REFERENCE

Glossary

Short reference notes on the terms that turn up around breakout boards and the chips that live on them.

• DIP

  Dual In-line Package — the classic through-hole IC format on 2.54 mm pitch. Rare on modern ICs, but the layout every solderless breadboard was designed around.

• ENIG

  Electroless Nickel Immersion Gold — a premium, very flat PCB finish. Well suited to fine-pitch and BGA assembly, with excellent storage life and a distinctive gold appearance.

• FR4

  The glass-reinforced epoxy substrate used for most rigid PCBs. What the name means, how PCB layers are built around it, and where specialised laminates make more sense.

• HASL

  Hot Air Solder Levelling — the classic solder-based finish for exposed copper pads. What your board ships with when we say “lead-free HASL”.

• OSP

  Organic Solderability Preservative — an ultra-thin organic film that keeps copper pads solderable without adding a metallic finish.

• RoHS

  Restriction of Hazardous Substances — the regulations that drove mainstream electronics assembly away from leaded solder, and what a “RoHS compliant” marking on a datasheet actually promises.

• SMD / SMT

  Surface Mount Device and Technology — the components and assembly methods that largely replaced through-hole in modern electronics, and the reason breakouts exist.