DESIGN GUIDELINES
D
LLE
RO
T
N
CO PY
UN CO
Issue No :
Date :
DESIGN GUIDELINES
FOR PCB DRAWINGS
05
August ‘13
DG 06
D
LLE
RO
T
N
CO PY
UN CO
DESIGN GUIDELINES
I.
Issue No :
Date :
05
August ‘13
DG 06
Drawing Definition
A PCB design document is a controlled document that contains all necessary information about
schematic, electronics components, physical properties and any other vital details which are
required to produce a PCB.
II. Purpose & Application
The purpose of this document is to establish a guide in order to aid Designers to fully complete
drawings. All Drawings shall be fully detailed in order to allow potential users of the information to
produce or supply components for the PCB without error or confusion.
III.
Drawing Details
Methode PCB Assembly drawings will consist of multiple sheets organised as follows:– Manufacturing notes and full revision history
– Schematic and last revision
– PCB assembly view, component BOMs, Manufacturing notes and last revision.
Assembly drawing numbers will begin 16xxx, where xxx will be defined by the part number issuing
authority.
Bare Board drawings will be prepared separately from the assembly drawings. Their numbers will
begin 44xxx, where xxx will be defined by the part number issuing authority
AMENDMENT BLOCK
1. Zone
Zone shall be filled in to identify the area where an amendment has taken place. The Y axis is
lettered and the X axis is numbered. The X-axis shall be typed in front of the Y axis, e.g. 4G (First
the number followed by a letter.) All drawings shall be prepared on the standard template.
2. Index
All drawings shall be issued with a “00A” index and marked “DRAWING ISSUED”. Index level shall
start from top to bottom of the amendment block. When the amendment description is longer than
one line, the index number shall be typed on the first line of the amendment and the date and name
shall be typed in line with the end of the amendment description.
3. Amendments
Amendments shall be recorded as concisely as possible, but shall contain a clear record of what
has been changed. All modifications shall be cross referenced to Change Notice (CN) and Change
Reference (CR) as applicable. This number shall be recorded in the next column – Supporting
Document field (SPRT DOC). Any modifications in the drawing shall be marked with an encircled
amendment index letter placed on the location where the amendment has taken place, as shown
below. The supported document should refer to the Index No.
A
B
In those sheets where no changes have been effected, the entry in the Amendments field shall read
“REFER TO SHEET x”, where x denotes the sheet number where changes are present. In case of
multiple sheets containing changes, these should be all listed in the same entry reading “REFER
TO SHEETS x, y, z”.
DESIGN GUIDELINES
D
LLE
RO
T
N
CO PY
UN CO
Issue No :
Date :
05
August ‘13
DG 06
4. CR & CN Usage
A CR is to be used to amend typing errors and to bring drawings in line with the mechanical PCB
(due to mechanical tolerances and so on).
A CN is to be used for anything else like change in resistor value, change in component and so on.
5. Date/Name
Date/Name shall be entered when Drawing is issued or amended. Name shall be written in the
following manner: first name initials only and surname in full, both in block form.
6. DWG NO. (Drawing Number)
All drawings shall be initially issued with “00A” index. The drawing shall get the next higher number
and letter index for amendments effected by an Engineering Change Notice e.g. from 00A to 01B.
The Drawing shall get the next revision letter only for every amendment effected by a Change
Reference e.g. from 00A to 00B.
TITLE BLOCK
7. DWN BY (Drawn By)
‘Drawn by’ shall be typed in by the PCB Designer.
8. CHK BY (Checked By)
‘Checked by’ shall be typed in by someone within the Product Development Department. This shall
commonly be the product designer nominated as Lead Engineer for the project.
9. APVD BY (Approved By)
