Relational Investors SC 13D/A PMC Sierra Inc

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934
(Amendment No. 5)*

PMC-Sierra, Inc.

(Name of Issuer)

Common Stock, $0.001 par value

(Title of Class of Securities)

69344F106

(CUSIP Number)

Ralph V. Whitworth

Relational Investors, LLC

12400 High Bluff Drive, Suite 600

San Diego, CA 92130

(858) 704-3333

(Name, Address and Telephone Number of Person
Authorized to Receive Notices and Communications)

May 8, 2015

(Date of Event Which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. o

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7 for other parties to whom copies are to be sent.

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No.   69344F106
	1.	Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (Entities Only) Relational Investors, LLC
	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)			x
		(b)			o
	3.	SEC Use Only
	4.	Source of Funds (See Instructions) OO
	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)  o
	6.	Citizenship or Place of Organization Delaware
Number of Shares Beneficially Owned by Each Reporting Person With			7.	Sole Voting Power 22,807,519
			8.	Shared Voting Power -0-
			9.	Sole Dispositive Power 22,807,519
			10.	Shared Dispositive Power -0-
	11.	Aggregate Amount Beneficially Owned by Each Reporting Person 22,807,519
	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)o
	13.	Percent of Class Represented by Amount in Row (11) 11.53%
	14.	Type of Reporting Person (See Instructions) IA/HC/OO

2

	1.	Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (Entities Only) Relational Investors Mid-Cap Fund I, L.P.
	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)			x
		(b)			o
	3.	SEC Use Only
	4.	Source of Funds (See Instructions) WC
	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)  o
	6.	Citizenship or Place of Organization Delaware
Number of Shares Beneficially Owned by Each Reporting Person With			7.	Sole Voting Power 4,623,841
			8.	Shared Voting Power -0-
			9.	Sole Dispositive Power 4,623,841
			10.	Shared Dispositive Power -0-
	11.	Aggregate Amount Beneficially Owned by Each Reporting Person 4,623,841
	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)o
	13.	Percent of Class Represented by Amount in Row (11) 2.34%
	14.	Type of Reporting Person (See Instructions) PN

3

	1.	Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (Entities Only) Relational Investors Mid-Cap Fund II, L.P.
	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)			x
		(b)			o
	3.	SEC Use Only
	4.	Source of Funds (See Instructions) WC
	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)  o
	6.	Citizenship or Place of Organization Delaware
Number of Shares Beneficially Owned by Each Reporting Person With			7.	Sole Voting Power 7,971,504
			8.	Shared Voting Power -0-
			9.	Sole Dispositive Power 7,971,504
			10.	Shared Dispositive Power -0-
	11.	Aggregate Amount Beneficially Owned by Each Reporting Person 7,971,504
	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)o
	13.	Percent of Class Represented by Amount in Row (11) 4.03%
	14.	Type of Reporting Person (See Instructions) PN

4

	1.	Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (Entities Only) Relational Fund Partners, L.P.
	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)			x
		(b)			o
	3.	SEC Use Only
	4.	Source of Funds (See Instructions) WC/OO
	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)  o
	6.	Citizenship or Place of Organization Delaware
Number of Shares Beneficially Owned by Each Reporting Person With			7.	Sole Voting Power 52,530
			8.	Shared Voting Power -0-
			9.	Sole Dispositive Power 52,530
			10.	Shared Dispositive Power -0-
	11.	Aggregate Amount Beneficially Owned by Each Reporting Person 52,530
	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)o
	13.	Percent of Class Represented by Amount in Row (11) 0.03%
	14.	Type of Reporting Person (See Instructions) PN

5

	1.	Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (Entities Only) Relational Coast Partners, L.P.
	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)			x
		(b)			o
	3.	SEC Use Only
	4.	Source of Funds (See Instructions) WC/OO
	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)  o
	6.	Citizenship or Place of Organization Delaware
Number of Shares Beneficially Owned by Each Reporting Person With			7.	Sole Voting Power 570,882
			8.	Shared Voting Power -0-
			9.	Sole Dispositive Power 570,882
			10.	Shared Dispositive Power -0-
	11.	Aggregate Amount Beneficially Owned by Each Reporting Person 570,882
	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)o
	13.	Percent of Class Represented by Amount in Row (11) 0.29%
	14.	Type of Reporting Person (See Instructions) PN

6

	1.	Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (Entities Only) R.H. Fund 1, L.P.
	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)			x
		(b)			o
	3.	SEC Use Only
	4.	Source of Funds (See Instructions) WC/OO
	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)  o
	6.	Citizenship or Place of Organization Delaware
Number of Shares Beneficially Owned by Each Reporting Person With			7.	Sole Voting Power 511,001
			8.	Shared Voting Power -0-
			9.	Sole Dispositive Power 511,001
			10.	Shared Dispositive Power -0-
	11.	Aggregate Amount Beneficially Owned by Each Reporting Person 511,001
	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)o
	13.	Percent of Class Represented by Amount in Row (11) 0.26%
	14.	Type of Reporting Person (See Instructions) PN

