<PAGE>

                                                                     Exhibit 4.5

THE SECURITIES REPRESENTED BY THIS CERTIFICATE WERE ORIGINALLY ISSUED ON MAY 18,
2000, HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE
"ACT"), OR UNDER ANY STATE SECURITIES LAWS AND MAY NOT BE SOLD OR TRANSFERRED IN
THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER THE ACT AND APPLICABLE
STATE SECURITIES LAWS OR AN EXEMPTION FROM REGISTRATION THEREUNDER.  THE
SECURITIES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO ADDITIONAL
RESTRICTIONS ON TRANSFER AND CERTAIN OTHER AGREEMENTS SET FORTH IN A
STOCKHOLDERS AGREEMENT DATED AS OF JULY 30, 1999 AMONG SMTC CORPORATION AND
CERTAIN STOCKHOLDERS THEREOF, A COPY OF WHICH MAY BE OBTAINED WITHOUT CHARGE BY
THE HOLDER HEREOF AT THE COMPANY'S PRINCIPAL PLACE OF BUSINESS.


No. W-1                                                           9008.76 Units


                              WARRANT TO PURCHASE

                              UNITS CONSISTING OF
                            CLASS A-1 COMMON STOCK
                           AND CLASS L COMMON STOCK

                                      OF

                               SMTC CORPORATION
             Incorporated Under the Laws of the State of Delaware

     THIS CERTIFIES THAT, for value received, and subject to the provisions
hereinafter set forth, Bain Capital Fund VI, L.P., or its registered assigns
(the "Holder") is entitled to purchase from SMTC Corporation, a Delaware
corporation (the "Company"), during the period specified in this Warrant,
9008.76 Units. Each Unit shall consist of nine (9) shares (subject to adjustment
as hereinafter provided) of the Company's duly authorized, validly issued, fully
paid and non-assessable Class A-1 Common Stock, par value .001 per share (the
"Class A Stock") and one (1) share (subject to adjustment as hereinafter
provided) of the Company's duly authorized, validly issued, fully paid and non-
assessable Class L Common Stock, par value .001 per share (the "Class L Stock
and, together with the Class A Stock, the "Common Stock"). The initial exercise
price per Unit shall be (i) the Remaining Class L Minimum Payment Amount, as
defined in the Amended and Restated Certificate of Incorporation of the Company,
less (ii) United States Forty-Two Dollars (US$42.00), (the "Initial Exercise
Price"). Certain capitalized terms used in this Warrant are defined in Section
10.
<PAGE>

1.    Duration.  The right to subscribe for and purchase Units represented
      --------
hereby shall commence on November  18,  2000 and shall expire at 5:00 P.M.,
Eastern Standard Time, on May 18, 2010 (the "Expiration Date").  The Mandatory
Redemption provisions of Section 3 hereto shall commence on the date hereof and
shall expire at the Expiration Date.

2.    Method of Exercise; Payment, Issuance of New Warrant; Transfer and
      ------------------------------------------------------------------
      Exchange.
      --------

      2.1. Method of Exercise.
           ------------------

           2.1.1. Exercise. This Warrant may be exercised by the Holder hereof,
                  --------
      in whole or in part, during normal business hours on any business day
      after November 18, 2000 and on or prior to the Expiration Date, by
      surrender of this Warrant to the Company at its principal office,
      accompanied by a subscription substantially in the form attached to this
      Warrant duly executed by such Holder and accompanied by (a) wire transfer
      of immediately available funds, (b) certified or official bank check
      payable to the order of the Company or (c) delivery to the Company of
      Notes (which for this purpose will be valued at par plus accrued and
      unpaid interest), in each case in the amount obtained by multiplying (i)
      the number of Units for which this Warrant is then being exercised, as
      designated in such subscription, by (ii) the Initial Exercise Price, and
      such Holder shall thereupon be entitled to receive the number of Units
      (consisting of the number of shares of Class A Stock and Class L Stock (or
      Other Securities) as provided in Section 5 hereof) for which this Warrant
      is then being exercised, as designated in such subscription.

