Exhibit 3.5.1

AMENDED AND RESTATED        CERTIFICATE OF INCORPORATION OF        SPECTRIAN CORPORATION

Spectrian Corporation, a corporation organized and existing under the laws of the State of Delaware (the "Corporation"), hereby certifies that:

A.    The
name of this Corporation, and the name under which it was originally incorporated, is Spectrian Corporation

B.    The
date of filing of this Corporation's original Certificate of Incorporation with the Secretary of State of Delaware was May 22, 1997.

C.    That
at the Corporation's Annual Meeting of Stockholders held on September 7, 2001, the stockholders of the Corporation representing greater than the minimum
number of shares required by the Delaware General Corporate Law and the Company's Certificate of Incorporation to approve this Amended and Restated Certificate of Incorporation (the "Amended
Certificate") voted in favor of the Amended Certificate.

D.    That
the Amended Certificate was duly adopted in accordance with the provisions of Sections 242 and 245 of the Delaware General Corporate Law.

Pursuant
to Sections 242 and 245 of the Delaware General Corporation Law, this Amended and Restated Certificate of Incorporation restates, integrates and amends the provisions of
the Corporation's Certificate of Incorporation as follows:

FIRST:The name of the Corporation is Spectrian Corporation.

SECOND:The address of the Corporation's registered office in the State of Delaware is Corporation Trust Center, 1209 Orange
Street, in the City of Wilmington, County of New Castle, zip code 19801. The name of its registered agent at such address is The Corporation Trust Company.

THIRD:The purpose of the Corporation is to engage in any lawful act or activity for which corporations may be organized
under the General Corporation Law of Delaware.

FOURTH:The Corporation is authorized to issue two classes of stock to be designated respectively Common Stock and Preferred
Stock. The total number of shares of all classes of stock which the Corporation has authority to issue is Thirty Million (30,000,000), consisting of Twenty Five Million (25,000,000) shares of Common
Stock, $0.001 par value (the "Common Stock"), and Five Million (5,000,000) shares of Preferred Stock, $0.001 par value (the "Preferred Stock"). Of the authorized shares of Preferred Stock, Twenty
Thousand (20,000) shares shall be designated "Series A Participating Preferred Stock" (sometimes referred to herein as "Series A Preferred").

The
Preferred Stock may be issued from time to time in one or more series. The Board of Directors is hereby authorized subject to limitations prescribed by law, to fix by resolution or
resolutions the designations, powers, preferences and rights, and the qualifications, limitations or restrictions thereof, of each such series of Preferred Stock, including without limitation
authority to fix by resolution or resolutions, the dividend rights, dividend rate, conversion rights, voting rights, rights and terms of redemption (including sinking fund provisions), redemption
price or prices, and liquidation preferences of any wholly unissued series of Preferred Stock, and the number of shares constituting any such series and the designation thereof, or any of the
foregoing.

The
Board of Directors is further authorized to increase (but not above the total number of authorized shares of the class) or decrease (but not below the number of shares of any such
series then outstanding) the number of shares of any series, the number of which was fixed by it, subsequent to the issue of shares of such series then outstanding, subject to the powers, preferences
and rights, and the

---

qualifications, limitations and restrictions thereof stated in the resolution of the Board of Directors originally fixing the number of shares of such series. If the number of shares of any series is
so decreased, then the shares constituting such decrease shall resume the status which they had prior to the adoption of the resolution originally fixing the number of shares of such series.

The
relative rights, preferences, privileges, and restrictions granted to or imposed upon the Common Stock, the Series A Preferred and the holders thereof (collectively, the
"Stockholders") are as follows:

1.Dividends and Distributions.



2

---



2.Voting Rights.The holders of shares of Series A Participating Preferred Stock shall have the
following voting rights:



3.Certain Restrictions.



3

---



4.Reacquired Shares.Any shares of Series A Participating Preferred Stock purchased or otherwise
acquired by the Corporation in any manner whatsoever shall be retired and canceled promptly after the acquisition thereof. All such shares shall upon their cancellation become authorized but unissued
shares of Preferred Stock and may be reissued as part of a new series of Preferred Stock to be created by resolution or resolutions of the Board of Directors, subject to the conditions and
restrictions on issuance set forth herein.

5.Liquidation, Dissolution or Winding Up.



