The SMT Industry Abbreviation: A Beginner’s Guide to Understanding the Technology

SMT: Surface Mount Technology
PCB: Printed Circuit Board
BGA: Ball Grid Array
QFN: Quad Flat No-leads
CSP: Chip Scale Package
LGA: Land Grid Array
QFP: Quad Flat Package
SOIC: Small Outline Integrated Circuit
SOP: Small Outline Package
TQFP: Thin Quad Flat Package
TDR: Time-domain reflectometry, a measurement technique that uses a pulse signal to measure the electrical characteristics of a PCB or SMD.
V-score: A process of scoring or grooving the PCB substrate to make it easier to separate the PCB after assembly.
PCB Panel: A large PCB divided into smaller individual PCBs, which are later separated and used as individual PCBs.
Panel Array: A group of identical SMDs placed on a PCB panel in a matrix arrangement.
PCB trace: A thin conductor on the surface of a PCB that connects one component to another.
Via: A small hole in a PCB that connects one layer of a PCB to another or connects the surface of the PCB to an internal layer.
Solder mask: A thin layer of polymer that covers the surface of a PCB to protect the traces and vias from damage and to provide insulation.
Solder paste: A mixture of tiny solder particles suspended in flux that is used to create the solder joints between SMDs and a PCB.
SMD: Surface Mount Device
PTH: Plated Through-Hole
BOM: Bill of Materials
stencil: a thin metal or polymer sheet with cutouts in the shape of the SMD pads, used to apply solder paste to the PCB before components are placed.
Reflow: The heating process that melts the solder paste and causes it to flow and solidify, creating a mechanical and electrical connection between the SMD and the PCB.
Pick and Place: The process of loading SMDs onto a PCB using a machine.
AOI: Automated Optical Inspection, A machine that uses cameras and software to inspect the placement and alignment of SMDs on a PCB.
ICT: In-Circuit Test, A test that verifies the electrical functionality of a PCB by applying test signals and measuring the response.
FCT: Functional Circuit Test, A test that verifies the functional performance of a PCB by applying real-world signals and measuring the response.
DFM: Design for Manufacturability, the practice of designing a PCB with consideration for the capabilities and constraints of the SMT assembly process.
DFT: Design for Testability, the practice of designing a PCB with consideration for the ability to test the functionality of the finished product.
ESD: Electrostatic Discharge, the release of static electricity that can cause damage to electronic components.
RoHS: Restriction of Hazardous Substances, a European Union directive that limits the use of certain hazardous materials in electronic products.
Lead-free: A term used to describe electronic components and materials that do not contain lead in compliance with RoHS regulations.
SIR: Surface Insulation Resistance, a measurement of the resistance to electrical leakage on the surface of an SMD.
CT: Capacitance Test, a measurement of the capacitance of an SMD.
LCR: Inductance, Capacitance and Resistance Test, a measurement of the inductance, capacitance and resistance of an SMD.
TDR: Time-domain reflectometry, a measurement technique that uses a pulse signal to measure the electrical characteristics of a PCB or SMD.
V-score: A process of scoring or grooving the PCB substrate to make it easier to separate the PCB after assembly.
PCB Panel: A large PCB divided into smaller individual PCBs, which are later separated and used as individual PCBs.
Panel Array: A group of identical SMDs placed on a PCB panel in a matrix arrangement.
PCB trace: A thin conductor on the surface of a PCB that connects one component to another.
Via: A small hole in a PCB that connects one layer of a PCB to another or connects the surface of the PCB to an internal layer.
Solder mask: A thin layer of polymer that covers the surface of a PCB to protect the traces and vias from damage and to provide insulation.
Solder paste: A mixture of tiny solder particles suspended in flux that is used to create the solder joints between SMDs and a PCB.