What is New in IPC-7351C.pdf - 第22页

PC B L ibr ar i es Pr e s ents : Wh at is N ew i n IPC- 7351C Com po ne nt Body & T e r m ina l Outline s • Th e N ominal C ompon e nt Bod y and T e r m i nal Le ad Outl in e s • Outp ut to CAD too l o n a me c hani …

PCB Libraries Presents:

What is New in IPC-7351C

Assembly Outline & Polarity Guidelines

Non-polarized Chip,

Crystal, Molded Body

Polarized Chip, SOD,

LED, SOT. Molded Body

Plastic Leaded Chip Carrier

PLCC, LCC, 4-sided Chip Array

Small Outline Package

SOP, SON, QFN, QFP

1.00 mm

0.10 mm

Line Width

PCB Libraries Presents:

What is New in IPC-7351C

Component Body & Terminal Outlines

• The Nominal Component Body and Terminal Lead Outlines

• Output to CAD tool on a mechanical layer

PCB Libraries Presents:

What is New in IPC-7351C

3-Tier Silkscreen Reference Designators

• Silkscreen reference designators are normally placed inside the

courtyard during library construction and typically located on the

land pattern origin. After part placement has been approved, the

silkscreen ref des are relocated outside the component body so

they are visible after assembly.

• The ref des line width is normally 10% of the text height

• In the past, we made all silkscreen reference designators 1.50 mm

height. Fabrication technology has improved it’s time to support a

3-Tier reference designator option

• New recommendations for the 3-Tier ref des

– Least Density Level: 1.00 mm Height

– Nominal Density Level: 1.20 mm Height

– Most Density Level: 1.50 mm Height

REFDES