Low electromagnetic interference clock oscillator module
OwnerPaul Fei-Ta Chen, James John Levante +1inventors
InventorsPaul Fei-Ta Chen, James John Levante, Chuong Dinh Nguyen
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Abstract
A low noise clock oscillator in standard surface mount plastic or ceramic form. With the same soldering pads design such devices can be replace with a convention standard surface mount clock oscillator to reduce Electro-magnetic Interference or RFI (Radio Frequency Interference) without redesign of the main board. The oscillator is characterized by using a spectrum spread clock generator and a spread controller on an elevated platform to reduce common mode emission currents.
Claims11
A low noise clock oscillator for plugging into a standard multi-pin DIP clock oscillator socket on the motherboard of a host device, comprising:
- a printed circuit board having a plurality of conductive traces and which is separate from the motherboard;
- a spread spectrum clock generator having a plurality of terminals coupled to predetermined ones of said conductive traces for generating a spread spectrum clock signal;
- a crystal coupled to predetermined ones of said conductive traces;
- a plurality of pins mechanically and electrically coupled to predetermined ones of said conductive traces of said printed circuit board, said pins spaced so as to engage specific pin receptacles on said DIP clock oscillator socket on said motherboard so as to provide electrical connections to couple Vcc power source and ground source conductive traces on said motherboard to said spread spectrum clock generator and to electrically couple said spread spectrum clock signal to a clock bus on said motherboard, said pins being long enough that said electrical connections can be made with said printed circuit board above and not in contact with any conductive traces on said motherboard, said electrical connection to a ground source conductive trace on said motherboard via a single pin;
- a plurality of EMC filters coupling each of said pins to predetermined terminals of said spread spectrum clock generator.
A low noise clock oscillator module for plugging into a standard DIP clock oscillator socket of a motherboard to replace the clock oscillator chip that normally plugs into said DIP clock oscillator socket, comprising:
- a printed circuit substrate separate from said motherboard and having a ground plane;
- clock generator means mounted on said substrate for generating spread spectrum clock signals from reference clock signals said clock generator means having an analog ground output coupled to analog circuitry therein and a digital ground output coupled to digital circuitry therein;
- and wherein said printed circuit substrate has separate digital and analog ground plane traces thereon, said analog ground plane being connected to said analog ground output and said digital ground plane connected to said digital ground output, and wherein said printed circuit substrate has a plurality of electrical connection pins having a physical configuration and layout and electrical coupling between said clock generator means and said pins such that said clock oscillator module can be substituted for a conventional clock oscillator chip by plugging said clock oscillator module directly into the same standard DIP integrated circuit socket into which said clock oscillator chip was formerly plugged, and wherein said analog and digital ground planes are electrically connected together at the location of a ground pin which makes an electrical connection to a ground bus of said motherboard through said standard DIP integrated circuit socket.
A low noise clock oscillator module for plugging into a standard DIP clock oscillator socket of a motherboard, comprising:
- a printed circuit substrate separate from said motherboard and having a ground plane;
- clock generator means mounted on said substrate for generating spread spectrum clock signals from reference clock signals;
- first connection means for providing a single point electrical connection between said ground plane on said printed circuit substrate and a ground conductive trace on said motherboard and for coupling said ground plane to said clock generator means;
- and
- second connection means for providing electrical connection between a power source on said motherboard and said clock generator means and for providing electrical connection of spread spectrum clock signals generated by said clock generator means and a clock bus on said motherboard.
Dependencies are inferred from the claim text.