Advanced atm switching system hardware technologies based on mcm-d for atm line interface circuits

This paper describes advanced ATM switching system hardware that uses a high-performance and cost-effective MCM-D module as an ATM-layer function device. The MCM-D module is fabricated on a Si-substrate using the stacking RAM technique to reduce module size. The MCM has a 4-layer Si substrate, a high-performance ASIC, 8 high-speed SRAMs, and an FPGA. By using the stacking RAM technique, MCM-D module size is reduced to 50.8mm x 50.8mm. This is 40% ofthat (100mm x 65mm) of a double-side mounted sub-board module with conventional packaging (QFP and SOP). The MCM-D module realizes the ATM-layer functions that require a highperformance ASIC with a high-speed (access time 20ns) and large-capacity (l MBytes) SRAM cache. The MCM approach is quite effective in increasing memory access speed because it realizes high-density packaging. The MCM-D module is mounted on an ATM line interface circuit, and realizes 150 Mbit/s throughput ATM-layer functions (header conversion and on-line monitoring) in an ATM switching system. In addition, advanced ATM switching system hardware technologies with sub-module structure are also described. The MCM-D module is one of the sub-modules of the system. This MCM technology and sub-module technology can be applied to advanced ATM switching systems.