Wizards of Electromagnetism

IC design isn’t finished until it’s packaged. What is the upper frequency limit that the package can operate? Is it possible to use a lower cost package type to lower the final product cost? What about the performance of package isolation? As an example, LO to RF leakage performance of an up- or down-converter IC depends not only on the IC’s isolation performance but also on the package. In this episode, a 3mm×3mm, 16-pin Quad Flat No Leads (QFN) package is optimized to improve the frequency performance using EM simulation.

Problem: The desired −18dB return loss was achievable at 15 GHz but not for a new design at 20 GHz. Need to improve from −7 dB to −18dB without resorting to a more expensive package.

Action: Use EM simulation to performance several “what if” analyses. Experiment with increasing the width of input/output transmission lines (to adjust the impedance) and with doubling up the bond wires and lead frames (to minimize the transition to the wider line).

Results: 10 dB improvement in return loss. −18 dB spec met.

Read the full details in our presentation EM Insights Series – Episode 1 – QFN Package

See the full series at EM Insights Series