<PAGE>

                                                                     EXHIBIT 4.2

          THE NOTE EVIDENCED HEREBY HAS NOT BEEN REGISTERED UNDER THE UNITED
STATES SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR ANY STATE
SECURITIES LAWS, AND, ACCORDINGLY, 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 ITS 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"); (2) AGREES THAT IT WILL NOT, PRIOR TO
EXPIRATION OF THE HOLDING PERIOD APPLICABLE TO SALES OF THE NOTE EVIDENCED
HEREBY UNDER RULE 144(K) UNDER THE SECURITIES ACT (OR ANY SUCCESSOR PROVISION),
RESELL OR OTHERWISE TRANSFER THE NOTE EVIDENCED HEREBY OR THE COMMON STOCK
ISSUABLE UPON CONVERSION OF SUCH NOTE EXCEPT (A) TO SEMTECH CORPORATION 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 STATE STREET BANK AND TRUST COMPANY OF CALIFORNIA, N.A.,
AS TRUSTEE (OR A SUCCESSOR TRUSTEE, AS APPLICABLE), 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 OR A SUCCESSOR TRUSTEE, AS APPLICABLE), (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 WHICH HAS BEEN DECLARED EFFECTIVE
UNDER THE SECURITIES ACT (AND WHICH CONTINUES TO BE EFFECTIVE AT THE TIME OF
SUCH TRANSFER); (3) PRIOR TO SUCH TRANSFER (OTHER THAN A TRANSFER PURSUANT TO
CLAUSE (2)(F) ABOVE), IT WILL FURNISH TO STATE STREET BANK AND TRUST COMPANY OF
CALIFORNIA, N.A., AS TRUSTEE (OR A SUCCESSOR TRUSTEE, AS APPLICABLE, SUCH
CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION AS THE TRUSTEE 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; AND (4) AGREES THAT IT WILL DELIVER TO EACH
PERSON TO WHOM THE NOTE EVIDENCED HEREBY IS TRANSFERRED A NOTICE SUBSTANTIALLY
TO THE EFFECT OF THIS LEGEND. IN CONNECTION WITH ANY TRANSFER OF THE NOTE
EVIDENCED HEREBY PRIOR TO THE EXPIRATION OF THE HOLDING PERIOD APPLICABLE TO
SALES OF THE NOTE EVIDENCED HEREBY UNDER RULE 144(K) UNDER THE SECURITIES ACT
(OR ANY SUCCESSOR PROVISION), 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 STATE STREET BANK AND TRUST COMPANY OF CALIFORNIA, N.A., AS
TRUSTEE (OR A SUCCESSOR TRUSTEE, AS APPLICABLE). IF
<PAGE>

THE PROPOSED TRANSFEREE IS AN INSTITUTIONAL ACCREDITED INVESTOR OR IS A
PURCHASER WHO IS NOT A U.S. PERSON, THE HOLDER MUST, PRIOR TO SUCH TRANSFER,
FURNISH TO STATE STREET BANK AND TRUST COMPANY OF CALIFORNIA, N.A., AS TRUSTEE
(OR A SUCCESSOR TRUSTEE, AS APPLICABLE), SUCH CERTIFICATIONS, LEGAL OPINIONS OR
OTHER INFORMATION AS SUCH TRUSTEE 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 UPON ANY TRANSFER OF THE NOTE EVIDENCED
HEREBY UNDER RULE 144(K) UNDER THE SECURITIES ACT (OR ANY SUCCESSOR PROVISION).
AS USED HEREIN, THE TERMS "UNITED STATES" AND "U.S. PERSON" HAVE THE MEANINGS
GIVEN TO THEM BY REGULATION S UNDER THE SECURITIES ACT.
<PAGE>

