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Source at commit 39c7ee76cf2de04bf8646e4c6c8b1966fcf99596 created 10 years 3 months ago.
By Werner Almesberger, Moved mini-usb.fpd and usb_a_plug_smt.fpd from ben-wpan to kicad-libs (incoming)
1#
2# Tags:
3#
4# F Footprint name (must be first)
5# N Data sheet identifier (N tag of BOOKSHELF; can be omitted if equal to F)
6#
7
8# Standard rectangular passive components
9F: stdpass
10
11# Solder pads and test points
12F: pads
13
14# Printed 8:10 card contacs
15F: 8_10-card
16
17# Fiducial (1 mm copper pad, 2 mm solder mask clearance)
18F: fiducial
19
20# "Generic" simple QFN
21F: qfn
22#
23# The information for these packages comes from various sources:
24#
25# - the C8051F326 data sheet, for the QFN28 footprint (N: mcu)
26# - the AT86F326 data sheet, for the QFN32 package dimensions (N: txrx)
27# - Atmel's general recommendations for QFN land patterns (N: atmel-qfn)
28# - NXP's SOT617-1 and SOT617-3, for package and land pattern:
29# http://www.nxp.com/package/SOT617-1.html
30# http://www.nxp.com/package/SOT617-3.html
31#
32# Solder paste:
33#
34# Footprint Center pad Closest NXP (with complete land pattern)
35# QFN28-Atmel 2.4 mm for further study
36# QFN28-SiLabs 3.3 mm use SiLab's specification
37# QFN32-VHHD-2 3.7 mm between SOT818-1 and SOT788-1
38# QFN32-VHHD-6 3.4 mm SOT818-1
39#
40# From NXP:
41#
42# Package Pad Paste zone Islands Isl. size Isl. gap
43# SiLabs 3.25 3.1 3 x 3 0.9
44# SOT818-1 3.4 1.75 2 x 2 0.75 0.25
45# SOT788-1 4.0 2.4 3 x 3 0.6 0.3
46#
47# NXP rules (AN10365):
48# - paste zone = 35% of pad area
49# - paste coverge = 20% of pad area
50#
51# Our parameters:
52#
53# Package Pad Paste zone Islands Isl. size Isl. gap Zone Coverage
54# QFN32-VHHD-2 3.7 2.15 3 x 3 0.55 0.25 34% 20%
55# QFN32-VHHD-6 3.4 1.95 2 x 2 0.75 0.45 33% 19%
56#
57# Known bugs:
58#
59# - really ought to merge all the various QFN definitions (we have more
60# over at gta02-core) into a single QFN file with a big mean table of
61# everything
62#
63N: sot617-3-lp
64
65# "Generic" simple QFP (for now, just for Silabs' C8051F320)
66F: qfp
67
68# Mini-USB B receptable (SMT; almost generic)
69F: mini_usb_b
70
71# USB A plug for SMT
72#
73# Note: the signal pads are enlarged by 0.2 mm and their center is shifted by
74# 0.1 mm with respect to the reference.
75#
76# According to the data sheet, the leads terminate at (2.00+/-0.10 mm)/2+
77# 2.48 mm = 3.48+/-0.10 mm from the center. The reference footprint puts the
78# edge of the pads at (2.00+/-0.10 mm)/2+2.6 mm = 3.6 mm+/-0.10 mm, so the
79# maximum lead end could be at 3.58 mm while the minimum pad edge could be at
80# 3.5 mm.
81#
82# Assuming that the pad is intended to extend a bit beyond the lead, we need
83# to add 0.2 mm to compensate for these tolerances. (The pad tolerance may not
84# be intended to be used this way, however, we still have to consider small
85# errors in registration, which also amount to about 0.1 mm, so the calculation
86# remains valid.)
87#
88F: usb_a_plug_smt
89

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