Return Path Routing — Why No One Does It, But You Really Should
At my first job, I took a few courses on signal integrity and circuit design techniques to limit noise. I learned the basic principles:
- Place ceramic capacitors close to the power pins of each chip.
- Don't mix digital and analog parts.
- Keep signal traces short.
- Provide a GND plane.
…
You know - the usual stuff. I thought I was well equipped for the challenges ahead.
At some point in my career, I had to design a circuit with several DC-DC converters and extremely sensitive analog circuitry. Now, if you've ever been dabbling with DC-DC converters, you know that they are a noisy nightmare. Given the requirements of the analog circuitry, I just felt that my knowledge wasn't sufficient. I was heading for failure.
To save the project, I dived into everything available about signal integrity and best PCB design practices. I experimented with feed-through capacitors, chokes, filters and whatnot. All these things must have contributed to the success. But there's one design technique that towered above all else: Return Path Routing. For the first time, I had a circuit where the noise levels were no longer perceivable with my fancy oscilloscope. Let's have a look at the technique after reviewing a few basic principles.
Find out more in this article:
https://medium.com/@kristofmulier/return-path-routing-why-no-one-does-it-but-you-really-should-aff41d1ae181
- Place ceramic capacitors close to the power pins of each chip.
- Don't mix digital and analog parts.
- Keep signal traces short.
- Provide a GND plane.
…
You know - the usual stuff. I thought I was well equipped for the challenges ahead.
At some point in my career, I had to design a circuit with several DC-DC converters and extremely sensitive analog circuitry. Now, if you've ever been dabbling with DC-DC converters, you know that they are a noisy nightmare. Given the requirements of the analog circuitry, I just felt that my knowledge wasn't sufficient. I was heading for failure.
To save the project, I dived into everything available about signal integrity and best PCB design practices. I experimented with feed-through capacitors, chokes, filters and whatnot. All these things must have contributed to the success. But there's one design technique that towered above all else: Return Path Routing. For the first time, I had a circuit where the noise levels were no longer perceivable with my fancy oscilloscope. Let's have a look at the technique after reviewing a few basic principles.
Find out more in this article:
https://medium.com/@kristofmulier/return-path-routing-why-no-one-does-it-but-you-really-should-aff41d1ae181
Medium
At my first job, I took a few courses on signal integrity and circuit design techniques to limit noise. I learned the basic principles:
