SAN FRANCISCO Electromagnetic compatibility (EMC) and signal integrity (SI) design requirements for printed circuit (pc) board design are frequently conflict, according to the majority of respondents to a survey of 91 designers conducted by virtual prototype provider Flomerics Inc.
Fifty-nine percent of respondents agreed that thermal and EMC requirements are usually in conflict in pc board design, with only 23 percent indicating that they disagreed, according to Flomerics (Surrey, U.K.). Sixty percent agreed that thermal and SI requirements, with 23 percent indicating that they disagreed, Flomerics said.
But Flomerics said the survey paints a positive picture with regard to communication and collaboration between electronic and mechanical design engineers at most companies, with 64 percent of respondents describing communication as "good" or "very good," 31 percent saying it "needs to improve," and just 4 percent describing it as "very poor."
Fifty-six percent of respondents stated that "better software interfaces between electronic and mechanical software would greatly improve collaboration between electronic design engineers and mechanical design engineers," while 28 percent said "software is not the issue good management, human interaction, etc. are more important," Flomerics said.
Flomerics said respondents were also asked to identify the percentage of new designs that overran time and cost budgets, and the most common causes of such overruns, with most respondents (50 percent) saying that 10-30 percent of new PCB designs overran time and cost budgets, while 28 percent said less than 10 percent, 18 percent said 30-50 percent and 4 percent said more than 50 percent, according to Flomerics.
The most common causes of time and budget overruns were: design requirement changes (59 percent); circuit design (39 percent); thermal problems (34 percent); EMC problems (32 percent); signal integrity problems (30 percent); physical layout problems (22 percent); and routing problems (19 percent), according to Flomerics (respondents were allowed to specify more than one cause).
The average design cycle time for a new pc board design from concept to final testing and manufacturing signoff was specified at six to 12 weeks by 50 percent of respondents, Flomerics said, with 29 percent saying more than 12 weeks and 21 percent saying less than six weeks.
When asked what generates the greatest pressure on the pc board design function, 54 percent said "functionality and performance," 30 percent said "time to market" and 14 percent said "cost," Flomerics said, When asked about the design flow, 62% of respondents indicated that there is "lots of interaction" between design stages such as concept design, detailed design, design verification, etc., while 38 percent said that design flow is performed in sequential stages with "little interaction between stages," Flomerics said.
Sixty-one percent of respondents said that "a person or group with clear responsibility for thermal aspects of pc board design exists," while 39 percent said there was "no such person or group," Flomerics said.
The survey results are based on 91 responses. The industry sectors most represented among survey respondents were telecommunications (23 percent), power electronics (18 percent), aerospace and defense electronics (17 percent), and automotive and transportation electronics (11 percent). The complete survey is available at Flomerics' Web site.