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Field-Programmable Gate Array (FPGA) and Factory Programmed Application Specific Integrated Circuit (ASIC)

Multiple FPGA architectures with different configuration technologies

Flexible general purpose data-path and control function where user inserts memory elements as desired.

    SRAM based (dynamic storage to personalize the logic function of 4-5 input "look-up-table" blocks and their interconnection)

    Xilinx, Altera, Lucent, and now Actel offer a variety of "course-grain" architectures. The Xilinx XC4000 and new VIRTEX families utilize an array of Configurable Logic Blocks (CLB) interconnected with variety of pass-transistor switched lines and Programmable Switch Matrices (PSM)
    Xilinx VIRTEX architecture:

Delay Locked LoopFourth Generation CLB and Routing Block SelectRAM+ MemoryVirtex I/O Performance

    Altera APEX architecture:

    APEX LookUpTable & SumOfProduct Logic + RAM

    Anti-Fuse based (one-time only personalization of unique fuse elements to configure logic function blocks and their interconnect)

    Actel offers a "fine-grain" architecture utilizing rows of logic blocks which can be configured for a variety of logic and memory functions Actel fine-grain FPGA

    FLASH based (reconfigurable personalization of logic elements and their interconnect)

Complex Programmable Logic Devices (CPLD) utilize a matrix of "Sum-of-Products" logic function with a global interconnection

Very fast decode and FSM control functions for shallow logic depth
CPLD Architecture
    UV-PROM based (reconfigurable personalization of wide AND & OR arrays with latched macrocell output)
    FLASH based (reconfigurable personalization of wide AND & OR arrays with latched macrocell output)

Mask Personalized Gate Array ASIC

Array of identical size P and N transistors personalized at the contact and metal layers to form columns of various size logic blocks spaced apart for vertical first metal and horizontal second layer routing. Additional metal routing layers are used for global signals and power/ground supply. New products utilize a "sea-of-gates" architecture, where the area allocated for vertical metal routing over unused transistors is flexible. Some large memory and logic functions can be interconnected without wasting transistors under routing tracks.
Simple double metal gate array:

Gate Array Architecture

Mask Personalized Cell-Based ASIC

Columns of various logic and memory blocks with optimized P and N transistor sizes personalized at all the mask layers. Optimum performance and density are obtained compared to gate array architecture. Multiple layers of metal routing are used to connect the transistors within the block and route signals between blocks. With more complex multi-level metalization deep-submicron IC processing, this approach offers superior cost and performance as well as incorporating hard IP macros.
Simple double metal cell-based array:

Cell-Based Architecture

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