SMD, COB or MIP: How the Package Choice Changes Your LED Display PCB

LED packages reach the board in three main ways, and each one changes what the PCB has to do. Choosing the package first and designing the board around it is the fastest route to a display that yields in production.

• SMD LED modules: Discrete 0404, 0606 or 1010 LEDs are reflow-soldered onto a pad array, so the PCB sets placement accuracy through pad geometry, solder-mask openings and thermal vias. Our 3/3 mil trace/space and ±0.15 mm routing tolerance keep those pad arrays consistent across a full panel.
• COB (chip-on-board): Bare LED dice are bonded directly to the board and sealed in protective resin, so there is no package to absorb mechanical stress. COB demands flatter copper, tighter pad tolerances and a matte black solder mask to keep contrast high — which is why we build P0.9-and-below routing with via-in-pad and resin-filled microvias.
• MIP (mini and micro LED in package): Individually packaged mini or micro LEDs are reflowed like SMD parts, combining very small pixel pitch with the repairability of standard reflow assembly. MIP panels sit between SMD and COB in PCB complexity and reuse the same via-in-pad stackup.

For designs that mix packages on one panel — SMD driver-side components with COB LEDs on the front, for example — send us the stackup and we will confirm pad geometry, via-in-pad and surface finish together. We build the same stackup on custom outlines for irregularly shaped LED display boards, and our P3.91 LED module PCB is a fine-pitch module built this way.

Flatness and Moisture Protection for Large-Format LED Display PCBs

A large LED display is mechanically one flat surface made from many boards. Any warp in a single board shows up as a visible seam or a brightness step in the finished wall, and outdoor cabinets add humidity to the list of failure modes. Both are decided at the PCB stage, not on site.

• Warpage control through balanced construction: Symmetric copper distribution across the stackup, matched laminate and prepreg builds, and a confirmed finished thickness keep panels flat through reflow so modules tile evenly. Copper balance is confirmed during DFM.
• Panel and thickness options for large displays: Standard boards run on 400 × 300 mm panels at 0.6 mm; mass production supports panels up to 800 × 600 mm and thicknesses from 0.2 mm to 6.4 mm, with sample runs reaching 1050 × 610 mm and 0.15-20 mm for stiff, large-format modules.
• Moisture and corrosion protection: Outdoor and rental displays cycle between humid nights and hot, powered-on days. Surface finish, solder-mask adhesion and via plugging decide how much moisture reaches fine-pitch traces and how resistant the board is to electrochemical migration, so we confirm all three against your cabinet design.
• Verification of the flatness-critical steps: Every panel passes 100% AOI and 100% electrical testing, and our HDI process capability covers laser-drilled microvias down to 0.10 mm with ±0.15 mm routing tolerance — the tolerances that decide whether a 0.9 mm pitch module tiles cleanly.

For outdoor installations, tell us the cabinet design and the expected humidity range and we will recommend the surface finish and solder mask combination before production starts.