           2.1.2. Voluntary Conversion. This Warrant may be converted by the
                  --------------------
      Holder hereof, in whole or in part, into Units during normal business
      hours on any business day after November 18, 2000 and on or prior to the
      Expiration Date, by surrender of this Warrant to the Company at its
      principal office, accompanied by a conversion notice substantially in the
      form attached to this Warrant duly executed by such Holder, and such
      Holder shall thereupon be entitled to receive a number of Units,
      (consisting of the number of shares of Class A Stock and Class L Stock (or
      Other Securities) as provided in Section 5 hereof) equal to:

           (a)  the excess of

                (i) (x) the number of Units for which this Warrant may be
           exercised, as designated in such conversion notice, multiplied by (y)
           the Current Market Price of each such Unit (consisting of the number
           of shares of Class A Stock and Class L Stock (or Other Securities) as
           provided in Section 5 hereof) so receivable upon such exercise

                over

                                      -2-
<PAGE>


                (ii) (x) the number of Units for which this Warrant may be
           exercised, as designated in such conversion notice, multiplied by (y)
           the Initial Exercise Price

                divided by

           (b) such Current Market Price of each such Unit (consisting of the
      number of Class A Stock and Class L Stock (or Other Securities) determined
      as provided in Section 5 hereof).

For all purposes of this Warrant (other than this Section 2.1), any reference
herein to the exercise of this Warrant shall be deemed to include a reference to
the voluntary conversion of this Warrant into Units, in accordance with the
terms of Sections 2.1.2.

      2.2. When Exercise Effective. Each exercise of this Warrant shall be
           -----------------------
deemed to have been effected immediately prior to the close of business on the
business day on which this Warrant shall have been surrendered to the Company as
provided in Section 2.1 hereof, and at such time the Person or Persons in whose
name or names any certificate or certificates for shares of Common Stock (or
Other Securities) shall be issuable upon such exercise as provided in Section
2.3 hereof shall be deemed to have become the holder or holders of record
thereof.

      2.3. Delivery of Stock Certificates, etc. As soon as practicable after
           -----------------------------------
each exercise of this Warrant, in whole or in part, the Company at its expense
(including the payment by it of any applicable issue taxes) will cause to be
issued in the name of and delivered to the Holder hereof or, subject to the
provisions of the Stockholders Agreement, as such Holder (upon payment by such
Holder of any applicable transfer taxes) may direct:

           (a) certificates for the number of duly authorized, validly issued,
      fully paid and nonassessable shares of Class A Stock and Class L Stock (or
      Other Securities) to which such Holder shall be entitled upon such
      exercise plus, in lieu of any fractional shares to which such Holder would
      otherwise be entitled, cash in an amount equal to the same fraction of the
      current Market Price of such shares on the business day next preceding the
      date of such exercise; and

           (b) in case such exercise is in part only, a new Warrant or Warrants
      of like tenor, dated the date hereof and calling in the aggregate on the
      face or faces thereof for the number of Units equal to the number of such
      Units called for on the face of this Warrant minus the number of such
      Units designated by the Holder upon such exercise as provided in Section
      2.1 hereof.

      2.4.  Exchange of Warrant.  This Warrant is exchangeable at the aforesaid
            -------------------
principal office of the Company for Warrants for the purchase of the same
aggregate number of Units,

                                      -3-
<PAGE>

each new Warrant to represent the right to purchase such number of Units as the
Holder hereof shall designate at the time of such exchange. All Warrants issued
on transfers or exchanges shall be dated the date hereof and shall be identical
with this Warrant except as to the number of Units issuable pursuant hereto.

