Sec Form 4/A Filing - BILLAT SUSAN @ PDF SOLUTIONS INC - 2008-08-19

FORM 4/A Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person BILLAT SUSAN 2. Issuer Name and Ticker or Trading Symbol PDF SOLUTIONS INC [ PDFS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 333 WEST SAN CARLOS STREET, SUITE 700 3. Date of Earliest Transaction (MM/DD/YY) 08/19/2008 (Street) SAN JOSE, CA95110 4. If Amendment, Date Original Filed (MM/DD/YY) 08/20/2008 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares 2001 Stock Plan Option (right to buy) $ 10.35 08/19/2008( 1 ) D 5,000 ( 2 ) 06/05/2017 Common Stock 5,000 $ 0 ( 3 ) 0 D 2001 Stock Plan Option (right to buy) $ 10.43 08/19/2008 D 15,000 ( 4 ) 05/29/2017 Common Stock 15,000 $ 0 ( 5 ) 0 D 2001 Stock Plan Option (Right to Buy) $ 13.6 08/19/2008 D 15,000 ( 6 ) 05/23/2016 Common Stock 15,000 $ 0 ( 7 ) 0 D 2001 Stock Plan Option (Right to Buy) $ 12.33 08/19/2008 D 15,000 ( 8 ) 05/25/2015 Common Stock 15,000 $ 0 ( 9 ) 0 D 2001 Stock Plan Option (Right to Buy) $ 10.73 08/19/2008 D 30,000 ( 10 ) 09/11/2013 Common Stock 30,000 $ 0 ( 11 ) 0 D Restricted Stock Right ( 12 ) 08/19/2008 A 7,144 ( 13 ) ( 13 ) Common Stock 7,144 ( 11 ) 7,144 D Restricted Stock Right ( 12 ) 08/19/2008 A 3,572 ( 14 ) ( 14 ) Common Stock 3,572 ( 7 ) 3,572 D Restricted Stock Right ( 12 ) 08/19/2008 A 3,572 ( 14 ) ( 14 ) Common Stock 3,572 ( 5 ) 3,572 D Restricted Stock Right ( 12 ) 08/19/2008 A 1,191 ( 14 ) ( 14 ) Common Stock 1,191 ( 3 ) 1,191 D Restricted Stock Right ( 12 ) 08/19/2008 A 3,572 ( 15 ) ( 15 ) Common Stock 3,572 ( 9 ) 3,572 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other BILLAT SUSAN 333 WEST SAN CARLOS STREET SUITE 700 SAN JOSE, CA95110 X Signatures /s/ P. Steven Melman, Attorney-in-Fact for Susan Billat 08/26/2008 Signature of Reporting Person Date

Explanation of Responses:

( 1 )All transactions on this Form 4 report occurred at 12:12 a.m. EDT on August 19, 2008 (the "Transaction Date"). This amended report is filed to correct a typographical error in Box 3 and Column 3 of Table II. ( 2 )The cancelled option provided for vesting as follows: 12/48ths of the total shares subject to the option vested on June 6, 2008 and 1/48th of the total shares vested on the 8th day of each month thereafter, subject to the reporting person's continued service with PDF Solutions, Inc., or an affiliate thereof through each vesting date and subject to accelerated vesting in certain circumstances. ( 3 )Pursuant to PDF Solutions, Inc.'s offer to exchange described in Schedule TO-1 filed on June 10, 2008, as amended (the "Exchange Offer") on the Transaction Date PDF Solutions, Inc. cancelled an option granted to the reporting person on June 6, 2007. In exchange for the option, the reporting person received 1,191 restricted stock rights. ( 4 )The cancelled option provided for vesting as follows: 12/48ths of the total shares subject to the option vested on May 30, 2008 and 1/48th of the total shares vested on the 30th day of each month thereafter, subject to the reporting person's continued service with PDF Solutions, Inc., or an affiliate thereof through each vesting date and subject to accelerated vesting in certain circumstances. ( 5 )Pursuant to the Exchange Offer, on the Transaction Date PDF Solutions, Inc. cancelled an option granted to the reporting person on May 30, 2007. In exchange for the option, the reporting person received 3,572 restricted stock rights. ( 6 )The cancelled option provided for vesting as follows: 12/48ths of the total shares subject to the option vested on May 24, 2007 and 1/48th of the to tal shares vested on the 27th day of each month thereafter, subject to the reporting person's continued service with PDF Solutions, Inc., or an affiliate thereof through each vesting date and subject to accelerated vesting in certain circumstances. ( 7 )Pursuant to the Exchange Offer, on the Transaction Date PDF Solutions, Inc. cancelled an option granted to the reporting person on May 24, 2006. In exchange for the option, the reporting person received 3,572 restricted stock rights. ( 8 )The cancelled option provided for vesting as follows: 12/48ths of the total shares subject to the option vested on May 26, 2006 and 1/48th of the total shares vested on the 26th day of each month thereafter, subject to the reporting person's continued service with PDF Solutions, Inc., or an affiliate thereof through each vesting date and subject to accelerated vesting in certain circumstances. ( 9 )Pursuant to the Exchange Offer, on on the Transaction Date PDF Solutions, Inc. cancelled an option granted to the reporting person on May 26, 2005. In exchange for the option, the reporting person received 3,572 restricted stock rights. ( 10 )The cancelled option provided for vesting as follows: 12/48ths of the total shares subject to the option vested on September 12, 2004 and 1/48th of the total shares vested on the 12th day of each month thereafter, subject to the reporting person's continued service with PDF Solutions, Inc., or an affiliate thereof through each vesting date and subject to accelerated vesting in certain circumstances. ( 11 )Pursuant to the Exchange Offer, on the Transaction Date PDF Solutions, Inc. cancelled an option granted to the reporting person on September 12, 2003. In exchange for the option, the reporting person received 7,144 restricted stock rights. ( 12 )Each restricted stock right ("RSR") represents a bookkeeping entry equal in value to one (1) share of common stock of PDF Solutions, Inc. ( 13 )50% of the total number of rights will vest on May 15, 2009 and 50% will vest six (6) months thereafter, subject to the reporting person's continued service with PDF Solutions, Inc., or an eligible affiliate thereof, through each vesting date and subject to accelerated vesting in certain circumstances. The RSR will be automatically settled in shares upon vesting of the RSR. ( 14 )12.5% of the total number of rights will vest on May 15, 2009 and 12.5% will vest every six (6) months thereafter, subject to the reporting person's continued service with PDF Solutions, Inc., or an eligible affiliate thereof, through each vesting date and subject to accelerated vesting in certain circumstances. The RSR will be automatically settled in shares upon vesting of the RSR. ( 15 )16.7% of the total number of rights will vest on May 15, 2009 and 16.66% will vest every six (6) months thereafter, subject to the reporting person's continued service with PDF Solutions, Inc., or an eligible affiliate thereof, through each vesting date and subject to accelerated vesting in certain circumstances. The RSR will be automatically settled in shares upon vesting of the RSR.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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