                              SEMTECH CORPORATION

                4 1/2% CONVERTIBLE SUBORDINATED NOTES DUE 2007

                                                             CUSIP:  ___________

No. ________                                                 $_______________

          Semtech Corporation, a corporation duly organized and validly existing
under the laws of the State of Delaware (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 its
registered assigns, the principal sum _____________ ($_____) on February 1,
2007, at the office or agency of the Company maintained for that purpose in
accordance with the terms of the Indenture, 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, and to pay interest, semi-annually on
February 1 and August 1 of each year, commencing August 1, 2000, on said
principal sum at said office or agency, in like coin or currency, at the rate
per annum of 4  1/2 %, from February 1 or August 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 hereof is a date to which interest has been paid or duly
provided for, in which case from the date of this Note, or unless no interest
has been paid or duly provided for on the Notes, in which case from February 14,
2000, until payment of said principal sum has been made or duly provided for.
Notwithstanding the foregoing, if the date hereof is after any February 1 or
August 1, as the case may be, and before the following February 1 or August 1,
this Note shall bear interest from such February 1 or August 1; PROVIDED,
HOWEVER, that if the Company shall default in the payment of interest due on
such February 1 or August 1, then this Note shall bear interest from the next
preceding February 1 or August 1 to which interest has been paid or duly
provided for or, if no interest has been paid or duly provided for on such Note,
from February 14, 2000.  Except as otherwise provided in the Indenture, the
interest payable on the Note pursuant to the Indenture on any February 1 or
August 1 will be paid to the Person entitled thereto as it appears in the Note
register at the close of business on the record date, which shall be the January
15 or July 15 (whether or not a Business Day) next preceding such February 1 or
August 1, as provided in the Indenture; provided, however, that any such
interest not punctually paid or duly provided for shall be payable as provided
in the Indenture.  Interest may, at the option of the Company, be paid either
(i) by check mailed to the registered address of such Person (provided that the
holder of Notes with an aggregate principal amount in excess of $2,000,000
shall, at the written election of such holder, be paid by wire transfer of
immediately available funds) or (ii) by transfer to an account maintained by
such Person located in the United States; PROVIDED, HOWEVER, that payments to
the Depositary will be made by wire transfer of immediately available funds to
the account of the Depositary or its nominee.

          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 the Notes 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 of the Company on the terms and subject to the limitations
referred to
                                       1
<PAGE>

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 the State of New York, without regard to principles
of conflicts of laws.

          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.

                                       2
<PAGE>

          IN WITNESS WHEREOF, the Company has caused this Note to be duly
executed.

                              SEMTECH CORPORATION

                              By:
                                 ---------------------------
                              Name:
                                   -------------------------
                              Title:
                                    ------------------------
Attest:
       --------------------
Name:
     ----------------------
Title:
      ---------------------
Dated:
      ---------------------

TRUSTEE'S CERTIFICATE OF AUTHENTICATION

This is one of the Notes described in the within-named Indenture.

STATE STREET BANK AND TRUST COMPANY OF CALIFORNIA, N.A., as Trustee

By:
   ---------------------------------
     Name:
     Title:

                                      S-1
<PAGE>

                            FORM OF REVERSE OF NOTE

                              SEMTECH CORPORATION

                4 1/2%  CONVERTIBLE SUBORDINATED NOTES DUE 2007

          This Note is one of a duly authorized issue of Notes of the Company,
designated as its 4  1/2% Convertible Subordinated Notes due 2007  (herein
called the "Notes"), limited to the aggregate principal amount of $400,000,000
all issued or to be issued under and pursuant to an Indenture dated as of
February 14, 2000 (herein called the "Indenture"), between the Company and State
Street Bank and Trust Company of California, N.A., as trustee (herein called the
"Trustee"), to which 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, premium, if any, and accrued
interest (including Liquidated Damages (as defined in the Registration Rights
Agreement), if any) on all Notes may be declared by either the Trustee or the
holders of not less than 25% in aggregate principal amount of the Notes then
outstanding, 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 a majority in
aggregate principal amount of the Notes at the time outstanding, 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 (i) 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 upon redemption thereof, or impair the
right of any Noteholder to institute suit for the payment thereof, or make the
principal thereof or 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 a manner adverse to
the Noteholders in any material respect, or change the obligation of the Company
to redeem any Note upon the happening of a Fundamental Change (as defined in the
Indenture) in a manner adverse to the holder of the Notes, 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.  Subject to
the provisions of the Indenture, 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 except a default in the payment of interest
(including Liquidated Damages, if any) or any premium on, or the principal of,
any of the Notes, or a failure by the Company to convert any Notes into Common
Stock of the Company, or a default in the payment of the redemption price
pursuant to Article Three of the Indenture, or a default in respect of a
covenant or provisions of the Indenture

