A coupon is a test structure built on the same panel as the boards, usually on the rail, so it goes through exactly the same process steps. Impedance coupons are measured with a TDR to verify controlled-impedance traces, and plated-hole coupons are microsectioned to check plating thickness, hole wall quality and lamination. Coupons let a fabricator prove quality without cutting up real boards.
Ship the impedance coupon readings and the microsection photos from the coupon with the boards.
Also heard as
- test coupon
Related terms
Impedance control
Designing and building traces to a target impedance, such as 50 or 100 ohms, within a set tolerance.
PTH
Plated through-hole: a drilled hole whose walls are copper-plated to connect every layer it passes through.
IPC class
Reliability class 1, 2 or 3 under IPC standards, setting the acceptance criteria a board is built to.
Same word, different worlds
A small test piece sprayed alongside production parts to stand in for them in destructive tests.
AdhesivesA small standard test piece, usually a metal or plastic strip, bonded to check adhesive strength or prep.
GeosyntheticsNarrow strip cut across a seam sample for peel or shear testing, usually one inch wide.