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                                                                     EXHIBIT 4.3

                               ALTERA CORPORATION
                 5-3/4% CONVERTIBLE SUBORDINATED NOTE DUE 2002

THE NOTE EVIDENCED HEREBY HAS NOT BEEN REGISTERED UNDER THE U.S. SECURITIES 
ACT  OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR ANY STATE SECURITIES LAWS, 
AND MAY NOT BE OFFERED OR SOLD WITHIN THE UNITED STATES OR TO, OR FOR THE 
ACCOUNT OR BENEFIT OF, U.S. PERSONS EXCEPT AS SET FORTH IN THE FOLLOWING 
SENTENCE.  BY ACQUISITION HEREOF, THE HOLDER (1) REPRESENTS THAT (A)
IT IS A "QUALIFIED INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE
SECURITIES ACT) OR (B) IT IS AN INSTITUTIONAL "ACCREDITED INVESTOR" (AS DEFINED
IN RULE 501(A)(1), (2), (3) OR (7) UNDER THE SECURITIES ACT) ("INSTITUTIONAL
ACCREDITED INVESTOR") OR (C) IT IS NOT A U.S. PERSON AND IS ACQUIRING THE NOTE
EVIDENCED HEREBY IN AN OFFSHORE TRANSACTION; (2) AGREES THAT IT WILL NOT WITHIN
THREE YEARS AFTER THE ORIGINAL ISSUANCE OF THE NOTE EVIDENCED HEREBY RESELL OR
OTHERWISE TRANSFER THE NOTE EVIDENCED HEREBY OR THE COMMON STOCK ISSUABLE UPON
CONVERSION OF SUCH NOTE EXCEPT (A) TO THE COMPANY OR ANY SUBSIDIARY THEREOF,
(B) INSIDE THE UNITED STATES TO A QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE
WITH RULE 144A UNDER THE SECURITIES ACT, (C) INSIDE THE UNITED STATES TO AN
INSTITUTIONAL ACCREDITED INVESTOR THAT, PRIOR TO SUCH TRANSFER, FURNISHES TO
THE FIRST NATIONAL BANK OF BOSTON, AS TRUSTEE, A SIGNED LETTER CONTAINING
CERTAIN REPRESENTATIONS AND AGREEMENTS RELATING TO THE RESTRICTIONS ON TRANSFER
OF THE NOTE EVIDENCED HEREBY (THE FORM OF WHICH LETTER CAN BE OBTAINED FROM
SUCH TRUSTEE), (D) OUTSIDE THE UNITED STATES IN COMPLIANCE WITH RULE 904 UNDER
THE SECURITIES ACT, (E) PURSUANT TO THE EXEMPTION FROM REGISTRATION PROVIDED BY
RULE 144 UNDER THE SECURITIES ACT (IF AVAILABLE), OR (F) PURSUANT TO A
REGISTRATION STATEMENT THAT HAS BEEN DECLARED EFFECTIVE UNDER THE SECURITIES
ACT (AND WHICH CONTINUES TO BE EFFECTIVE AT THE TIME OF SUCH TRANSFER); AND (3)
AGREES THAT IT WILL DELIVER TO EACH PERSON TO WHOM THE NOTE EVIDENCED HEREBY IS
TRANSFERRED (OTHER THAN A TRANSFER PURSUANT TO CLAUSE 2(F) ABOVE) A NOTICE
SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND. IN CONNECTION WITH ANY TRANSFER OF
THE NOTE EVIDENCED HEREBY WITHIN THREE YEARS AFTER THE ORIGINAL ISSUANCE OF THE
NOTE (OTHER THAN A TRANSFER PURSUANT TO CLAUSE 2(F) ABOVE), THE HOLDER MUST
CHECK THE APPROPRIATE BOX SET FORTH ON THE REVERSE HEREOF RELATING TO THE
MANNER OF SUCH TRANSFER AND SUBMIT THIS CERTIFICATE TO THE FIRST NATIONAL BANK
OF BOSTON, AS TRUSTEE.  IF THE PROPOSED TRANSFER IS PURSUANT TO CLAUSE 2(C),
2(D) OR 2(E) ABOVE, THE HOLDER MUST, PRIOR TO SUCH TRANSFER, FURNISH TO THE
FIRST NATIONAL BANK OF BOSTON, AS TRUSTEE, SUCH CERTIFICATIONS, LEGAL OPINIONS
OR OTHER INFORMATION AS THE COMPANY MAY REASONABLY REQUIRE TO CONFIRM THAT SUCH
TRANSFER IS BEING MADE PURSUANT TO AN EXEMPTION FROM, OR IN A TRANSACTION NOT
SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT.  THIS LEGEND
WILL BE REMOVED UPON THE EARLIER OF THE TRANSFER OF THE NOTE EVIDENCED HEREBY
PURSUANT TO CLAUSE 2(F) ABOVE OR THE EXPIRATION OF THREE YEARS FROM THE
ORIGINAL ISSUANCE OF THE NOTE EVIDENCED HEREBY.  AS USED HEREIN, THE TERMS
"OFFSHORE TRANSACTION," "UNITED STATES" AND "U.S. PERSON" HAVE THE MEANINGS
GIVEN TO THEM BY REGULATION S UNDER THE SECURITIES ACT.