                                       4
<PAGE>

which under Article Eleven of the Indenture cannot be modified without the
consent of the holders of each or all Notes then outstanding or affected
thereby. 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
notation 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 subordinated and subject in right of
payment to the prior payment in full of all Senior Indebtedness of the Company,
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 its 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 obligation of the Company, which is
absolute and unconditional, to pay the principal of and any premium and interest
(including Liquidated Damages, if any) 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
of twelve 30-day months.

          The Notes are issuable in fully registered form, without coupons, in
denominations of $1,000 principal amount and any integral multiple of $1,000. At
the office or agency of the Company referred to on the face hereof, and in the
manner and subject to the limitations provided in the Indenture, without payment
of any service charge but with payment of a sum sufficient to cover any tax,
assessment 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 any other authorized denominations.

          The Notes will not be redeemable at the option of the Company prior to
February 6, 2003.  At any time on or after February 6, 2003, and prior to
maturity, the Notes may be redeemed at the option of the Company, in whole or in
part, upon notice as set forth in Section 3.2, at the following redemption
prices (expressed as percentages of the principal amount), together in each case
with accrued and unpaid interest, if any (including Liquidated Damages, if any)
to, but excluding, the date fixed for redemption:
<TABLE>
<CAPTION>
     Period                                                                      Redemption Price
     ------                                                                      ----------------
    <S>                                                                            <C>
     Beginning on February 6, 2003 and ending on January 31, 2004..........         102.571%
     Beginning on February 1, 2004 and ending on January 31, 2005..........         101.929%
     Beginning on February 1, 2005 and ending on January 31, 2006..........         101.286%
     Beginning on February 1, 2006 and ending on January 31, 2007..........         100.643%
</TABLE>

                                       5
<PAGE>

and 100% on February 1, 2007; provided, however, that if the date fixed for
redemption is on a February 1 or August 1, then the interest payable on such
date shall be paid to the holder of record on the preceding January 15 or July
15, respectively.

          The Company may not give notice of any redemption of the Notes if a
default in the payment of interest or premium, if any, on the Notes has occurred
and is continuing.

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

          If a Fundamental Change occurs at any time prior to maturity of the
Notes, the Notes will be redeemable on the 30th day after notice thereof (the
"Repurchase Date") at the option of the holder of the Notes at a redemption
price equal to 100% of the principal amount thereof, together with accrued
interest to (but excluding) the date of redemption; provided, however, that, if
such Repurchase Date is a February 1 or August 1, the interest payable on such
date shall be paid to the holder of record of the Notes on the preceding January
15 or July 15, respectively.  The Notes will be redeemable in multiples of
$1,000 principal amount.  The Company shall mail to all holders of record of the
Notes a notice of the occurrence of a Fundamental Change and of the redemption
right arising as a result thereof on or before the 10th day after the occurrence
of such Fundamental Change.  For a Note to be so redeemed at the option of the
holder, the Company must receive at the office or agency of the Company
maintained for that purpose in accordance with the terms of the Indenture, such
Note with the form entitled "Option to Elect Repayment Upon a Fundamental
Change" on the reverse thereof duly completed, together with such Note, duly
endorsed for transfer, on or before the 30th day after the date of such notice
of a Fundamental Change (or if such 30th day is not a Business Day, the
immediately succeeding Business Day).

