MICROCHIP TECHNOLOGY CALDICOT LIMITED

NATIONAL WESTMINSTER BANK PLC

CHARGE OF DEPOSIT

CANADIAN IMPERIAL BANK OF COMMERCE (THE "SECURITY AGENT")

SUPPLEMENTAL DEBENTURE MADE BETWEEN (1) MITEL SEMICONDUCTOR LIMITED (2) MITEL TELECOM LIMITED AND (3) CANADIAN IMPERIAL BANK OF COMMERCE (AS SECURITY AGENT)

CANADIAN IMPERIAL BANK OF COMMERCE ("THE SECURITY AGENT") AS SECURITY AGENTFOR ITSELF, THE LENDERS AND THE LENDER COUNTERPARTIES

GUARANTEE & DEBENTURE

CANADIAN IMPERIAL BANK OF COMMERCE(AS SECURITY AGENT FOR THE SECURED PARTIES IN ACCORDANCE WITH THE DEBENTURE)

SECURITY ACCESSION DEED