Diodes Incorporated ATS277H-PG-B-A

Overview

ATS277H-PG-B-A from Diodes Incorporated is a complementary-output Hall-effect latch IC designed for electronic commutation in dual-coil brushless DC fans. It features 3.5V–20V operating voltage, 400mA average output sink current per channel, ±300G magnetic operate/release thresholds (A-grade), built-in reverse-polarity protection diode, and SIP-4L package. Its latched DO/DOB outputs drive fan coils directly in motor phase control.

For engineers reviewing the ATS277H-PG-B-A datasheet, ATS277H-PG-B-A pinout, ATS277H-PG-B-A application, or ATS277H-PG-B-A equivalent, key selection criteria include magnetic sensitivity grade (A vs B), complementary open-collector output timing differential (≤10 µs), thermal derating above 85°C, and coil-side reverse-current protection requirements.

Technical Context

The ATS277H integrates a Hall plate, low-noise amplifier, comparator with hysteresis, voltage regulator, and dual complementary open-collector drivers (DO and DOB) on a single die. It operates as a bipolar magnetic latch: DO turns ON (low) when B ≥ +300G and remains latched until B ≤ –300G, while DOB mirrors the inverse state.

Internal circuitry includes a reverse-voltage protection diode across VCC–GND (rated –20V), enabling robustness against accidental power reversal at the IC side-but not coil-side. Output saturation voltage is specified at 0.3–0.6V (VCC = 14V, IL = 300mA), supporting efficient switching into typical fan coil impedances.

Key Specifications

Pinout & Package

ATS277H-PG-B-A uses a low-profile, lead-free SIP-4L package (1.95mm × 3.8mm × 1.1mm), optimized for surface-mount assembly in compact fan modules. The package exposes no exposed thermal pad and requires Diodes Inc. AP02001 recommended pad layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with A3281LUA-T and US1881EUA-ABA-002-SP, ATS277H-PG-B-A uniquely combines complementary latched outputs, integrated reverse-voltage protection, SIP-4L SMT packaging, and A-grade hysteresis-making it optimal for cost-sensitive, high-volume BLDC fan commutation without added logic or protection components.

Availability

ATS277H-PG-B-A is available at Aetrix Electronics and suitable for brushless DC fan control, revolution counting, speed measurement, and dual-coil motor commutation requiring stable component supply across industrial, computing, and HVAC applications.

Supply support for ATS277H-PG-B-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 manufacturer of discrete semiconductors and analog ICs, specializing in power management, signal integrity, and sensor solutions for industrial, computing, and consumer markets.

The ATS277H belongs to Diodes' Hall-effect sensor product line, engineered specifically for reliable, low-cost electronic commutation in 2-coil brushless DC fans and motors-emphasizing latch stability, thermal robustness, and system-level integration.

FAQ

What magnetic polarity triggers the DO output on ATS277H-PG-B-A?

DO turns ON (low) when a south pole (S) magnetic field with flux density ≥ +10G to +50G (A-grade) is applied perpendicular to the marked side of the package. The output remains latched until the field reverses to north (N) polarity and reaches ≤ –50G to –10G, at which point DO turns OFF and DOB turns ON.

Does ATS277H-PG-B-A require external pull-up resistors on DO and DOB?

Yes-DO and DOB are open-collector NPN outputs and must be pulled up externally (typically 4.7kΩ–10kΩ to VCC) to generate valid logic-high levels. Pull-up voltage may differ from VCC (e.g., 3.3V logic interface), but must not exceed the 46V zener breakdown rating of the outputs.

Can ATS277H-PG-B-A drive fan coils directly without external transistors?

It can drive low-power fan coils directly if coil current stays within 400mA average and 700mA peak limits. For higher-current fans, external N-channel MOSFETs are required. The 0.3–0.6V saturation voltage ensures minimal power loss during conduction, but thermal design must account for PD derating above 85°C ambient.

Why does the datasheet specify "coil-side" reverse-current protection as external?

The internal diode protects only the IC's VCC-to-GND terminals from reverse polarity. During fan coil back-EMF events or wiring faults, reverse current can flow from the coil into DO/DOB pins-bypassing the internal diode. An external series diode on each output is mandatory to block this path and prevent latch malfunction or damage.