      2.5. Company to Reaffirm Obligations. The Company will, at the time of or
           -------------------------------
at any time after each exercise of this Warrant, upon the request of the Holder
hereof, acknowledge in writing its continuing obligation to afford to such
Holder all rights to which such Holder shall continue to be entitled after such
exercise in accordance with the terms of this Warrant, provided that if any such
Holder shall fail to make any such request, the failure shall not affect the
continuing obligation of the Company to afford such rights to such Holder.

3.  Conversion Upon Sale or IPO
    ---------------------------

      3.1. Conversion Upon Sale of the Company.  In the event of any Sale of the
           -----------------------------------
Company, this Warrant shall be exercisable,  immediately prior to the closing of
the Sale of the Company, by surrender of this Warrant to the Company at its
principal office, accompanied by a conversion notice substantially in the form
attached to this Warrant, duly executed by such Holder and such Holder shall be
entitled to receive an amount of common stock of the Company calculated as
follows:

           I.  Determine Pre-Discount Sale Conversion Value

               (a)  the excess of

                    (i)  $11.25 million

                    over

                    (ii) the aggregate redemption price of the Notes, pursuant
               to Section 3.3 of the Senior Subordinate Loan Agreement, on the
               closing date of the Sale of the Company

           multiplied by

               (b) the maximum number of Units for which this Warrant may be
           exercised, divided by the total number Units for which all Warrants
           issued by the Company on May 18, 2000 may be exercised (whether or
           not such warrants are then outstanding); (the "Pre-Discount Sale
           Conversion Value").

                                      -4-
<PAGE>

           II.  Apply Discount

                (a) Determine the percent of consideration to be received by the
           HTM Investors, as defined in the Stockholders Agreement, for the Sale
           of the Company, in : (x) cash (the "Cash Percent"), (y) classes of
           stock that are publicly traded (the "Stock Percent"), and (z) all
           other securities or property (the "Other Percent"). For this purpose,
           all securities or other property shall be valued as they are valued
           as consideration for the Sale of the Company.

                (b) Multiply the Pre-Discount Sale Conversion Value by the Cash
           Percent.

                (c) Multiply the Pre-Discount Sale Conversion Value by the Stock
           Percent and divide the result by 0.9.

                (d) Multiply the Pre-Discount Sale Conversion Value by the Other
           Percent and divide the result by 0.8.

                (e) The amount determined in (b) plus the amount determined in
           (c) plus the amount determined in (d) are together the "Sale
           Conversion Value." For purposes of determining the number of shares
           of common stock of the Company equal to the Sale Conversion Value,
           the common stock of the Company shall be valued as it is valued in
           the Sale of the Company.

      3.2. Conversion on Initial Public Offering. In the event of an Initial
           -------------------------------------
Public Offering, this Warrant shall be exercisable by surrender of this Warrant
to the Company at its principal office, accompanied by a conversion notice
substantially in the form attached to this Warrant, duly executed by such Holder
and such Holder shall be entitled to receive the number of shares of the
Company's duly authorized, validly issued, fully paid and non-assessable common
stock (of the same class as issued in the Initial Public Offering) equal to:

                (a)  the excess of

                     (i)  $11.25 million

           over

                     (ii) the aggregate redemption price of the Notes, pursuant
                to Section 3.3 of the Senior Subordinated Loan Agreement, on the
                closing date of the Initial Public Offering

                                      -5-
<PAGE>

           multiplied by

                 (b) the maximum number of Units for which this Warrant may be
           exercised, divided by the total number Units for which all Warrants
           issued by the Company on May 18, 2000 may be exercised (whether or
           not such warrants are then outstanding)

           divided by

                 (c) the Initial Public Offering Price multiplied by 0.8; (the
           "IPO Conversion Value").

      3.3. When Exercise Effective. The exercise of this Warrant pursuant to
           -----------------------
this Section 3 shall be deemed to have been effected immediately prior to the
closing of the Sale of the Company or Initial Public Offering, as applicable.
Any right to exercise this Warrant shall terminate upon the closing of the Sale
of the Company or Initial Public Offering, as applicable.

