[exhibit10104subsidiarygu001.jpg]
SUBSIDIARY GUARANTOR SUPPLEMENT THIS SUBSIDIARY GUARANTOR SUPPLEMENT (the
“Subsidiary Guarantor Supplement”), dated as of October 22, 2018 is made by each
of LITTELFUSE INTERNATIONAL HOLDING, LLC, a Delaware limited liability company,
LITTELFUSE HOLDING, LLC, a Delaware limited liability company, and MONOLITH
SEMICONDUCTOR INC., a Delaware corporation (each, an “Additional Subsidiary
Guarantor”), in favor of the holders from time to time of the Notes issued
pursuant to the Note Agreement described below: PRELIMINARY STATEMENTS: I.
Pursuant to the Note Purchase Agreement dated as of December 8, 2016 (as
amended, modified, supplemented or restated from time to time, the “Note
Agreement”), by and among LITTELFUSE, INC., a Delaware corporation (together
with any successor thereto that becomes a party to the Note Agreement pursuant
to Section 10.2, the “Company”) and the Persons listed on the signature pages
thereto (the “Purchasers”), the Company has issued and sold (i) $25,000,000
aggregate principal amount of its 3.03% Senior Notes, Series A, due February 15,
2022 (the “Series A Notes”) and (ii) $100,000,000 aggregate principal amount of
its 3.74% Senior Notes, Series B, due February 15, 2027 (the “Series B Notes”
and together with the Series A Notes as amended, restated or otherwise modified
from time to time and including any such notes issued in substitution therefor,
the “Notes” and individually a “Note”). II. The Company is required pursuant to
the Note Agreement to cause each Additional Subsidiary Guarantor to deliver this
Subsidiary Guarantor Supplement in order to cause each Additional Subsidiary
Guarantor to become a Subsidiary Guarantor under the Subsidiary Guaranty
Agreement dated as of February 15, 2017 executed by certain Subsidiaries of the
Company (together with each entity that from time to time becomes a party
thereto by executing a Subsidiary Guarantor Supplement pursuant to Section 14.1
thereof, collectively, the “Subsidiary Guarantors”) in favor of each holder from
time to time of any of the Notes (as the same may be amended, restated,
supplemented or otherwise modified from time to time, the “Subsidiary Guaranty
Agreement”). III. Each Additional Subsidiary Guarantor has received and will
receive substantial direct and indirect benefits from the Company’s compliance
with the terms and conditions of the Note Agreement and the Notes issued
thereunder. IV. Capitalized terms used and not otherwise defined herein have the
definitions set forth in the Note Agreement. Now therefore, in consideration of
the funds advanced to the Company by the Purchasers under the Note Agreement and
to enable the Company to comply with the terms of the Note Agreement, each
Additional Subsidiary Guarantor hereby covenants, represents and warrants to the
holders as follows: 4833-2142-8856.2

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The Additional Subsidiary Guarantor hereby becomes a Subsidiary Guarantor (as
defined in the Subsidiary Guaranty Agreement) for all purposes of the Subsidiary
Guaranty Agreement. Without limiting the foregoing, the Additional Subsidiary
Guarantor hereby (a) jointly and severally with the other Subsidiary Guarantors
under the Subsidiary Guaranty Agreement (including the other Additional
Subsidiary Guarantors party to this Subsidiary Guarantor Supplement), guarantees
to the holders from time to time of the Notes the prompt payment in full when
due (whether at stated maturity, by acceleration or otherwise) and the full and
prompt performance and observance of all Guaranteed Obligations (as defined in
Section 1 of the Subsidiary Guaranty Agreement) in the same manner and to the
same extent as is provided in the Subsidiary Guaranty Agreement, (b) accepts and
agrees to perform and observe all of the covenants set forth therein, (c) waives
the rights set forth in Section 3 of the Subsidiary Guaranty Agreement, (d)
agrees to perform and observe the covenants contained in Section 8 of the
Subsidiary Guaranty Agreement, (e) makes the representations and warranties set
forth in Section 9 of the Subsidiary Guaranty Agreement and (f) waives the
rights, submits to jurisdiction, and waives service of process as described in
Section 14.6 of the Subsidiary Guaranty Agreement. Notice of acceptance of this
Subsidiary Guarantor Supplement and of the Subsidiary Guaranty Agreement, as
supplemented hereby, is hereby waived by the Additional Subsidiary Guarantor.
The address for notices and other communications to be delivered to the
Additional Subsidiary Guarantor pursuant to Section 13 of the Subsidiary
Guaranty Agreement is set forth on the signature page below. [REMAINDER OF PAGE
INTENTIONALLY LEFT BLANK] 4833-2142-8856.2

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[exhibit10104subsidiarygu003.jpg]
IN WITNESS WHEREOF, each Additional Subsidiary Guarantor has caused this
Subsidiary Guarantor Supplement to be duly executed and delivered as of the date
and year first above written. LITTELFUSE INTERNATIONAL HOLDING, LLC By: /s/ Ryan
Stafford Name: Ryan Stafford Title: Manager LITTELFUSE HOLDING, LLC By: /s/ Ryan
Stafford Name: Ryan Stafford Title: Manager MONOLITH SEMICONDUCTOR INC. By: /s/
Hans Weinburger Name: Hans Weinburger Title: Assistant Secretary Notice Address
for each Additional Subsidiary Guarantor: c/o Littelfuse, Inc. Attention: Legal
Department 8755 W. Higgins Road, Suite 500 Chicago, IL 60631 SIGNATURE PAGE TO
SUBSIDIARY GUARANTOR SUPPLEMENT

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