The present invention relates to a printed circuit board (PCB), and more particularly to a quartz crystal oscillator layout for a PCB which readily sends noise generated by the oscillator to ground.
Quartz crystal oscillators control timing and operation of logic circuitry. The use of quartz crystal oscillators is widespread in consumer and industrial electronic products. A personal computer system, for example, may use quartz crystal oscillators in the processing unit as well as video graphics adapters, and in peripheral devices such as printers, modems, and networking equipment.
Referring to
The quartz crystal oscillator transmits clock signals to corresponding layers of the PCB 200 through the vias 20 and 21. Noise of the quartz crystal oscillator generating from high levels to low levels should be transmitted from a metal enclosure of the quartz crystal oscillator to the ground layer of the PCB 200 through the wire. However, contact area between the metal enclosure and the wire is small, thereby limiting an amount of noise sent to ground, which interferes with the transmitting characteristics of the PCB 200.
What is needed is a quartz crystal oscillator layout for a PCB which more readily sends noise generated by the oscillator to ground which can improve transmitting characteristics of the PCB.
An exemplary quartz crystal oscillator layout for a printed circuit board (PCB) in accordance with a preferred embodiment includes a mounting area for receiving the quartz crystal oscillator, two first vias, and two second vias. A copper foil is arranged on the mounting area. Pins of the quartz crystal oscillator are inserted into the first vias. The second vias are connected to a ground layer of the PCB and communicate with the copper foil, for transmitting noise of the quartz crystal oscillator to the ground layer of the PCB.
Other advantages and novel features will become more apparent from the following detailed description, in which:
Referring to
Referring to
In the embodiment, when the quartz crystal oscillator 58 is secured to the mounting area 40, contact between the copper foil 42 and the metal enclosure of the quartz crystal oscillator 58 allows the noise of the quartz crystal oscillator 58 to be transmitted to the ground layer of the PCB via a shortest route. The layout of the quartz crystal oscillator 58 improves the stability of the PCB 100. Furthermore, the solder masks 44 prevent an electrical connection from being formed between the copper foil 42 and the soldered ends of the wire 59 at the vias 54 and 56.
It is believed that the present embodiment and it's advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the embodiment or sacrificing all of its material advantages, the example hereinbefore described merely being preferred or exemplary embodiment.
Number | Date | Country | Kind |
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2005 1 010768 | Nov 2005 | CN | national |
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Number | Date | Country | |
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20070114638 A1 | May 2007 | US |