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FARADAY SHIELD IMPLEMENTATION IN A POWER STACK FOR A HYBRID CIRCUIT

IP.com Disclosure Number: IPCOM000005923D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2001-Nov-15
Document File: 1 page(s) / 51K

Publishing Venue

Motorola

Related People

John Herrmann H. (Samuel) No: AUTHOR [+2]

Abstract

Figure 1 shows a side view of the power stack for a hybrid circuit design. The multilayer substrate is composed of both alumina and copper layers, constructed using direct bond copper (DBC) technology. DBC technology is a method of bonding copper directly to a ceramic substrate, without an additional bonding layer. This technology is particularly useful in applications requiring low thermal resistance and high current carrying capability as it minimizes the number of thermal interfaces.

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MOTOROLA Technical Developments Volume 10 March 1990

FARADAY SHIELD IMPLEMENTATION IN A POWER STACK FOR A HYBRID CIRCUIT

by John Herrmann H. (Samuel) No and Kenneth Sikora

   Figure 1 shows a side view of the power stack for a hybrid circuit design. The multilayer substrate is composed of both alumina and copper layers, constructed using direct bond copper (DBC) technology. DBC technology is a method of bonding copper directly to a ceramic substrate, without an additional bonding layer. This technology is particularly useful in applications requiring low thermal resistance and high current carrying capability as it minimizes the number of thermal interfaces.

   The power stack described herein is designed to provide both a top and an intermediate conductor layer that are electrically isolated from the copper base plate. The purpose of the intermediate copper layer is to shield the base plate from electrical noise resulting from high frequency, high power switching of surface mounted components by providing a capacitive conductive path back to AC ground, i.e. by providing a Faraday shield. The intermediate, or Faraday shield, layer may be connected to either the negative or positive line of the power supply. The unique feature of this power stack design is the method employed to achieve this connection. The Faraday shield layer is patterned to extend beyond one edge of the alumina substrate such that it can be folded onto the top conductor and soldered simultaneousl...