‘Approved By’ shall be typed in by the PCB Designer’s Principal, or in his absence the Product
Development Manager.
10. CAD Filename
The full Drawing file name and extension shall be identified in the field.
11. Title
The title of the drawing shall identify the PCB name and Product Function. e.g. “PCB Assy. – Main
Board - SAS” etc. It is not acceptable to simply write “PCB Assembly”.
IV.
Drawing Types
The above guidelines shall apply to all PCB drawings.
1. THE PCB ASSEMBLY DRAWING – 16XXX
All sheets of all PCB Assembly drawings will carry the standard border, including the Title Block and
Amendment Block (see Figure 1). Special notes related to standards, finishes and any other
notable features which affect the PCB assembly shall be included in the first sheet. All notes should
be collected in a single numbered list, except where individual notes may relate specifically to a
particular view. In that case it is acceptable to place the unnumbered note close to the
corresponding view.
The number of sheets in the drawing shall be kept to the minimum amount possible, by using larger
page sizes where necessary. However, it is important that the drawing maintains clarity and avoids
DESIGN GUIDELINES
D
LLE
RO
T
N
CO PY
UN CO
Issue No :
Date :
05
August ‘13
DG 06
clutter; hence when necessary it is acceptable to increase the number of pages if this enhances
readability. All sheets should have the same page size, where possible.
Where multiple variants of a PCB exist, each variant shall have as unique assembly number. All
assemblies will refer to the same bare board number. The assemblies will traceable through their
use of a common bare board.
Figure 1: The Standard PCB Assembly Border. Note that that Amendments block should be extended to the
maximum amount of lines possible on the sheet, to allow room for detailed descriptions of modifications.
A. The Schematic View
The circuit Schematic shall be included in the PCB assembly drawing. This shall include the
following:i)
The circuit diagram.
ii)
The connector pin numbering and functions.
iii)
Where a mechanical movement or contact system influences inputs or outputs of the
circuit, such mechanical features should be represented in the schematic to aid
understanding.
iv)
Passive component values shall be shown on the schematic.
v)
Semiconductor part numbers.
vi)
All components will be identified by a designator that shall be referred to in the bill of
materials and PCB assembly drawings. Refer to the table below for the prefixes to be
used for each component type.
D
LLE
RO
T
N
CO PY
UN CO
DESIGN GUIDELINES
Resistor
Capacitor
Diode
Transistor
IC
LED
Inductor
Connector
Crystal
Switch
vii)
viii)
ix)
x)
Issue No :
05
DG 06
August ‘13
Date :
R
C
D
Q
U
LED
L
CON
X
SW
Components shown on the schematic but not fitted must be identified by drawing a
broken line box around the component. There should be text adjacent to the box “NOT
FITTED”. Alternatively, the component may be crossed out on the schematic, and a note
reading “CROSSED OUT COMPONENTS IN THE SCHEMATIC VIEW ARE NOT TO
BE FITTED” shall be included. The best way to denote this shall be chosen according to
the complexity of the schematic and the grouping of the components in question, in such
a way as maintain clarity and avoid clutter in the schematic.
Signals and terminal names required to improve understanding in other documents and
software should also be shown in the schematic.
For simplicity the schematic may be drawn in blocks with off page connectors.
The schematic may be spread over several sheets if necessary for clarity.
B. Bill Of Materials
The Bill Of Materials (BOM) Table must identify all electronic components and their description in
an unambiguous way. The component reference designators used in the BOM must be consistent
with those shown in the Schematic View. All components shown in the schematic view have to be
listed in the BOM. Those which are not to be mounted should be placed in separate lines and have
