Issue link: https://iconnect007.uberflip.com/i/666328
24 The PCB Design Magazine • April 2016 This perception is backed up by the lack of formal qualification for PCB designers—for my generation, we generally started off as mechani- cal draughtsman in the traditional drawing of- fice and then moved to the PCB section. This perception means that the status of the PCB designer is quite low, so when they advise the engineer that something is not possible this can be met with a certain amount of derision. The engineer possibly thinks that the PCB de- signer is just being obstructive, while converse- ly, the PCB designer thinks that the engineer is very dismissive of his knowledge, capabilities, opinion, etc. Let's look at the issue from the engineer's perspective. By providing design consultancy, we are fortunate enough to be a lot more in- volved in the engineer's world, including some of the problems that they have to deal with as part of the overall product development. One engineer explained that the design part was relatively straightforward, but the need to meet cost, functionality, component sourcing, obso- lescence, test plans, as well as reading through 150+ pages of documentation on a device's tim- ing "makes life interesting." As PCB designers, we tend to have a lot of questions, especially about the newer technology, so we can bom- bard the engineer with a number of questions concerning unfamiliar topics expecting imme- diate answers, and normally at this point the pressure to get it finished is already building. Shaughnessy: What do you think is the proper role for a PCB design engineer? Critcher: This is a difficult one to answer. There are so many aspects of the design engineer's role that are not obvious to the PCB designer, such as component selection, obsolescence man- agement, test plans/specs, etc. I thought that I would answer this question in relation to their interaction with the PCB designer. The definition of the circuit itself goes with- out saying; the engineer should also drive the PCB layout with the necessary constraints to en- sure that the PCB will function to within spec. So, together with the circuit diagram the engi- neer should also indicate the following (this list is not exhaustive) a. Impedance requirements b. Trace length/matching requirements c. Current handling requirements d. Stackup requirements e. Placement constraints f. Connector locations g. Board outline (could be the mechanical engineer) Depending upon the software and the indi- vidual company process, the engineer may be able to enter these constraints directly into the schematic capture tool. Shaughnessy: What do you think is the proper role for a PCB designer? Critcher: The role of the PCB designer is to take the data from the engineer and create the lay- out, drawings, fabrication and assembly data while adhering to constraints and the relevant standards, including both company, IPC and any specific to the manufacture. The PCB has many outside influences such as enclosure, thermal, EMC requirements that may not be under the remit of the engineer so they should also liaise with these people or teams. Essentially the PCB designer takes all the de- sign requirement inputs from the various sourc- es and then has to find a solution that hits as many as the requirements as possible. At this Designers anD Design engineers: tWo siDes of the same coin " The engineer possibly thinks that the PCB designer is just being obstructive, while conversely, the PCB designer thinks that the engineer is very dismissive of his knowledge, capabilities, opinion, etc. "