Diodes Incorporated AH3725-P-A

Overview

AH3725-P-A from Diodes Incorporated is a high-voltage bipolar Hall-effect latch IC designed for position sensing and speed measurement in automotive and industrial brushless DC motor commutation systems. It operates from 3.0V to 28V, features open-drain output with 30–55mA current limiting, and delivers magnetic operate/release points of ±50G to ±90G (typ) with 100–180G hysteresis. Its chopper-stabilized architecture ensures stable switching across –40°C to +125°C.

For engineers reviewing the AH3725-P-A datasheet, AH3725-P-A pinout, AH3725-P-A application, or AH3725-P-A equivalent, key selection considerations include its SIP-3 (Ammo Pack) package, South-on/North-off latching behavior, 10µs startup time, robust 8kV HBM ESD rating, and integrated reverse-blocking diode with zener clamp on VDD.

Technical Context

The AH3725-P-A implements a chopper-stabilized Hall sensor with dynamic offset cancellation, delivering minimal switch-point drift over temperature and supply voltage. Its internal bandgap regulator supplies temperature-compensated bias to analog circuitry, enabling consistent BOP/BRP thresholds across the full –40°C to +125°C range.

It uses a single-pole latching mechanism: output switches low when perpendicular magnetic flux exceeds +50G (South pole), remains latched until flux reverses and falls below –50G (North pole). The open-drain output includes overcurrent limiting and zener clamping, while VDD features reverse-blocking diode protection and transient-rated 32V absolute maximum.

Key Specifications

Pinout & Package

Package: SIP-3 (Ammo Pack), 3-pin single-inline package with gull-wing leads, RoHS-compliant and halogen-free.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Hall-effect latch applications.

Compared with AH3725-P-A, AL3725Q-P-A adds automotive compliance overhead without performance gain in non-automotive settings, while US1881LUA-AB sacrifices voltage range, thermal stability, and noise immunity-making AH3725-P-A the optimal choice for demanding industrial and automotive-adjacent designs requiring 3–28V operation and ±125°C reliability.

Availability

AH3725-P-A is available at Aetrix Electronics and suitable for brushless DC motor commutation, RPM measurement, and flow meter sensing requiring stable component supply across automotive, industrial automation, and energy infrastructure programs.

Supply support for AH3725-P-A includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global semiconductor company specializing in discrete, analog, and mixed-signal solutions for power management, signal integrity, and sensing applications.

The AH372X series belongs to Diodes' high-reliability Hall-effect sensor product line, engineered specifically for robust position and speed sensing in electrically noisy, high-temperature, and high-voltage environments such as automotive powertrain and industrial motor control.

FAQ

What is the magnetic polarity response of AH3725-P-A?

The AH3725-P-A is a bipolar latch: it turns ON (pulls OUTPUT low) when a sufficient South pole magnetic field is applied perpendicular to the marked side of the SIP-3 package, and remains latched until a sufficient North pole field is applied to release it. This behavior is confirmed in the magnetic characteristics table (BOP = +50G to +90G, BRP = –90G to –50G) and functional block diagram.

Does AH3725-P-A require an external capacitor on VDD?

Yes - a 10nF to 100nF ceramic decoupling capacitor (CIN) is required between VDD and GND per the Typical Applications Circuit. This stabilizes the internal bandgap regulator, improves noise immunity, and ensures reliable startup within 10µs; omission risks erratic switching or failure to initialize under EMI or supply ripple.

Can AH3725-P-A be used with a 3.3V microcontroller I/O pin?

Yes - its open-drain OUTPUT pin is compatible with 3.3V logic when paired with a 3.3V pull-up resistor. The output saturation voltage is ≤0.4V at 20mA, ensuring valid LOW level; leakage current is <10µA when off, guaranteeing clean HIGH level. No level-shifting circuitry is needed.

What is the difference between AH3725-P-A and AH3725-SA-7?

AH3725-P-A uses the SIP-3 (Ammo Pack) package - a 3-pin straight-lead inline package optimized for through-hole or selective soldering in high-reliability industrial assemblies. AH3725-SA-7 uses the SOT23 (Type S) surface-mount package - smaller footprint, reflow-compatible, and intended for space-constrained PCBs. Both share identical electrical specs and magnetic thresholds.