Breakthrough of micro USB placement in printed circuit board

Design reuse is a common approach employed to improve design productivity and efficiency, thus resulting shorter product time-to-market. For the goal of engineering excellence, development team is always looking for opportunity to reuse some of the electrical and mechanical concept, ideas and design. Chassis, as a major component of a radio, is identified as a good candidate for design reuse due to its longer lead-time to design, evaluate and qualification. This presents a challenge for the design team as component skyline is limited on both sides of PCB. For PCB component placement, it is commonly divided to primary and secondary side. Primary side is defined as the location of light components, whereas secondary side is for through holes and heavy components. Micro USB connector is categorized as heavy component with lead. It should be placed at secondary side of printed circuit board (PCB). However, in this project, the chassis was reused and limiting the component skyline on the secondary side of PCB. The existing chassis design does not allow micro USB connector to be placed at the secondary side of PCB due to mechanical Z-height interference. This paper attempts to discuss and elaborate in detail the approach and breakthrough idea of placing a heavy component (micro USB) at primary side of PCB, yet meeting PCB assembly and product reliability requirements.