
<PAGE>   1
                                                                EXHIBIT 99(a)(3)
 
                         NOTICE OF GUARANTEED DELIVERY
                                      for
                        Tender of Shares of Common Stock
                                       of
 
                        Amati Communications Corporation
                                       to
 
                          DSL Acquisition Corporation
                        a direct wholly owned subsidiary
                                       of
 
                         Texas Instruments Incorporated
 
     As set forth in Section 3 of the Offer to Purchase (as defined below), this
form, or a form substantially equivalent to this form, must be used to accept
the Offer (as defined below) if the certificates representing shares of common
stock, par value $.20 per share of Amati Communications Corporation (the
"Shares"), are not immediately available or time will not permit all required
documents to reach the Depositary prior to the Expiration Date (as defined in
the Offer to Purchase) or the procedures for book-entry transfer cannot be
completed on a timely basis. Such form may be delivered by hand or transmitted
by telegram, facsimile transmission or mail to the Depositary and must include a
guarantee by an Eligible Institution (as defined in Section 3 of the Offer to
Purchase). See Section 3 of the Offer to Purchase.
 
                        The Depositary for the Offer is:
                        CHASEMELLON SHAREHOLDER SERVICES
 
<TABLE>
<C>                                  <C>                              <C>
             By Mail:                  By Facsimile Transmission:                  By Hand:
 ChaseMellon Shareholder Services            (201) 329-8936            ChaseMellon Shareholder Services
     Attention: Reorganization         (For Eligible Institutions          Attention: Reorganization
             Department                           Only)                           Department
       Post Office Box 3301                                                120 Broadway, 13th Floor
South Hackensack, New Jersey 07660   Confirm Facsimile by Telephone:       New York, New York 10271
                                             (201) 296-4860
                                         (For Confirmation Only)             By Overnight Courier:
                                                                       ChaseMellon Shareholder Services
                                                                           Attention: Reorganization
                                                                                  Department
                                                                              85 Challenger Road
                                                                       Ridgefield Park, New Jersey 07660
</TABLE>
 
                             ---------------------
 
    DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY TO AN ADDRESS OTHER THAN
     AS SET FORTH ABOVE, OR TRANSMISSION VIA A FACSIMILE NUMBER OTHER THAN
           AS SET FORTH ABOVE, WILL NOT CONSTITUTE A VALID DELIVERY.
 
     This Notice of Guaranteed Delivery is not to be used to guarantee
signatures. If a signature on a Letter of Transmittal is required to be
guaranteed by an "Eligible Institution" under the instructions thereto, such
signature guarantee must appear in the applicable space provided in the
signature box on the Letter of Transmittal.
<PAGE>   2
 
Ladies and Gentlemen:
 
     The undersigned hereby tenders to DSL Acquisition Corporation, a Delaware
corporation and a direct wholly owned subsidiary of Texas Instruments
Incorporated, a Delaware corporation, upon the terms and subject to the
conditions set forth in the Offer to Purchase dated November 25, 1997 (the
"Offer to Purchase") and the related Letter of Transmittal (which, together with
any amendments and supplements, collectively constitute the "Offer"), receipt of
which is hereby acknowledged, the number of Shares indicated below pursuant to
the guaranteed delivery procedure set forth in Section 3 of the Offer to
Purchase.
 
Number of Shares:
                 ---------------------------------------------------------------
 
Stock Certificate Numbers (if available):
                                         ---------------------------------------
 
If Shares will be delivered by book-entry transfer, check one box:
 
[ ]  The Depository Trust Company
 
[ ]  Philadelphia Depository Trust Company
 
Account Number
              ------------------------------------------------------------------
 
Dated:
      ------------------------, 199_
      
 
                              PLEASE TYPE OR PRINT
 
Name(s) of Record Holder(s):
                            ----------------------------------------------------
 
Address(es)
           ---------------------------------------------------------------------
 
--------------------------------------------------------------------------------
                               (Include Zip Code)
 
Area Code and Telephone Number:
                               -------------------------------------------------
 
--------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------
                                  SIGNATURE(S)
<PAGE>   3
 
                                   GUARANTEE
                    (NOT TO BE USED FOR SIGNATURE GUARANTEE)
 
     The undersigned, a participant in the Security Transfer Agents Medallion
Program, the New York Stock Exchange Medallion Signature Guarantee Program or
the Stock Exchange Medallion Program (each, an "Eligible Institution"), hereby
guarantees that either the certificates representing the Shares tendered hereby
in proper form for transfer, or timely confirmation of a book-entry transfer of
such Shares into the Depositary's account at The Depository Trust Company or the
Philadelphia Depository Trust Company (pursuant to procedures set forth in
Section 3 of the Offer to Purchase), together with a properly completed and duly
executed Letter of Transmittal (or facsimile thereof) with any required
signature guarantees (or, in the case of a book-entry transfer, an Agent's
Message (as defined in the Offer to Purchase)) and any other documents required
by the Letter of Transmittal, will be received by the Depositary at one of its
addresses set forth above within three (3) New York Stock Exchange trading days
after the date of execution hereof.
 
     The Eligible Institution that completes this form must communicate the
guarantee to the Depositary and must deliver the Letter of Transmittal,
certificates for Shares and any other required documents to the Depositary
within the time period shown herein. Failure to do so could result in a
financial loss to such Eligible Institution.
 
Name of Firm:
             -------------------------------------------------------------------
 
Address:
        ------------------------------------------------------------------------
 
--------------------------------------------------------------------------------
                               (Include Zip Code)
 
Area Code and
Telephone Number:
                 ---------------------------------------------------------------
 
--------------------------------------------------------------------------------
                              AUTHORIZED SIGNATURE
 
Name:
     ---------------------------------------------------------------------------
                              PLEASE TYPE OR PRINT
 
Title:
      --------------------------------------------------------------------------
 
Dated:
      ---------------------- , 199_
                                  
 
NOTE: DO NOT SEND CERTIFICATES FOR SHARES WITH THIS NOTICE OF GUARANTEED
      DELIVERY. CERTIFICATES FOR SHARES ARE TO BE DELIVERED WITH THE LETTER OF
      TRANSMITTAL.