                                                               CUSIP 021441 AA 8

ALTERA CORPORATION, a corporation duly organized and validly existing under the
laws of the State of California (herein called the "Company", which term
includes any successor corporation under the Indenture referred to on the
reverse hereof), for value received hereby promises to pay to 
                                                      , or registered assigns, 
the principal sum of                                                     Dollars
   2

on June 15, 2002, and to pay interest on said principal sum semi-annually on
June 15 and December 15 of each year, commencing December 15, 1995, at the rate
per annum specified in the title of this Note, accrued from the June 1 or
December 1 as the case may be, next preceding the date of this Note to which
interest has been paid or duly provided for, unless the date of this Note is a
date to which interest has been paid or duly provided for, in which case
interest shall accrue from the date of this Note, or unless no interest has
been paid or duly provided for on this Note, in which case interest shall
accrue from June 21, 1995, until payment of said principal sum has been made or
duly provided for.  Notwithstanding the foregoing, if the date hereof is after
any June 1 or December 1, as the case may be, and before the following June 15
or December 15, this Note shall bear interest from such June 15 or December 15,
respectively; provided, however, that if the Company shall default in the
payment of interest due on such June 15 or December 15, then this Note shall
bear interest from the next preceding June 15 or December 15 to which interest
has been paid or duly provided for or, if no interest has been paid or duly
provided for on this Note, from June 21, 1995.  The interest so payable on any
June 15 or December 15 will be paid to the person in whose name this Note (or
one or more Predecessor Notes) is registered at the close of business on the
record date, which shall be the June 1 or December 1 (whether or not a Business
Day) next preceding such June 15 or December 15, respectively; provided that
any such interest not punctually paid or duly provided for shall be payable as
provided in the indenture.  Payment of the principal of and interest accrued on
this Note shall be made at the office or agency of the Company maintained for
that purpose in the Borough of Manhattan, The City of New York, or, at the
option of the Holder of this Note, at the Corporate Trust Office, in such coin
or currency of the United States of America as at the time of payment shall be
legal tender for the payment of public and private debts, provided however,
that at the Company's option, payment of interest may be made by check mailed
to the registered address of the person entitled thereto.

         Reference is made to the further provisions of this Note set forth on
the reverse hereof, including, without limitation, provisions subordinating the
payment of principal of and premium, if any, and interest on this Note to the
prior payment in full of all Senior Indebtedness, as defined in the Indenture,
and provisions giving the Holder of this Note the right to convert this Note
into Common Stock on the terms and subject to the limitations referred to on
the reverse hereof and as more fully specified in the Indenture.  Such further
provisions shall for all purposes have the same effect as though fully set
forth at this place.

         This Note shall be deemed to be a contract made under the laws of the
State of New York, and for all purposes shall be construed in accordance with
and governed by the laws of said State.

         This note shall not be valid or become obligatory for any purpose
until the certificate of authentication hereon shall have been manually signed
by the Trustee or a duly authorized authenticating agent under the Indenture.

         IN WITNESS WHEREOF, the Company has caused this Note to be duly
executed under its corporate seal.

