1. Field of the Invention
The present invention relates to a personal computer peripheral device, and more particularly to a flash memory device and an assembly thereof with improved planar contact portions compatible to mate with USB 2.0 and USB 3.0 receptacle connectors.
2. Description of Related Art
With the fast development of the electrical domain, flash memory is currently used in variety of apparatus including digital cellular phone, digital camera, PC card, and digital setup box or inner controller for notebook computer. A flash memory device such as a U-disk is widely used as an intermedium for accessing data files from one device to another, or like a portable hard drive for installing data.
Usually, a flash memory device includes a circuit board with a plurality of electronic components, such as driver chip, memory chip, oscillator, resistor, etc. for saving and loading data, functioning as a miniature hard drive or wireless communication/transmission, a connector port connected to one end of the circuit board, and a cover enclosing the circuit board. In order to decrease profile of the flash memory device, a so-called Chip-On-Board (COB) IC packaging technology comes into being. Usually, a COB type circuit board includes an embedded chip and a plurality of golden fingers connected to the chip via a plurality of bonding wires.
Universal Serial Bus (USB) has been widely used as a standard connector port because of its self detection and hot plug etc. Nowadays, the most widely used USB ports measure up to USB specification version 2.0 and such USB connectors are accordingly called USB 2.0 connectors as shown in FIG. 1A. However, with the fast development of the information technologies, the current transmission speed of the USB 2.0 connectors can't meet higher demands. As a result, USB 3.0 connectors with transmission speed decouple faster than the USB 2.0 connectors come with the tide of fashion.
As shown in FIG. 1A, a USB 2.0 receptacle connector A1 includes four deformable contact sections A11 extending downwardly beyond a mating surface A12 thereof for mating with a corresponding USB 2.0 plug to transmit USB 2.0 signals.
As shown in FIG. 1B, a USB 3.0 receptacle connector A2 includes five front contact sections A22 and four rear contact sections A21 located behind the front contact sections A22. The front contact sections A22 are planar and recessed from a mating surface A23 of the USB 3.0 receptacle A2. The front contact sections A22 are disposed near a mating end A24 of the USB 3.0 receptacle A2. The rear contact sections A21 are of the same configuration as the contact sections A11 of the USB 2.0 receptacle connector A1 and protrude downwardly beyond the mating surface A23. The front and the rear contact sections A22, A21 jointly abut against a corresponding USB 3.0 plug to transmit USB 3.0 signals.
In the interim, USB 2.0 and USB 3.0 receptacle connectors are coexisted in the market, so there is a demand to provide USB flash memory devices which are compatible to USB 2.0 and USB 3.0 receptacle connectors.