<PAGE>

                                  EXHIBIT 4.2

                          Certificate of Designations
                          ---------------------------

                                      38
<PAGE>

                          CERTIFICATE OF DESIGNATIONS

                                      OF

                           SERIES A PREFERRED STOCK

                          (Par Value $.01 Per Share)

                                      OF

                              VIRATA CORPORATION

                              __________________

                        Pursuant to Section 151 of the
               General Corporation Law of the State of Delaware

                              __________________

     Virata Corporation, a Delaware corporation (the "Corporation"), certifies
                                                      -----------
that pursuant to the authority conferred upon the Board of Directors of the
Company (the "Board of Directors") by the Certificate of Incorporation of the
              ------------------
Company (the "Certificate of Incorporation"), and in accordance with the
              ----------------------------
provisions of Section 151 of the General Corporation Law of the State of
Delaware, as amended (the "GCL"), the Board of Directors, on April 27, 2001,
                           ---
adopted the following resolution creating a series of its Preferred Stock, par
value $.01 per share:

     RESOLVED, that (1) pursuant to the authority conferred upon the Board of
Directors of the Corporation by the Certificate of Incorporation of the
Corporation, the Board of Directors hereby designates 500,000 shares of the
preferred stock, par value $.01 per share, of the Corporation as "Series A
Preferred Stock" (the "Preferred Shares"), and the powers, designations,
                       ----------------
preferences and relative, participating, optional and other rights of the
Preferred Shares and the qualifications, limitations and restrictions thereof,
be, and they hereby are, as set forth below (the "Certificate of Designations")
                                                  ---------------------------
and (2) in connection therewith, the officers of the Corporation be, and each of
them hereby is, authorized, empowered and directed on behalf of the Corporation
and in its name to execute and file the Certificate of Designations with the
Delaware Secretary of State:

     Section 1.   Designation and Amount. The shares of such series shall be
                  ----------------------
designated as "Series A Preferred Stock" and the number of shares constituting
such series so designated shall be 500,000 (the "Series A Preferred Stock").
                                                 ------------------------
Such number of shares may be increased or decreased by resolution of the Board
of Directors; provided, however, that no decrease shall reduce the number of
              --------  -------
shares of Series A Preferred Stock to a number less than the number of shares
then outstanding plus the number of shares reserved for issuance upon the
exercise of outstanding options, rights or warrants or upon the conversion of
any outstanding securities issued by the Corporation convertible into Series A
Preferred Stock.

     Section 2.   Dividends and Distributions.
                  ---------------------------

     (a)  Subject to the rights of the holders of any shares of any series of
Preferred Stock (or any similar stock) ranking prior and superior to the Series
A Preferred Stock with respect to dividends, the holders of shares of Series A
Preferred Stock, in preference to the holders of

                                      39
<PAGE>

shares of Common Stock, par value $.01 per share (the "Common Stock"), of the
                                                       ------------
Corporation, and of any other junior stock, shall be entitled to receive, when,
as and if declared by the Board of Directors out of funds legally available for
the purpose, quarterly dividends payable in cash on the first day of March,
June, September and December in each year (each such date being referred to
herein as a "Quarterly Dividend Payment Date"), commencing on the first
             -------------------------------
Quarterly Dividend Payment Date after the first issuance of a share or fraction
of a share of Series A Preferred Stock, in an amount per share (rounded to the
nearest cent) equal to the greater of (i) $.25 per share ($1.00 per annum) or
(ii) subject to the provision for adjustment hereinafter set forth, 10,000 times
the aggregate per share amount of all cash dividends, and 10,000 times the
aggregate per share amount (payable in kind) of all non-cash dividends or other
distributions, other than a dividend payable in shares of Common Stock or a
subdivision of the outstanding shares of Common Stock (by reclassification or
otherwise), declared on the Common Stock since the immediately preceding
Quarterly Dividend Payment Date or, with respect to the first Quarterly Dividend
Payment Date, since the first issuance of any share or fraction of a share of
Series A Preferred Stock. In the event the Corporation shall at any time declare
or pay any dividend on the Common Stock payable in shares of Common Stock, or
effect a subdivision or combination or consolidation of the outstanding shares
of Common Stock (by reclassification or otherwise than by payment of a dividend
in shares of Common Stock) into a greater or lesser number of shares of Common
Stock, then in each such event the amount to which the holder of each share of
Series A Preferred Stock was entitled immediately prior to such event under
clause (ii) of the preceding sentence 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 outstanding immediately prior to such
event.

     (b)  The Corporation shall declare a dividend or distribution on the Series
A Preferred Stock as provided in paragraph (a) of this Section 2 immediately
after it declares a dividend or distribution on the Common Stock (other than a
dividend payable in shares of Common Stock); provided, however, that, in the
                                             --------  -------
event no dividend or distribution shall have been declared on the Common Stock
during the period between any Quarterly Dividend Payment Date and the next
subsequent Quarterly Dividend Payment Date, a dividend of $.25 per share ($1.00
per annum) on the Series A Preferred Stock shall nevertheless be payable on such
subsequent Quarterly Dividend Payment Date.

