Forming the basis of a considerable proportion of electronic designs, application-specific integrated circuits (ASICs) are custom designed semiconductor devices that are optimised for a particular task or function - rather than being generic devices intended for multi-purpose adoption.
Often when serving the military and avionics sectors, these will in fact manifest themselves in the form of a system-on-chip (SoC) and will comprise microprocessor blocks and memory cells, as well as a range of analogue input and output elements. Typical examples of application use include interfacing with mission-critical sensors or providing key targeting and flight data.
In the consumer, telecoms and industrial sectors, field programmable gate arrays (FPGAs) can offer financially attractive, low volume solutions. However, for military and aerospace systems, ASICs deliver more stable and secure options, with extensive program lives. Assuming the right technology and wafer fabs are chosen then theoretically there is no end stop to ASIC production and prolonged supply can be assured. Conversely, recent trends in programmable logic mean that FPGAs generally have a commercial life of less than eight years before they become obsolete.
TT Electronics can offer custom designs for ASICs capable of addressing the most demanding applications (on processes from 980nm to 3µm) and assemble the requested units in hybrid format to give greater flexibility. These can support standard serial communication protocols such as Arinc. Other more demanding requirements can be met with the use of both partner design houses and fabs - delivering additional know-how in respect to radiation tolerance or encryption mechanisms, for instance. The Bedlington facility, which was acquired from GE Newmarket (and formally known as Welwyn Microcircuits), offers full ASIC conversions from obsolete FPGAs, plus in-depth packaging knowledge (in fully hermetic or lower cost COTS solutions).
Over the course of many years the engineering team at Bedlington has built up world class expertise in creating complex hybrids - with above 1500 wire bonds seen on some solutions for mission-critical aerospace applications. The test capabilities at this site have recently been expanded to include a pair of state-of-the-art Teradyne ETS 600 automatic testers. These enable testing of up to 224 digital pin/channel with 4Mb vector depth at a 66MHz vector rate and up to 32 analogue channels. These testers incorporate waveform digitisation and arbitrary waveform generation, enough to simulate the operation of the most uncompromising of application conditions, and enable testing of both at die and packaged level components. TT Electronics also has access to a comprehensive range of EDA, physical layout and analogue simulation tools.
Given that the quantity of ASICs used in an aircraft is still relatively small, for economic reasons this may result in the production of several wafers in one batch and some of them subsequently being kept in storage. Wafers stored under the correct conditions have an almost infinite shelf life. TT Electronics’ expertise in die storage means that ongoing continuity of supply can be ensured, thereby future proofing against the threat posed by obsolescence.