin plastic SIP (Single Line In-Line Package). All packages are lead-free versions (suffix, –T) with 100% matte tin plating on the pin frame.
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集成跟踪电容器
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可感测环形磁铁或铁氧体目标的运动
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较宽的工作温度范围
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可在磁性输入信号频率为 20 Hz 至 30 kHz 的条件下工作
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抗 EMI/ESD
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较大的有效气隙
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4.0 至 26.5 V 电源电压范围
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输出兼容 CMOS 逻辑系列
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电池反接保护
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抗机械和热应力
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精密的真过零开关点（仅限 A1421）
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在运行模式下抗高振动（仅限 A1423）