Standard Chips
- The 7400 series of chips is available in different types of logic gates. Below is the structural diagram of the 7404 chip containing 6
NOTgates - Function provided by a 7400 series chip is fixed and cannot be changed
Programmable Logic Devices
- Several programmable language devices (PLD) exist such as
- programmable logic arrays (PLA)
- programmable array logic (PAL)
- field-programmable gate arrays (FPGA)
- All PLDs are pre-fabricated but allow users configure (i.e program) the device
FPGAs:
Standard Cells & Custom Chips
- Standard Cells
- Pre-designed standard cells of logic gates are placed in rows and connected by wires through routing channels to create circuits (called application specific integrated circuits – ASIC). See below
- ASIC designs require fabrication and does not have programmable switches
- Custom Chips: These are created from scratch and provide most circuit density, highest speed, lowest power. It’s suitable for large volume manufacturing.