FPGA - Field Programmable Gate Array

About 25 to 40 percent of chip sale revenue now comes from field-programmable logic devices. These are chips that can be programmed electronically on the user's site to provide the desired function.

PALs and CPLDs are forms of programmable logic that are fast and small. But the most important form today is the FPGA.

Recall the Xilinx/Altera FPGA parts used in the Part IB E+A classes.

Field-programmable devices may be volatile (need programming every time after power up), reprogrammable or one-time programmable. This depends on how the programming information is stored inside the devices, which can be in RAM cells or in any of the ways used for ROM, such as electrostatic charge storage (e.g. FLASH). Except for niche applications (such as GaAs instead of Si), FPGAs are now always used instead of masked gate arrays and are starting to kill ASCIs (see link above).

Example: The part Ib practical classes use FPGAs from Altera: »ECAD and Architecture Practical Classes

Summary data for a Virtex 5 Xilinx FPGA:

Part number	XC5VLX110T-2FFG1136C
Vendor	Xilinx Inc
Category	Integrated Circuits (ICs)
Number of Gates	110000
Number of I /O	640
Number of Logic Blocks/Elements	8640
Package / Case	1136-FCBGA
Operating Temperature	0C ~ 85C
Voltage - Supply	1.14 V ~ 3.45 V

Circa 2009, 65 nm technology, 6-input LUT, 64 bit D/P RAMs.

Today Xilinx has the Virtex 7 series that includes the Zync SoC (of which more later) »wikipedia: Virtex FPGA

Field-programmable gate array structure, showing I/O blocks around the edge, interconnection matrix blocks and configurable logic blocks. In recent parts, the regular structure is broken up by custom blocks, including RAMs and multiplier (aka DSP) blocks.