     (c)  Dividends shall begin to accrue and be cumulative on outstanding
shares of Series A Preferred Stock from the Quarterly Dividend Payment Date next
preceding the date of issue of such shares, unless the date of issue of such
shares is prior to the record date for the first Quarterly Dividend Payment
Date, in which event dividends on such shares shall begin to accrue from the
date of issue of such shares, or unless the date of issue is a Quarterly
Dividend Payment Date or is a date after the record date for the determination
of holders of shares of Series A Preferred Stock entitled to receive a quarterly
dividend and before such Quarterly Dividend Payment Date, in either of which
events such dividends shall begin to accrue and be cumulative from such
Quarterly Dividend Payment Date. Accrued but unpaid dividends shall cumulate but
shall not bear interest. Dividends paid on the shares of Series A Preferred
Stock in an amount less than the total amount of such dividends at the time
accrued and payable on such shares shall be allocated pro rata on a share-by-
share basis among all such shares at the time outstanding. The Board of
Directors may fix a record date for the determination of holders of shares of
Series A Preferred Stock entitled to receive payment of a dividend or
distribution declared thereon, which record date shall be not more than 60 days
prior to the date fixed for the payment thereof.

                                      40
<PAGE>

     Section 3.   Voting Rights.  The holders of shares of Series A Preferred
                  -------------
Stock shall have the following voting rights:

     (a)  Subject to the provision for adjustment hereinafter set forth, each
share of Series A Preferred Stock shall entitle the holder thereof to 10,000
votes on all matters submitted to a vote of the stockholders of the Corporation.
In the event the Corporation shall at any time declare or pay any dividend on
the Common Stock payable in shares of Common Stock, or effect a subdivision or
combination or consolidation of the outstanding shares of Common Stock (by
reclassification or otherwise than by payment of a dividend in shares of Common
Stock) into a greater or lesser number of shares of Common Stock, then in each
such case the number of votes per share to which holders of shares of Series A
Preferred Stock were entitled immediately prior to such event shall be adjusted
by multiplying such number 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 outstanding
immediately prior to such event.

     (b)  Except as otherwise provided herein, in the Corporation's Certificate
of Incorporation, as amended (the "Charter"), in any other certificate of
                                   -------
designations creating a series of Preferred Stock or any similar stock or by
law, the holders of shares of Series A Preferred Stock and the holders of shares
of Common Stock and any other capital stock of the Corporation having general
voting rights shall vote together as one class on all matters submitted to a
vote of stockholders of the Corporation.

     (c)  Except as set forth herein, or as otherwise provided by law, holders
of Series A Preferred Stock shall have no special voting rights and their
consent shall not be required (except to the extent they are entitled to vote
with holders of Common Stock as set forth herein) for taking any corporate
action.

     Section 4.   Certain Restrictions.
                  --------------------

     (a)  Whenever quarterly dividends or other dividends or distributions
payable on the Series A Preferred Stock as provided in Section 2 are in arrears,
thereafter and until all accrued and unpaid dividends and distributions, whether
or not authorized or declared, on shares of Series A Preferred Stock outstanding
shall have been paid in full, the Corporation shall not, directly or indirectly:

          (i)    authorize, declare or pay dividends on, or make any other
distributions with respect to, any shares of stock ranking junior (either as to
dividends or upon liquidation, dissolution or winding up) to the Series A
Preferred Stock;

          (ii)   authorize, declare or pay dividends on, or make any other
distributions with respect to, any shares of stock ranking on a parity (either
as to dividends or upon liquidation, dissolution or winding up) with the Series
A Preferred Stock, except dividends paid ratably on the Series A Preferred Stock
and all such parity stock on which dividends are payable or in arrears in
proportion to the total amounts to which the holders of all such shares are then
entitled;

          (iii)  redeem or purchase or otherwise acquire for consideration
shares of any stock ranking junior (either as to dividends or upon liquidation,
dissolution or winding up) to the Series A Preferred Stock, provided that the
Corporation may at any time redeem, purchase or

                                      41
<PAGE>

otherwise acquire shares of any such junior stock in exchange for shares of any
stock of the Corporation ranking junior (either as to dividends or upon
liquidation, dissolution or winding up) to the Series A Preferred Stock; or

          (iv)   redeem or purchase or otherwise acquire for consideration any
shares of Series A Preferred Stock, or any shares of stock ranking on a parity
with the Series A Preferred Stock, except in accordance with a purchase offer
made in writing or by publication (as determined by the Board of Directors) to
all holders of such shares upon such terms as the Board of Directors, after
consideration of the respective annual dividend rates and other relative rights
and preferences of the respective series and classes, shall determine in good
faith will result in fair and equitable treatment among the respective series or
classes.