         Dated:
                                                              ALTERA CORPORATION


                                                                                          
             TRUSTEE'S CERTIFICATE OF AUTHENTICATION
This is one of the Notes described in the within-named indenture.       Attest:                 By:
                THE FIRST NATIONAL BANK OF BOSTON,
                                                       as Trustee

By:

     AUTHORIZED SIGNATORY           ASSISTANT SECRETARY           PRESIDENT





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                               ALTERA CORPORATION
                 5-3/4% CONVERTIBLE SUBORDINATED NOTE DUE 2002

         This Note is one of a duly authorized issue of Notes of the Company,
designated as its 5-3/4% Convertible Subordinated Notes due 2002 (herein called
the "Notes"), limited to the aggregate principal amount of $230,000,000, all
issued or to be issued under and pursuant to an indenture, dated as of June 15,
1995 (herein called the "Indenture"), between the Company and The First
National Bank of Boston (herein called the "Trustee"), to which the Indenture
and all indentures supplemental thereto reference is hereby made for a
description of the rights, limitations of rights, obligations, duties and
immunities thereunder of the Trustee, the Company and the Holders of the Notes.

         In case an Event of Default, as defined in the Indenture, shall have
occurred and be continuing, the principal of and accrued interest on all Notes
may be declared, and upon said declaration shall become, due and payable, in
the manner, with the effect and subject to the conditions provided in the
Indenture.

         The Indenture contains provisions permitting the Company and the
Trustee, with the consent of the Holders of not less than sixty-six and
two-thirds percent (66-2/3%) of the aggregate principal amount of the Notes at
the time outstanding, evidenced as in the Indenture provided, to execute
supplemental indentures adding any provisions to or changing in any manner or
eliminating any of the provisions of the Indenture or of any supplemental
indenture or modifying in any manner the rights of the Holders of the Notes;
provided, however, that no such supplemental indenture shall (1) extend the
fixed maturity of any Note, or reduce the rate or extend the time of payment of
interest thereon, or reduce the principal amount thereof or premium, if any
thereon, or reduce any amount payable on redemption or repurchase thereof,
change or impair the obligation of the Company to repurchase any Note at the
option of the Holder upon the happening of a Designated Event, or impair or
affect the right of any Noteholder to institute suit for the payment thereof,
or make the principal thereof of interest or premium, if any, thereon payable
in any coin or currency other than that provided in the Notes, or modify the
provisions of the Indenture with respect to the subordination of the Notes in
manner adverse to the Noteholders, or impair the right to convert the Notes
into Common Stock subject to the terms set forth in the Indenture, including
Section 15.6 thereof, without the consent of the Holder of each Note so
affected, or (ii) reduce the aforesaid percentage of Notes, the Holders of
which are required to consent to any such supplemental indenture, without the
consent of the Holders of all Notes then outstanding.  It is also provided in
the Indenture that, prior to any declaration accelerating the maturity of the
Notes, the Holders of a majority in aggregate principal amount of the Notes at
the time outstanding may on behalf of the Holders of all of the Notes waive any
past default or Event of Default under the Indenture and its consequences
expect a default in the payment of interest or any premium on or the principal
of or any redemption price or Repurchase Price of any of the Notes or the
company's failure to convert any Notes into Common Stock.  Any such consent or
waiver by the Holder of this Note (unless revoked as provided in the Indenture)
shall be conclusive and binding upon such Holder and upon all future Holders
and owners of this Note and any Notes which may be issued in exchange or
substitution hereof, irrespective of whether or not any notion thereof is made
upon this Note or such other Notes.

         The indebtedness evidenced by the Notes is, to the extent and in the
manner provided in the Indenture, expressly subordinate and subject in right of
payment to the prior payment in full of all Senior Indebtedness, as defined in
the Indenture, whether outstanding at the date of the Indenture or thereafter
incurred, and this Note is issued subject to the provisions of the Indenture
with respect to such subordination.  Each Holder of this Note, by accepting the
same, agrees to and shall be bound by such provisions and authorizes the
Trustee on his behalf to take such action as may be necessary or appropriate to
effectuate the subordination so provided and appoints the Trustee his attorney
in fact for such purpose.

