sales@pcbjhy.com

Sales Manager: Ms. Megan

+86-13825274100

24/7 Customer Support

+86-13825274100

WeChat and WhatsApp

PCB Design Guidelines

With the popularization of electronic products and the expansion of market scale, as one of the core components of electronic products, printed circuit boards are used more and more. According to different end products and usage scenarios, PCB production process limitations, the design of PCB circuit boards should also follow certain rules.

Printed Circuit Board

Below are a number of Guideline Rules to follow and keep in mind when designing PCBs. These are general rules that apply for the most PCB manufacturers, but it is advisable to check with your fabricator.

  • Board Size

PCB manufacturers have a maximum size board they can handle. Typically this is also their panel size. The PCB fabrication house’s panel size is also important when mass producing boards. In this situation, one would want to fit as many boards as possible on a panel with as little wasted board space as possible (in order to reduce costs). Normal board spacing for routing (how boards are separated on a panel) is 0.3″, plus there is typically a 1.0″ to 2.0″ border on the board for handling it during processing.

Board thickness may also be specified. A standard thickness and type of board is .062″ FR4. Other typical board thickness are .010″, .020″, .031″, and .092″.

  • Trace Width and Spacing

The chemical and photographic processes used to produce a PCB put requirements on the minimum width of trace and the minimum spacing between traces. If a trace is made smaller than this minimum width there is some chance it will open (no connection) when manufactured. If two traces are closer together than the minimum spacing there is some chance they will short when manufactured. These parameters are usually specified as “x/y rules”, where x is the minimum trace width and y is the minimum trace spacing. For example, “8/10 rules” would indicate 8 mil minimum trace width and 10 mil minimum trace spacing. These rules (especially spacing) apply to any metal on the PCB, including a pad to track spacing and line widths for strings on the PCB.

Typical modern process rules are 8/8 rules with values as small as 2/2 rules being available. For Press-n-Peel people have had success using 12/12 rules, but values a little larger are easier to make work consistently. However, keep in mind that the board must be soldered and a trace within 8 mils (8/8 rules) of a pad is easier to short than one with greater spacing when hand soldered. For hand soldering, 10/10 rules are much easier to solder (if the design density can allow spacing this large).

  • Pad Sizes

The biggest issues with pad size are solderability and manufacturability. Solderability is really just a matter of skill and will not be discussed here. Manufacturability is concerned with whether or not the pad will be broken when the hold is drilled in it. This is mainly a function of the accuracy of the PCB manufacturer’s drilling. If a drill hole is slightly off-center the pad may be broken at one edge possibly leading to an open in the circuit. A standard requirement for pad sizes is a 5 mil annulus. This means there must be .005″ all around the hole (i.e. a 28 mil hole would require a 38 mil pad). Something a little larger than this (maybe 10 mils) is recommended for solderability. AP Circuits states they have had relatively consistent success with a 2.5 mil annulus (i.e. a 20 mil hole with only a 25 mil pad), but they don’t recommend it.

  • Hole Sizes

Most PCB manufacturers have a wide selection of drill (hole) sizes available. Some charge per drill size used, others offer a standard set of drill sizes for no charge and then charge for any non-standard drill sizes. AP Circuits uses the latter approach. When choosing a hole size remember that the plate-through will cause the hole to effectively be more narrow. The plate-through thickness varies from .001″ to .003″. AP Circuits’ plate-through thickness is approximately .015″ (meaning the “finished hole” diameter is 3 mils smaller).

Standard Drill Sizes

 

Drill Number

Hole Size

Finished Hole Size

70

.028″

.025″

65

.035″

.032″

58

.042″

.039″

55

.052″

.049″

53

.0595″

.056″

44

.086″

.083″

1/8″

.125″

.122″

24

.152″

.149″

  • Hole Density

Hole density is purely a cost issue. The more holes there are on a board the more wear and tear manufacturing will put on the equipment (and thus the more the board will cost). Most PCB manufacturers have a maximum hole density and boards with greater density are charged more. For AP Circuits, there is a per-hole charge for densities above 24 holes per square inch.

Drill Chart

Drill No.

Inches

Drill No.

Inches

Drill No.

