SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G UNDER THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. ___)* PDF SOLUTIONS, INC. ------------------- (Name of Issuer) COMMON STOCK ------------------------------ (Title of Class of Securities) 693282 -------------- (CUSIP Number) JANUARY 22, 2002 ---------------- (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [ ] Rule 13d-1(b) [X] Rule 13d-1(c) [ ] Rule 13d-1(d) - ---------------------- * The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 (the "Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act.

CUSIP No. 693282 Schedule 13G Page 2 of 5 Pages - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON: CADENCE DESIGN SYSTEMS, INC. I.R.S. IDENTIFICATION NO. OF ABOVE PERSON: 77-0148231 - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) [ ] (b) [ ] - -------------------------------------------------------------------------------- 3. SEC USE ONLY - -------------------------------------------------------------------------------- 4. CITIZENSHIP OR PLACE OF ORGANIZATION: DELAWARE - -------------------------------------------------------------------------------- 5. SOLE VOTING POWER: 1,745,443 NUMBER OF ------------------------------------------------------ SHARES 6. SHARED VOTING POWER: -0- BENEFICIALLY ------------------------------------------------------ OWNED BY THE 7. SOLE DISPOSITIVE POWER: 1,745,443 REPORTING ------------------------------------------------------ PERSON WITH 8. SHARED DISPOSITIVE POWER: -0- - -------------------------------------------------------------------------------- 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY THE 1,745,443 REPORTING PERSON: - -------------------------------------------------------------------------------- 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES CERTAIN SHARES [ ] - -------------------------------------------------------------------------------- 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9: 7.6% - -------------------------------------------------------------------------------- 12. TYPE OF REPORTING PERSON: CO - --------------------------------------------------------------------------------

CUSIP No. 693282 Schedule 13G Page 3 of 5 Pages ITEM 1. (a) NAME OF ISSUER: PDF Solutions, Inc. (b) ADDRESS OF PRINCIPAL EXECUTIVE OFFICES OF ISSUER: 333 West San Carlos Street Suite 700 San Jose, CA 95110 ITEM 2. (a) NAME OF PERSON FILING: Cadence Design Systems, Inc. (b) ADDRESS OF PRINCIPAL BUSINESS OFFICE: 2655 Seely Road, Building 5 San Jose, CA 95134 (c) CITIZENSHIP OR PLACE OF ORGANIZATION: Delaware (d) TITLE OF CLASS OF SECURITIES: Common Shares (e) CUSIP NUMBER: 693282 ITEM 3. Inapplicable ITEM 4. OWNERSHIP. (a) Amount beneficially owned: 1,745,443 (b) Percent of Class: 7.6% (c) Number of shares as to which such person has: (i) Sole power to vote or to direct the vote: 1,745,443 (ii) Shared power to vote or to direct the vote: -0- (iii) Sole power to dispose or to direct the disposition of: 1,745,443 (iv) Shared power to dispose or to direct the disposition of: -0-

CUSIP No. 693282 Schedule 13G Page 4 of 5 Pages ITEM 5. Inapplicable ITEM 6. Inapplicable ITEM 7. Inapplicable ITEM 8. Inapplicable ITEM 9. Inapplicable ITEM 10. CERTIFICATIONS. By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of, or with the effect of changing or influencing the control of the Issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

CUSIP No. 693282 Schedule 13G Page 5 of 5 Pages SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. January 31, 2002 --------------------------------- Date /s/ Charles H. Eldredge --------------------------------- Signature Charles H. Eldredge - Treasurer --------------------------------- Name/Title