Field-programmable analog array

A field-programmable analog array (FPAA) is an <a href="/facts/Integrated_circuit/fjn6vg7C">integrated circuit device</a> containing computational <a href="/facts/Analog_signal/xDbb4uB5">analog</a> blocks (CABs) and interconnects between these blocks offering <a href="/facts/Field-programmability/1lhMNpdT">field-programmability</a>. Unlike their <a href="/facts/Digital_signal/pKYKbxfK">digital</a> cousin, the <a href="/facts/Field-programmable_gate_array/M8LSGcAU">FPGA</a>, the devices tend to be more application driven than general purpose as they may be <a href="/facts/Current-mode_logic/nBzkH5vL">current mode</a> or voltage mode devices. For voltage mode devices, each block usually contains an <a href="/facts/Operational_amplifier/hunKdYb9">operational amplifier</a> in combination with programmable configuration of passive components. The blocks can, for example, act as <a href="/facts/Analog_adder/KU8MfcyE">summers</a> or <a href="/facts/Integrator/VTqXQuQU">integrators</a>.
FPAAs usually operate in one of two modes: <a href="/facts/Discrete_time_and_continuous_time/RR8wpS9e">continuous time and discrete time</a>.

<ul><li>Discrete-time devices possess a <a href="/facts/Clock_signal/9UfTzGHx">system sample clock</a>. In a <a href="/facts/Switched_capacitor/kSxkQzyH">switched capacitor</a> design, all blocks sample their input signals with a <a href="/facts/Sample_and_hold/Ts9mWGWr">sample and hold</a> circuit composed of a semiconductor switch and a capacitor. This feeds a programmable <a href="/facts/Operational_amplifier/hunKdYb9">op amp</a> section which can be routed to a number of other blocks. This design requires more complex <a href="/facts/Semiconductor/zFf3mGTE">semiconductor</a> construction. An alternative, switched-current design, offers simpler construction and does not require the input capacitor, but can be less accurate, and has lower <a href="/facts/Fan-out/lCm5joyw">fan-out</a> - it can drive only one following block. Both discrete-time device types must compensate for switching noise, aliasing at the system sample rate, and sample-rate limited bandwidth, during the design phase.</li>
<li>Continuous-time devices work more like an array of <a href="/facts/Transistor/Bmr8zwL0">transistors</a> or op amps which can operate at their full <a href="/facts/Bandwidth_(signal_processing)/7eMDzfJI">bandwidth</a>. The components are connected in a particular arrangement through a configurable array of switches. During <a href="/facts/Circuit_design/wVL89XsX">circuit design</a>, the switch matrix's <a href="/facts/Parasitic_element_(electrical_networks)/aJf6UtNm">parasitic</a> inductance, capacitance and <a href="/facts/Noise_(signal_processing)/JT3lGj8v">noise</a> contributions must be taken into account.</li></ul>
Currently there are very few manufactures of FPAAs. On-chip resources are still very limited when compared to that of an FPGA. This resource deficit is often cited by researchers as a limiting factor in their research.

Field-programmable analog array open-in-new

Field-programmable analog array