      3.4. Delivery of Sale Conversion Value. Immediately prior to the closing
           ---------------------------------
of the Sale of the Company, the Company at its expense shall cause to be
delivered to the Holder hereof or, as such Holder (upon payment by such Holder
of any applicable transfer taxes) may direct:

                (a) a certificate, setting forth in reasonable detail, the
           amount and composition of the Pre-Discount Sale Conversion Value and
           the Sale Conversion Value and the calculations by which such Pre-
           Discount Sale Conversion Value and the Sale Conversion Value were
           determined;

                (b) a certificate or certificates in the name of the Holder
           related to the common stock to which such Holder shall be entitled
           upon such redemption, as included in the Sale Conversion Value, plus
           in lieu of any fractional share of common stock to which such Holder
           would otherwise be entitled, cash in an amount equal to the same
           fraction of the value of the common stock as determined in the Sale
           of the Company;

      3.5. Delivery of IPO Conversion Value. On the closing date of the Initial
           --------------------------------
Public Offering, the Company at its expense (including the payment by it of any
applicable issue taxes) will cause to be issued in the name of and delivered to
the Holder hereof or, as such Holder (upon payment by such Holder of any
applicable transfer taxes) may direct: a certificate of certificates for the
number of duly authorized, validly issued, fully paid and nonassessable shares
of common stock (of the same class as issued in the Initial Public Offering) to
which such Holder shall be entitled upon such redemption plus, in lieu of any
fractional share to which such holder

                                      -6-
<PAGE>

would otherwise be entitled, cash in an amount equal to the same fraction of the
Initial Public Offering Price.

4.   Stock Fully Paid; Reservation of Shares.  The Company represents, warrants,
     ---------------------------------------
covenants and agrees that all shares of Common Stock which may be issued upon
the exercise of the rights represented by this Warrant will, upon issuance, be
duly authorized, validly issued, fully paid and non-assessable.  The Company
further covenants and agrees that during the period within which the rights
represented by this Warrant may be exercised, the Company will at all times have
authorized and reserved solely for the purpose of the issuance upon exercise of
this Warrant a sufficient number of shares of Common Stock to provide for the
exercise of the rights represented by this Warrant.

     If any shares of Common Stock required to be reserved for issuance
upon exercise of this Warrant require registration or qualification with any
governmental authority under any federal or state law before such shares may be
so issued, the Company will in good faith and as expeditiously as reasonably
possible use reasonable efforts to cause such shares to be duly registered or
qualified; provided, however, that the Company shall not be required to effect
any registration under federal or state securities laws other than as provided
in Section 6 of the Stockholders Agreement.

     The Company will (a) not increase the par value of any shares of
Common Stock receivable upon the exercise of this Warrant above the amount
payable therefor upon such exercise immediately prior to such increase in par
value, (b) take all such action as may be necessary or appropriate in order that
the Company may validly and legally issue fully paid and nonassessable shares of
Common Stock upon the exercise of this Warrant, and (c) use its reasonable
efforts to obtain all such authorizations, exemptions or consents from any
public regulatory body having jurisdiction thereof as may be necessary to enable
the Company to perform its obligations under this Warrant; provided, however,
that the Company shall not be required to effect any registration under federal
or state securities laws other than as provided in Section 6 of the Stockholders
Agreement.

