Browse Prior Art Database

INCREASED DISSIPATION SCREENED CHIP RESISTOR

IP.com Disclosure Number: IPCOM000009874D
Original Publication Date: 2000-May-01
Included in the Prior Art Database: 2002-Sep-25
Document File: 1 page(s) / 58K

Publishing Venue

Motorola

Related People

Clark Fischbach: AUTHOR [+3]

Abstract

Higher power resistors are desired in high power applications such as a power amplifier. Conventional rectangular screened chip type resistors have the typical hot spot in the center of the device. This hot spot thermally limits the device's operation and defines its dissipation rating. Currently, to increase this rating, the physical size of the part must be increased. However, increasing the size of the part is often not an option for either real estate or size limit of available low cost parts.

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MOTOROLA

Technical Developments

INCREASED DISSIPATION SCREENED CHIP RESISTOR

by Clark Fischbach, David Frendreiss and Heather Kang

Higher power resistors are desired in high power applications such as a power amplifier.

Conventional rectangular screened chip type resistors have the typical hot spot in the center of the device. This hot spot thermally limits the device's operation and defines its dissipation rating.

Currently, to increase this rating, the physical size of the part must be increased. However, increasing the size of the part is often not an option for either real estate or size limit of available low cost parts.

By altering the geometry of the resistive ink, the heat generated by the resistor can be located in areas that are more conducive to heat transfer. In an end terminated chip resistor, the heat flow path is

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through the end terminations to the PC board beneath. By concentrating the dissipating elements near these end terminations, the bulk of the heat generated now sees a lower effective thermal resistance. Compared to a conventional chip resistor, this approach results in a lower peak temperature when dissipating the same power or more power can be dissipated in the same package size.

The illustration shows how the resistive ink is concentrated close to the end terminations. The resistive ink areas are electrically connected on the chip by a higWy con...