Date:2010-11-06 05:45:37 (8 years 10 months ago)
Author:Werner Almesberger
Commit:f8ff8bbe29d7645cd639fa15f153a880416ab29b
Message:modules/usb_a_plug_smt.fpd: enlarge signal pads by 0.2 mm

- modules/usb_a_plug_smt.fpd: move the far edge of the signal pads out by
0.2 mm, moving their center by 0.1 mm
- modules/INFO: explain why Molex' calculation seems to be questionable
Files: modules/INFO (1 diff)
modules/usb_a_plug_smt.fpd (2 diffs)

Change Details

modules/INFO
6666N: 73415-0961
6767
6868# USB A plug for SMT
69#
70# Note: the signal pads are enlarged by 0.2 mm and their center is shifted by
71# 0.1 mm with respect to the reference.
72#
73# According to the data sheet, the leads terminate at (2.00+/-0.10 mm)/2+
74# 2.48 mm = 3.48+/-0.10 mm from the center. The reference footprint puts the
75# edge of the pads at (2.00+/-0.10 mm)/2+2.6 mm = 3.6 mm+/-0.10 mm, so the
76# maximum lead end could be at 3.58 mm while the minimum pad edge could be at
77# 3.5 mm.
78#
79# Assuming that the pad is intended to extend a bit beyond the lead, we need
80# to add 0.2 mm to compensate for these tolerances. (The pad tolerance may not
81# be intended to be used this way, however, we still have to consider small
82# errors in registration, which also amount to about 0.1 mm, so the calculation
83# remains valid.)
84#
6985F: usb_a_plug_smt
7086
7187# SOT-323 package with counter-clockweise or clockwise pin assignment
modules/usb_a_plug_smt.fpd
33frame pad {
44    table
55        { h, w }
6        { 2mm, 1.2mm }
6        { 2mm+2*enlarge, 1.2mm }
77
88    __0: vec @(w/2, h/2)
99    __1: vec @(-w/2, -h/2)
...... 
1818        { 3, -1mm }
1919        { 4, -3.5mm }
2020
21    __0: vec @(0mm, 2.6mm)
21    set enlarge = 0.1mm
22
23    __0: vec @(0mm, 2.6mm+enlarge)
2224    __1: vec .(x, 0mm)
2325    frame pad .
2426}

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