ON SEMICONDUCTOR CORP — Director's Dealing 2011

Nov 7, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: ON SEMICONDUCTOR CORP (ONNN)
CIK: 0001097864
Period of Report: 2011-11-03

Reporting Person: Mahoney Robert Charles (Exec VP Sales & Marketing)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-11-03	Common	A	58478.0000	$7.7900	Acquired	173744.0000	Direct
2011-11-03	Common	F	24298.0000	$7.7900	Disposed	149446.0000	Direct
2011-11-04	Common	M	12500.0000	$5.9300	Acquired	161946.0000	Direct
2011-11-04	Common	S	12500.0000	$8.0469	Disposed	149446.0000	Direct
2011-11-04	Common	S	25000.0000	$8.0417	Disposed	124446.0000	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2011-11-04	Stock Option (right to buy)	$5.9300	M	12500.0000	Disposed	2018-03-03	Common (12500.0000)	Direct

Footnotes

F1: This transaction reports the acquisition, effective November 3, 2011, of 58,478 shares of common stock resulting from the attainment of a performance goal under an earlier Performance Based Restricted Stock Units Award ("PBRSU Award"), as described more below. The Compensation Committee of the Issuer originally awarded 701,740 PBRSUs to the Reporting Person with an effective grant date of March 2, 2009 subject to the Issuers 2000 Stock Incentive Plan and a related award agreement. The PBRSU Award will vest, generally, over a three-year (twelve quarter) period but only upon the Issuer achieving certain adjusted non-GAAP earnings before interest, taxes, depreciation and amortization ("EBITDA") base and target performance measurements as set forth in the PBRSU Award agreement.

F2: This disposition transaction represents shares withheld by the Issuer pursuant to the Reporting Person's March 2, 2009 PBRSU award. On November 3, 2011, 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.

F3: This disposition transaction was executed in multiple trades at prices ranging from $8.04 to $8.05. 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.

F4: This disposition transaction was executed in multiple trades at prices ranging from $8.03 to $8.05. 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.