    <SEC-DOCUMENT>0000950170-25-089734-index.html : 20250625
    <SEC-HEADER>0000950170-25-089734.hdr.sgml : 20250625
    <ACCEPTANCE-DATETIME>20250625073634
    ACCESSION NUMBER:		0000950170-25-089734
    CONFORMED SUBMISSION TYPE:	DEF 14A
    PUBLIC DOCUMENT COUNT:		45
    CONFORMED PERIOD OF REPORT:	20250807
    FILED AS OF DATE:		20250625
    DATE AS OF CHANGE:		20250625

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			ALLEGRO MICROSYSTEMS, INC.
    		CENTRAL INDEX KEY:			0000866291
    		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
    		ORGANIZATION NAME:           	04 Manufacturing
    		EIN:				462405937
    		FISCAL YEAR END:			0331

    	FILING VALUES:
    		FORM TYPE:		DEF 14A
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	001-39675
    		FILM NUMBER:		251070975

    	BUSINESS ADDRESS:
    		STREET 1:		955 PERIMETER ROAD
    		CITY:			MANCHESTER
    		STATE:			NH
    		ZIP:			03103
    		BUSINESS PHONE:		(603) 626-2300

    	MAIL ADDRESS:
    		STREET 1:		955 PERIMETER ROAD
    		CITY:			MANCHESTER
    		STATE:			NH
    		ZIP:			03103

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	ALLEGRO MICROSYSTEMS INC
    		DATE OF NAME CHANGE:	19900730
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>DEF 14A
    <SEQUENCE>1
    <FILENAME>algm-20250620.htm
    <DESCRIPTION>DEF 14A
    <TEXT>
    Document 1 - file: algm-20250620.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>2
    <FILENAME>img123831105_0.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 2 - file: img123831105_0.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>3
    <FILENAME>img123831105_1.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 3 - file: img123831105_1.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>4
    <FILENAME>img123831105_2.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 4 - file: img123831105_2.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>5
    <FILENAME>img123831105_3.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 5 - file: img123831105_3.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>6
    <FILENAME>img123831105_4.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 6 - file: img123831105_4.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>7
    <FILENAME>img123831105_5.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 7 - file: img123831105_5.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>8
    <FILENAME>img123831105_6.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 8 - file: img123831105_6.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>9
    <FILENAME>img123831105_7.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 9 - file: img123831105_7.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>10
    <FILENAME>img123831105_8.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 10 - file: img123831105_8.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>11
    <FILENAME>img123831105_9.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 11 - file: img123831105_9.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>12
    <FILENAME>img123831105_10.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 12 - file: img123831105_10.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>13
    <FILENAME>img123831105_11.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 13 - file: img123831105_11.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>14
    <FILENAME>img123831105_12.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 14 - file: img123831105_12.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>15
    <FILENAME>img123831105_13.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 15 - file: img123831105_13.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>16
    <FILENAME>img123831105_14.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 16 - file: img123831105_14.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>17
    <FILENAME>img123831105_15.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 17 - file: img123831105_15.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>18
    <FILENAME>img123831105_16.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 18 - file: img123831105_16.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>19
    <FILENAME>img123831105_17.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 19 - file: img123831105_17.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>20
    <FILENAME>img123831105_18.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 20 - file: img123831105_18.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>21
    <FILENAME>img123831105_19.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 21 - file: img123831105_19.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>22
    <FILENAME>img123831105_20.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 22 - file: img123831105_20.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>23
    <FILENAME>img123831105_21.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 23 - file: img123831105_21.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>24
    <FILENAME>img123831105_22.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 24 - file: img123831105_22.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>25
    <FILENAME>img123831105_23.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 25 - file: img123831105_23.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>26
    <FILENAME>img123831105_24.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 26 - file: img123831105_24.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>27
    <FILENAME>img123831105_25.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 27 - file: img123831105_25.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>28
    <FILENAME>img123831105_26.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 28 - file: img123831105_26.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>29
    <FILENAME>img123831105_27.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 29 - file: img123831105_27.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>30
    <FILENAME>img123831105_28.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 30 - file: img123831105_28.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>31
    <FILENAME>img123831105_29.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 31 - file: img123831105_29.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>32
    <FILENAME>img123831105_30.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 32 - file: img123831105_30.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>33
    <FILENAME>img123831105_31.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 33 - file: img123831105_31.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.SCH
    <SEQUENCE>34
    <FILENAME>algm-20250620.xsd
    <DESCRIPTION>XBRL TAXONOMY EXTENSION SCHEMA WITH EMBEDDED LINKBASES DOCUMENT
    <TEXT>
    Document 34 - file: algm-20250620.xsd

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>36
    <FILENAME>R1.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 36 - file: R1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>37
    <FILENAME>R2.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 37 - file: R2.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>38
    <FILENAME>R3.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 38 - file: R3.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>39
    <FILENAME>R4.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 39 - file: R4.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>40
    <FILENAME>Show.js
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 40 - file: Show.js

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>41
    <FILENAME>report.css
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 41 - file: report.css

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>43
    <FILENAME>FilingSummary.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 43 - file: FilingSummary.html

    Document 43 - RAW XML: FilingSummary.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>JSON
    <SEQUENCE>45
    <FILENAME>MetaLinks.json
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 45 - file: MetaLinks.json

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>ZIP
    <SEQUENCE>46
    <FILENAME>0000950170-25-089734-xbrl.zip
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 46 - file: 0000950170-25-089734-xbrl.zip

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>47
    <FILENAME>algm-20250620_htm.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 47 - file: algm-20250620_htm.html

    Document 47 - RAW XML: algm-20250620_htm.xml

    </DOCUMENT>
    </SEC-DOCUMENT>