International Business Machines Corporation

Kent Barclay Howieson

Bhyrav M Mutnury

Moises Cases

Pravin S Patel

Bradley Donald Herrman

Nam Huu Pham

Erdem Matoglu

Caleb James Wesley

Peter Robert Seidel

Rubina Firdaus Ahmed

An apparatus having reduced noise coupling includes a core layer having an upper and lower surface, the upper and lower surface each including a copper sheet layer, a pre-preg layer having an upper surface and a lower surface, the upper surface of the pre-preg layer coupled to the lower surface of the core layer, a core insulating layer having an upper surface and a lower surface, the upper surface of the core insulating layer coupled to the lower surface of the pre-preg layer, a return current reference layer disposed on the lower surface of the core insulator layer and high-speed signal traces disposed on the upper surface of the core insulating layer, each of the high speed signal traces disposed on a pedestal defined by a section of the pre-preg layer and the core insulating layer, each pedestal being separated by an air gap disposed between adjacent pedestals.

Reducing noise coupling in high speed digital systems

A method for testing a printed circuit board to determining the dielectric loss associated with the circuit board material relative to a standard. Dielectric losses in the material generate heat when a high frequency electronic signal, such as a microwave frequency signal, is communicated through a microstrip that is embedded within the printed circuit board. The temperature or spectrum at the surface of printed circuit board is measured and compared against the temperature or spectrum of the standard to determine whether the material under test is acceptable. While various temperature measurement devices may be used, the temperature is preferably measured without contacting the surface, such as using an infrared radiation probe.

Method for validating printed circuit board materials for high speed applications

Methods and systems for reducing noise coupling in high-speed digital systems. Exemplary embodiments include a method, including etching a plurality of high speed signal traces onto a core insulating layer, forming trenches on respective sides of the plurality of high speed signal traces, thereby removing insulating material adjacent to the plurality of high speed signal traces and forming pedestals having remaining insulating material, the plurality of high speed signal traces disposed on and coupled to the remaining insulating material, coupling pre-preg material on the high speed signal traces, removing the pre-preg material adjacent the trenches, thereby retaining the pre-preg material aligned with the high speed signal traces, and heating and pressing a core layer to the pre-preg layer, and heating and pressing the pre-preg layer to the core insulating layer.

Method for reducing noise coupling in high speed digital systems

A method of electrically qualifying high speed printed circuit board (PCB) connectors includes mounting a PCB connector on a test card, sending bit patterns through a first portion of the test card, evaluating a waveform on a sense signal on a second portion of the test card for the bit patterns launched on said first portion of the test card to measure common mode noise, and comparing the measured common mode noise of the second portion of the test card to a golden standard performed on a pre-qualified connector. The first portion of the test card comprises connectors to inject bit patterns. The second portion of the test card includes a split plane which induces common mode noise on a sense signal, the sense signal, and a termination pack. If the measured common mode noise on the PCB connector is worse than the golden standard, then the PCB connector is disqualified. If the measured common mode noise on the PCB connector is as good as or better than the golden standard, then the PCB connector is qualified. A first section of the PCB connector connects to the first portion of the test card and a second section of the PCB connector connects to the second portion of the test card. Transmission lines in the test card and the sense line are tightly coupled by shortening a distance between the sense line and the transmission lines.

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Austin, TX, United States of America

Kent Barclay Howieson