          Subject to the provisions of the Indenture, the holder hereof has the
right, at its option, at any time after the original issuance of any Notes
through the close of business on the final maturity date of the Notes, or, as to
all or any portion hereof called for redemption, prior to the close of business
on the Business Day immediately preceding the date fixed for redemption (unless
the Company shall default in payment due upon redemption thereof), to convert
the principal hereof or any portion of such principal which is $1,000 or an
integral multiple thereof into that number of shares of the Company's Common
Stock (as such 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 $84.46, as may 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 (the form entitled "Conversion Notice" on the
reverse hereof), to the Company at the office or agency of the Company
maintained for that purpose in accordance with the terms of the Indenture, 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 on any Note converted or dividends on any
shares issued upon conversion of such Note will be made upon any conversion
except as set forth in the next sentence.  If this Note (or portion hereof) is
surrendered for conversion during the period from the close of business on any
record date for the payment of interest to the close of business on the Business
Day preceding the following
                                       6
<PAGE>

interest payment date and either (x) has not been called for redemption on a
redemption date that occurs during such period or (y) is not to be redeemed in
connection with a Fundamental Change on a Repurchase Date that occurs during
such period, this Note (or portion hereof being converted) must be accompanied
by an amount, in New York Clearing House funds or other funds acceptable to the
Company, equal to the interest payable on such interest payment date on the
principal amount being converted; provided, however, that no such payment shall
be required if there shall exist at the time of conversion a default in the
payment of interest on the Notes. No fractional shares will be issued upon any
conversion, but an adjustment and payment in cash will be made, 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. A Note in
respect of which a holder is exercising its right to require redemption upon a
Fundamental Change may be converted only if such holder withdraws its election
to exercise such right in accordance with the terms of the Indenture. Any Notes
called for redemption, unless surrendered for conversion by the holders thereof
on or before the close of business on the Business Day preceding the date fixed
for redemption, may be deemed to be redeemed from the holders of such Notes for
an amount equal to the applicable redemption price, together with accrued but
unpaid interest (including Liquidated Damages, if any) to (but excluding) the
date fixed for redemption, by one or more investment banks or other purchasers
who may agree with the Company (i) to purchase such Notes from the holders
thereof and convert them into shares of the Company's Common Stock and (ii) to
make payment for such Notes as aforesaid to the Trustee in trust for the
holders.

          Upon due presentment for registration of transfer of this Note at the
office or agency of the Company maintained for that purpose in accordance with
the terms of the Indenture, 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, assessment or other governmental charge imposed in
connection therewith.

          The Company, the Trustee, any authenticating agent, any paying agent,
any conversion agent and any Note registrar 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 other purposes, and neither the Company nor the Trustee nor any other
authenticating agent nor any paying agent nor 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 or sums 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 supplemental indenture or in any Note, or
because of the creation of any indebtedness represented thereby, shall be had
against any incorporator, stockholder, employee, agent, officer or 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

                                       7
<PAGE>

penalty or otherwise, all such liability being, by acceptance hereof and as part
of the consideration for the issue hereof, expressly waived and released.

          This Note shall be deemed to be a contract made under the laws of New
York, and for all purposes shall be construed in accordance with the laws of New
York, without regard to principles of conflicts of laws.

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

                                       8
<PAGE>

                                 ABBREVIATIONS

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

          TEN COM =  tenants in common

          UNIF GIFT MIN ACT = Uniform Gift to Minors Act

          TEN ENJ =  tenants by the entireties

          CUST = custodian

          JT TEN = joint tenants with right of survivorship and not as tenants
in common

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

                                       9
<PAGE>

                               CONVERSION NOTICE

TO:       SEMTECH CORPORATION
          STATE STREET BANK AND TRUST COMPANY OF CALIFORNIA, N.A.

