# EDGAR Filing Document

**Accession Number:** 0001445300
**File Stem:** 0001214659-26-003030
**Filing Date:** 2026-3
**Character Count:** 8319
**Document Hash:** 5c648b32be35ef731ed2d3852979cf59
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001214659-26-003030.hdr.sgml**: 20260309

**ACCESSION NUMBER**: 0001214659-26-003030

**CONFORMED SUBMISSION TYPE**: 3

**PUBLIC DOCUMENT COUNT**: 2

**CONFORMED PERIOD OF REPORT**: 20260227

**FILED AS OF DATE**: 20260309

**DATE AS OF CHANGE**: 20260309

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** DEAN ROBERT W II
- **CENTRAL INDEX KEY:** 0001445300

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 3
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 000-51026
- **FILM NUMBER:** 26736623

**MAIL ADDRESS:**
- **STREET 1:** 3120 HANSEN WAY
- **STREET 2:** M/S D-083
- **CITY:** PALO ALTO
- **STATE:** CA
- **ZIP:** 93404-1030
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** MONOLITHIC POWER SYSTEMS INC
- **CENTRAL INDEX KEY:** 0001280452
- **STANDARD INDUSTRIAL CLASSIFICATION:** SEMICONDUCTORS & RELATED DEVICES [3674]
- **ORGANIZATION NAME:** 04 Manufacturing
- **EIN:** 770466789
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 1555 PALM BEACH LAKES BLVD.
- **CITY:** WEST PALM BEACH
- **STATE:** FL
- **ZIP:** 33401
- **BUSINESS PHONE:** 561-839-3999

**MAIL ADDRESS:**
- **STREET 1:** 5808 LAKE WASHINGTON BLVD. NE
- **CITY:** KIRKLAND
- **STATE:** WA
- **ZIP:** 98033

## Ex-24

```
<pre>
      LIMITED POWER OF ATTORNEY
FOR MONOLITHIC POWER SYSTEMS
SECTION 16(a) FILINGS
Know all by these presents, that the undersigned, Robert Dean, hereby
constitutes and appoints Saria Tseng, signing singly, the undersigned's true and
lawful attorney-in-fact to:
(1) Complete and execute for and on behalf of the undersigned, in the
undersigned's capacity as an officer, director and/or stockholder of Monolithic
Power Systems, Inc. (the "Company"), Forms ID, 3, 4, and 5 and other forms and
all amendments thereto as such attorney-in-fact shall in his or her discretion
determine to be required or advisable in accordance with Section 16(a) of the
Securities Exchange Act of 1934 and the rules and regulations promulgated
thereunder, or any successor laws and regulations, as consequence of the
undersigned's ownership, acquisition or disposition of securities of the
Company;
(2) Do and perform any and all acts for and on behalf of the undersigned which
may be necessary or desirable to complete and execute any such forms or
amendment thereto and timely file such forms with the United States Securities
and Exchange Commission (the "SEC") and any stock exchange or similar authority;
and
(3) Take any other action of any type whatsoever which, in the opinion of such
attorney-in-fact, may be necessary or desirable in connection with the foregoing
authority, it being understood that the documents executed by such
attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney
shall be in such form and shall contain such terms and conditions as such
attorney-in-fact may approve.
The undersigned hereby grants to each such attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney-in-fact, or such
attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be
done by virtue of this Power of Attorney and the rights and powers herein
granted. The undersigned acknowledges that the foregoing attorneys-in-fact, in
serving in such capacity at the request of the undersigned, are not assuming,
nor is the Company assuming, any of the undersigned's responsibilities to comply
with Section 16 of the Securities Exchange Act of 1934.
This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms ID, 3, 4, and 5 with respect to
the undersigned's holdings of and transaction in securities of the Company,
unless earlier revoked by the undersigned in a signed writing delivered to the
Company and the foregoing attorneys-in-fact. This Power of Attorney may be filed
with the SEC as a confirming statement of the authority granted herein.
IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of this day of February 27, 2026.
/s/ Robert Dean
    </pre>
```

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 3

### INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>DEAN ROBERT W II<br><sub>(Last) (First) (Middle)</sub><br>1555 PALM BEACH LAKES BLVD.<br><sub>(Street)</sub><br>WEST PALM BEACH, FL 33401<br><sub>(City) (State) (Zip)</sub> | **3. Issuer Name and Ticker or Trading Symbol**<br>MONOLITHIC POWER SYSTEMS INC [ MPWR ] | **5. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  |
| **2. Date of Event Requiring Statement (Month/Day/Year)**<br>2026-02-27 | **4. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director   [ ] 10% Owner<br>[X] Officer (give title below)   [ ] Other (specify below)<br>_Interim CFO_ | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities Beneficially Owned

---

|  |  |  |  |
| --- | --- | --- | --- |
| 1. Title of Security | 2. Amount of Securities Beneficially Owned | 3. Ownership Form | 4. Nature of Indirect Beneficial Ownership |
| Common Stock | 8060<sup>(1)</sup> | D |  |
| Common Stock | 65 | I | Held by Parent & Daughter |

---

## Table II - Derivative Securities Beneficially Owned

---

|  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 3. Title and Amount of Underlying Securities | 3. Title and Amount of Underlying Securities | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
|  |  |  |  |  |  |  |  |

---

### Footnotes:

(1) Includes an aggregate of 1,420 shares of restricted stock units that vest, subject to continued employment, as follows: 11 shares on 05/15/2026; 59 shares on 05/22/2026; 11 shares on 08/15/2026; 61 shares on 08/22/2026; 12 shares on 11/15/2026; 59 shares on 11/22/2026; 400 shares on 02/03/2027; 11 shares on 02/15/2027; 63 shares on 02/22/2027; 12 shares on 05/15/2027; 39 shares on 05/22/2027; 11 shares on 08/15/2027; 39 shares on 08/22/2027; 12 shares on 11/15/2027; 39 shares on 11/22/2027; 400 shares on 02/03/2028; 11 shares on 02/15/2028; 40 shares on 02/22/2028; 11 shares on 05/15/2028; 9 shares on 05/22/2028; 12 shares on 08/15/2028; 10 shares on 08/22/2028; 11 shares on 11/15/2028; 9 shares on 11/22/2028; 12 shares on 02/15/2029; 10 shares on 02/22/2029; 11 shares on 05/15/2029; 12 shares on 08/15/2029; 11 shares on 11/15/2029; and 12 shares on 02/15/2030.

**Signature:** /s/ Saria Tseng, attorney-in-fact for Mr. Robert W. Dean II  
**Date:** 2026-03-09

### Remarks:

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**