| 摘要 |
PURPOSE:To prevent the short circuit between terminals for a writing prohibition signal and the terminals of a battery by packaging a switching circuit on a substrate so as to cover this circuit with the battery and packaging SRAMs of bare chips directly onto the substrate, then covering the entire periphery thereof with an insulating resin 24 for sealing. CONSTITUTION:The voltage (a) of an external power source is supplied to the SRAM 1 by the switching circuit 3 during the operation of equipment. The writing prohibition signal is generated from the switching circuit 3 to prohibit the writing to the SRAM 1 for the purpose of preventing data destruction when the external power source is turned off. The switching circuit 3 is packed onto the substrate 11 so as to be covered with the coin type battery 2 and, therefore, the output terminals of the writing prohibition signal are hardly touchable by the fingers and the short circuit between the output terminals of the writing prohibition signal and the terminals of the battery 2 and the output terminal to the SRAM 1 is prevented at the time of attaching and detaching the substrate to and from the socket of the equipment body or carrying the substrate and dissipation of data is prevented. The entire circumference of the bare SRAM 21 is sealed by an insulating resin 24 after connection.
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