FORM 4
[ ] 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 OF SECURITIES
                                                                                  
OMB APPROVAL
OMB Number: 3235-0287
Estimated average burden
hours per response... 0.5
                      
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(f) of the Investment Company Act of 1940
                      

1. Name and Address of Reporting Person *

Mahoney Robert Charles 		2. Issuer Name and Ticker or Trading Symbol

ON SEMICONDUCTOR CORP [ ONNN ] 		5. Relationship of Reporting Person(s) to Issuer (Check all applicable)

_____ Director                      _____ 10% Owner
__ X __ Officer (give title below)      _____ Other (specify below)
Exec VP Sales & Marketing
(Last)          (First)          (Middle)

5005 EAST MCDOWELL ROAD 		3. Date of Earliest Transaction (MM/DD/YYYY)

5/3/2012
(Street)

PHOENIX, AZ 85008
(City)        (State)        (Zip)
4. If Amendment, Date Original Filed (MM/DD/YYYY)

 
6. Individual or Joint/Group Filing (Check Applicable Line)

_ X _ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3) 		2. Trans. Date 2A. Deemed Execution Date, if any 3. Trans. 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
Common   5/3/2012     A    58478.0000   (1) A $8.3900   252493.0000   D    
Common   5/3/2012     F    18768.0000   (2) D $8.3900   233725.0000   D    
Common   5/4/2012     S    60000.0000   D $8.4027   173725.0000   D    

Table II - Derivative Securities Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security
(Instr. 3) 		2. Conversion or Exercise Price of Derivative Security 3. Trans. Date 3A. Deemed Execution Date, if any 4. Trans. 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 7. Title and Amount of Securities Underlying Derivative Security
(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

Explanation of Responses:
( 1)  This transaction reports the acquisition, effective May 3, 2012, 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, which vested generally over a three-year (twelve quarter) period 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, is now fully vested.
( 2)  This disposition transaction represents shares withheld by the Issuer pursuant to the Reporting Person's March 2, 2009 PBRSU award. On May 3, 2012, 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.

Remarks:
Judith A. Boyle is signing on behalf of the Reporting Person pursuant to a Power of Attorney attached hereto as an Exhibit. mahoney2012poa.txt

Reporting Owners
Reporting Owner Name / Address
Relationships
Director 10% Owner Officer Other
Mahoney Robert Charles
5005 EAST MCDOWELL ROAD
PHOENIX, AZ 85008

Exec VP Sales & Marketing

Signatures
Judith A. Boyle, Attorney-in-Fact 5/7/2012
** Signature of Reporting Person Date


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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.
ON Semiconductor (NASDAQ:ON)
Historical Stock Chart
From Mar 2024 to Apr 2024 Click Here for more ON Semiconductor Charts.
ON Semiconductor (NASDAQ:ON)
Historical Stock Chart
From Apr 2023 to Apr 2024 Click Here for more ON Semiconductor Charts.