A refdes, reference designator, is the unique name of each component, built from a letter prefix for the part type (R resistor, C capacitor, U integrated circuit, J connector, Q transistor) and a number. It ties the schematic, layout, BOM, centroid file and silkscreen together, and technicians use it to find parts on the board. Renumbering refdes by location after layout makes boards much easier to debug.
Silk on the bottom is unreadable, half the refdes are under parts, move them before the next spin.
Also heard as
- reference designator
- ref des
- designator
Related terms
Silkscreen
Printed ink layer on a board showing reference designators, outlines, polarity marks and logos.
BOM
Bill of materials: list of every part on an assembly with designators, values and part numbers.
Footprint
Pattern of copper pads, outline and markings on a board that matches one component package.
Centroid file
File listing the X-Y position, rotation and side of every surface mount part for the pick-and-place machine.