A multimedia card includes a substrate, and a main control chip, a memory chip, and an interface contacts that are disposed on the substrate. The main control chip and the memory chip are covered with a packaging layer. The interface contacts includes a power contact, configured to receive a first voltage that is input from the outside; and a transformer circuit is further disposed on the substrate, is coupled to the interface contacts, the main control chip, and the memory chip, and is configured to convert the input first voltage into a second voltage, to provide two types of power supplies with the first voltage and the second voltage for the main control chip and the memory chip. In the foregoing manner, an area of the multimedia card is reduced, and a quantity of working modes of the multimedia card increases.