4

---



(d)Consolidation, Merger, etc.In case the Corporation shall enter into any consolidation, merger, combination
or other transaction in which the shares of Common Stock are exchanged for or changed into other stock or securities, cash and/or any other property, then in any such case the shares of
Series A Participating Preferred Stock shall at the same time be similarly exchanged or changed in an amount per share (subject to the provision for adjustment hereinafter set forth) equal to
1,000 times the aggregate amount of stock, securities, cash and/or any other property (payable in kind), as the case may be, into which or for which each share of Common Stock is changed or exchanged.
In the event the Corporation shall at any time after the Rights Dividend Declaration Date (i) declare any dividend on Common Stock payable in shares of Common Stock, (ii) subdivide the
outstanding Common Stock, or (iii) combine the outstanding Common Stock into a smaller number of shares, then in each such case the amount set forth in the preceding sentence with respect to
the exchange or change of shares of Series A Participating Preferred Stock shall be adjusted by multiplying such amount by a fraction the numerator of which is the number of shares of Common
Stock outstanding immediately after such event and the denominator of which is the number of shares of Common Stock that were outstanding immediately prior to such event.

6.No Redemption.The shares of Series A Participating Preferred Stock shall not be redeemable.

7.Ranking.The Series A Participating Preferred Stock shall rank junior to all other series of the
Corporation's Preferred Stock as to the payment of dividends and the distribution of assets, unless the terms of any such series shall provide otherwise.

8.Amendment.This Certificate of Incorporation of the Corporation shall not be further amended in any manner
which would materially alter or change the powers, preference or special rights of the Series A Participating Preferred Stock so as to affect them adversely without the affirmative vote of the
holders of a majority or more of the outstanding shares of Series A Participating Preferred Stock, voting separately as a class.

9.Fractional Shares.Series A Participating Preferred Stock may be issued in fractions of a share which
shall entitle the holder, in proportion to such holder's fractional shares, to exercise voting rights, receive dividends, participate in distributions and to have the benefit of all other rights of
holders of Series A Participating Preferred Stock.

FIFTH:The Corporation is to have perpetual existence.

SIXTH:The election of directors need not be by written ballot unless a stockholder demands election by written ballot at a
meeting of stockholders and before voting begins or unless the Bylaws of the Corporation shall so provide.

SEVENTH:The number of directors which constitute the whole Board of Directors of the Corporation shall be designated in the
Bylaws of the Corporation.

EIGHTH:In furtherance and not in limitation of the powers conferred by the laws of the State of Delaware, the Board of
Directors is expressly authorized to adopt, alter, amend or repeal the Bylaws of the Corporation.

5

---

NINTH:To the fullest extent permitted by the Delaware General Corporation Law as the same exists or may hereafter be
amended, no director of the Corporation shall be personally liable to the Corporation or its stockholders for monetary damages for breach of fiduciary duty as a director.

Neither
any amendment nor repeal of this Article, nor the adoption of any provision of this Certificate of Incorporation inconsistent with this Article, shall eliminate or reduce the
effect of this Article in respect of any matter occurring, or any cause of action, suit or claim that, but for this Article, would accrue or arise, prior to such amendment, repeal or adoption of an
inconsistent provision.

TENTH:At the election of directors of the Corporation, each holder of stock or of any class or series of stock shall be
entitled to as many votes as shall equal the number of votes which such stockholder would be entitled to cast for the election of directors with respect to his or her shares of stock multiplied by the
number of directors to be elected and may cast all such votes for any director or for any two or more of them as such stockholder may see fit.

ELEVENTH:Meetings of stockholders may be held within or without the State of Delaware, as the Bylaws may provide. The books
of the Corporation may be kept (subject to any provision contained in the laws of the State of Delaware) outside of the State of Delaware at such place or places as may be designated from time to time
by the Board of Directors or in the Bylaws of the Corporation.

TWELFTH:The Corporation reserves the right to amend, alter, change or repeal any provision contained in this Certificate of
Incorporation, in the manner now or hereafter prescribed by the laws of the State of Delaware, and all rights conferred herein are granted subject to this reservation.

[THE
REMAINDER OF THIS PAGE WAS INTENTIONALLY LEFT BLANK.]

6

---

IN WITNESS WHEREOF, Spectrian Corporation has caused this Amended and Restated Certificate of Incorporation to be signed by Thomas H. Waechter, its President and Chief Executive
Officer, and attested by Michael D. Angel, its Executive Vice President, Finance and Administration, Chief Financial Officer and Secretary, this 4th day of March 2002, each hereby
declaring and certifying, under penalties of perjury, that the facts herein stated are true.

|Dated: March 4, 2002                                                                                                            |  | /s/THOMAS H. WAECHTERThomas H. Waechter,President and
Chief Executive Officer
|------------------------------------------------------------------------------------------------------------------------------- |  | -----------------------------------------------------------------------------
|Attested:                                                                                                                       |  |                                                                              
|/s/MICHAEL D. ANGELMichael D. Angel,Executive Vice President, Finance and Administration, Chief Financial
Officer and Secretary |  |                                                                              

---

QuickLinks