         No reference herein to the Indenture and no provision of this Note or
of the Indenture shall alter or impair the Company's obligation, which is
absolute and unconditional, to pay the principal of and any premium and
interest on this Note at the place, at the respective times, at the rate and in
the coin or currency herein prescribed.

         Interest on the Notes shall be computed on the basis of a 360-day year
comprised of twelve 30-day months.

         The Notes are issuable in registered form without coupons in
denominations of One Thousand Dollars ($1,000) principal amount and integral
multiples thereof.  At the office or agency of the Company, and in the manner
and subject to the limitations provided in the Indenture, without payment of
any service charge but with payment





                                      -3-
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of a sum sufficient to cover any tax or other governmental charge that may be
imposed in connection with any registration or exchange of Notes, Notes may be
exchanged for a like aggregate principal amount of Notes of other authorized
denominations.

         The Notes will not be redeemable at the Company's option prior to June
16, 1998.  On or after such date and prior to maturity the Notes may be
redeemed at the Company's option as a whole, or from time to time in part, upon
mailing a notice of such redemption not less than thirty (30) nor more than
sixty (60) days before the date fixed for redemption to the Holders of Notes at
their last registered addresses, all as provided in the Indenture, at the
following redemption prices (expressed as percentages of the principal amount),
together in each case with accrued interest to, but excluding, the date fixed
for redemption.

         If redeemed during the 12-month period beginning June 15 (or June 16,
in the case of 1998):



                 Year      Percentage      Year      Percentage
                 ----      ----------      ----      ----------
                                              
                 1998        103.29%       2000        101.64%
                 1999        102.46        2001        100.82


and one hundred percent (100%) at June 15, 2002; provided that if the date
fixed for redemption is a June 15 or December 15, then the interest payable on
such date shall be paid to the Holder of record on the next preceding June 1 or
December 1, respectively.

         The Notes are not subject to redemption through the operation of any
sinking fund.

         Upon the occurrence of a "Designated Event" prior to June 15, 2002,
the Noteholder has the right, at such Holder's option, to require the Company
to repurchase all or any portion of such Holders' Notes on the thirtieth (30th)
day after notice of such Designated Event at a price equal to one hundred
percent (100%) of the principal amount of the Notes, together in each case with
accrued interest to the date fixed for redemption; provided that if such
repurchase date is June 15 or December 15, then the interest payable on such
date shall be paid to the Holder of record of the Note on the next preceding
June 1 or December 1, respectively.  The Company shall mail to all Holders of
record of the Notes a notice of the occurrence of a Designated Event and of the
repurchase right arising as a result thereof on or before fifteen (15) calendar
days after the occurrence of such Designated Event.

         Subject to the provisions of the Indenture, the Holder hereof has the
right, at its option, at any time after sixty (60) days following the latest
date of original issuance of the Notes and prior to the close of business on
June 15, 2002, or, as to all or any portion hereof called for redemption, prior
to the close of business on the Trading Day next preceding the date fixed for
redemption (unless the Company shall default in payment due upon redemption),
to convert the principal hereof or any portion of such principal which is One
Thousand Dollars ($1,000) or an integral multiple thereof, into that number of
fully paid and non-assessable shares of Company's Common Stock, as said shares
shall be constituted at the date of conversion, obtained by dividing the
principal amount of this Note or portion thereof to be converted by the
Conversion Price of $51.17 or such Conversion Price as adjusted from time to
time as provided in the Indenture, upon surrender of this Note, together with a
conversion notice as provided in the Indenture and this Note, to the Company at
the office or agency of the Company maintained for that purpose in the Borough
of Manhattan, The City of New York, or at the option of such Holder, the
Corporate Trust Office, and, unless the shares issuable on conversion are to be
issued in the same name as this Note, duly endorsed by, or accompanied by
instruments of transfer in form satisfactory to the company duly executed by,
the Holder or by his duly authorized attorney.  No adjustment in respect of
interest or dividends will be made upon any conversion; provided, however, that
if this Note shall be surrendered for conversion during the period from the
close of business on any record date for the payment of interest through the
close of business on the Trading Day next preceding the following interest
payment date, this Note (unless it or the portion being converted shall have
been called for redemption on a date in such period) must be accompanied by an
amount, in funds acceptable to the Company, equal to the interest otherwise
payable on such interest payment date on the principal amount being converted.
No fractional shares of Common Stock will be issued upon conversion, but an
adjustment in cash will be paid to the Holder, as provided in the Indenture, in
respect of any fraction of a share which would otherwise be issuable upon the
surrender of any Note or Notes for conversion.





