A3281LUA-T Equivalent & Substitute Parts

Part Overview

The A3281LUA-T is a digital switch latch Hall Effect magnetic sensor manufactured by Allegro MicroSystems in a 3-SIP through-hole package. This component functions as an open collector magnetic switch with latch capability, designed for applications requiring latching magnetic field detection. The product is currently obsolete, making identification of suitable substitute components essential for ongoing system support and new design implementations.

Substiute Parts

A3281LUA-T

Allegro MicroSystemsIn Stock: 1242A3281LUA-T Datasheet

Current PartRFQ

A1221LUA-T

Allegro MicroSystemsIn Stock: 7503A1221LUA-T Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the A3281LUA-T is determined by the following critical parameters:

• Hall Effect technology with south pole polarization
• Latch function with 9mT trip and -9mT release thresholds
• Through-hole 3-SSIP package configuration
• Operating temperature range of -40°C to 150°C
• Output stage compatibility (open collector or open drain)
• Supply voltage and current specifications

The A1221LUA-T qualifies as a direct substitute based on matching technology, polarization, sensing thresholds, temperature range, package type, and mounting configuration. Both components share identical magnetic sensing characteristics and physical form factors.

Parameter Comparison

Engineering Selection Recommendations

The A1221LUA-T is the manufacturer-recommended substitute for the obsolete A3281LUA-T. Both components maintain identical magnetic sensing characteristics, operating temperature range, and physical package specifications. The A1221LUA-T offers the advantage of active product status with established supply availability.

Key differences between the main part and substitute are:

• Supply voltage range: A1221LUA-T extends lower voltage operation to 3V (versus 4.2V minimum for A3281LUA-T)
• Supply current: A1221LUA-T operates at reduced maximum supply current of 4mA (versus 8mA)
• Output stage: A1221LUA-T uses open drain output versus open collector on A3281LUA-T
• Qualification: A1221LUA-T carries AEC-Q100 automotive qualification

The A1221LUA-T is suitable for applications where the lower supply voltage capability and reduced current consumption are compatible with system requirements. The open drain output requires appropriate pull-up resistor configuration in the application circuit.

Frequently Asked Questions (FAQ)

Q: Can the A1221LUA-T directly replace the A3281LUA-T in existing designs?

A: The A1221LUA-T shares identical magnetic sensing thresholds, operating temperature range, and 3-SSIP package configuration. However, the output stage differs (open drain versus open collector), requiring circuit-level evaluation. The lower minimum supply voltage (3V) and reduced supply current (4mA) may also affect system compatibility.

Q: What is the difference between open collector and open drain outputs?

A: Both output types are switch-to-ground configurations requiring external pull-up resistors. The functional behavior in most applications is equivalent, though the underlying semiconductor technology differs. Circuit design must accommodate the pull-up resistor requirement in either case.

Q: Are there any compliance or qualification differences?

A: The A1221LUA-T carries AEC-Q100 automotive qualification and is ROHS3 compliant. The A3281LUA-T is also ROHS3 compliant. Both components are REACH unaffected and classified as EAR99 for export purposes.

Q: What is the supply voltage compatibility range?

A: The A3281LUA-T operates from 4.2V to 24V. The A1221LUA-T operates from 3V to 24V, providing extended lower voltage capability. System supply voltage must fall within the substitute component's specified range.

Q: Are the packages physically identical?

A: Both components use the 3-SSIP through-hole package with identical pin configuration and mounting requirements. Physical board layout compatibility is maintained.