What is New in IPC-7351C.pdf - 第38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 No mi n al “E” No min al “L ” T o e P a d Lengt h = No m “L ” + He el + T o e He el P a d Ce n ter s P ad L e n g t h P …
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
PCB Libraries Presents:
What is New in IPC-7351C
Solder Joint Goals for Chip Components
Chip Capacitor
Chip Fuse
Chip Thermistor
Chip Non-polarized Diode
Chip Inductor
Chip Varistor
Chip Resistor
Polarized Chip Capacitor
Chip Diode
Chip LED