ON SEMICONDUCTOR CORP — Director's Dealing 2010

Mar 4, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: ON SEMICONDUCTOR CORP (ONNN)
CIK: 0001097864
Period of Report: 2010-03-02

Reporting Person: NELSON WILLIAM JOHN (Exec VP & COO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-03-02	Common	S	15000	$8.3802	Disposed	313663	Direct
2010-03-03	Common	S	2267	$8.29	Disposed	311396	Direct
2010-03-03	Common	F	4204	$8.2	Disposed	307192	Direct

Footnotes

F1: This transaction was 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 $8.38 to $8.3825. 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.

F2: This transaction was 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).

F3: This disposition transaction represents shares withheld by the Issuer pursuant to the Reporting Person's March 3, 2008 award of restricted stock units. On March 3, 2010, certain of these units vested. These shares were withheld to satisfy the Reporting Person's withholding obligations for various taxes and similar items. The Issuer will pay these taxes on behalf of the Reporting Person.