What is New in IPC-7351C.pdf - 第37页

PC B L ibr ar i es Pr e s ents : Wh at is N ew i n IPC- 7351C S old e r Joi nt Go al s f or Gu ll Win g • P e r f ec t P ad C ente r ing • Vi s i bl e W e tting U nde r Le ad • Hee l L ar g e r Than T o e • Bad P ad C en…

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PCB Libraries Presents:
What is New in IPC-7351C
Old/New Solder Joint Goal Recommendations
1.00 pitch
0.35 Toe / Heel
Toe
1.00 pitch
0.25 Toe / 0.35 Heel
0.80 pitch
0.35 Toe / Heel
0.80 pitch
0.20 Toe / 0.30 Heel
0.65 pitch
0.35 Toe / Heel
0.65 pitch
0.16 Toe / 0.20 Heel
Heel
Toe
Heel
0.40 pitch
0.35 Toe / Heel
0.40 pitch
0.10 Toe / 0.12 Heel
0.35 pitch
0.35 Toe / Heel
0.35 mm pitch
0.09 Toe / 0.10 Heel
0.50 pitch
0.35 Toe / Heel
0.50 pitch
0.13 Toe / 0.15 Heel
Toe
Heel
PCB Libraries Presents:
What is New in IPC-7351C
Solder Joint Goals for Gull Wing
• Perfect Pad Centering
• Visible Wetting Under Lead
• Heel Larger Than Toe
• Bad Pad Centering
• Wetting Under Lead Unachievable
• Possible Short Circuit with Trace
PCB Libraries Presents:
What is New in IPC-7351C
New Pad Center Calculation
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