Steward, Inc.

Digital Equipment Corporation

Alexander Metsler

A common mode choke has a generally rectangular ferrite body for surface mounting on a printed circuit board. First and second spaced apart slotted openings extend vertically between the top face and the bottom face of the ferrite body. At least one pair of electrical conductors extend along parallel paths from the bottom face through the first slotted opening to the top face, along a portion of the top face, and back down through the second slotted opening to the bottom face. One pair of opposing side faces preferably has lower portions extending outwardly past a plane of the bottom face to thereby serve as a support to mount the bottom face of the ferrite body in spaced relation from the circuit board. The electrical conductors may then extend outwardly from the bottom face of the ferrite body for electrical connection through corresponding openings of a circuit board or extend laterally outwardly for electrical connection to corresponding portions of the circuit board in a gull wing configuration. A continuous upstanding ridge may be formed around the periphery of the top face of the ferrite body and defines a recess at the top face of the ferrite body. A sealant may be positioned within the recess defined by the upstanding ridge for forming a continuous top face to facilitate automated handling of the common mode choke.

Ferrite common mode choke adapted for circuit board mounting

An integrated electromagnetic and radio frequency interference (EMI/RFI) shielding apparatus contains EMI/RFI produced by a computer system. In particular the apparatus isolates input/output (I/O) connectors of the computer system from EMI/RFI produced by noisy components of the system. The shielding apparatus comprises a printed circuit board (PCB) partitioned into two electromagnetically isolated zones separated by a non-conducting void. Components that are EMI/RFI producers, such as the CPU and clock, are mounted in a first zone, and components which need to be isolated, such as input/output connectors are mounted in a second zone. The various conducting layers in the PCB are arranged and filtered to inhibit EMI/RFI propagation to the I/O connectors. Additionally, the I/O connectors are isolated from EMI/RFI by a secondary EMI/RFI shield.

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Newton, MA, United States of America

Alexander Metsler