     (b)  The Corporation shall not permit any subsidiary of the Corporation to
purchase or otherwise acquire for consideration, directly or indirectly, any
shares of stock of the Corporation unless the Corporation could, under paragraph
(a) of this Section 4, purchase or otherwise acquire such shares at such time
and in such manner.

     Section 5.   Reacquired Shares.  Any shares of Series A 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
subject to the conditions and restrictions on issuance set forth herein, in the
Charter, in any other certificate of designations creating a series of Preferred
Stock or any similar stock or as otherwise required by law.

     Section 6.   Liquidation, Dissolution or Winding Up.  Upon any liquidation,
                  --------------------------------------
dissolution or winding up of the Corporation, no distribution shall be made to:
(i) the holders of shares of stock ranking junior (either as to dividends or
upon liquidation, dissolution or winding up) to the Series A Preferred Stock
unless, prior thereto, the holders of shares of Series A Preferred Stock shall
have received the greater of (A) $10,000.00 per share ($1.00 per one one-ten
thousandth of a share), plus an amount equal to accrued and unpaid dividends and
distributions thereon, whether or not declared, to the date of such payment, or
(B) an aggregate amount per share, subject to the provision for adjustment
hereinafter set forth, equal to 10,000 times the aggregate amount to be
distributed per share of Common Stock to holders thereof; or (ii) the holders of
shares of stock ranking on a parity (either as to dividends or upon liquidation,
dissolution or winding up) with the Series A Preferred Stock, except
distributions made ratably on the Series A Preferred Stock and all such parity
stock in proportion to the total amounts to which the holders of all such shares
are entitled upon such liquidation, dissolution or winding up. In the event the
Corporation shall at any time declare or pay any dividend on the Common Stock
payable in shares of Common Stock, or effect a subdivision or combination or
consolidation of the outstanding shares of Common Stock (by reclassification or
otherwise than by payment of a dividend in shares of Common Stock) into a
greater or lesser number of shares of Common Stock, then in each such event the
aggregate amount to which each holder of a share of Series A Preferred Stock was
entitled immediately prior to such event under clause (i) of the preceding
sentence 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 outstanding immediately prior to such event.

                                      42
<PAGE>

     Section 7.   Consolidation, Merger or Other.  In the event 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 or otherwise changed, then in any
such event each share of Series A Preferred Stock shall at the same time be
similarly exchanged or changed into an amount per share, subject to the
provision for adjustment hereinafter set forth, equal to 10,000 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 declare
or pay any dividend on the Common Stock payable in shares of Common Stock, or
effect a subdivision or combination or consolidation of the outstanding shares
of Common Stock (by reclassification or otherwise than by payment of a dividend
in shares of Common Stock) into a greater or lesser number of shares of Common
Stock, then in each such event the amount set forth in the preceding sentence
with respect to the exchange or change of shares of Series A 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
outstanding immediately prior to such event.

     Section 8.   No Redemption.  The shares of Series A Preferred Stock shall
                  -------------
not be redeemable.

     Section 9.   Rank.  The Series A Preferred Stock shall rank, with respect
                  ----
to the payment of dividends and the distribution of assets, junior to all series
or classes of the Corporation's Preferred Stock whether issued before or after
the issuance of the Series A Preferred Stock.

     Section 10.  Amendment.  The Charter shall not be amended in any manner
                  ---------
that would materially alter or change the powers, preferences or special rights
of the Series A Preferred Stock, as set forth herein, so as to affect them
adversely without the affirmative vote of the holders of at least two-thirds of
the outstanding shares of Series A Preferred Stock, voting together as a single
class.

                                      43
<PAGE>

     IN WITNESS WHEREOF, Virata Corporation has caused this Certificate of
Designations to be executed on its behalf by its Chief Financial Officer, Senior
Vice President, Finance and Administration, and Secretary, Andrew M. Vought, and
attested to by its Assistant Secretary, Steven Moore, this fourth day of May,
2000.

                                    VIRATA CORPORATION

                                    By: __________________________________
                                          Name:  Andrew M. Vought
                                          Title: Chief Financial Officer, Senior
                                                 Vice President, Finance and
                                                 Administration, and Secretary


     THE UNDERSIGNED, the Assistant Secretary of Virata Corporation , hereby
acknowledges, in the name and on behalf of said corporation, the foregoing
Certificate of Designations to be the corporate act of said corporation and
further certifies that, to the best of his knowledge, information and belief,
the matters and facts set forth therein with respect to the approval thereof or
otherwise required to be verified under oath are true in all material respects,
under the penalties of perjury.

By: ____________________________________
      Name:  Steven Moore
      Title: Assistant Secretary

                                      44