| 摘要 |
A printed circuit board is adjacently mounted on a part of a chassis substantially in parallel with each other and the chassis serves as an all-overlaying GND pattern layer. Furthermore, by placing an insulator between the printed circuit board and the chassis, the stray capacitance around signal lines D+ and D- is stabilized in a proper range. Thus, a differential impedance between the USB signal lines D+ and D- is made in compliance with standard concerned. As a result, in an electronic device equipped with an interface in conformity to the USB 2.0 standard, the differential impedance can be made in compliance with the standard in spite of using an inexpensive two-layered board.
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