Browse Prior Art Database

LASER TRIMMABLE CERAMIC CHIP INDUCTOR

IP.com Disclosure Number: IPCOM000008454D
Original Publication Date: 1997-Dec-01
Included in the Prior Art Database: 2002-Jun-14
Document File: 2 page(s) / 81K

Publishing Venue

Motorola

Related People

Clark Fischbach: AUTHOR [+2]

Abstract

Presently, circuit traces on non-ceramic PC boards can not be actively laser trimmed without severe damage to the laminate material. As such, when using non-ceramic PC boards, laser trimma- ble discrete components are required in order to allow active laser trimming. However, the only laser trimmable component types commercially available are resistors and chip capacitors. Many circuit designs require inductive elements and in many cases, these elements need to be adjusted for proper circuit performance. Presently, no inductive or phase shifting elements are available that are laser trimmable. This defines the need for laser trimmable inductive components.

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MOTOROLA Technical Developments

LASER TRIMMABLE CERAMIC CHIP INDUCTOR

by Clark Fischbach and Gregor Mitringa

BACKGROUND

  Presently, circuit traces on non-ceramic PC boards can not be actively laser trimmed without severe damage to the laminate material. As such, when using non-ceramic PC boards, laser trimma- ble discrete components are required in order to allow active laser trimming. However, the only laser trimmable component types commercially available are resistors and chip capacitors. Many circuit designs require inductive elements and in many cases, these elements need to be adjusted for

proper circuit performance. Presently, no inductive or phase shifting elements are available that are laser trimmable. This defines the need for laser trimmable inductive components.

SOLUTION

  The design is constructed from a base ceramic substrate. Coils of an inductor are formed by a series of interconnected lines and plated vias (Figure 1).

11 Laser Trim Points

Fig. 1

  The top-most layer of this component contains a increases in inductance value as shorting runners shorting runner that shorts out the coils of the struc- are removed via a laser. The amount of inductance tore. When this component is trimmed, the shorting change per shorting runner cut can be controlled by runner is cut such that individual "coils" are no the geometry of the component. Because the induc- longer shorted by the shorting runner. This trim- tance is controlled by the geometry, it is possible...