Signal integrity problems may arise at many levels: within an IC, at the package level, on a PCB, at the backplane of boards, at inter-system communication.
There are issues that hold at various levels. But practical reasons often cause different approaches at different levels. This course concentrates on signal integrity on the PCB and around the interface between IC and PCB and is therefore highly relevant both for a PCB designer and an IC designer. The examples applied during the course, however, stem from the PCB area.
There are problems on signal integrity (and power integrity) that manifest themselves on a PCB but that should have been resolved on an IC. In case an IC strongly radiates (EMC), there are additional costs at PCB-level such as with housing or a metal shield, possibly the required performance may even not be reached. To prevent these problems the PCB designer might choose a chip set from another supplier.
Furthermore, a relationship exists between the pinning of an IC and the number of layers of a PCB. For financial reasons there is a strong preference for e.g. a 4 layers above a 6 layers PCB (costs are rising sharply with the number of layers). However, this can make demands on the pinning. If these demands are not handled properly, a 6 layer PCB might be necessary because of SI reasons. An alternative is to select an IC from another supplier.
Lessons:
- Signal integrity: high speed signal propagation, reflection, ringing, transmission-lines, termination, balanced lines, edge control, cross-talk, stack-up, simulation of high speed nets;
- Power integrity: high speed power distribution, power planes topology, board stack-up, bypassing capacitors, embedded passives, PCB production and materials, power supply noise classes, power integrity simulation demo;
- IBIS modelling: creating IBIS models, modifying models, understanding the most important parameters of an IBIS model;
- EMC introduction: EMC compliance tests, emission, immunity to RF fields, EFT, bursts, pre-compliance testing, ESD, latch-up;
- EMC signals: identify the sources of radiation, narrow spectra signals versus wide spectra signals, clamping noise, board stack-up improvements for EMC, crosstalk;
- EMC coupling and cabling: ground bounce, VCC coupling, optimisation of cable connections to a board, antenna's, radiation gain caused by cavities;
- EMC advanced partitioning: noise sources, SNR, common mode radiation versus differential mode, common mode isolation, unshielded housing, aperture antennas, creating common mode quite islands (moats);
- Cost-price optimisation: 2-layer boards for high speed, 4 layer boards, board production costs;
- High speed memory connection: DDRx and SSTL.
Hands-on sessions:
- Transmission line termination simulations, simulation of different board stack-ups;
- IBIS modelling, IBIS modelling theory, debugging IBIS models + IBIS editor;
- Topology simulation, board partitioning, crosstalk.
