Patent ID: 7805643

Claim:
A semiconductor device, comprising: plural functional blocks including a non-volatile memory block; a voltage supply circuit supplying a power supply voltage to said functional blocks; a cut-off circuit cutting off the supply of said power supply voltage from said voltage supply circuit to said memory block; and a self test circuit performing tests of said functional blocks, wherein in a data retention test of said memory block, said self test circuit instructs said cut-off circuit to start an operation after writing predetermined data into said memory block, and instructs said cut-off circuit to stop the operation to check retention of said predetermined data in said memory block in a predetermined time after the instruction to said cut-off circuit to start the operation, wherein the voltage supply circuit supplies the power supply voltage to at least one of the plural functional blocks other than the memory block while cutting off the supply of said power supply voltage from said voltage supply circuit to said memory block.