FIRST AMENDMENT TO AMENDED AND RESTATED CREDIT AND SECURITY AGREEMENT

Exhibit 10.1

FIRST AMENDMENT TO

AMENDED AND RESTATED CREDIT AND SECURITY AGREEMENT

THIS FIRST AMENDMENT TO AMENDED AND RESTATED CREDIT AND SECURITY AGREEMENT (the “ Amendment ”), dated May 30, 2008, is entered into by and between RF MONOLITHICS, INC., a Delaware corporation (the “ Borrower ”), and WELLS FARGO BANK, NATIONAL ASSOCIATION (the “ Lender ”), acting through its Wells Fargo Business Credit operating division.

RECITALS

A. The Borrower and the Lender are parties to a Credit and Security Agreement dated as of August 29, 2007 (as amended from time to time, the “ Credit Agreement ”). Capitalized terms used in these recitals have the meanings given to them in the Credit Agreement unless otherwise specified.

B. The Borrower has requested that certain amendments be made to the Credit Agreement, which the Lender is willing to make pursuant to the terms and conditions set forth herein.

NOW, THEREFORE, in consideration of the premises and of the mutual covenants and agreements herein contained, it is agreed as follows:

1. Defined Terms . (a) Capitalized terms used in this Amendment which are defined in the Credit Agreement shall have the same meanings as defined therein, unless otherwise defined herein.

(b) Section 1.1 of the Credit Agreement is amended by adding the following definitions thereto in alphabetical order:

“Cirronet” means Cirronet Inc., a Georgia corporation.

“Cirronet Finished Goods Advance Rate” means up to eighty-five percent (85%) of the orderly liquidation value – customer sell through.

“Cirronet Raw Materials Advance Rate” means up to eight (8%) of the orderly liquidation value – customer sell through.

“Borrower Finished Goods Advance Rate” means up to fifty percent (50%) of the orderly liquidation value – customer sell through.

“Borrower Raw Materials Advance Rate” means up to nine (9%) of the orderly liquidation value – customer sell through.

(c) Section 1.1 of the Credit Agreement is amended by deleting the definition of “Inventory Advance Rate”.

(d) Section 1.1 of the Credit Agreement is amended by amending and restating the following definitions:

“Borrowing Base” means at any time the lesser of:

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(i) The lesser of (A) the product of the Accounts Advance Rate times Eligible Accounts or (B) $11,000,000, plus

(ii) The lesser of (A) (1) the product of the Borrower Finished Goods Advance Rate times Borrower’s finished goods Eligible Inventory, plus (2) the product of the Cirronet Finished Goods Advance Rate times Cirronet’s finished goods Eligible Inventory, plus (3) the product of the Borrower Raw Materials Advance Rate times Borrower’s raw materials Eligible Inventory, plus (4) the product of the Cirronet Raw Materials Advance Rate times Cirronet’s raw materials Eligible Inventory, or (B) $3,000,000, less

(iii) Indebtedness that the Borrower owes to the Lender that has not yet been advanced on the Revolving Note, including, without limitation, the L/C Amount, and the dollar amount that the Lender in its reasonable discretion then determines to be a reasonable determination of the Borrower’s credit exposure with respect to any swap, derivative, foreign exchange, hedge, deposit, treasury management or other similar transaction or arrangement offered to Borrower by Lender that is not described in Article II of this Agreement and any indebtedness owed by Borrower to Wells Fargo Merchant Services, L.L.C, less

(iv) a Borrowing Base reserve in the amount of (A) $100,000 for the month ending June 30, 2008, (B) $200,000 for the month ending July 31, 2008, (C) $300,000 for the month ending August 31, 2008, (D) $400,000 for the month ending September 30, 2008 and (E) $500,000 for the month ending October 31, 2008 and all periods thereafter.

“Floating Rate” means (i) with respect to Revolving Advances evidenced by the Revolving Note, an annual interest rate equal to the Prime Rate plus two percent (2.00%), and (ii) with respect to Term Advances evidenced by the Term Note, an annual interest rate equal to the Prime Rate plus two percent (2.00%), which interest rate shall, in each case, change when and as the Prime Rate changes.

“LIBOR Advance Rate” means (i) with respect to Revolving Advances evidenced by the Revolving Note, an annual interest rate equal to the sum of LIBOR plus 4.50 percent, and (ii) with respect to Term Advances evidenced by the Term Note, an annual interest rate equal to the sum of LIBOR plus 4.50 percent.

2. Financial Covenants . Section 6.2 of the Credit Agreement shall be deleted in its entirety and restated as follows:

(a) Minimum Net Income . The Borrower will achieve for each period described below, Net Income of not less than the amount set forth for each such period (numbers appearing between “( )” are negative):

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(b) Stop Loss . The Borrower will not, (i) during the fiscal quarter ending May 31, 2008, suffer a Net Loss in excess of $1,500,000, and (ii) during the fiscal quarter ending August 31, 2008, suffer a Net Loss in excess of $900,000.

(c) Minimum Debt Service Coverage Ratio . Intentionally Omitted.

(d) Capital Expenditures . The Borrower will not incur or contract to incur Capital Expenditures of more than $1,200,000 in the aggregate during any fiscal year.

(e ) Consultant . If