Diodes Incorporated AH3722A-P-B

Overview

AH3722A-P-B from Diodes Incorporated is a high-voltage, high-sensitivity bipolar Hall-effect latch IC with internal pullup resistor, designed for brushless DC motor commutation and position sensing in industrial and consumer appliances. It operates from 3.0V to 28V, features BOP/BRP of ±25G to ±40G typical, latched output switching (South-on/North-off), and chopper-stabilized architecture for temperature stability.

For engineers reviewing the AH3722A-P-B datasheet, AH3722A-P-B pinout, AH3722A-P-B application, or AH3722A-P-B equivalent, key selection criteria include magnetic sensitivity tolerance (±25G–±40G), internal 10–18 kΩ pullup, 3.0–28V supply range, -40°C to +125°C operation, and SIP-3 bulk-pack package compatibility with flow meter and encoder designs.

Technical Context

The AH3722A-P-B uses chopper-stabilized architecture with dynamic offset cancellation and an internal bandgap regulator to deliver temperature-compensated operation across -40°C to +125°C. Its bipolar latch behavior requires South-pole activation (B > +25G) to pull output low and North-pole deactivation (B < -25G) to release the latch.

It integrates Zener clamping on VDD and output, overcurrent limiting (30–55 mA), and reverse-blocking diode protection. The internally pulled-up output eliminates external pullup components while maintaining robust noise immunity and stress resistance in rotating machinery environments.

Key Specifications

Pinout & Package

SIP-3 (Bulk Pack) package: 3-pin single-inline package with straight leads, 14.5 mm body length, 3.0 mm width, and 1.5 mm height; optimized for automated through-hole insertion and high-reliability industrial assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AH3722A-P-B, AL3722QSA-7 adds automotive qualification at the cost of SIP-3 compatibility and higher unit price, while US1881LUA-AAA-000 sacrifices sensitivity and integration to reduce footprint and cost-making AH3722A-P-B optimal for industrial BLDC and flow meter designs requiring balance of performance, integration, and SIP-3 manufacturability.

Availability

AH3722A-P-B is available at Aetrix Electronics and suitable for brushless DC motor control, flow metering, RPM sensing, and linear position encoding requiring stable component supply across industrial OEM and appliance production programs.

Supply support for AH3722A-P-B 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.

AH3722A-P-B belongs to Diodes' high-voltage Hall-effect latch product line, engineered specifically for robust, maintenance-free commutation and position feedback in harsh industrial and high-volume consumer environments.

FAQ

What is the magnetic sensitivity range of AH3722A-P-B, and how does it affect design margin?

AH3722A-P-B has a typical operate point (BOP) of +25G to +40G and release point (BRP) of -25G to -40G, with hysteresis of 20–80 G. This sensitivity enables reliable detection with small, low-cost ferrite magnets positioned ≥2 mm from the package marking surface. Designers should allow ±15% margin around the 25G minimum to accommodate magnet aging, temperature drift, and mechanical misalignment in final assemblies.

Can AH3722A-P-B drive a MOSFET gate directly, and what are the limitations?

Yes-AH3722A-P-B's open-drain output can sink up to 55 mA continuously and pulls low to ≤0.4 V at 20 mA, making it suitable for direct gate driving of small-signal N-channel MOSFETs (e.g., 2N7002-class) in low-power commutation circuits. However, for >100 nF gate capacitance or >1 MHz switching, an external buffer is recommended due to output rise/fall times being load-dependent (0.1–1 µs with RL = 1 kΩ, CL = 20 pF).

Does AH3722A-P-B require an external bypass capacitor, and what value is recommended?

Yes-a 0.1 µF ceramic capacitor between VDD and GND is required per the datasheet (CIN in Typical Applications Circuit). This stabilizes the internal bandgap regulator and suppresses supply noise coupling into the chopper amplifier. Place it within 2 mm of the VDD/GND pins using short, low-inductance traces to maintain immunity to RF noise and switching transients in motor-drive environments.

How does the internal pullup resistor behave across temperature and supply voltage?

The internal pullup resistor ranges from 10 kΩ (min) to 18 kΩ (max) across -40°C to +125°C and 3V–28V supply. At 12V and +25°C, it measures 14 kΩ typical. This variation causes <±8% change in pullup current (0.86–0.67 mA), which remains well within logic-high recognition thresholds for standard CMOS inputs and avoids false triggering in noisy industrial settings.