Dual Interposer Overview
Taiwan Patent No. 121834

Dual Interposer is an FR4 PCM (Personal Computer Module) design, which connects two 360-lead CBGA PowerPC microprocessors and a 288-pin PGA. It structures individual backside L2 cache devices, and integrates MPC750 and MPC7400 (MPC7410)** bus interface for symmetric multiprocessor architecture. The Dual Interposer provides 1M / 4M bytes with 150MHz on L2 cache interface and 100 / 133 MHz 60X system bus.

The additional power supply filtering on the processor module consists of a PLL voltage supply (AVdd) which is filtered on the PGA PCM, and a Core voltage supply (Vdd) which is filtered on PCM. The former is close to the processor and improves the noise immunity, and the latter can reduce voltage variations.

The PCM signals determine both the selection of processor voltage and the self-identification of module type. They can encode and control the power supply modules directly. Furthermore, a Four-voltage-ID-pins design has the ability to select operating core voltage from 1.3V to 3.5V and to encode in order to match industry-standard power-controllers. For encoding simple modules, there is another 3-pin design available.