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Home > Products > Sensors, Transducers > Magnetic Sensors > Switches (Solid State)

Diodes Incorporated AH3725-P-B

Name: AH3725-P-B
Brand: Diodes Incorporated
SKU: AH3725-P-B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AH3725-P-B

Manufacturer:: Diodes Incorporated

Category:: Switches (Solid State)

Package:: -

Datasheet:: AH3725-P-B.pdf

Description:: HALL LATCH SWITCH SIP-3 BULK 1K

Quantity:: RFQ Add To RFQ list

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Inventory:3,370

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Product details

Overview

AH3725-P-B from Diodes Incorporated is a high-voltage bipolar Hall-effect latch IC designed for position sensing and commutation in brushless DC motors, flow meters, and angular encoders. It operates from 3.0V to 28V, features BOP/BRP of 50–90G / –90––50G (typ), open-drain output with 30–55mA current limit, and supports –40°C to +125°C ambient operation in SIP-3 (Bulk Pack) package.

For engineers reviewing the AH3725-P-B datasheet, AH3725-P-B pinout, AH3725-P-B application, or AH3725-P-B equivalent, key selection criteria include magnetic operate/release thresholds, supply voltage range robustness, open-drain drive capability, thermal stability across automotive-grade temperature extremes, and SIP-3 mechanical compatibility for through-hole motor control PCBs.

Technical Context

The AH3725-P-B uses chopper-stabilized architecture with dynamic offset cancellation to minimize switch-point drift over temperature and supply voltage. Its internal bandgap regulator provides temperature-compensated biasing for the Hall sensor and signal chain, enabling stable BOP/BRP hysteresis of 100–180G across –40°C to +125°C.

It integrates reverse-blocking diode and zener clamp on VDD, plus output overcurrent limiting and zener clamping. The single open-drain output switches low when South pole flux exceeds BOP (≥50G typ), latches until North pole flux drops below BRP (≤–50G typ), and releases only upon magnetic polarity reversal - ensuring noise-immune, bounce-free digital position detection.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage Range	3.0V to 28V - supports direct connection to 12V/24V automotive and industrial rails without external regulation.
Operate Point (BOP)	50G to 90G (typ) - enables reliable activation with moderate-strength magnets at air gaps up to 2.5mm in motor rotor sensing.
Release Point (BRP)	–90G to –50G (typ) - ensures clean release with sufficient hysteresis (100–180G) to reject mechanical vibration and EMI-induced false triggers.
Output Type	Open-drain, rated 60mA continuous - allows flexible pull-up to any logic rail (3.3V/5V/12V) and direct interface with microcontroller GPIO or PLC inputs.
Startup Time	10µs typical - guarantees valid output state within one microcontroller instruction cycle after power-on, critical for real-time RPM measurement.
ESD Rating	HBM ±8kV - meets IEC 61000-4-2 Level 4 for robustness in assembly, handling, and end-equipment environments.
Operating Temperature	–40°C to +125°C - qualified for under-hood automotive, industrial motor drives, and HVAC blower applications.

Pinout & Package

SIP-3 (Bulk Pack) package: 3-pin straight-lead, through-hole mount with 2.54mm pitch, 14.5mm body length, and 3.0mm width - optimized for high-reliability motor control PCBs requiring mechanical stability and thermal mass.

Pin/Terminal	Circuit Role	Design Meaning
1	VDD	Power input with integrated reverse-blocking diode and 28V zener clamp - tolerates load-dump transients and incorrect battery polarity during service.
2	GND	Ground reference for Hall sensor, amplifier, and output stage - requires low-impedance connection to minimize switching noise coupling.
3	OUTPUT	Open-drain NMOS output with 30–55mA current limit - sinks current when active; requires external pull-up for logic-high level translation.

Key Features

Feature	Design Value
Bipolar Latch Operation	South pole activates (output low), North pole deactivates (output high-Z) - eliminates need for external polarity logic in BLDC rotor position decoding.
Chopper-Stabilized Sensing	500kHz chopping frequency - reduces 1/f noise and offsets to <±0.5G drift over temperature, enabling stable zero-speed detection.
Integrated Protection	VDD reverse-blocking diode + zener clamp, output overcurrent limit + zener clamp - removes need for discrete protection components in cost-sensitive designs.
RF Noise Immunity	Validated against 100MHz–1GHz RF fields per ISO 11452-2 - maintains correct switching in proximity to inverters, wireless modules, and switching PSUs.
Lead-Free & Green Compliance	Fully RoHS 3 compliant, halogen- and antimony-free (<900ppm Br/Cl, <1000ppm Sb) - satisfies Tier 1 automotive and EU industrial environmental mandates.

Applications

Brushless DC Motor Commutation

RPM Measurement

Use Scenario: Detecting rotor magnet polarity in 3-phase BLDC motors for electronic commutation timing.

IC Role / Device Role / Timing Role: Provides synchronized, latched Hall signals to MCU timer capture inputs for precise 120° phase alignment.

Use Value: Enables sensor-based FOC or trapezoidal control with <1° electrical angle error across –40°C to +125°C, eliminating encoder cost.

Use Scenario: Counting magnetic transitions from rotating gear or impeller in industrial pumps and HVAC blowers.