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         Any Notes called for redemption, unless surrendered for conversion on
or before the close of business on the date fixed for redemption, may be deemed
to be purchased from the Holder of such Notes at an amount equal to the
applicable redemption price, together with accrued interest to the date fixed
for redemption, by one or more investment bankers or other purchasers who may
agree with the Company to purchase such Notes from the Holders thereof and
convert them into Common Stock and to make payment for such Notes as aforesaid
to the Trustee in trust for such Holders.

         Upon due presentment for registration of transfer of this Note at the
office or agency of the Company in the Borough of Manhattan, The City of New
York, or at the option of the Holder of this Note, at the Corporate Trust
Office, a new Note or Notes of authorized denominations for an equal aggregate
principal amount will be issued to the transferee in exchange thereof, subject
to the limitations provided in the Indenture, without charge except for any tax
or other governmental charge imposed in connection therewith.

         The Company, the Trustee, any authenticating agent, any paying agent,
any conversion agent and any Note Register may deem and treat the registered
Holder hereof as the absolute owner of this Note (whether or not this Note
shall be overdue and notwithstanding any notation of ownership or other writing
hereon made by anyone other than the Company or any Note Registrar), for the
purpose of receiving payment hereof, or on account hereof, for the conversion
hereof and for all purposes, and neither the Company nor the Trustee nor any
other authenticating agent nor any paying agent nor any other conversion agent
nor any Note Registrar shall be affected by any notice to the contrary.  All
payments made to or upon the order of such registered Holder shall, to the
extent of the sum paid, satisfy and discharge liability for monies payable on
this Note.

         No recourse for the payment of the principal of or any premium or
interest on this Note, or for any claim based hereon or otherwise in respect
hereof, and no recourse under or upon any obligation, covenant or agreement of
the Company in the Indenture or any indenture supplemental thereto or in any
Note, or because of the creation of any indebtedness represented thereby, shall
be had against any incorporator, stockholder, employee, agent, officer,
director or subsidiary, as such, past, present or future, of the Company or of
any successor corporation, either directly or through the Company or any
successor corporation, whether by virtue of any constitution, statute or rule
of law or by the enforcement of any assessment or penalty or otherwise, all
such liability being, by the acceptance hereof and as part of the consideration
for the issue hereof, expressly waived and released.

         Terms used in this Note and defined in the Indenture are used herein
as therein defined.


                                 ABBREVIATIONS

         The following abbreviations, when used in the inscription on the face
of this Note, shall be construed as though they were written out in full
according to applicable laws or regulations:

TEN COM - as tenants in common                   UNIF GIFT MIN ACT-- 
TEN ENT - as tenants by entireties               _____________________ Custodian
JT TEN  - as tenants with right of                      (Cust)
          survivorship and not as                _____________________ under
          tenants in common                             (Minor)
                                                 Uniform Gifts to 
                                                 Minors Act ____________________
                                                                   (State)

    Additional abbreviations may also be used though not in the above list.





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                               CONVERSION NOTICE

To:   Altera Corporation:

         The undersigned registered owner of this Note hereby irrevocably
exercises the option to convert this Note, or the portion hereof (which is One
Thousand Dollars ($1,000) principal amount or an integral multiple thereof)
below designated, into shares of Common Stock in accordance with the terms of
the indenture referred to in this Note, and directs that the shares issuable
and deliverable upon such conversion, together with any check in payment for
fractional shares and any Notes representing any unconverted principal amount
hereof, be issued and delivered to the registered Holder hereof unless a
different name has been indicated below.  If shares or any portion of this Note
not converted are to be issued in the name of a person other than the
undersigned, the undersigned will pay all transfer taxes payable with respect
thereto.  Any amount required to be paid to the undersigned on account of
interest accompanies this Note.

