**Exhibit 31.2**

**CERTIFICATION OF CHIEF FINANCIAL OFFICER**

**PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF2002**

I, Robert G. Gargus, Senior Vice President and Chief Financial Officer, certify that: 

1. I have reviewed this Annual Report on Form 10-K of Applied Micro Circuits Corporation; 

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to makethe statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report; 

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flowsof the registrant as of, and for, the periods presented in this report; 

4. The registrant’s other certifying officer and I areresponsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and15d-15(f)) for the registrant and have: 

(a) Designed such disclosure controls and procedures, or caused suchdisclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularlyduring the period in which this report is being prepared; 

(b) Designed such internal control over financialreporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for externalpurposes in accordance with generally accepted accounting principles; 

(c) Evaluated the effectiveness of theregistrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on suchevaluation; and 

(d) Disclosed in this report any change in the registrant’s internal control over financialreporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, theregistrant’s internal control over financial reporting; and 

5. The registrant’s other certifying officer and I havedisclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control overfinancial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and 

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in theregistrant’s internal control over financial reporting. 

 

Date: January 9, 2007