Multimedia DTAB packages for a 125-MHz computer

Challenges in packaging a 430-pin IC chip that operates at 2 V and draws 15 A with risetimes of about 200 ps are discussed. A highly optimized 407-pin multilayer ceramic package (PGA) with wirebonds was evaluated for this application and failed most of the noise specifications. An analysis of the failure mechanisms led to the design of a two-metal-layer 432-pin tape automated bonding (TAB) package. Performance capabilities and limitations of these two packages are compared through detailed simulations and measurements. It is concluded that TAB packages meet or exceed the performance goals for low transition times and/or large operating currents. The initial design was modified with the addition of a third metal layer. Performance results of this three-metal-layer TAB are included. >