ON SEMICONDUCTOR CORP — Director's Dealing 2010

Mar 3, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: ON SEMICONDUCTOR CORP (ONNN)
CIK: 0001097864
Period of Report: 2010-03-01

Reporting Person: KLOSTERBOER ROBERT A. (SVP & GM, Dig & MxdSig Prd Grp)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-03-01	Common	F	895	$8.2	Disposed	26681	Direct
2010-03-02	Common	S	7500	$8.3133	Disposed	19181	Direct

Footnotes

F1: On March 1, 2010, the Reporting Person vested in 2,836 restricted stock units ("RSUs") and as a result acquired 2,836 shares of common stock of the Issuer pursuant to the Reporting Person's January 29, 2007 grant of RSUs. The RSUs acquisition was previously reported on an earlier Form 4 filed by the Reporting Person. This Form 4 reports the disposition of shares withheld by the Issuer pursuant to the RSUs' grant agreement in order to satisfy the Reporting Person's withholding obligations for various taxes due upon the vesting of the RSUs. The Issuer will pay the taxes on behalf of the Reporting Person.

F2: These transactions were made pursuant to the Reporting Person's existing Rule 10b5-1 plan (i.e. a stock trading plan designed to comply with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended). This disposition transaction was executed in multiple trades at prices ranging from $8.30 to $8.32. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide, upon request, to the SEC staff, the Issuer, or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected.