A Field-Programmable Analog Array (FPAA) is a reconfigurable analog integrated circuit that lets engineers build and modify real analog functions through software instead of fixing every amplifier, filter, comparator, and signal path permanently in hardware.
FPAAs bring software-defined flexibility into the analog signal chain. They can be configured for filtering, gain, comparison, signal conditioning, waveform generation, analog computation, sensor interfacing, and other functions, then updated as requirements change.
Engineers sometimes use the phrase “analog FPGA” to describe the concept because an FPAA brings FPGA-like reconfigurability to analog hardware. The comparison is useful, but the devices are not the same: an FPGA configures digital logic, while an FPAA configures analog circuitry that operates directly on continuous voltages and signals.
An FPAA combines configurable analog building blocks with programmable interconnections. Instead of committing an analog function to a fixed set of components, the designer can determine what those internal resources do and how they connect.
Build amplifiers, filters, integrators, comparators, oscillators, arithmetic functions, and other analog circuits from reusable configurable resources.
Change values such as gain, cutoff frequency, thresholds, coefficients, timing, or signal-routing behavior through software-controlled configuration.
Reconnect internal blocks to change the structure of the analog circuit itself, not only the values of individual parameters.
Traditional analog circuits are often optimized around a specific sensor, bandwidth, gain, filter response, or operating condition. When those requirements change, engineers may need to replace components, modify the PCB, or qualify a new signal chain.
An FPAA moves more of that iteration into configuration. The same physical device can implement different analog functions, support multiple operating modes, or be updated as the application evolves.
“Analog FPGA” is a useful shorthand, but FPAA is the technically correct term. Both technologies provide field programmability and configurable routing, but they operate in different signal domains.
Configures digital logic, registers, memory, arithmetic structures, and digital interconnect. Signals are represented as discrete logic states.
Configures analog functions, analog parameters, and signal paths. Real-world voltages are processed directly, so bandwidth, noise, gain, dynamic range, loading, and other analog effects still matter.
For designers searching for an analog FPGA, an FPAA is generally the class of device they are looking for: programmable hardware for the analog portion of a system.
FPAA architectures differ by manufacturer and device family. Okika’s FlexAnalog™ AN231E04 provides a useful example of how configurable analog resources, I/O, routing, configuration memory, and clocking work together.
CABs contain analog resources that can be combined into higher-level functions. The AN231E04 contains four CABs arranged as a 2 × 2 analog matrix.
Its analog resources include operational amplifiers, differential comparators, programmable capacitor structures, and supporting logic used by Configurable Analog Modules.
CAMs are software-visible functional blocks that make the underlying analog resources easier to use. A designer can work with functions such as filters, amplifiers, integrators, oscillators, comparators, signal converters, multipliers, and other analog blocks.
Routing resources connect I/O cells and internal analog blocks. Changing those connections changes the signal path and can produce an entirely different circuit topology using the same silicon.
I/O resources connect the programmable analog fabric to external sensors, circuits, converters, and other hardware. The AN231E04 family provides seven flexible analog I/O cells.
A digital configuration bitstream controls analog functions, routing, and operating parameters. Configuration data can be supplied by a host processor or stored externally for loading at startup.
FlexAnalog™ devices combine conventional analog elements with switched-capacitor circuitry. Clock configuration is therefore part of the design process for functions that depend on switched-capacitor operation.
Okika's AN2X1E04 FlexAnalog™ family combines conventional analog circuitry with switched-capacitor elements. Each device provides seven analog I/O cells and four Configurable Analog Blocks controlled by a digital configuration bitstream.
Within the programmable analog resources, the family provides:
These lower-level resources are allocated and interconnected by the design tools to implement the higher-level CAMs used in a practical circuit design.
The key idea is simple: software describes the analog circuit, but the resulting signal processing occurs in physical analog hardware.
Choose the required functional blocks, such as gain stages, filters, comparators, integrators, oscillators, rectifiers, or arithmetic functions.
Configure gain, frequency response, thresholds, timing, coefficients, or other parameters appropriate to the circuit.
Connect the I/O cells and analog modules through the programmable interconnect to form the desired analog topology.
The design software maps the requested functions and routing onto the physical resources of the target FPAA and produces configuration data.
The configuration is loaded from a host processor, development board, or nonvolatile memory. The FPAA then behaves as the configured analog circuit.
FlexAnalog™ devices support dynamic reconfiguration. A new configuration can be loaded while the existing circuit continues operating, then activated when the update is ready.
Dynamic reconfiguration is one of the most distinctive FlexAnalog™ capabilities. A companion processor or controlled nonvolatile memory can send a new configuration to the FPAA while the existing analog circuit continues operating.
After the new configuration data has been loaded, the device can transfer to the updated analog-array configuration in a single clock cycle. The update can be partial or complete, allowing a system to modify only the functions that need to change.
This also makes it possible to reuse the same physical analog resources for different functions at different points in a duty cycle. Instead of permanently dedicating separate analog circuitry to every operating mode, one FPAA can be reconfigured as the system moves between tasks.
FPAAs are one option within a larger mixed-signal design toolbox. They are most valuable when the analog portion of a system needs more flexibility than a fixed circuit provides.
| Technology | Primary Strength | What Changes | Best Fit |
|---|---|---|---|
| Fixed Analog | Optimized implementation of a known analog function | Usually requires component or PCB changes | Stable, high-volume, fixed-function designs |
| Analog Front-End IC | Integrated signal conditioning for a defined sensor or application class | Often offers parameter programmability within a fixed architecture | Known sensor families and established front-end requirements |
| MCU / DSP | Flexible digital algorithms and control | Software and digital processing | Control, communications, sampled-signal processing, algorithms |
| FPGA | Parallel configurable digital logic | Digital gates, routing, state, memory, interfaces | High-speed digital pipelines and custom digital hardware |
| FPAA | Reconfigurable analog signal processing | Analog function, parameters, and topology | Adaptive front ends, analog prototyping, configurable sensing and control |
FPGAs excel when a problem is fundamentally digital. FPAAs operate directly on analog signals and are therefore suited to functions such as filtering, gain control, comparison, integration, detection, and other continuous-signal operations before or alongside digitization.
Hybrid systems are common. An FPAA can condition or preprocess the analog signal, an MCU can manage configuration and system control, and an FPGA can perform high-speed digital processing.
Change gains, filters, routing, and functional blocks through configuration instead of rebuilding the entire analog signal chain for every experiment.
FlexAnalog™ devices can load new configuration data while the current circuit is operating, allowing systems to switch modes or adapt their analog behavior under host control.
Multiple analog operations can be consolidated into one configurable IC, potentially reducing the number of separate amplifiers, filters, comparators, switches, and supporting components.
A programmable front end can support changing gain, bandwidth, thresholds, or filter response when sensors, environments, or operating modes change.
Filtering, amplification, comparison, feature extraction, and other useful operations can occur in the analog domain before the digital system receives the signal.
The same configurable platform can be reused across experiments, prototypes, product variants, or multiple signal-processing modes.
FPAAs are useful when a system needs analog processing that is configurable, adaptive, reusable, or easier to prototype than a fixed-function signal chain.
Configure gain, filtering, offset handling, comparison, anti-aliasing, and other front-end functions for sensors and measurement systems.
Implement programmable filters, gain control, equalization, waveform shaping, effects, and acoustic-signal conditioning.
Use adaptive gain, filtering, detection, and time-varying analog processing in changing acoustic environments.
Adapt analog preprocessing for vibration, position, current, pressure, acoustic, and other industrial sensing signals.
Place configurable filtering, signal conditioning, comparison, integration, or control functions close to sensors and actuators.
Explore configurable analog front ends, feature extraction, physiological signal conditioning, and low-power sensing architectures.
Detect, filter, or extract useful features before sending every raw sample into a larger digital processing pipeline.
Build software-configurable measurement paths, filters, generators, signal conditioners, and laboratory prototypes.
Teach and explore analog circuits with configurable hardware that can be redesigned repeatedly without replacing the entire physical circuit.
Okika FlexAnalog™ products use AnadigmDesigner2® to capture, configure, simulate, and program FPAA circuits through a graphical design environment.
Build the analog system graphically using drag-and-drop functional blocks rather than drawing every underlying transistor-level circuit.
Configure and optimize filter functions through dedicated design tools and parameter forms.
Work with low-level resources and higher-level functions including filters, multipliers, signal converters, Rauch filters, and additional CAMs.
Evaluate the configured circuit with an integrated simulator and waveform viewer before moving to the physical development board.
Modify parameters and circuit structure within the same environment and regenerate a hardware configuration without rebuilding the board.
Use the same environment for design capture, parameter configuration, simulation, configuration generation, and rapid hardware prototyping.
Identify the input and output signals, required gain, frequency response, signal range, channel count, control requirements, and expected operating modes.
Build the design graphically using CAMs for filters, amplifiers, comparators, integrators, oscillators, converters, multipliers, and other analog functions.
Configure gain, cutoff frequency, Q, thresholds, clocking, coefficients, and other values through each module’s design interface.
Connect the modules and I/O cells to define the complete signal path. The software maps those connections onto the target device.
Use the integrated simulator and waveform tools to evaluate the circuit before loading it onto the development hardware.
Download the generated configuration to a supported development board or transfer the bitstream through a host processor in an embedded design.
Compare measured performance with the intended response, then adjust parameters, topology, or external circuitry as needed.
Store a startup configuration or allow a companion MCU, Raspberry Pi, or other host to load new FPAA configurations as system requirements change.
Designer2 bridges the gap between the physical FPAA resources and the functions engineers want to build. A CAM exposes useful design parameters through a graphical interface, while the software determines how those requirements are implemented with the available analog resources.
This abstraction is important to the FPAA concept. The user designs at the level of useful analog behavior, while the tools map those functions onto the configurable amplifiers, capacitors, comparators, routing, and switched-capacitor resources inside the target device.
Okika’s non-SoC FPAA lineup ranges from the AN231E04 integrated circuit itself to single-, dual-, and quad-FPAA development boards, Raspberry Pi and Arduino platforms, and a specialized FPAA-based filter module.
Four-CAB dynamically reconfigurable FlexAnalog™ FPAA for engineers integrating programmable analog directly into a custom PCB or embedded product.
Best use: custom signal-conditioning hardware, embedded products, adaptive analog subsystems, and production designs after prototyping.
Explore AN231E04 →Single-AN231E04 development board with USB programming, PIC32 support, prototyping area, filters, and accessible I/O.
Best use: first-time FPAA evaluation, education, filter/amplifier development, single-device prototypes, and laboratory experiments.
Explore SING1 →Two AN231E04 devices with programmable interconnection, PIC32 control, USB, onboard filters, and prototyping resources.
Best use: larger signal chains, additional filter stages, multiple analog functions, and designs that need more resources than one FPAA provides.
Explore DUAL2 →Four AN231E04 FPAAs with flexible routing, PIC32 control, USB programming, breadboard space, and selectable multi-device signal paths.
Best use: multi-channel processing, cascaded filter systems, larger experimental architectures, and complex bench prototypes.
Explore QUAD4 →Raspberry Pi HAT with four independently configurable AN231E04 FPAAs, SPI control, flexible routing, onboard input filters, and Python-oriented host integration.
Best use: Raspberry Pi-controlled instrumentation, multi-channel sensing, software-defined analog experiments, automation, and host-driven reconfiguration.
Explore PIKA →Arduino Uno-compatible shield using the AN231E04 with analog I/O conditioning, SPI configuration, onboard power, and support for real-time circuit reconfiguration.
Best use: Arduino and MCU projects, teaching, embedded sensor interfaces, adaptive filters, programmable audio, and compact prototyping.
