Reliability, VHDL, Traceability and ESD Flashcards
Define FPGA
field-programmable gate array - an integrated circuit configured after manufacture
Define CLB
Configurable logic block which is a component in an FPGA
-allows user to implement any logic function
Define HDL and its purpose
Hardware description language - Describes a circuit so it can be physically replicated
Define VHDL
Very high speed integrated circuit HDL
Name 2 FPGA applications
computer vision systems
-search engine algorithms
How does VHDL describe circuits?
-the interface - what are the inputs and outputs
-the behaviour - what does it do
What are signals in VHDL
The “wires” in a circuit
In VHDL, what does X, -, and U mean
X - strongly driven unknown signal
‘-‘ - dont care
U - unitialised
Define MTBF
Mean time between failure - how long a device can go between repairs
Define MTTF
Mean time to failure - How long an unrepaired device can function before it fails
Define FIT
Failures in time - Number of failures expected per 10^9 hours of operation
How many parts does the bathtub failure rate curve have?
Infant mortality
-Random failure
-Wear-out failure
What variable does failure rate depend on?
Temperature
What does the Weibull Distribution show?
it models a range of random variables in the context of FIT and possible factors of failure
What does the Arrhenius equation show?
-the acceleration factor
-ratio between failure rates at different temperatures
How can reliability be improved?
-Thermal management
-Simplicity or a circuit that is not reliant on just one component
Define FMEA and its purpose
Failure Mode and effect analysis
-used to find the reason for failure
-starts within the subsytems and works outwards
Define Risk Priority Number
The higher the risk priority number, the more it must be worked on to reduce risk
Define traceability
knowning the origin of parts/materials and what they are
Define ESD
Electrostatic discharge - the release of static electricity when 2 objects come into contact
How is ESD prevented?
fast-switching diodes are used to divert high-voltage current away from sensitive parts of the circuit
What are 2 ways components can be recycled?
-remove, test and sell as commercial-grade
-sell as military grade
