Largo Circuit Design, Inc. Largo Circuit design is a leading PCB layout service company that provides experience, knowledge, and reliability. Largo specializes in PCB Design, PCB Manufacturing and Assembly. Find out more about Largo Circuit design is a leading PCB layout service company that provides experience, knowledge, and reliability. Largo specializes in PCB Design, PCB Manufacturing and Assembly. Find out more about our printed circuit board design and layout services (Cadence Allegro, Altium, Mentor). We are committed to quality and the requirements of ISO 9001-2015. Our services include Schematic Capture, Netlist Input, Netlist Conversions, Auto and Interactive Routing, Thermal Analysis, Signal Noise Analysis, Line Characteristics Analysis, Test Points Creation, PCB Data Base Conversions, GERBER to CAD Regeneration.