The DRV5021A1QDBZR: That means it remains a valid line item for new designs and production builds, not a part you need to qualify a replacement for.
Magnetic thresholds and what they decide
The DRV5021A1QDBZR switches on at 4.4 mT (south pole) and releases at 0.4 mT. That 4.0 mT hysteresis prevents chatter near the threshold — useful when the magnet moves slowly or the assembly vibrates. For a typical N35 neodymium disc, 4.4 mT is roughly 3–5 mm air gap; the actual distance depends on magnet size and orientation. Because it is a unipolar switch, only a south-pole field triggers the output. A north pole of any strength is ignored. That simplifies the magnet polarity in assembly — no risk of a flipped magnet causing a false trigger.
Temperature range and compensation
The temperature-compensated design keeps the switch point stable across that span — a basic uncompensated Hall sensor can drift 20–30% over temperature, which would change the detection distance.
Supply and output — driving a microcontroller input
The open-drain output sinks up to 30 mA — enough to drive a small LED or a logic input directly. Supply current is 2.8 mA typical, low enough for battery-powered sensing.
Package and hand-soldering
SOT-23-3 surface-mount package — three pins, 0.95 mm pitch. Hand-solderable with a fine-tipped iron and some flux; the pads are large enough for a hobbyist to work with. Available in cut tape for small quantities, not just full reels.