The Definitive Guide to an Electronic Assembly Design Review / 6
Often a customer requests a detailed review of their schematic as part of the
design review. At Ansys, we begin by reviewing product specifications to fully
understand the requirements and environments. We often ask questions like:
Do we have a sufficient operating temperature range?
Are there appropriate standards and high enough levels?
Are shock and vibration involved environments?
A circuit analysis includes an assessment to ensure the circuit will function as
intended. Electromagnetic capability (EMC) and electrostatic discharge (ESD)
risks are identified and the derating of the components are verified by assess-
ing power dissipation, voltage ratings, dV/dt ratings for field effect transistors
(FETs), Vgs breakdown of FETs and the temperature rating of the parts.
To examine circuit stability, engineers check feedback loop circuitry, low
dropout regulators (LDOs) and capacitor configurations. Electrolytic
capacitors are known to be a weak link in designs, particularly the power
supply, so life expectancy is assessed as a function of circuit stress levels.
Magnetics are also assessed by looking at saturation currents and core loss.
As a result of this analysis, components are flagged that exhibit a risk. The
analysis then looks at component placement for inclusion in the design for
manufacturing (DfM) analysis.
3
Circuit Analysis
