Document And Entity Information (USD $)	12 Months Ended
	Mar. 31, 2011	May 20, 2011	Sep. 30, 2010
Document And Entity Information [Abstract]
Entity Registrant Name	MICROCHIP TECHNOLOGY INC
Entity Central Index Key	0000827054
Current Fiscal Year End Date	--03-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 5,717,290,437
Entity Common Stock, Shares Outstanding		190,479,654
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Mar. 31, 2011