5.    Adjustment to Number of Shares of Common Stock (or Other Securities)
      --------------------------------------------------------------------
Comprising a Unit.
-----------------

      5.1. In the event that at any time or from time to time after the date
hereof the Company shall (i) pay a dividend or make a distribution on its Common
Stock in shares of its Common Stock or other shares of capital stock, (ii)
subdivide its outstanding shares of Common Stock into a larger number of shares
of Common Stock, (iii) combine its outstanding shares of Common Stock into a
smaller number of shares of Common Stock or (iv) increase or decrease the number
of shares of Common Stock outstanding by reclassification of its Common Stock,
then the number of shares of Common Stock purchasable upon exercise of this
Warrant immediately after the happening of such event shall be adjusted
(including by adjusting the

                                      -7-
<PAGE>

definition of "Units") so that, after giving effect
to such adjustment, the Holder of this Warrant shall be entitled to receive the
number of shares of each class of Common Stock (or other securities) upon
exercise that such Holder would have owned or have been entitled to receive had
this Warrant been exercised immediately prior to the happening of the events
described above (or, in the case of a dividend or distribution of Common Stock,
immediately prior to the record date therefor). An adjustment made pursuant to
this Section 5.1 shall become effective immediately after the effective date,
retroactive to the record date therefor in the case of a dividend or
distribution in shares of Common Stock, and shall become effective immediately
after the effective date in the case of a subdivision, combination or
reclassification.

      5.2. Other Events. If any event occurs as to which the foregoing
           ------------
provisions of Section 5.1 are not strictly applicable or, if strictly
applicable, would not, in the good faith judgment of the Board, fairly and
adequately protect the purchase rights represented by the Warrants in accordance
with the essential intent and principles of such provisions, then the Board
shall make such adjustments in the application of such provisions, in accordance
with such essential intent and principles, as shall be reasonably necessary, in
the good faith opinion of the Board, to protect such purchase rights as
aforesaid.

6.  Notice of Adjustments.  Whenever the number of shares of Class A Stock or
    ---------------------
Class L Stock (or Other Securities) comprising a Unit is adjusted pursuant to
Section 5 hereof, the Company will promptly deliver to the Holder of this
Warrant at the address provided in the Stockholders Agreement a certificate
setting forth, in reasonable detail, the event that triggered the adjustment,
the amount of the adjustment, the method by which such adjustment was calculated
(including a description of the basis on which the Board made any determination
hereunder), and the number of shares of Class A Stock and Class A Stock and
Class L Stock (or Other Securities) comprising a Unit after giving effect to
such adjustment.

7.  Dividends/Distributions/Sale of the Company/Initial Public Offering.  The
    -------------------------------------------------------------------
Company shall give the Holder of this Warrant not less than 15 days prior
written notice of its intent to pay a dividend, make any other distribution on
any shares of its capital stock, effect an Initial Public Offering, or effect a
Sale of the Company and shall set forth in such notice the amount and type of
such dividend or distribution and the shares of capital stock on which such
dividend or distribution will be paid, or in the case of an Initial Public
Offering or a Sale of the Company, the economic terms thereof.  If the Holder of
this Warrant does not elect to exercise this Warrant prior to such dividend or
distribution, an amount equal to the cash which the Holder would have received
on the Common Stock had the Holder exercised this Warrant immediately prior to
such dividend or distribution shall at the option of the Holder (a) be used as a
credit against the Exercise Price or (b) be retained by the Company and paid to
such Holder upon the exercise of this Warrant.

8.  Restrictions; Legends.
    ---------------------

                                      -8-
<PAGE>

      8.1.  Stockholders Agreement. This Warrant and the Common Stock (or Other
            ----------------------
Securities) issuable upon the exercise hereof are subject in all respects to the
provisions of the Stockholders Agreement.  This Warrant and each certificate
issued upon the exercise of this Warrant and each certificate issued upon any
direct or indirect transfer of this Warrant or of any share of Common Stock (or
Other Securities) issuable upon exercise of this Warrant shall be transferable
only upon satisfaction of the conditions set forth in the Stockholders
Agreement, and shall be stamped or otherwise imprinted with legends in the form
required under Section 9 of the Stockholders Agreement.