          The undersigned registered owner of this Note hereby irrevocably
exercises the option to convert this Note, or the portion thereof (which is
$1,000 or an integral multiple thereof) below designated, into shares of Common
Stock of Semtech Corporation 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
provide the appropriate information below and pay all transfer taxes payable
with respect thereto.  Any amount required to be paid by the undersigned on
account of interest accompanies this Note.

Dated: ______________________

_____________________________

_____________________________
Signature(s)

          Signature(s) must be guaranteed by an "eligible guarantor institution"
          meeting the requirements of the Note registrar, which requirements
          include membership or participation in the Security Transfer Agent
          Medallion Program ("STAMP") or such other "signature guarantee
          program" as may be determined by the Note registrar in addition to, or
          in substitution for, STAMP, all in accordance with the Securities
          Exchange Act of 1934, as amended.

          _______________________________
          Signature Guarantee

                                      10
<PAGE>

          Fill in the registration of shares of Common Stock if to be issued,
and Notes if to be delivered, other than to and in the name of the registered
holder:

_____________________________________
(Name)

_____________________________________
(Street Address)

_____________________________________
(City, State and Zip Code)

_____________________________________
Please print name and address

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


$____________________________________
Social Security or Other Taxpayer
Identification Number:

_____________________________________

                                      11
<PAGE>

                           OPTION TO ELECT REPAYMENT

                           UPON A FUNDAMENTAL CHANGE

TO:       SEMTECH CORPORATION
          STATE STREET BANK AND TRUST COMPANY OF CALIFORNIA, N.A.

          The undersigned registered owner of this Note hereby irrevocably
acknowledges receipt of a notice from Semtech Corporation (the "Company") as to
the occurrence of a Fundamental Change 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 $1,000 or an integral multiple thereof) below
designated, in accordance with the terms of the Indenture referred to in this
Note at the price of 100% of such entire principal amount or portion thereof,
together with accrued interest to, but excluding, such repayment date, to the
registered holder hereof.

Dated: ____________________

___________________________

___________________________
Signature(s)

                              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):

                              $_________________________________
                              __________________________________
                              Social Security or Other Taxpayer Identification
                              Number

                                      12
<PAGE>

                                   ASSIGNMENT

          For value received __________________________________________ hereby
sell(s) assign(s) and transfer(s) unto _____________________________________
(Please insert social security or other Taxpayer Identification Number of
assignee) the within Note, and hereby irrevocably constitutes and appoints
____________________________________ attorney to transfer said Note on the books
of the Company, with full power of substitution in the premises.

          In connection with any transfer of the Note prior to the expiration of
the holding period applicable to sales thereof under Rule 144(k) under the
Securities Act (or any successor provision) (other than any transfer pursuant to
a registration statement that has been declared effective under the Securities
Act), the undersigned confirms that such Note is being transferred:

     [ ]  To Semtech Corporation or a subsidiary thereof; or
     [ ]  Inside the United States pursuant to and in compliance with Rule 144A
          under the Securities Act of 1933, as amended; or
     [ ]  Inside the United States to an Institutional Accredited Investor
          pursuant to and in compliance with the Securities Act of 1933, as
          amended, in a minimum denomination of $100,000; or
     [ ]  Outside the Unites States in compliance with Rule 904 under the
          Securities Act; or
     [ ]  Pursuant to and in compliance with Rule 144 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: ___________________
                              __________________________________

                              __________________________________
                              Signature(s)

                              Signature(s) must be guaranteed by an "eligible
                              guarantor institution" meeting the requirements of
                              the Note registrar, which requirements include
                              membership or participation in the Security
                              Transfer Agent Medallion Program ("STAMP") or such
                              other "signature guarantee program" as may be
                              determined by the Note registrar in addition to,
                              or in substitution for, STAMP, all in accordance
                              with the Securities Exchange Act of 1934, as
                              amended.

                              ___________________________________
                              Signature Guarantee

                                      13
<PAGE>

NOTICE:  The signature of the conversion notice, the option to elect repayment
upon a Fundamental Change 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.

                                      14