"Chapter 1 - The Op Amp's Place in the World" - HTL Wien 10

17.8.4 Routing
17.8.5 Bypass
17.9 References
Circuit Board Layout Techniques
References
Keep analog circuitry close to the power connector of the board.
Never route digital traces through analog sections of the board, or vice versa.
Make sure that traces to the inverting input of the op amp are short.
Make sure that traces to the inverting and noninverting inputs of the op amp do not
parallel each other for any significant length.
It is better to avoid vias, but the self-inductance of vias is small enough that a few
should cause few problems.
Do not use right angle traces, use curves if at all possible.
Use the correct type of capacitor to reject the conducted frequency range.
Use tantalum capacitors at power input connectors for filtering power supply ripple.
Use ceramic capacitors at power input connectors for high frequency conducted
noise.
Use ceramic capacitors at the power connections of every op amp IC package. More
than one capacitor may be necessary to cover different frequency ranges.
Change the capacitor to a smaller value — not larger — if oscillation occurs.
Add series inductors or resistors for stubborn cases.
Bypass analog power only to analog return, never to digital return.
1. Analog Dialog 30 th Anniversary Issue, Analog Devices, Ask the Applications Engineer
–10, James Bryant
2. High-Speed Operational Amplifier Layout Made Easy, Texas Instruments, Andy Hahn,
SLOA046
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