Explore Arduino Shield →Preconfigured switched-capacitor Butterworth low-pass filter modules built around FPAA technology, available in characterized cutoff-frequency variants.
Best use: engineers who need a compact, characterized low-pass filter module rather than a general-purpose FPAA development platform.
Explore Chameleon →See how configurable analog hardware moves more iteration from board changes into software.
Read the Guide →Learn how analog, MCU, and FPGA responsibilities can be partitioned in hybrid architectures.
Read the Guide →Explore gain, filtering, anti-aliasing, and adaptive analog front-end design.
Read the Guide →Compare reconfigurable analog hardware with conventional discrete analog implementation.
Browse FPAA Articles →Access technical notes covering interfacing, multipliers, multi-FPAA SPI control, integration, and more.
View Application Notes →Get the graphical software environment used to design, simulate, and configure FlexAnalog™ devices.
Get the Software →FPAA stands for Field-Programmable Analog Array. It is a reconfigurable analog integrated circuit containing configurable analog functions and programmable signal routing.
FPAAs can implement functions such as filtering, amplification, comparison, integration, oscillation, signal conditioning, analog arithmetic, sensor interfacing, feature extraction, and configurable control. They are especially useful when those functions need to be changed or tuned after the hardware has been built.
“Analog FPGA” is an informal phrase often used to explain the idea of an FPAA. Both technologies are field programmable, but an FPGA configures digital logic while an FPAA configures real analog circuitry and analog signal paths. FPAA is the technically correct device category.
An FPGA operates on digital signals and is built around configurable digital logic and routing. An FPAA contains configurable analog resources and processes continuous analog signals directly.
The two can be complementary: an FPAA can handle analog-domain preprocessing while an FPGA performs high-speed digital processing.
A programmable analog front-end IC usually offers adjustable parameters such as gain or filter settings within a predefined architecture. An FPAA generally provides broader configurability by allowing both analog functions and their interconnections to be changed.
No. An FPAA can perform useful analog processing before an ADC, but an ADC is still required whenever the system needs a digital representation of the signal. FPAAs give designers more control over what processing should occur before digitization.
Usually not. An FPAA is often used alongside an MCU, DSP, FPGA, or host computer. The FPAA handles analog-domain functions while the digital processor manages configuration, communications, software, algorithms, and system-level control.
Okika FlexAnalog™ AN2X1E04 devices support dynamic reconfiguration. New configuration data can be loaded while the current analog configuration continues operating and then transferred to the active array when ready.
Okika FlexAnalog™ devices are designed using AnadigmDesigner2®. The designer places and configures analog functional blocks, simulates the circuit, and generates configuration data. That data can be downloaded through a development board or loaded from a companion host processor or external memory.
The available design library includes configurable functions such as amplifiers, low-pass, high-pass and band-pass filters, comparators, integrators, oscillators, multipliers, signal converters, and other analog processing modules.
FPAA performance depends on the target device, configured function, signal range, bandwidth, routing, clocking, noise requirements, loading, I/O path, and external circuitry. As with any analog design, the implemented circuit must be evaluated against the actual application requirements.
The AN231K04-SING1 is a strong general-purpose bench platform because it provides one AN231E04 FPAA, USB programming, a PIC32 controller, accessible I/O, filters, and prototyping space. The OTC2312 Arduino Shield is a natural choice for users who specifically want Arduino or MCU integration.
The OTC2310K04-PIKA is designed as a Raspberry Pi HAT and contains four AN231E04 FPAAs. It is suited to host-controlled multi-channel analog processing and Raspberry Pi-based experimentation.
Use a development board while evaluating the technology and building the prototype. The standalone AN231E04 is the better fit when you are ready to integrate the FPAA into a custom PCB or embedded product architecture.
Start with a development board, design and simulate your analog circuit in AnadigmDesigner2®, and move to the AN231E04 device when you are ready to integrate programmable analog into your own hardware.
FPAAs extend programmability into the analog signal path. Configure the function, simulate the circuit, program the hardware, and refine the design without rebuilding the entire analog chain.
