IC CHIP CARRIER WITH INTERNAL GROUND AND VCC BUS

Publishing Venue

Motorola

Related People

Abstract

In order to achieve high volume and low unit cost, most integrated circuits are designed to satisfy the needs Of as many different user applications as possible. For example, one user of an IF chip might require an on-chip second mixer but no squelch or second local oscillator whereas another user might require atf three. For maximum flexibility, the IC designers would include all of these circuits on-chip with some provision for the ability to disable or turn off sections of unused circuitry. Similarly, for digital designs there may be many unneeded circuit functions with unused circuit-enable and logic inputs.

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MOTOROLA Technical Developments Volume 8 October 1988

IC CHIP CARRIER WITH INTERNAL GROUND AND VCC BUS

by Walt Kehler and Richard Meador

   tn order t0 achieve high volume and low unit cost, most integrated circuits are designed to satisfy the needs Of as many different user applications as possible. For example, one user of an IF chip might require an on-chip second mixer but no squelch or second local oscillator whereas another user might require atf three. For maximum flexibility, the IC designers would include all of these circuits on-chip with some provision for the ability to disable or turn off sections of unused circuitry. Similarly, for digital designs there may be many unneeded circuit functions with unused circuit-enable and logic inputs.

   However, this multi-user design philosophy creates a number of problems, two of which are the increased number of pin-outs required on the IC chip carrierand the increased circuit board inter-connect runs to proper- ly connect these pin-outs. More pin-outs require larger chip carriers, more circuit board space, more metal inter- connect and greater cost.

   These problems can be alleviated by an IC chip carrier designed to accommodate internal wire bonding between the IC die and the chip carrier. Figure A provides a drawing of a leadless chip carrier which accom- modates internal wire bonding. By metallizing an unused portion of the surface of the chip carrier, a Ground bus and/or VCC voltage supply bus are made availab...