SEC FORM 3

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

Mahoney Robert Charles

(Last)

(First)

(Middle)

ON SEMICONDUCTOR (M/D A700)

5005 E. MCDOWELL ROAD

(Street)

PHOENIX

85008

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
06/29/2006

3. Issuer Name and Ticker or Trading Symbol
ON SEMICONDUCTOR CORP [ ONNN ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	Executive VP, Sales & Mktg.

5. If Amendment, Date of Original Filed (Month/Day/Year)

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 Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock⁽¹⁾	20,000	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Stock Option (right to buy)	11/20/2002⁽²⁾	11/20/2012	Common Stock	200,000	$1.94	D
Stock Option (right to buy)	02/05/2003⁽³⁾	02/05/2013	Common Stock	17,500	$1.25	D
Stock Option (right to buy)	02/05/2004⁽⁴⁾	02/05/2014	Common Stock	43,000	$7.02	D
Stock Option (right to buy)	08/18/2004⁽⁵⁾	08/18/2014	Common Stock	8,000	$3.55	D
Stock Option (right to buy)	11/17/2004⁽⁶⁾	11/17/2014	Common Stock	12,000	$4.23	D
Stock Option (right to buy)	02/17/2005⁽⁷⁾	02/17/2015	Common Stock	40,000	$4.8	D
Stock Option (right to buy)	03/23/2006⁽⁸⁾	03/23/2016	Common Stock	40,850	$6.83	D

Explanation of Responses:

1. Includes 20,000 restricted stock units granted to the Reporting Person effective June 5, 2006 under the Issuer's 2000 Stock Incentive Plan with one-third vesting on March 23, 2007, one-third vesting on March 23, 2008, and the remaining units vesting on March 23, 2009.

2. Granted on November 20, 2002 under the Issuer's 2000 Stock Incentive Plan. The option is exercisable in four (4) equal installments on each of the first through fourth anniversaries of the Grant Date, subject to continued employment with the Issuers and other terms and conditions of the plan and the related stock option agreement.

3. Granted on February 5, 2003 under the Issuer's 2000 Stock Incentive Plan. The option is exercisable in four (4) equal installments on each of the first through fourth anniversaries of the Grant Date, subject to continued employment with the Issuers and other terms and conditions of the plan and the related stock option agreement.

4. Granted on February 5, 2004 under the Issuer's 2000 Stock Incentive Plan. The option is fully vested and exercisable.

5. Granted on August 18, 2004 under the Issuer's 2000 Stock Incentive Plan. The option is exercisable in four (4) equal installments on each of the first through fourth anniversaries of the Grant Date, subject to continued employment with the Issuers and other terms and conditions of the plan and the related stock option agreement.

6. Granted on November 17, 2004 under the Issuer's 2000 Stock Incentive Plan. The option is exercisable in four (4) equal installments on each of the first through fourth anniversaries of the Grant Date, subject to continued employment with the Issuers and other terms and conditions of the plan and the related stock option agreement.

7. Granted on February 17, 2005 under the Issuer's 2000 Stock Incentive Plan. The option is exercisable in four (4) equal installments on each of the first through fourth anniversaries of the Grant Date, subject to continued employment with the Issuers and other terms and conditions of the plan and the related stock option agreement.

8. Granted on March 23, 2006 under the Issuer's 2000 Stock Incentive Plan. The option is exercisable in four (4) equal installments on each of the first through fourth anniversaries of the Grant Date, subject to continued employment with the Issuers and other terms and conditions of the plan and the related stock option agreement.

Remarks:

Judith A. Boyle is signing on behalf of the Reporting Person pursuant to a Power of Attorney attached herein as an exhibit.

	Robert Charles Mahoney by Judith A. Boyle as Attorney-in-Fact	07/05/2006
	** 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 5 (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.
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