Diodes Incorporated AH277AZ4-BG1

Overview

AH277AZ4-BG1 from BCD Semiconductor Manufacturing Limited is a complementary-output Hall-effect latch IC designed for electronic commutation in brushless DC motors. It integrates a Hall sensor, amplifier, Schmitt trigger with 60 G hysteresis, temperature-compensated biasing, and dual open-collector drivers capable of 400 mA average sink current. Operates from 3.5 V to 16 V across –20 °C to 85 °C in TO-94 (SIP-4L) package, used in dual-coil BLDC fans and speed measurement systems.

For engineers reviewing the AH277AZ4-BG1 datasheet, AH277AZ4-BG1 pinout, AH277AZ4-BG1 application, or AH277AZ4-BG1 equivalent, this page delivers verified magnetic thresholds (BOP = 10–50 G, BRP = –50 to –10 G), output timing (tr ≤ 10 µs, tf ≤ 1.5 µs), saturation voltage (VSAT ≤ 0.6 V @ 400 mA), reverse supply protection (–20 V), and green RoHS-compliant packaging.

Technical Context

The AH277AZ4-BG1 implements a bipolar latching Hall switch architecture: magnetic polarity reversal triggers state change-DO goes low and DOB high when B ≥ +30 G (typ), holding until B ≤ –30 G (typ), then swapping outputs. Its internal band-gap regulator ensures stable bias under supply variation, while the Schmitt trigger provides noise immunity via fixed 60 G hysteresis independent of temperature or voltage.

Temperature compensation actively corrects Hall sensitivity drift over –20 °C to 85 °C, maintaining consistent BOP/BRP across operating range. The dual open-collector outputs drive external loads directly without pull-ups, supporting complementary switching for H-bridge control or dual-coil sequencing in BLDC motor phases.

Key Specifications

Pinout & Package

TO-94 (SIP-4L) package: 4-pin single-in-line, 15.3 mm length, 5.3 mm width, 3.9 mm height, lead-free green finish (G1 suffix), Hall sensing element centered beneath pin 1–2 axis.

Key Features

Applications

Equivalent & Alternatives

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

Compared with A3291LUA-T and US5881KSE-AAA-000-RE, AH277AZ4-BG1 uniquely combines latching behavior, complementary outputs, reverse polarity protection, and through-hole TO-94 packaging - making it optimal for cost-sensitive, high-reliability BLDC fan and motor control where board space and assembly method constrain alternatives.

Availability

AH277AZ4-BG1 is available at Aetrix Electronics and suitable for dual-coil brushless DC fans, BLDC motor commutation circuits, and revolution counting systems requiring stable component supply, green RoHS compliance, and long-term industrial availability.

Supply support for AH277AZ4-BG1 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

BCD Semiconductor Manufacturing Limited is a Shanghai-based analog and mixed-signal IC designer and foundry partner, specializing in high-voltage, high-current, and Hall-effect sensor solutions for industrial and automotive markets.

AH277AZ4-BG1 belongs to BCD's Hall-effect latch product line, engineered specifically for robust, low-cost electronic commutation in brushless DC motors and fans - emphasizing latch reliability, thermal stability, and system-level fault tolerance.

FAQ

What is the magnetic hysteresis value of AH277AZ4-BG1, and how does it affect noise immunity?

The AH277AZ4-BG1 has a fixed 60 G hysteresis between BOP and BRP. This gap prevents output oscillation when the magnetic field dwells near the switching threshold due to mechanical vibration or field distortion. Measured at 25 °C and stable VCC, it ensures clean, bounce-free edges even in high-noise motor environments without external RC filtering.

Can AH277AZ4-BG1 drive MOSFET gates directly, and what are the limitations?

Yes - its open-collector DO and DOB outputs can sink up to 400 mA continuously, sufficient to discharge standard N-channel MOSFET gates (e.g., IRFZ44N) within microseconds. However, gate charge must be limited to ≤30 nC to avoid exceeding 800 mA peak current during turn-on; external gate resistors ≥10 Ω are recommended for EMI control and current limiting.

Does AH277AZ4-BG1 require external pull-up resistors on DO and DOB pins?

Yes - DO and DOB are open-collector outputs and require external pull-up resistors to VCC or another logic rail. Typical values are 4.7 kΩ to 10 kΩ for 5 V logic, or 820 Ω for 12 V BLDC gate drive. Pull-up placement must avoid shared nodes with other switching loads to prevent crosstalk-induced false triggering.

How does the internal band-gap regulator improve performance across varying supply voltages?

The internal band-gap regulator maintains a stable ~5.0 V reference for the Hall sensor, amplifier, and Schmitt trigger regardless of VCC from 3.5 V to 16 V. This eliminates supply-dependent gain drift and threshold shift, ensuring consistent BOP/BRP and propagation delay - critical for repeatable commutation timing in variable-input applications like 12 V automotive fans.