IC Role / Device Role / Timing Role: Generates clean, jitter-free pulse train proportional to shaft speed for microcontroller frequency measurement.

Use Value: Delivers stable 10µs startup and <4µs propagation delay, supporting accurate RPM calculation up to 100k RPM with 1% resolution.

Flow Meter Sensing

Linear/Angular Position Indexing

Use Scenario: Detecting rotation of turbine or paddle-wheel in water/gas metering systems.

IC Role / Device Role / Timing Role: Acts as contactless, wear-free magnetic switch converting fluid flow into digital pulse output.

Use Value: SIP-3 bulk-pack mechanical robustness and 28V tolerance enable direct 24V loop-powered operation in hazardous-area flow transmitters.

Use Scenario: Monitoring angular position of valve actuators, robotic joints, or printer carriage assemblies.

IC Role / Device Role / Timing Role: Provides absolute position feedback via magnetic pole counting or index pulse generation.

Use Value: 100–180G hysteresis prevents chatter at mechanical stop points, ensuring reliable end-of-travel detection in precision motion systems.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
Allegro A1220LLHLT-T	BOP/BRP ±35G (typ), 3.3–24V supply, SOIC-8 package	Lower sensitivity and narrower voltage range; requires PCB space for larger SOIC-8 footprint	Select when board layout favors surface-mount and magnetic field strength is consistently >40G.
Melexis US1881EUA-ABA-002-SP	BOP/BRP ±50G (typ), 3.5–24V supply, TSOT-23 package	Same sensitivity tier but smaller TSOT-23 footprint; lacks reverse-voltage protection	Select for space-constrained consumer devices where external reverse-protection is already present.

Compared with A1220LLHLT-T and US1881EUA-ABA-002-SP, AH3725-P-B offers wider 3.0–28V operation, integrated reverse-voltage protection, and SIP-3 through-hole reliability - making it preferred for industrial motor controls and automotive subsystems where ruggedness and supply resilience are primary.

Availability

AH3725-P-B is available at Aetrix Electronics and suitable for brushless DC motor commutation, flow metering, and angular position sensing requiring stable component supply across extended temperature and voltage ranges.

Supply support for AH3725-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 industrial, automotive, computing, and consumer markets.

The AH372X series belongs to Diodes' high-voltage Hall-effect sensor product line, engineered specifically for robust position and speed sensing in harsh environments where wide supply range, thermal stability, and integrated protection are mandatory.

FAQ

What is the magnetic polarity behavior of AH3725-P-B?

The AH3725-P-B is a bipolar latch: it turns ON (pulls OUTPUT low) when exposed to a South pole magnetic field exceeding its operate point (BOP ≥50G typ), and remains latched until a North pole field exceeding its release point (BRP ≤–50G typ) is applied. This ensures stable, bounce-free switching in rotating magnet applications like BLDC rotors.

Does AH3725-P-B require an external pull-up resistor?

Yes - AH3725-P-B has an open-drain OUTPUT pin and requires an external pull-up resistor (typically 1kΩ–10kΩ) to the desired logic rail (e.g., 3.3V, 5V, or 12V). The value affects rise time: RL = 1kΩ yields ~0.2µs rise time with 20pF load, per datasheet characterization.

Can AH3725-P-B operate directly from a 24V truck battery system?

Yes - AH3725-P-B is rated for 3.0V to 28V continuous operation and includes integrated reverse-blocking diode and 28V zener clamp on VDD. It withstands automotive load-dump transients up to 32V (transient rating) and operates reliably across cold-crank (6.5V) to alternator-overvoltage (18V+) conditions.

Is AH3725-P-B pin-compatible with other AH372X variants?

Yes - all AH372X variants (AH3722, AH3724, AH3725, AH3727) share identical SIP-3, SC59, and SOT23 (Type S) pinouts and electrical interfaces. Only magnetic sensitivity (BOP/BRP) differs; no PCB redesign is needed when upgrading sensitivity tiers within the same package.

AH3725-P-B Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: -

Packaging:: Bulk

Product Status:: Active

Function:: -

Technology:: -

Polarization:: -

Sensing Range:: -

Test Condition:: -

Voltage - Supply:: -

Current - Supply (Max):: -

Current - Output (Max):: -

Output Type:: -

Features:: -

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: -

Supplier Device Package:: -

AH3725-P-B FAQ

1.How can I place an order for AH3725-P-B through Aetrix?

Please submit a Request for Quotation (RFQ) for AH3725-P-B on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for AH3725-P-B reliable?

The price and inventory of AH3725-P-B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AH3725-P-B is usually 5 days.

3.What payment methods are accepted for AH3725-P-B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AH3725-P-B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AH3725-P-B?

AH3725-P-B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AH3725-P-B order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for AH3725-P-B?

For technical support, including AH3725-P-B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AH3725-P-B requirements.

6.How does Aetrix verify that AH3725-P-B is sourced from the original manufacturer or authorized distributors?

All AH3725-P-B products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that AH3725-P-B meets industry standards.

7.What is the process for return or replacement of AH3725-P-B?

All AH3725-P-B units undergo pre-shipment inspection (PSI). If there is an issue with AH3725-P-B, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The AH3725-P-B part is unused and in its original packaging.

Return procedure for AH3725-P-B:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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