Abstract: A PC card has a plastic frame provided along the periphery of a substrate. Metal plates, such as stainless steel plates and the like, cover both surfaces of the substrate and are attached to the plastic frame. External surfaces of the metal plates located in an area on the opposite side of a connector and which are touched by a person's hand are covered by an insulation tape, so that, even if a person charged with static electricity touches the PC card when the PC card is inserted or withdrawn from an external apparatus such as a personal computer (PC), the static electricity (charge) of the person does not flow into the external apparatus. Thus, malfunctions or erroneous operations of the external apparatus do not occur.

Abstract: A PC card has a plastic frame 8 provided along the periphery of a substrate 4. Metal plates 2 such as stainless steel plates and the like cover both surfaces of the substrate and are attached to the plastic frame 8. External surfaces of the metal plates 2 in an area on the opposite side of a connector 1 which are touched by a person's hand are covered by an insulation tape 7, so that, even if a person charged with static electricity touches the PC card when the PC card is inserted or withdrawn from an external apparatus such as a personal computer (PC), the static electricity (charge) of the person does not flow into the external apparatus. Thus, malfunctions or erroneous operations of the external apparatus do not occur.

Abstract: The logic circuit area 20 of, for example, a memory card, is equipped with an enable signal conversion circuit 22 which, based on the external enable signal CE(bar), generates the internal enable timing signal CEX for supplying the timing for the internal enable signals, MCE0(bar) through MCE7(bar), to be applied to the semiconductor memory. Even when the address signal changes randomly and the card enable signal CE (bar) repeatedly changes between high and low levels, an internal enable signal CEX which continues to be active is sent out, thus maintaining the internal enable signals MCE0(bar) through MCE7(bar) in the active state without any high-low changes. As a result, it becomes possible to control the pass-through current, etc. and to minimize the current consumption of the semiconductor memory area 10.

Abstract: An objective of the present invention is to provide a highly reliable IC card which is large in the scale of integration, fast, and low power-consuming, which contains the latest type of IC that has an operating voltage of 3.3 V and a maximum rated voltage of 5 V or less, and which can be used in either the latest equipment rated at 3.3 V or existing equipment rated at 5 V, or which does not cause this latest type of IC to be destroyed. The interface circuit comprises an analog switch, an external interface circuit, an interval interface circuit, and a high-voltage detection circuit. If the voltage of the power supply Vcc of the host system is less than or equal to an upper-limit voltage of 4 V, the power supply voltage is applied unchanged through the analog switch to a ROM that is the main circuit. On the other hand, if the power supply voltage is greater than this upper-limit voltage of 4 V, the analog switch is made non-conductive and thus the power supply voltage is not applied to the ROM.

Abstract: A dynamic access random access card is provided with a dynamic random access memory and a source for generating a plurality of reference clock pulses. A control circuit generates refresh operations of the dynamic access memory in response to the plurality of reference clock pulses generated by the source, the initiation of the refresh operations being independent of any external refresh request. The refresh operations are interrupted and the dynamic random access memory is set to a standby condition upon detection of a predetermined external signal, thereby permitting read/write operations of the dynamic random access memory.

Abstract: A memory card mounted with a storage device and an electronic appliance using such a memory device. The memory card has an RAM (36), a battery (38), a voltage converter (40) for boosting a voltage of the battery and for outputting the boosted voltage, and a switching circuit (42) for receiving an output voltage of the voltage converter and an externally supplied voltage and for supplying one of the received voltages to the RAM as a driving voltage therefor, so that a voltage higher than the battery voltage is supplied to the RAM at the time of backup to thereby reduce soft errors.