IEC 60191-1:2018

Overview - IEC 60191-1:2018 (Mechanical standardization of semiconductor devices - Part 1)

IEC 60191-1:2018 provides general rules for preparing outline drawings of discrete semiconductor devices, including discrete surface-mounted devices (SMD) with a lead count less than 8. Its primary aim is to standardize the way device outlines, terminal positions and related dimensional information are presented so equipment designers and manufacturers can ensure mechanical interchangeability and correct space allocation on PCB and in equipment enclosures.

Key topics and technical requirements

• Scope and purpose
  • Guidelines for outline drawings of discrete and small-count SMD devices; helps indicate the space to be allowed for devices and ensures mechanical interchangeability.
• Drawing layout and content
  • Rules for views, notes, and presentation of outline drawings so that they are consistent and unambiguous.
• Dimensions, tolerances and units
  • Principles for dimensioning, tolerance specification, and inch-to-millimetre conversion/rounding rules.
• Datum location methods
  • Methods to locate datums extended to be suitable for SMD-packages, enabling consistent measurement and verification.
• Terminal specification and numbering
  • Rules for numbering terminals (linear, circular, double-ended, square/rectangular peripheries, lozenge-shaped bases) and how to indicate terminal dimensions and positions.
• Visual identification for automation
  • Clarified rules for marking terminal position one to support automatic handling and pick-and-place machinery.
• Terminals and standoffs
  • Clarified rules for the drawing of terminals and a newly added definition of stand-off.
• SMD-specific provisions
  • A normative annex with special rules for SMD-packages, new symbols in Table A.1 for SMD, and updated examples aligned to current package styles.
• Additional elements
  • Gauge drawings, coding rules, reference letter symbols, and normative/informative annexes with examples.

Practical applications - who uses IEC 60191-1

• Package and mechanical designers - produce compliant outline drawings for datasheets and internal use.
• PCB designers and layout engineers - allocate correct land pattern area and mechanical keep-outs.
• Component manufacturers and test houses - define manufacturing tolerances, gauges and inspection procedures.
• Procurement and quality teams - verify mechanical interchangeability across suppliers.
• Automation/integration engineers - rely on terminal position identification for pick-and-place and handling equipment.

Related standards

• IEC 60191 series - other parts cover bases, multi-lead SMD packages and specialized rules.
• For SMD devices with lead count ≥ 8, refer to IEC 60191-6 for complementary rules on outline drawings.

By following IEC 60191-1:2018 you improve consistency of outline drawings, reduce mechanical mismatches across suppliers, and facilitate automated assembly and quality control for discrete semiconductor packages.