Issue link: https://iconnect007.uberflip.com/i/1256432
JUNE 2020 I DESIGN007 MAGAZINE 21 a sudden, they didn't understand why things worked the way they did, and they started test- ing and trying to come up with concepts. But they got most of them wrong. Beeker: When we first started adding multi- ple features onto a device to go from a mi- croprocessor to a microcontroller, they started adding clock outputs and the A/D converters. They started seeing problems with the A/D converters on the accuracy or bit count, so they would always lean on the IP people de- signing A/D converters. They started becom- ing paranoid about what the system wanted to be, and nobody looked at the root cause: The circuit board design was crap. They found that if they put a ground pin close to the A/D con- verter, it worked better. These design guide- lines and pin-outs of the devices evolved into band-aids that became the design philosophy because nobody, until recently, found the root cause, which was a poor distribution of en- ergy in the circuit board or not designing the spaces. You go in, and with everything that's sup- posed to be ground, something is ground to only one. Then, you design the circuit boards so that the energy flow from the power supply to the ICs, which are multi-port power distri- bution systems. They turn on and off transmis- sion lines. When they turn on a transmission line, they need energy to come from the pow- er supply through the switch net into the new transmission line until the switch is turned off, and then the energy flow stops. But this is plumbing. Hartley: I loved Lee Hill's comment that he made years ago. "When I'm doing a review of a circuit with a problem, if I see more than one ground, I know there's money to be made." Beeker: Look at where you're moving the en- ergy on the board. If you have a pipe in your basement and you want to get water upstairs, and if you don't put a pipe between the base- ment and the upstairs, eventually, you'll get water upstairs. That's exactly what happens on a lot of these circuit boards is the field gets there eventually, but it has to fill up everything between here and there. Shaughnessy: This has been great. We appreci- ate your time and thoughts on this. Beeker: You've unleashed the dragon. Hartley: Thank you very much. Matties: Stay healthy, both of you. Take care. DESIGN007