an entry of ‘0’ in the ‘Quantity’ column (see Table 1).
The table shall have the following format: BILL OF MATERIALS TABLE 1
PREFERRED
PACKAGE
SUPPLIER
ALT.
SUPPLIER
PART NOS
VISHAY
PHICOMP
CRCW-1206-270F-100-RT6
1206
N/A
N/A
N/A
0603
PANASONIC
VISHAY
ECJ1VB1H103M
REF. DES.
QTY
DESCRIPTION
R1
1
RESISTOR 270Ω 1% - 0.25W
1206
R2
0
NOT FITTED
2
CERAMIC CAPACITOR 20%,
10nF, 50V
C1,C2
Table 1: Bill Of Materials Table
If PCB is to be assembled in-house at MEM, a new column with the MEM part number s MUST be
added.
The preferred and alternative suppliers for the components, as well as the part number of the
preferred supplier have to be listed in the BOM.
Microcontrollers should be identified and the software part number should be shown in the BOM as
a component. Software numbers and revisions should be assigned according to the Software
Development Procedure as follows: -
D
LLE
RO
T
N
CO PY
UN CO
DESIGN GUIDELINES
Issue No :
05
August ‘13
Date :
16xxx
-
Uxx
-
S
xx
PCB article
number
-
IC reference
designator
-
Software
Mark
Revision
DG 06
For example: 16234-U16-S02 refers to the software which should be in microcontrollers with
reference designator U16 of PCB assembly 16234 and has revision 02.
C. Connector Pin-Out
The connector numbering shall be shown on the schematic view as described previously. The
signals shall be described in a separate table that relates to the same connector pin numbering.
The table shall have the following format: CONNECTOR PIN-OUT TABLE 2
PIN NUMBER
FUNCTION
1
+5V SUPPLY
2
GROUND
GEAR POSITION
3
OUTPUT
Table 2: Connector Pin-Out Table
D. In-Circuit Testing
An In-Circuit Testing table shall be included in the PCB assembly drawing. This table should
indicate which electrical tests are to be performed on the PCBs after the components have been
assembled. The table shall have the following format: TEST
SW1 (NC)
R1 // R2
D1
IN-CIRCUIT TESTING TABLE 3
TESTING POINTS
EXPECTED VALUE
TP2 – TP11
<0.5 OHM
TP9 – TP12
470 OHMS ± 10%
TP2 – TP3
0.75 ± 0.05V @ I = 10mA
Table 3: In-Circuit Testing Table
In the case that any programming and/or calibration procedure is required, this has to be specified
in a separate process instructions document. The PCB assembly drawing shall contain a note
(either in the general notes list or in this ICT table) referring to this process instructions document,
including the file name and version.
E. LED illumination intensity bins
In most cases, different resistors may be fitted on the PCB, depending on which of the specified
LED illumination intensity bins are being assembled. In this case a table showing which resistor
values are required for each LED intensity bin shall be included for each LED. It should be noted
that two identical LEDs on the same PCB may require different resistor values for same bins,
because the illumination may have different optical paths in the product.
When such resistor/LED bin tables are included, an additional table showing similar fields to those
in the BOM table will be required for these resistors.
DESIGN GUIDELINES
D
LLE
RO
T
N
CO PY
UN CO
Issue No :
Date :
05
August ‘13
DG 06
New Boards and or new Plastic will require LED tweaking across all acceptable BINs, resistors
values for non-tweaked BINs shall be entered as TBE. This value will then be updated via a CN
once the PCB assembler provides PCBs mounted with the available BINs.
A note in the 16xxx drawing is to require the PCB assembler to allow two weeks from the receipt of
the new BIN PCBAs for a tweak and drawing update to occur.
F. PCB assembly Views
The PCB assembly views should show the view of the PCB with the components placed on the
board. Dimensioning is not necessary unless to define the location of a component with respect to
some PCB datum. However it should be noted that SMD component locations are determined by
the pad location and pad design and the tolerances will be wide, so if special tolerances are
required, they should be indicated accordingly. Other dimensions shall be shown as REF DIMS.