      8.2. Termination of Restrictions; Removal of Legends. The restrictions
           -----------------------------------------------
imposed by Section 8.1 upon the transferability of this Warrant and the Common
Stock (or Other Securities) issuable upon exercise of this Warrant shall cease
and terminate at such time as this Warrant or any such shares of Common Stock
shall no longer be subject to the provisions of Sections 3 and 9 of the
Stockholders Agreement. Whenever such restrictions cease and terminate as to
this Warrant or any such Common Stock, the Holder thereof shall be entitled to
receive from the Company, without expense (other than applicable transfer taxes,
if any), new securities not bearing the applicable legends required by Section
8.1 hereof.

9.  No Rights or Liabilities as Stockholder.  Nothing contained in this Warrant
    ---------------------------------------
shall be construed as conferring upon the Holder hereof any rights as a
stockholder of the Company or as imposing any obligation on such Holder to
purchase any Securities or as imposing any liabilities on such Holder as a
stockholder of the Company, whether such obligation or liabilities are asserted
by the Company or by creditors of the Company.

10.  Definitions.  For the purposes of this Warrant, the following terms have
     -----------
the following meanings:

      "Board" shall mean the Board of Directors of the Company.

      "Cash Percent" shall have the meaning set forth in Section 3.1.

      "Class A Stock"  shall have the meaning set forth in the first
paragraph hereof.

      "Class L Stock" shall have the meaning set forth in the first
paragraph hereof.

      "Common Stock" shall have the meaning set forth in the first
paragraph hereof.

      "Company" shall mean SMTC Corporation, a Delaware corporation, and
its successors and assigns.

      "Current Market Price" shall mean on any date specified herein, the
average daily Market Price during the period of the most recent 20 days, ending
on such date, on which the national

                                      -9-
<PAGE>

securities exchanges were open for trading, except that if any component of a
Unit is not then listed or admitted to trading on any national securities
exchange or quoted in the over-the-counter market, the Current Market Price of
such component shall be the Market Price of such component on such date.

      "Expiration Date" shall have the meaning set forth in Section 1.

      "Holder" shall have the meaning set forth in the first paragraph
hereof.

      "Initial Exercise Price" shall have the meaning set forth in the
first paragraph hereof.

      "IPO Conversion Value" shall have the meaning set forth in Section
3.2.

      "Initial Public Offering" means the initial public offering and sale
of the Company's common stock for cash pursuant to an effective registration
statement on Form S-1 under the Securities Act (or any successor form under the
Securities Act).

      "Initial Public Offering Price" means the price per share at which
common stock is first offered to the public in the Initial Public Offering, as
disclosed on the cover of the prospectus related to the Initial Public Offering.

      "Majority Holders" shall mean at any time Holders of Warrants
exercisable for 50%   of the shares of Common Stock issuable under the Warrants
at such time outstanding.

      "Market Price" shall mean on any date specified herein, the amount per
Unit based on (a) the last sale price of each component of a Unit, regular way,
on such date or, if no such sale takes place on such date, the average of the
closing bid and asked prices thereof on such date, in each case as officially
reported on the principal national securities exchange on which Common Stock is
then listed or admitted to trading, or (b) if any component of a Unit is not
then listed or admitted to trading on any national securities exchange but is
designated as a national market system security by the NASD, the last trading
price of such component  on such date, or (c) if there shall have been no
trading on such date or if any component of a Unit is not so designated, the
average of the closing bid and asked prices of such component on such date as
shown by the NASD automated quotation system, or (d) if any component of a Unit
is not then listed or admitted to trading on any national exchange or quoted in
the over-the-counter market, the fair market value thereof determined in good
faith by the Board.

      "Notes" shall mean the Notes of the Company issued pursuant to the
Senior Subordinated Loan Agreement.

      "Other Percent" shall have the meaning set forth in Section 3.1.

                                      -10-
<PAGE>

      "Other Securities" shall mean any stock (other than the Units) and
other securities of the Company or any other Person which the Holders of the
Warrants at any time shall be entitled to receive, or shall have received, upon
the exercise of the Warrants, in lieu of or in addition to the Units, or which
at any time shall be issuable or shall have been issued in exchange for or in
replacement of the Units or Other Securities pursuant to Section 5 hereof or
otherwise.

