AstroPCB
PCB Manufacturing Case Studies
Real engineering challenges and manufacturing solutions.
Engineering case studies from AstroPCB manufacturing projects. Each case study describes a real design challenge — the technical requirements, material and construction decisions, DFM issues encountered and resolved, and the results achieved. These examples illustrate the engineering review process that accompanies every AstroPCB order and the types of complex PCB constructions we manufacture routinely.
HDI for AI Accelerator Module
A 28-layer board on Megtron 7 with 3-level stacked microvias for 0.5 mm pitch BGA escape. The challenge: maintaining 90-ohm differential impedance for 56G PAM4 channels while routing escape vias through a dense BGA field. The engineering team optimized the stackup to reduce the sequential lamination cycle count from 7 to 5, cutting fabrication cost by 25% without compromising impedance or routing density.
Rigid-Flex for Medical Endoscope
A 10-layer rigid-flex with 4-mil polyimide flex zones connecting three rigid sections. The design required controlled impedance through the flex zones for high-speed camera data, dynamic flex endurance for repeated insertion/withdrawal cycles, and IPC Class 3 quality with full material traceability for FDA submission. Adhesiveless polyimide with rolled annealed copper was specified for maximum flex life.
77 GHz Automotive Radar
A hybrid stackup combining Rogers RO4835 for the antenna array and patch feed network with high-Tg FR-4 for the digital processing and power supply sections. Impedance control at 77 GHz required tight Dk tolerance and registration accuracy across the full antenna panel. The engineering team worked with the customer to optimize the transition between Rogers and FR-4 layers, minimizing delamination risk from CTE mismatch during automotive temperature cycling.
Heavy Copper EV Inverter
A 6-layer board with 4 oz copper on the power layers carrying 200A peak switching current. Thermal via arrays beneath the IGBT driver section conduct heat to the aluminum heatsink. The challenge was maintaining controlled impedance on the 1 oz signal layers adjacent to the 4 oz power layers — the asymmetric copper weight required careful stackup engineering to achieve target impedance values.