The drawing shall show top and bottom view, whether or not components are assembled on
both sides.
Each component shall be shown in outline.
Polarity or orientation indicator and component reference designator shall be shown.
The component reference shall be traceable to the schematic view and the BOM table.
Test points shall be identified with the same detail as components.
A 3D view of the PCB may be shown if this will improve understanding of the assembly, but
it is not strictly necessary.
Dimensions, notes and information which are related to the bare board shall NOT be
included in the PCB assembly drawing, but in the Bare Board drawing.
The PCB assembly views normally occupy the last sheet of the drawing.
G. Connector Detail View
Where applicable, views showing connector dimensions, materials, plating and coining details shall
be included in the PCB assembly drawing.
DESIGN GUIDELINES
D
LLE
RO
T
N
CO PY
UN CO
Issue No :
Date :
05
August ‘13
DG 06
2. THE BARE BOARD DRAWING - 44XXX
The PCB bare board drawing is a separate drawing from the assembly drawings. The PCB 44XXX
drawing will have a full title block and revisions control as shown in Figure 2. Since the PCB
assembly refer to the single board, any changes will affect both drawings.
Figure 2: The standard bare board drawing border
This drawing shall detail all the mechanical dimensions and tolerances that are important to the
design. It shall also clearly identify and label the Top and Bottom layers of the PCB. When
applicable, intermediate inner layers shall also be identified and labelled. These shall follow the
naming convention of Inner 1, Inner 2, etc..., with the first inner layer being the one closest to the
top layer. Dimensioning of the holes shall only be included if critical to the assembly. The drawing
shall also detail the following as applicable: i)
ii)
iii)
iv)
v)
vi)
vii)
viii)
ix)
x)
xi)
xii)
xiii)
xiv)
Board material.
Copper and all other plating thickness specification and tolerances.
Areas of the PCB requiring additional plating processes.
Solder resist finishes.
Silk screen and identification where applicable.
Reference to any manufacturing standards that must be observed.
Carbon finishes tolerances, potentiometer resistance and linearity.
Edges or edge sections which shall be routed.
Edges or edge sections which should be scored for snap-off.
Indicate if the circuit tracks should be tested for continuity.
Indicate conformal coating if required and coating type and locations.
Indicate where the supplier may place their traceability identification data.
Indicate an unused area for the panelisation reference co-ordinates.
Indicate ‘keep out’ zones
The panelisation details shall only be defined when Methode are to purchase PCBs in panelised
form. Otherwise a note reading “Panelisation to be defined by PCB assembly supplier” shall be
included with the general notes list.
The bare board drawing does not need to the show the artwork pattern unless it aids the
understanding of the design.
Flexible PCBs shall be drawn with the same details.
DESIGN GUIDELINES
D
LLE
RO
T
N
CO PY
UN CO
Issue No :
Date :
05
August ‘13
DG 06
Artwork data
The bare board drawing shall include a table containing the file names and description of the
manufacturing data of the PCB. The table shall have the following format: -
ARTWORK DATA REFERENCE TABLE 1
FILE NAME
FILE DESCRIPTION
44999-02.AST
COMPONENT ASSEMBLY TOP
44999-02.ASB
COMPONENT ASSEMBLY BOTTOM
44999-02.ELT
ETCH LAYER TOP
44999-02.IN1
ETCH LAYER INNER 1
44999-02.IN2
ETCH LAYER INNER 2
44999-02.ELB
ETCH LAYER BOTTOM
44999-02.SMT
SOLDER MASK TOP
44999-02.SMB
SOLDER MASK BOTTOM
44999-02.SPT
SOLDER PASTE TOP
44999-02.SPB
SOLDER PASTE BOTTOM
44999-02.BDR
BOARD OUTLINE DATA
44999-02.RTG
ROUTING DATA
44999-02.DDT
DRILL DATA
44999-02.DDS
DRILL SYMBOL TABLE
44999-02-XY.TXT
COMPONENT PLACEMENT COORDINATES
44999-02-TOP.DXF
TOP VIEW
44999-02-BOT.DXF
BOTTOM VIEW
NOTE: EXCELLON DRILL DATA FILES IN NCDRILL FOLDER
Table 4: Artwork Data Reference Table
A ZIP file with the number of the PCB and revision shall be created for each PCB and each
revision. The file will contain all Gerber files, Excellon drill files and any other output files needed for
the manufacture of the PCB, as listed in Table 4. The Excellon drill files shall be called
‘ContourNonPlated.ncd’, ‘ThruHoleNonPlated.ncd’ and ‘ThruHolePlated.ncd’, and shall be placed in
a folder within the zip file called ‘NCDrill’. The file name of the zipped file shall be 44xxx-nn.zip,
where 44xxx is the bare board number and nn is its revision number, which shall correspond to the
drawing revision number.
DESIGN GUIDELINES
D
LLE
RO
T
N
CO PY
UN CO
Issue No :
Date :
05
August ‘13
DG 06
3. TOLERANCES
Tolerances on dimensions of PCBs, placement of components, hole diameters, etc… will vary
between PCB suppliers, depending on their equipment. Thus, when tolerances are critical on
particular dimensions it is recommended that these are specifically highlighted during a design
review with the supplier, in order to verify that they can be maintained.
The table below gives an overview of typical dimensions that can be achieved by most PCB
suppliers and can be used as a guideline.
Copper layer thickness
Board thickness
Board thickness tolerance
Bow & twist of PCB
Minimum copper track width
Minimum copper track separation
Minimum SMT pad to pad distance
Minimum copper track to hole/routed edge distance
Minimum copper track to punched edge distance
Minimum copper track to V-cut edge distance
Minimum non-plated through-hole (NPTH) edge to board edge
Copper artwork shift tolerance
Minimum solder mask width
Solder mask misalignment tolerance
NPTH diameter tolerance
Plated through hole (PTH) diameter tolerance
Through-hole misalignment tolerance
Minimum drilled hole diameter
Minimum punched hole diameter
Routed edge tolerance
V-cut edge tolerance
17, 35 or 70 µm
0.6, 1.0, 1.6 or 2.0 mm
±10%
±1%
0.15mm
0.15mm
0.4mm
0.3mm
0.8mm
0.5mm
1.25mm
±0.1mm
0.2mm
±0.15mm
±0.1mm
±0.15mm
±0.08mm
0.4mm
0.8mm
±0.15mm
±0.3mm
4. GENERAL RECOMMENDATIONS