7

	1.	Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (Entities Only) Relational Investors IX, L.P.
	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)			x
		(b)			o
	3.	SEC Use Only
	4.	Source of Funds (See Instructions) WC
	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)  o
	6.	Citizenship or Place of Organization Delaware
Number of Shares Beneficially Owned by Each Reporting Person With			7.	Sole Voting Power 654,813
			8.	Shared Voting Power -0-
			9.	Sole Dispositive Power 654,813
			10.	Shared Dispositive Power -0-
	11.	Aggregate Amount Beneficially Owned by Each Reporting Person 654,813
	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)o
	13.	Percent of Class Represented by Amount in Row (11) 0.33%
	14.	Type of Reporting Person (See Instructions) PN

8

	1.	Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (Entities Only) Relational Investors XV, L.P.
	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)			x
		(b)			o
	3.	SEC Use Only
	4.	Source of Funds (See Instructions) WC
	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)  o
	6.	Citizenship or Place of Organization Delaware
Number of Shares Beneficially Owned by Each Reporting Person With			7.	Sole Voting Power 607,142
			8.	Shared Voting Power -0-
			9.	Sole Dispositive Power 607,142
			10.	Shared Dispositive Power -0-
	11.	Aggregate Amount Beneficially Owned by Each Reporting Person 607,142
	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)o
	13.	Percent of Class Represented by Amount in Row (11) 0.31%
	14.	Type of Reporting Person (See Instructions) PN

9

	1.	Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (Entities Only) Relational Investors XVI, L.P.
	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)			x
		(b)			o
	3.	SEC Use Only
	4.	Source of Funds (See Instructions) WC
	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)  o
	6.	Citizenship or Place of Organization Delaware
Number of Shares Beneficially Owned by Each Reporting Person With			7.	Sole Voting Power 270,926
			8.	Shared Voting Power -0-
			9.	Sole Dispositive Power 270,926
			10.	Shared Dispositive Power -0-
	11.	Aggregate Amount Beneficially Owned by Each Reporting Person 270,926
	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)o
	13.	Percent of Class Represented by Amount in Row (11) 0.14%
	14.	Type of Reporting Person (See Instructions) PN

10

	1.	Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (Entities Only) Relational Investors XX, L.P.
	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)			x
		(b)			o
	3.	SEC Use Only
	4.	Source of Funds (See Instructions) WC/OO
	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)  o
	6.	Citizenship or Place of Organization Delaware
Number of Shares Beneficially Owned by Each Reporting Person With			7.	Sole Voting Power 547,764
			8.	Shared Voting Power -0-
			9.	Sole Dispositive Power 547,764
			10.	Shared Dispositive Power -0-
	11.	Aggregate Amount Beneficially Owned by Each Reporting Person 547,764
	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)o
	13.	Percent of Class Represented by Amount in Row (11) 0.28%
	14.	Type of Reporting Person (See Instructions) PN

11

	1.	Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (Entities Only) Relational Investors XXIII, L.P.
	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)			x
		(b)			o
	3.	SEC Use Only
	4.	Source of Funds (See Instructions) WC/OO
	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)  o
	6.	Citizenship or Place of Organization Delaware
Number of Shares Beneficially Owned by Each Reporting Person With			7.	Sole Voting Power 767,727
			8.	Shared Voting Power -0-
			9.	Sole Dispositive Power 767,727
			10.	Shared Dispositive Power -0-
	11.	Aggregate Amount Beneficially Owned by Each Reporting Person 767,727
	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)o
	13.	Percent of Class Represented by Amount in Row (11) 0.39%
	14.	Type of Reporting Person (See Instructions) PN

12

	1.	Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (Entities Only) Relational Investors XXIV, L.P.
	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)			x
		(b)			o
	3.	SEC Use Only
	4.	Source of Funds (See Instructions) WC
	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)  o
	6.	Citizenship or Place of Organization Delaware
Number of Shares Beneficially Owned by Each Reporting Person With			7.	Sole Voting Power 84,124
			8.	Shared Voting Power -0-
			9.	Sole Dispositive Power 84,124
			10.	Shared Dispositive Power -0-
	11.	Aggregate Amount Beneficially Owned by Each Reporting Person 84,124
	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)o
	13.	Percent of Class Represented by Amount in Row (11) 0.04%
	14.	Type of Reporting Person (See Instructions) PN

13

	1.	Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (Entities Only) Ralph V. Whitworth
	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)			x
		(b)			o
	3.	SEC Use Only
	4.	Source of Funds (See Instructions) NA
	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)  o
	6.	Citizenship or Place of Organization United States
Number of Shares Beneficially Owned by Each Reporting Person With			7.	Sole Voting Power -0-
			8.	Shared Voting Power 22,807,519
			9.	Sole Dispositive Power -0-
			10.	Shared Dispositive Power 22,807,519
	11.	Aggregate Amount Beneficially Owned by Each Reporting Person 22,807,519
	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)o
	13.	Percent of Class Represented by Amount in Row (11) 11.53%
	14.	Type of Reporting Person (See Instructions) IN

14

	1.	Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (Entities Only) David H. Batchelder
	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)			x
		(b)			o
	3.	SEC Use Only
	4.	Source of Funds (See Instructions) NA
	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)  o
	6.	Citizenship or Place of Organization United States
Number of Shares Beneficially Owned by Each Reporting Person With			7.	Sole Voting Power -0-
			8.	Shared Voting Power 22,807,519
			9.	Sole Dispositive Power -0-
			10.	Shared Dispositive Power 22,807,519
	11.	Aggregate Amount Beneficially Owned by Each Reporting Person 22,807,519
	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)o
	13.	Percent of Class Represented by Amount in Row (11) 11.53%
	14.	Type of Reporting Person (See Instructions) IN

15

Item 1.