Dated: ________________________________     ____________________________________

Fill in for registration of shares to 
be issued, and Notes if to be delivered,    ____________________________________
other than to and in the name of the                    (Signatures)
registered Holder:
                                            Signature(s) must be guaranteed by
_______________________________________     an eligible Guarantor Institution
                (Name)                      (banks, stock, brokers, savings and
                                            loan associations and credit 
_______________________________________     unions) with membership in an 
           (Street Address)                 approved signature guarantee 
                                            medallion program pursuant to 
_______________________________________     Securities and Exchange Commission 
      (City, State and Zip Code)            Rule 17Ad-15 if shares of Common 
     Please print name and address          Stock are to be issued, or Notes to
                                            be delivered, other than to and in 
                                            the name of the registered Holder.

                                            ____________________________________
                                                     Signature Guaranteed

                                              Principal amount to be converted
                                                      (if less than all):

                                                    $_________________,000

                                            ____________________________________
                                              Social Security or Other Taxpayer 
                                                    Identification Number





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              OPTION TO ELECT REPURCHASE UPON A DESIGNATED EVENT

To:   Altera Corporation

         The undersigned registered new owner of this Note hereby irrevocably
acknowledges receipt of a notice from Altera Corporation (the "Company") as to
the occurrence of a Designated Event with respect to the Company and requests
and instructs the Company to repay the entire principal amount of this Note, or
the portion thereof (which is One Thousand Dollars ($1,000) principal amount or
an integral multiple thereof) below designated, in accordance with the terms of
the indenture referred to in this Note, together with accrued interest to such
date, to the registered Holder hereof.


Dated: ________________________________     ____________________________________


                                            ____________________________________
                                                        (Signatures)

                                            NOTICE:  The above signatures of the
                                            Holder(s) hereof must correspond 
                                            with the name as written upon the 
                                            face of the Note in every particular
                                            without alteration or enlargement or
                                            any change whatever.

                                                 Principal amount to be repaid
                                                      (if less than all):

                                                    $_________________,000

                                            ____________________________________
                                              Social Security or Other Taxpayer 
                                                    Identification Number





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                                   ASSIGNMENT

For value received _____________________________________________________________
hereby sell(s), assign(s) and transfer(s) unto

________________________________________________________________________________
    (Please insert social security or other identifying number of assignee)

the within Note, and hereby irrevocably constitutes and appoints

________________________________________________________________________________
attorney to transfer the said Note on the books of the Company, with full power 
of substitution in the premises.

         In connection with any transfer of the within Note occurring within
three years of the original issuance of such Note, the undersigned confirms
that such Note is being transferred:

         [ ]  To Altera Corporation or a subsidiary thereof; or
         [ ]  Pursuant to and in compliance with Rule 144A under the Securities 
Act of 1933, as amended; or
         [ ]  To an Institutional Accredited Investor pursuant to and in 
compliance with the Securities Act of 1933, as amended; or
         [ ]  Pursuant to and in compliance with Regulation S under the 
Securities Act of 1933, as amended; and unless the box below is checked, the 
undersigned confirms that such Note is not being transferred to an "affiliate" 
of the Company as defined in Rule 144 under the Securities Act of 1933, as 
amended (an "Affiliate"):
         [ ]  The transferee is an Affiliate of the Company.

Dated: ________________________________     ____________________________________


                                            ____________________________________
                                                        (Signatures)

                                            Signature(s) must be guaranteed by 
                                            an eligible Guarantor Institution 
                                            (banks, stock brokers, savings and 
                                            loan associations and credit 
                                            unions) with membership in an 
                                            approved signature guarantee 
                                            medallion program pursuant to 
                                            Securities and Exchange Commission
                                            Rule 17Ad-15 if shares of Common 
                                            Stock are to be issued, or Notes 
                                            to be delivered, other than to and 
                                            in the name of the registered 
                                            Holder.

                                            ____________________________________
                                                     Signature Guaranteed


NOTICE:   The signature on the conversion notice, the option to elect
repurchase upon a Designated Event or the assignment must correspond with the
name as written upon the face of the Note in every particular without
alteration or enlargement or any change whatever.





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