Block letters shall be used for all text, except for units.
All tables shall be numbered.
Ensure the standard Notes are included in the panelisation and single PCB drawings.
All drawings must be readable when printed on A4. Use appropriate scaling to ensure
readable prints.
The schematic should be laid out in blocks if necessary with named block to block
connectors to aid legibility. Avoid a “rats nest appearance”.
Make notes on the schematic that will aide suppliers in the understanding of the circuit and
provide them with the information they need to test the PCBs.
Name signals where this aids understanding.
LED tables should be included on the BOM sheet where resistors are defined for each LED
bin. Ensure LEDs are defined fully by colour range and intensity bin range.
Drawing may only be release on the standard PCB border or the reduced standard PCB
border.
DESIGN GUIDELINES
D
LLE
RO
T
N
CO PY
UN CO
Issue No :
Date :
05
August ‘13
DG 06
5. STANDARD DRAWING NOTES.
The notes below will be shown on all drawings. Those maked “A” are assembly drawing notes and
those marked “B” are bare board drawing notes.
A/B
A,B
Note
No changes in the artwork data are allowed, including markings of the ground planes,
Copper etch, unless specifically approved by the Product Development departments
of Methode Electronics prior to manufacturing.

A

Handling: Prior to production, Methode Electronics must approve all handling
procedures.
A

Suppliers: All suppliers to be approved by Methode Electronics.
A

Components more than 6 months old (or the period guaranteed by manufacturer, as
long as it does not exceed 18 months) shall not be used without a solderability test
performed every 6 months thereafter.
A,B

Solderability: There shall be no visible non-wetting and/or exposed base metal within
any soldered area.
A,B

Inspection: There shall be no solder balls, solder splash and/or other debris on the
PCB and its components.
A,B

Board edges must remain clear of solder mask.
A,B

Board fabricator to apply date/batch code and approval marks (e.g. UL marking) on
any side of PCB where space is available. Note 1 must still be adhered to.
A

Repair of damaged PCB tracks is not permissible.
A

PCB manufacturing and assembly to be according to data files shown in Gerber file
table listed in bare board drawing.
A

Solder mask to be according to IPC-SM-840C. Misregistration to be less than 0.1mm.
No overlap is permitted on SMD rectangular lands. Solder mask material to be light
green in colour and transparent.
A

A certificate of compliance is to be submitted with each batch according to IPC2221/22.
A, B

Testing: End-Of-Line electrical testing to be performed according to specification
provided. All Bare board to be electrical tested.
A

Placement of SMT components to be according to IPC-610 standard Class 3.
A

Placement of Through-Hole components to be according to IPC-610 standard Class
2.
A

Workmanship shall be per IPC-J-STD 001 and IPC-A-610 latest revision.
DESIGN GUIDELINES
D
LLE
RO
T
N
CO PY
UN CO
Issue No :
Date :
05
August ‘13
DG 06
A,B

Finished assembly to be RoHS compliant.
A

LEDs of the same colour with different intensity or chromaticity bins are not to be mounted on
the same board unless distinctly identified in the BOM.
A

Crossed-out components are only for package-proofing. They are not to be mounted
and not to be included in quotations.
A

Packaging: Returnable Electrostatic Dissipative (ESD) trays to be used where
specified.
A,B

A

Minimum gold plating is: 0.05um minimum at 4-sigma below the mean and typical
0.075 to 0.125um per IPC-4552 3.2.2.
Supplier is to allow a minimum of two weeks following Methode's receipt of PCBAs
with non-tweaked LED bins for a tweak and drawing update to occur.