Security and Issuer

This Schedule 13D/A constitutes the fifth amendment to the Schedule 13D originally filed by the Reporting Persons with the Securities and Exchange Commission (the “SEC”) on January 17, 2012 and amended by Amendment No. 1, No. 2, No. 3 and No. 4 filed by the Reporting Persons with the SEC on November 9, 2012, January 11, 2013, August 1, 2013 and February 28, 2014 (the “Statement”) with respect to the common stock, $0.001 par value (the “Shares”), of PMC-Sierra, Inc. (the “Issuer” or the “Company”). Except as specifically amended by this Schedule 13D/A, the Statement remains in full force and effect.

Item 3. Source and Amount of Funds or Other Consideration

The Reporting Persons purchased an aggregate of 22,807,519 Shares for total consideration (including brokerage commissions) of $155.8 million derived from their working capital.

Item 4. Purpose of Transaction

Item 4 is hereby amended and supplemented as follows:

On May 8, 2015, Mr. Kirt P. Karros, a principal of Relational Investors LLC, resigned from the Board of Directors of the Company.

16

Item 5. Interest in Securities of the Issuer

(a) As of the date of this Statement, the Reporting Persons beneficially own in the aggregate 22,807,519 Shares, constituting approximately 11.53% of the outstanding Shares. The percentage of Shares owned is based upon 197,891,832 Shares reported to be outstanding on April 29, 2015, as set forth in the Company’s Annual Report on Form 10-Q for the period ended March 28, 2015. The Reporting Persons may be deemed to have direct beneficial ownership of the Shares as follows:

NAME	NUMBER OF SHARES	% OF OUTSTANDING SHARES	VOTING AND DISPOSITIVE POWER
RILLC	6,145,265	3.11%	Sole
MC I	4,623,841	2.34%	Sole
MC II	7,971,504	4.03%	Sole
RFP	52,530	0.03%	Sole
RCP	570,882	0.29%	Sole
RH 1	511,001	0.26%	Sole
RI IX	654,813	0.33%	Sole
RI XV	607,142	0.31%	Sole
RI XVI	270,926	0.14%	Sole
RI XX	547,764	0.28%	Sole
RI XXIII	767,727	0.39%	Sole
RI XXIV	84,124	0.04%	Sole

RILLC, individually and in its capacity as an investment adviser, may be deemed to possess direct beneficial ownership of the 6,145,265 Shares that are owned by it and the Managed Accounts. Additionally, RILLC, as the sole general partner, of each of Relational LPs may be deemed to beneficially own (as that term is defined in Rule 13d-3 under the Securities Exchange Act of 1934, as amended) the 16,662,254 Shares beneficially owned by the Relational LPs because the limited partnership agreements of the Relational LPs specify that RILLC has sole investment discretion and voting authority with respect to those Shares. Each of Messrs. Whitworth and Batchelder, as Principals of RILLC, may be deemed to have indirect beneficial ownership of the Shares which RILLC may beneficially own. Each of Messrs. Whitworth and Batchelder disclaims beneficial ownership of such Shares except to the extent of his pecuniary interest therein.

To the best of the knowledge of each of the Reporting Persons, other than as set forth above, none of the persons named in Item 2 is the beneficial owner of any Shares.

(b) See item (a) above.

(c) Not applicable.

(d) No other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the Shares covered by this Statement, except that dividends from, and proceeds from the sale of, the Shares held by accounts managed by RILLC may be delivered to such accounts.

(e) Not applicable.

17

Signature

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated:  May 11, 2015

RELATIONAL INVESTORS MID-CAP FUND I, L.P.
RELATIONAL INVESTORS MID-CAP FUND II, L.P.
RELATIONAL COAST PARTNERS, L.P.

RELATIONAL FUND PARTNERS, L.P.

RH FUND 1, L.P.

RELATIONAL INVESTORS IX, L.P.

RELATIONAL INVESTORS XV, L.P.

RELATIONAL INVESTORS XVI, L.P.

RELATIONAL INVESTORS XX, L.P.

RELATIONAL INVESTORS XXIII, L.P.

RELATIONAL INVESTORS XXIV, L.P.

By:	RELATIONAL INVESTORS, LLC
	as general partner to each,

	By:	/s/ Ralph V. Whitworth
		Ralph V. Whitworth, Principal
RELATIONAL INVESTORS, LLC
	By:	/s/ Ralph V. Whitworth
		Ralph V. Whitworth, Principal
/s/ Ralph V. Whitworth
Ralph V. Whitworth
/s/ David H. Batchelder
David H. Batchelder

18