      "Person" shall mean an individual, a corporation, a limited liability
company, a partnership, a trust, an unincorporated organization or a government
organization or an agency or political subdivision thereof.

      "Pre-Discount Sale Conversion Value" shall have the meaning set
forth in Section 3.1.

      "Sale of the Company" means (a) any change in the ownership of the
capital stock of the Company if, immediately after giving effect thereto, any
Person (or group of Persons acting in concert) other than the stockholders of
the Company as of the date hereof (and their Permitted Transferees, as defined
in the Stockholders Agreement) will have the direct or indirect power to elect a
majority of the members of the Board, (b) any change in the ownership of the
capital stock of the Company if, immediately after giving effect thereto, the
stockholders of the Company as of the date hereof (and their Permitted
Transferees, as defined in the Stockholders Agreement) shall own less than 25%
of the Company's common stock on a fully diluted basis (assuming the exercise of
all outstanding options and warrants and the conversion of all outstanding
convertible securities), or (c) the acquisition of all or substantially all of
the Company's assets by any Person, unless immediately after giving effect
thereto the stockholders of the Company as of the date hereof (and their
Permitted Transferees, as defined in the Stockholders Agreement) will have the
direct or indirect power to elect a majority of the members of such acquiring
Person's board of directors.

      "Sale Conversion Value" shall have the meaning set forth in Section
3.1.

      "Securities" shall mean any debt or equity securities of the Company,
whether now or hereafter authorized, and any instrument convertible into or
exchangeable for Securities or a Security.  "Security" shall mean one of the
Securities.

      "Securities Act" shall mean as of any date of the Securities Act of
1933, as amended, or any similar Federal statute then in effect.

      "Senior Subordinated Loan Agreement" shall mean the Senior
Subordinated Loan Agreement dated as of May 18, 2000 among the Company and the
lenders listed therein.

      "Stock" shall include any and all shares, interests or other
equivalents (however designated) of, or participants in, the capital stock of a
corporation of any class.

                                      -11-
<PAGE>

      "Stockholders Agreement" shall mean the Stockholders Agreement dated
as of  July 30, 1999 among the Company and certain holders of the Company's
outstanding capital stock, and as such Stockholders Agreement may hereafter from
time to time be amended, modified or supplemented in accordance with its terms.

      "Stock Percent" shall have the meaning set forth in Section 3.1.

      "Subscription Agreement" shall mean the Warrant Subscription Agreement
dated as of May 18, 2000 among the Company and certain purchasers of the
Warrants.

      "Warrants" shall mean the Warrants issued and sold pursuant to the
Subscription Agreement.  The term "Warrants" shall include, without limitation,
this Warrant and any Warrants issued in substitution or exchange for any
thereof.

11.   Amendment and Waiver.  Any term, covenant, agreement or condition in this
      --------------------
Warrant may be amended, or compliance therewith may be waived (either generally
or in a particular instance and either retroactively or prospectively), by a
written instrument or written instruments executed by the Company and the
Majority Holders; provided, however, that no such amendment or waiver shall
increase the Exercise Price, shorten the period during which the Warrants may be
exercised or modify any provision of this Section 11 without consent of the
Holders of all Warrants then outstanding affected by such amendment or waiver.

12.   Governing Law.  This Warrant shall be governed by and construed in
      -------------
accordance with the internal laws of the State of Delaware (without giving
effect to the choice of law principles of such state).

