A3240LLTTR Equivalent & Substitute Parts

Part Overview

The A3240LLTTR is a unipolar Hall Effect magnetic switch manufactured by Allegro MicroSystems in SOT-89-3 surface mount packaging. This component functions as a digital switch with open collector output, designed for magnetic field detection applications. The product is currently obsolete, making equivalent substitute parts necessary for ongoing system support and new design implementations. Substitute components must maintain functional compatibility through matching electrical characteristics and mechanical form factors.

Key Parameters

Parameter	A3240LLTTR
Manufacturer	Allegro MicroSystems
Function	Unipolar Switch
Technology	Hall Effect
Polarization	South Pole
Sensing Range	5mT Trip, 5mT Release
Voltage Supply	4.2V – 24V
Current Supply (Max)	6mA
Current Output (Max)	25mA
Output Type	Open Collector
Operating Temperature	-40°C to 150°C
Mounting Type	Surface Mount
Package / Case	TO-243AA
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the A3240LLTTR is based on the following critical parameters:

Technology: Hall Effect digital switch with open collector output
Mounting: Surface mount in TO-243AA package variant
Voltage Range: Supply voltage compatibility within 4.2V – 24V
Current Ratings: Output current capability of 20mA or greater
Operating Temperature: Support for -40°C to 150°C range
Output Configuration: Open collector topology

The substitute parts listed are Honeywell Sensing and Productivity Solutions components from the SS5 series. While these parts function as bipolar switches (detecting both north and south poles) rather than unipolar, they maintain electrical and mechanical compatibility through matching package types, output configurations, and overlapping operational parameters. The bipolar characteristic provides broader magnetic field detection capability, making these parts functionally suitable for applications requiring the A3240LLTTR's core switching behavior.

Parameter Comparison

Parameter	A3240LLTTR	SS50AT	SS511AT	SS513AT	SS51T
Manufacturer	Allegro MicroSystems	Honeywell	Honeywell	Honeywell	Honeywell
Function	Unipolar Switch	Bipolar Switch	Bipolar Switch	Bipolar Switch	Bipolar Switch
Technology	Hall Effect	Hall Effect	Hall Effect	Hall Effect	Hall Effect
Sensing Range	5mT Trip, 5mT Release	17mT Trip, -17mT Release	6mT Trip, -6mT Release	14mT Trip, -14mT Release	14mT Trip, -14mT Release
Voltage Supply	4.2V – 24V	4.5V – 24V	3.8V – 30V	3.8V – 30V	4.5V – 24V
Current Supply (Max)	6mA	10mA	10mA	10mA	10mA
Current Output (Max)	25mA	20mA	20mA	20mA	20mA
Output Type	Open Collector	Open Collector	Open Collector	Open Collector	Open Collector
Operating Temperature	-40°C to 150°C	-40°C to 125°C	-40°C to 150°C	-40°C to 150°C	-40°C to 150°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	TO-243AA	TO-243AA, Variant	TO-243AA, Variant	TO-243AA, Variant	TO-243AA, Variant
RoHS Status	Non-compliant	Compliant	Compliant	Compliant	Compliant
Product Status	Obsolete	Active	Active	Active	Active

Engineering Selection Recommendations

SS511AT and SS513AT are the primary substitutes for the A3240LLTTR. Both parts maintain the full -40°C to 150°C operating temperature range of the original component and include temperature compensation features. SS511AT offers the closest sensing range match at 6mT trip threshold, compared to the A3240LLTTR's 5mT specification. SS513AT provides a 14mT trip threshold with extended voltage supply range (3.8V – 30V), offering greater design flexibility.

SS51T is suitable for applications with voltage supply constraints between 4.5V and 24V, matching the original part's supply range more closely. This part also supports the full temperature range and includes temperature compensation.

SS50AT operates within a narrower temperature range (-40°C to 125°C) and is suitable only for applications not requiring the full 150°C upper limit. This part has the highest sensing threshold at 17mT.

All substitute parts are RoHS compliant and in active production status, ensuring long-term availability and regulatory compliance. The original A3240LLTTR is RoHS non-compliant and obsolete.

Frequently Asked Questions (FAQ)

Q: Can SS50AT directly replace A3240LLTTR in all applications?

A: SS50AT is mechanically and electrically compatible but operates only to 125°C maximum. Use this substitute only in applications where the operating temperature does not exceed 125°C. For applications requiring the full -40°C to 150°C range, select SS511AT or SS513AT instead.

Q: What is the functional difference between the unipolar A3240LLTTR and bipolar substitute parts?

A: The A3240LLTTR detects only south pole magnetic fields. The SS5 series substitutes detect both north and south poles. In applications where magnetic field polarity is fixed and controlled, this difference has no practical impact. In applications with variable or unknown polarity, bipolar detection provides enhanced functionality.

Q: Are the TO-243AA package variants between A3240LLTTR and SS5 series parts pin-compatible?

A: All parts use TO-243AA package variants with identical pin configurations and spacing. Physical and electrical pin compatibility is maintained across all listed substitutes.

Q: Which substitute offers the closest sensing range to the original A3240LLTTR?

A: SS511AT provides the closest match with a 6mT trip threshold, compared to the A3240LLTTR's 5mT specification. This represents a 1mT difference and is suitable for most applications designed around the original part's sensing characteristics.

Q: Do the substitute parts require circuit modifications?

A: No circuit modifications are required. All substitute parts maintain open collector output topology and operate within compatible voltage and current ranges. Direct PCB substitution is possible without design changes.

Q: What is the inventory status of substitute parts?

A: SS50AT (55,824 pcs), SS513AT (21,400 pcs), SS511AT (9,432 pcs), and SS51T (2,260 pcs) are all in active stock as new original components.

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