IPC-A-610 Chapter 8 Flashcards

Staking Adhesive - Component Bonding

• Acceptable (Class 1): Adhesive material visible in termination area, with end joint width meeting minimum requirements.
• Defect (Class 3): Adhesive material visible in termination area, not meeting acceptable criteria.

Staking Adhesive - Mechanical Strength

• Acceptable (Class 1, 2, 3): On round components, adhesive covers at least 25% of component height and requires a minimum of three beads evenly placed around the component.
• Defect (Class 1, 2, 3): Fewer than three beads of staking material on round components.

SMT Leads - Plastic Components

• Solder should not contact the package body or seal unless specific lead configurations cause contact with plastic components like SOIC family.

SMT Leads - Damage

• Defect (Class 1, 2, 3): Damage or deformation to leads exceeding 10% of their diameter, width, or thickness.

SMT Connections

• Components with non-wettable areas by design are exempt from solder wetting requirements in those regions.

Chip Components - Bottom Only Terminations

• Side Overhang (Class 1, 2): Side overhang must be ≤ 50% of component termination or land width.
• End Joint Width (Class 1, 2): Minimum width must be ≥ 50% of component termination or land width.

Rectangular or Square End Chip Components

• Acceptable Side Overhang (Class 1, 2): ≤ 50% of termination or land width.
• End Joint Width (Class 3): Minimum end joint width must be ≥ 75% of termination or land width.

Cylindrical End Cap Terminations

• Referred to as MELF (Metal Electrode Leadless Face).
• Acceptable Side Overhang (Class 1, 2, 3): Must be ≤ 25% of component width or land width.

Castellated Terminations

• Acceptable Side Overhang (Class 1, 2): Maximum ≤ 50% castellation width.
• Minimum End Joint Width (Class 3): Should be ≥ 75% of castellation width.

Flat Gull Wing Leads

• Side Overhang (Class 1, 2): Maximum overhang should not exceed 50% of lead width or 0.5 mm.
• Minimum End Joint Width (Class 3): Minimum end joint width should be ≥ 75% lead width.

J-Leads

• Toe Overhang (Class 1, 2, 3): This parameter is unspecified, offering flexibility in design.

Surface Mount Area Array

• Process guidance provided in IPC-7095 with a focus on addressing process development issues.
• Solder Connections (Class 1, 2, 3): BGA solder balls must contact and wet the land to form a complete connection.

Additional Notes on Fillets and Joints

• Minimum Heel Fillet Height (Flat Gull Wing): In toe-down configurations, minimum height should extend to at least the midpoint of outside lead bends.
• End Overlap (Cylindrical Terminations): Must be ≥ 50% the length of component termination for acceptable standards.

Familiarize with the criteria detailed above for various components to ensure compliance with IPC-A-610 standards across different classes.### Components with Bottom Thermal Plane Terminations

• Thermal plate terminations are characterized by their end joint width.
• Acceptable standards include Class 1, 2, and 3.

Flattened Post Connections

• Connections should comply with dimensional and solder fillet standards as per specific tables.
• Maximum termination overhang differs based on solder land shape and class.

Maximum Termination Overhang - Square Solder Land

• Class 1: Overhang must be less than 75%.
• Class 2: Overhang must be less than 50%.

Maximum Termination Overhang - Round Solder Land

• Class 1 defect: Overhang exceeds 50%.
• Class 2 defect: Overhang exceeds 25%.

Maximum Fillet Height

• Defect classifications for Class 1 and 2 occur when solder touches the package body.

P-Style Connections - Maximum Side Overhang

• Class 1: Acceptable overhang is equal to or less than 50% of the termination width.
• Class 2: Acceptable overhang is equal to or less than 25% of the termination width.
• Class 3 requires no side overhang.

P-Style Connections - Minimum Side Overhang

• Acceptable classifications for minimum side overhang are unspecified and marked as Class.

Surface Mount Connections

• Defects in Classes 1, 2, and 3 must meet form, fit, and function requirements, often necessitating trial mating for acceptance.

Jumper Wires

• Refer to IPC-7711/7721 for guidelines on rework and repair.
• Criteria for wire includes selection, routing, and adhesive staking relevant to SMT jumper wires.

General Conditions for Lap Solder Connections

• Key conditions include insulation clearance, no fractures, and specific wire contour standards, including wire overhang regulations.

Jump Wires - SMT - Chip and Cylindrical End Cap

• Acceptable in Classes 1, 2, and 3 if properly adhered.
• A defect occurs when the wire is soldered on top of the chip component termination.

Gull Wing Configuration

• Jump wires in this configuration are acceptable across all classes ensuring proper wire extends past the knee of the bend.