Dated:  May 18, 2000


                             SMTC CORPORATION



                             By: /s/ Richard Smith
                                -------------------------------------------
                                Name:  Richard Smith
                                Title: Vice President
                                       Finance and Administration

                                      -12-
<PAGE>

                             FORM OF SUBSCRIPTION

                [To be executed only upon exercise of Warrant]


To SMTC Corporation

      The undersigned registered Holder of the within Warrant hereby irrevocably
exercises such Warrant for, and purchases thereunder, _____/1/ Units and
herewith makes payment of $__________ therefor, and requests that the
certificates for such shares be issued in the name of, and delivered to
______________________________, whose address is

Dated:
                          ----------------------------------------------
                          (Signature must conform in all
                          respects to name of Holder as
                          specified on the face of Warrant)



                          -------------------------------------
                          (Street Address)



                          -------------------------------------
                          (City)     (State)     (Zip Code)

-------------------
/1/  Insert here the number of Units called for on the face of this Warrant
(or, in the case of a partial exercise, the portion thereof as to which this
Warrant is being exercised). In the case of a partial exercise, a new Warrant or
Warrants will be issued and delivered, representing the unexercised portion of
the Warrant, to the holder surrendering the Warrant.


<PAGE>

                              FORM OF ASSIGNMENT

                [To be executed only upon transfer of Warrant]

      For value received, the undersigned registered Holder of the within
Warrant hereby sells, assigns and transfers unto                          the
                                                --------------------------
right represented by such warrant to purchase               /2/ Units of SMTC
                                             --------------
Corporation to which such Warrant relates, and appoints
                                                       ----------------------
Attorney to make such transfer on the books of SMTC Corporation maintained for
such purpose, with full power of substitution in the premises.


Dated:                     _________________________________
                           (Signature must conform in all
                           respects to name of Holder as
                           specified on the face of Warrant)


                           __________________________________
                                    (Street Address)


                           __________________________________
                           (City)    (State)    (Zip Code)


Signed in the presence of:


______________________________




--------------------
/2/ Insert here the number of Units called for on the face of this Warrant (or,
in the case of a partial assignment, the portion thereof as to which this
Warrant is being assigned). In the case of a partial assignment, a new Warrant
or Warrants will be issued and delivered, representing the unassigned portion of
the Warrant, to the Holder assigning a portion of the Warrant.


<PAGE>

                           FORM OF CONVERSION NOTICE

To SMTC Corporation


      The undersigned registered Holder of the within Warrant hereby irrevocably
converts such Warrant with respect to       /3/ Units which such Holder would be
                                     ------
entitled to receive upon the exercise hereof, and requests that the certificates
for such shares be issued in the name of, and delivered to
                               , whose address is
-------------------------------

Dated:                           ____________________________________
                                 (Signature must conform in all
                                 respects to name of Holder as
                                 specified on the face of Warrant)


                                 _____________________________________
                                 (Street Address)


                                 _____________________________________
                                 (City)    (State)    (Zip Code)


-------------------
/3/ Insert here the number of Units called for on the face of this Warrant (or,
in the case of a partial conversion, the portion thereof as to which this
Warrant is being converted).  In the case of a partial conversion, a new Warrant
or Warrants will be issued and delivered, representing the unconverted portion
of the Warrant, to the Holder surrendering the Warrant.


<PAGE>

Warrant Subscription Schedule to Exhibit 4.5

                                   Number of       Warrant          Warrant
Name of Subscriber                   Units      Purchase Price      Number
-----------------                  ---------    --------------      -------
Bain Capital Fund VI, L.P.          9008.76       $540,525.90         W-1

BCIP Associates II                 3,286.21       $197,172.87         W-2

BCIP Associates II-B                 550.45       $ 33,027.16         W-3

BCIP Associates II-C                 402.75       $ 24,165.12         W-4

Celerity Partners III, L.P.        7,987.67       $479,260.27         W-5

CFE, Inc.                            601.29       $ 36,077.31         W-6

Venteura Limited                   2,582.17       $154,930.38         W-7

Kilmer Electronics Group Limited   7,580.05       $454,802.88         W-8

P.N. Walker Consulting             4,409.92       $264,595.34         W-9

Nichal Inc.                        4,409.92       $264,595.34         W-10

Philip Woodard                       847.46       $ 50,847.42         W-11