What is New in IPC-7351C.pdf - 第43页

PC B L ibr ar i es Pr e s ents : Wh at is N ew i n IPC- 7351C N ew P a d Ce n te r Ca lcu la t io n s Nom ina l “ E ” Nom ina l “ L ” T oe P a d Lengt h = No m “L ” + He el + T o e Hee l Pad C ent er s Pa d Lengt h P a d…

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PCB Libraries Presents:
What is New in IPC-7351C
J-STD-001 Chip Component Solder Joints
• Visible Wetting Evident on the vertical surfaces of the component termination
• Minimum End Solder Fillet 25% of Height or 0.50 mm Whichever is Less – Class 3
• Minimum End Solder to be 75% of the Length. The Pad Width is Critical – Class 3
• The Side and Heel are Nominal Values But Must Insure Centering
• The Pad Spacing Center to Center is Critical To Avoid Excess Heel
PCB Libraries Presents:
What is New in IPC-7351C
New Pad Center Calculations
Nominal “E”
Nominal “L”
Toe
Pad Length = Nom “L” + Heel + Toe
Heel
Pad Centers
Pad Length
Pad Centers = Nom “E” + 2 Toes – Pad Length
C
L
PCB Libraries Presents:
What is New in IPC-7351C
Old BGA Solder Joint Goal Recommendations
Nominal Ball Diameter
Reduction
Nominal Land Diameter
Land Variation
0.75 25% 0.55
0.60
-
0.50
0.65 25% 0.50
0.55
-
0.45
0.60 25% 0.45
0.50
-
0.40
0.55 25% 0.40
0.50
-
0.40
0.50 20% 0.40
0.45
-
0.35
0.45 20% 0.35
0.40
-
0.30
0.40 20% 0.30
0.35
-
0.25
0.35 20% 0.28
0.33
-
0.23
0.30 20% 0.25
0.25
-
0.20
0.25 20% 0.20
0.20
-
0.17
0.20 15% 0.17
0.20
-
0.14