FPGA vs. CPLD
Tags: fpga, cpld, electronic
Published: 2023-11-07 08:47:35

## What is FPGA?
Programmable interconnects link the configurable logic block (CLB) matrix of [field programmable gate arrays (FPGAs)](https://www.ersaelectronics.com/c/fpgas), which are [electronic devices](https://www.ersaelectronics.com/). An FPGA board can be reprogrammed after it is created to fulfill particular features or application requirements. This characteristic sets FPGA chips apart from Application-Specific Integrated Circuits (ASICs), created specifically for certain design requirements. Compared to one-time programmable (OTP) FPGA development boards, SRAM-based FPGAs are more widely used since they may be updated as requirements change.
Unlike PALs or other programmable devices, the structure of Field Programmable Gate Arrays is similar to that of gate array ASICs. FPGAs are employed in ASIC prototypes and other scenarios where ASICs are eventually intended to be deployed.

## What is CPLD?
[Complex programmable logic devices](https://www.ersaelectronics.com/c/cplds), or CPLDs, live up to the hype. They are essentially designed to resemble several PALs that have been merged into a single chip and connected by a crosspoint switch. They are able to handle more volume and complexity of reasoning because they use the same development tools, employ the same programmers, and are built on the same technology.
The FPGA and SPLD perform similarly to the CPLD (complex programmable logic device), despite being more sophisticated. Compared to FPGAs, CPLDs are less complex but still more complex than SPLDs. The most commonly used SPLDs (generic array logic) are PAL (programmable array logic), PLA (programmable logic array), and GAL.

## How does CPLD work?
CPLD is a programming technology that produces extremely dense, quick, and energy-efficient programmable logic devices by utilizing CMOS EPROM, EEPROM, flash memory, and SRAM programming technologies. They are enormous and have comparatively complicated structures, classed as large-scale integrated circuits. A custom logic circuit (CPL) is a type of digital integrated circuit that lets users design custom logic circuits according to their specifications. The primary method of design is to use the hardware description language and integrated development software platform to implement the intended digital system, then use the download cable to send the code (also known as "in-system" programming) to the target chip and create the corresponding target file.

## How does FPGA work?
FPGAs are members of the programmable logic, or programmable hardware, family of semiconductors. Even though it is a passive device, an FPGA can be configured to function as almost any type of digital circuit. Given that nothing genuinely changes, this state is miraculous. The FPGA can be configured to operate like the desired circuit just by loading a configuration onto it. It is not required to solder, use jumper wires, or be hassled. It is then possible to modify an FPGA to act in a manner similar to that of an additional circuit and so on. Because the arrangement is RAM-based, it may essentially be changed as often as needed.  
Even while we talk about utilizing FPGAs to develop digital circuits, you don't usually design them by drawing diagrams. The complexity and size of the circuits that FPGAs could have make creating a design difficult. Alternatively, you can utilize the tools to design a circuit that emulates the desired behavior by specifying the intended behavior.

Conclusion of CPLD vs. FPGA
Simple programmable logic devices (SPLDs) and complex programmable logic devices (CPLDs), which are less sophisticated components, enable the switch from discrete logic devices to entry-level FPGAs. Entry-level FPGAs are characterized by low power consumption, low logic density, and minimal complexity per chip. Devices with increased functionality add functional blocks with specified functions: A few examples include deserializers, high-speed serializers, Ethernet MACs, PCI express controllers, and phase-locked loops (PLLs). With these basic components, solo circuits (hard IP) or CLBs (soft IP) can be designed. Hard IP blocks boost performance at the cost of reconfigurability.
The FPGA product family's most advanced system-on-chip (SoC) components integrate the FPGA architecture, hard IP, and a microprocessor CPU core into a single unit. A SoC FPGA provides more integration, lower power consumption, a smaller board footprint, and higher-bandwidth communication between the core and additional blocks in comparison to standalone devices.