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us1881
US1881 is mixed‑signal CMOS bipolar hall latch from Melexis, integrating hall element, voltage regulator, chopper‑stabilized amplifier, Schmitt trigger and open‑drain output driver inside single chip. Chopper‑stabilization eliminates offset drift, delivers stable magnetic switching threshold over full temperature range.
TO‑92‑UA version latches output low by S‑pole magnetic field, reset to high‑impedance by N‑pole; SOT‑23 version has opposite magnetic polarity response. Supply voltage 3.5‑24V suits 5V,12V,24V system. Open‑drain output requires external pull‑up resistor, max sink output current 50mA, maximum switching frequency 10kHz.
Three temperature options for different working conditions: E grade ‑40℃~+85℃ for consumer; K grade ‑40℃~+125℃ for general industrial; L grade ‑40℃~+150℃ for high‑temperature automotive environmentmedia.digi.... Pinout(TO‑92 UA): Pin1 VDD, Pin2 GND, Pin3 OUTMelexis. RoHS compliant.
Typical applications include brushless DC motor commutation, encoder speed counting, rotary position detection, linear position sensing, non‑contact solid‑state switch, automotive sensor modules and industrial automation. Add 0.1μF decoupling capacitor between VDD and GND for anti‑interference performance.
1. Bipolar Latch‑Type High‑Sensitivity Hall‑Effect Sensor US1881 is a bipolar hall‑effect latch IC manufactured by Melexis, built on mixed‑signal CMOS chopper‑stabilized technology. It responds to alternating north‑pole and south‑pole magnetic field, latches output state until opposite magnetic pole arrives. Integrates hall element, voltage regulator, offset cancellation circuit and Schmitt trigger inside single chip, delivers stable magnetic‑trigger performance with excellent temperature consistency。
2. Chopper‑Stabilized Design & High Anti‑interference Capability Chopper‑stabilized amplifier eliminates hall‑element offset drift caused by temperature change. Built‑in Schmitt trigger provides hysteresis, suppresses signal jitter and external magnetic noise. High magnetic sensitivity supports detection for weak‑magnet scenarios, maximum switching frequency up to 10kHz, suitable for high‑speed pulse‑counting tasks。
3. Wide Supply Voltage & Multiple Temperature Grade Options Operating supply voltage 3.5V‑24V DC, compatible with 5V,12V,24V industrial and automotive power rails. Multiple temperature grades: E grade ‑40℃~+85℃, K grade ‑40℃~+125℃, L grade ‑40℃~+150℃. Two package options: flat TO‑92 through‑hole and SOT‑23 surface‑mount for different assembly requirementsMelexis。
4. Open‑Drain Output & Simple Peripheral Circuit Open‑drain output structure requires external pull‑up resistor. Max sink current 50mA, can directly drive LED, small relay and CMOS/TTL logic circuits. Low quiescent current below 5mA, reduces system power consumption. Easy connection with MCU IO ports for position feedback and pulse‑signal acquisition。
5. Automotive‑Grade Reliable Sensing Component Qualified for automotive and industrial environments. RoHS compliant. Widely used for new‑equipment design, BLDC fan/motor phase‑change detection, prototype development and BOM replacement for legacy magnetic‑sensing equipmentMelexis。
Item | Specifications |
|---|---|
Part Number | US1881 |
Product Series | Bipolar Hall‑Effect Latch Sensor IC |
Manufacturer | Melexis |
Sensing Type | Bipolar Latch, responds to alternating N/S magnetic pole |
Technology | Mixed‑signal CMOS, Chopper‑Stabilized |
Output Type | Open‑Drain Output, external pull‑up required |
Supply Voltage | 3.5V ~ 24V DC |
Quiescent Current | Max 5mA |
Max Sink Current | 50mA |
Max Switching Frequency | 10kHz |
Package Variant | TO‑92 Flat (UA) Through‑Hole; SOT‑23 (SE) SMD |
Pin Definition | Pin1:VDD; Pin2:GND; Pin3:OUT |
Operating Temperature | E:‑40℃~+85℃; K:‑40℃~+125℃; L:‑40℃~+150℃ |
Mounting Style | Through‑Hole / Surface Mount |
Compliance | RoHS Compliant |
Core Advantages | Bipolar latch function, chopper‑stabilized low drift, wide voltage & multi‑temperature grade, high anti‑noise performance, low power consumption, dual‑package option for SMD/THT assembly |
Application Grade | BLDC Motor Commutation, Rotational Speed & Pulse Counting, Non‑contact Position Sensing, Automotive Auxiliary Switch, Industrial Automation Trigger, Educational Development Platforms, BOM Replacement & Equipment Refurbishment |
1. BLDC Motor & Fan Commutation Control Rotor position feedback for brushless DC motor and cooling fan, provide phase‑change trigger signal for motor drive circuit.
2. Rotational Speed & Pulse‑Counting Detection Cooperate with rotary magnet for tachometer signal acquisition, flow‑meter pulse counting, encoder auxiliary sensing for automation equipment.
3. Non‑contact Position & Proximity Trigger Magnetic‑trigger limit switch, position state detection for mechanical equipment, replace mechanical contact switch to reduce wear failure.
4. Automotive & Harsh‑condition Industrial Control Magnetic proximity sensing for vehicle auxiliary modules, cabinet door state detection and industrial equipment safety trigger circuit.
5. Prototype‑Verification & Equipment Repair Replacement Common hall‑latch component for embedded experimental projects, standard replacement IC for legacy magnetic‑detection equipment maintenance, convenient for BOM material matching。
