Design Methods

With designing any product, the first step is to be involved with identifying the market the product will be sold into and the need the product will fill, then this expands into identifying the competing products that can already perform the job, and culminates in a specification for a new product positioned successfully in the market.

 

In a competitive market, customers choose manufacturers with a reputation for quality and good understanding of design methods. Customers want the designer to understand their specific requirements where PCB design is concerned. If the designer fails to meet the specification, the PCB is of no use as the final product will not be able to utilize the incorrect circuitry. The designer should go as far as developing a new electronic circuit board, which is usually designed to fit a certain enclosure or case, with labeling and graphics and perhaps a keyboard and display. It is better to provide a technical documentation package for the customer, so that they understand the circuits and PCB layout in detail. Thus when they encounter an error, correction can be done easily.

A good PCB design and structure optimizes the workings of the circuits. Different PCBs have different specifications, mainly because they have various functions in the final product. Large manufacturers often have no problem in meeting with the variety of PCB requirements, but small manufacturers have limited equipment so they encounter this problem quite often.

A company called PCC circuits Inc. is a large PCB manufacturer based in Australia. Listed below are the requirements of customers and how PCC copes with their demands.

The advanced technology has cost PCC a lot of money, involving multi-million dollar investments. But as you can clearly see from the table, their engineering capabilities are well beyond customers’ expectation, making them one of the leading PCB manufacturers in Australia.

Later on in the project, you will see a listing of automation and machinery that PCC Circuits Inc. use in their manufacture of PCBs. They have specialized departments to treat waste water from their production plant and incoming water treatment .

The product proceeds to the final steps in the development, which comprise of: customer acceptance testing, refinement, brochures, pilot run, and product release.

 

ATTRIBUTES

TYPICAL CUSTOMER USAGE

PRESENT PCC CAPABILITY

NEXT 2 YEARS PCC CAPABILITY
Layer Count (min/max)

2-16

2-20

2-28
Board Thickness (range)

0.062" - 0.093"

0.015" - 0.190"

.012" - .225"
Dielectric Spacing (min)

0.005"-0.020"

0.004"

0.0025"
Dielectric Material/ Tg

FR-4/140 - 150c

FR-4/140-170c

FR-4 /140 - 180 c
Line Width/Space: 
Outer Layer

7/5

4/4

4/4

Inner Layer

7/5

4/4

3/3
Copper Foil Thickness:
Outer Layer min - max

.5/5oz.

.5/5oz.

.25/5 oz.
Inner Layer min - max

.5/2oz.

.5/2oz.

.25/4 oz.
Drilled Hole Diameter (min)

0.0135" - 0.025"

.010"

.008"
Pad Diameter: 
Signal (min)

0.035"

0.025"

0.020"
Clearance (min)

0.045"

0.040"

0.038"
Annular Ring Size

.005"

.002"

.001"
Aspect Ratio

3:1-6:1

6:1

9:1
SMT Pitch (min)

.025" - .050"

.020"

.015"
Surface Finish: 
HASL SMOBC

Yes

Yes

HASL + ?
NICKEL/GOLD

<1%

Yes

2 - 8%
BGA (Customer Driven)

<1%

YES

2 - 10%
Buried Vias (Customer Driven)

<1%

YES

2 - 8%
Blind Vias (Customer Driven)

<1%

YES

2 - 8%
Largest Panel Size

18" x 24" M/L

20" x 24" M/L

24" x 30" M/L

20" x 24" D/S

21" x 24" D/S

24" x 30" D/S
Controlled Impedance

50-100 Ohm +/-10%

50-100 Ohm +/-10%

50-100 Ohm +/-10%

 

                          

                                                         A chart from Airborn Electronics.

 

 

An Introduction  l Printed Circuit Board Etching l The Specifications  l EMI-Firmware l EMI-Pilot Run l EMI - The Circuit Design

                           EMI PCB Layout l  Equipment and Machinery used for PCB Manufacture l Back To Index