Inches

80

.0135

53

.0595

27

.1440

79

.0145

52

.0635

26

.1470

78

.0160

51

.0670

25

.1495

77

.0180

50

.0700

24

.1520

76

0200

49

.0730

23

.1540

75

.0210

48

.0760

22

.1570

74

.0225

47

.0785

21

.1590

73

.0240

46

.0810

20

.1610

72

.0250

45

.0820

19

.1660

71

.0260

44

.0860

18

.1695

70

.0280

43

.0890

17

.1730

69

.0292

42

.0935

16

.1770

68

.0310

41

.0960

15

.1800

67

.0320

40

.0980

14

.1820

66

.0330

39

.0995

13

.1850

65

.0350

38

.1015

12

.1890

64

.0360

37

.1040

11

.1910

63

.0370

36

.1065

10

.1935

62

.0380

35

.1100

09

.1960

61

.0390

34

.1110

08

.1990

60

.0400

33

.1130

07

.2010

59

.0410

32

.1160

06

.2040

58

.0420

31

.1200

05

.2055

57

.0430

1/8″

.1250

04

.2090

56

.0465

30

.1285

03

.2130

55

.0520

29

.1360

02

.2210

54

.0550

28

.1405

01

.2280

dBm – Volts – Watts Conversion

dBm

V

Po

dBm

V

Po

dBm

uV

Po

+53

100.0

200W

+7

0.50

5mW

-37

3.2

+50

70.0

100W

+6

0.445

4mW

-38

2.85

+49

64.0

80W

+5

0.40

3.2mW

-39

2.5

+48

58.0

64W

+4

0.355

2.5mW

-40

2.25

0.1uW

+47

50.0

50W

+3

0.320

2.0mW

-41

2.0

+46

44.5

40W

+2

0.280

1.6mW

-42

1.8

+45

40.0

32W

+1

0.252

1.25mW

-43

1.6

+44

32.5

25W

0

0.225

1.00mW

-44

1.4

+43

32.0

20W

-1

0.200

0.80mW

-45

1.25

+42

28.0

16W

-2

0.180

0.64mW

-46

1.18

+41

26.2

12.5W

-3

0.160

0.50mW

-47

1.00

+40

22.5

10W

-4

0.141

0.40mW

-48

0.90

+39

20.0

8W

-5

0.125

0.32mW

-49

800

+38

18.0

6.4W

-6

0.115

0.25mW

-50

710

0.01uW

+37

16.0

5W

-7

0.100

0.20mW

-51

640

+36

14.1

4W

-8

0.090

0.16mW

-52

570

+35

12.5

3.2W

-9

0.080

0.125mW

-53

500

+34

11.5

2.5W

-10

0.071

0.10mW

-54

450

+33

10.0

2W

-11

64

-55

0.40

+32

9.0

1.6W

-12

58

-56

351

+31

8.0

1.25W

-13

50

-57

320

+30

7.10

1.0W

-14

45

-58

286

+29

6.40

800mW

-15

40

-59

251

+28

5.80

640mW

-16

35.5

-60

225

0.001uW

+27

5.00

500mW

-17

31.5

-61

200

+26

4.45

400mW

-18

28.5

-62

180

+25

4.00

320mW

-19

25.1

-63

160

+24

3.55

250mW

-20

22.5

0.01mW

-64

141

+23

3.20

200mW

-21

20.0

-65

128

+22

2.80

160mW

-22

17.9

-66

115

+21

2.52

125mW

-23

15.9

-67

100

+20

2.25

100mW

-24

14.1

-68

90

+19

2.00

80mW

-25

12.8

-69

80

+18

1.80

64mW

-26

11.5

-70

71

0.1nW

+17

1.60

50mW

-27

10.0

-71

65

+16

1.41

40mW

-28

8.9

-72

58

+15

1.25

32mW

-29

8.0

-73

50

+14

1.15

25mW

-30

7.1

0.001mW

-74

45

+13

1.00

20mW

-31

6.25

-75

40

+12

0.90

16mW

-32

5.8

-76

35

+11

0.80

12.5mW

-33

5.0

-77

32

+10

0.71

10mW

-34

4.5

-78

29

+9

0.64

8mW

-35

4.0

-79

25

+8

0.58

6.4mW

-36

3.5

-80

22.5

0.01nW

Getek® Laminates – Epoxy / Polyphenylene Oxide Resin

(Type: NEMA FR-4, IPC-L-108B/04)

Nominal thickness

Thickness tolerance

GE grade

E-Glass construction

Dk@1MHz.

0.0027″

±0.0005″

ML200D

1080

3.8

0.004″

±0.0005″

ML200D

2313

3.9

0.005″

±0.0007″

ML200M

2313/106

3.8

0.006″

±0.0007″

ML200D

2313/1080

3.9

0.007″

±0.0010″

ML200M

(2)2313

3.8

0.008″

±0.0010″

ML200D

2313/2116

3.9

0.010″

±0.0010″

ML200D

(2)2116

3.9

0.012″

±0.0010″

ML200D

1080/7628/1080

3.9

0.014″

±0.0015″

ML200D

(2)7628

4.2

0.018″

±0.0015″

ML200D

7628/2313/7628

4.1

0.021″

±0.0020″

ML200D

(3)7628

4.2

0.024″

±0.0020″

ML200C

2116/(2)7628/2116

4.1

0.028″

±0.0020″

ML200D

(4)7628

4.2

0.028″(Alt.)

±0.0020″

ML200C

1080/2313/(3)2116/2313/1080

3.8

0.031″

±0.0030″

ML200C

2116/(3)7628/2116

4.1

0.031″1

±0.0040″

ML200D

(4)7628

4.2

0.044″1

±0.0050″

ML200D

(6)7628

4.2

0.059″1

±0.0050″

ML200D

(8)7628

4.2

VSWR Vs. Return Loss

VSWR

Ret. Loss

VSWR

Ret. Loss

VSWR

Ret. Loss

VSWR

Ret. Loss

VSWR

Ret. Loss

1.01

-46.064

1.51

-13.842

1.79

-10.960

2.18

-8.611

2.57

-7.135

1.02

-40.086

1.52

-13.708

1.80

-10.881

2.19

-8.565

2.58

-7.105

1.03

-36.608

1.53

-13.577

1.81

-10.804

2.20

-8.519

2.59

-7.074

1.04

-34.151

1.54

-13.449

1.82

-10.729

2.21

-8.474

2.60

-7.044

1.05

-32.256

1.55

-13.324

1.83

-10.654

2.22

-8.430

2.61

-7.014

1.06

-30.714

1.56

-13.201

1.84

-10.581

2.23

-8.386

2.62

-6.984

1.07

-29.417

1.57

-13.081

1.85

-10.509

2.24

-8.342

2.63

-6.954

1.08

-28.299

1.58

-12.964

1.86

-10.437

2.25

-8.299

2.64

-6.925

1.09

-27.318

1.59

-12.849

1.87

-10.367

2.26

-8.257

2.65

-6.896

1.10

-26.444

1.60

-12.736

1.88

-10.298

2.27

-8.215

2.66

-6.867

1.11

-25.658

1.61

-12.626

1.89

-10.230

2.28

-8.173

2.67

-6.839

1.12

-24.943

1.62

-12.518

1.90

-10.163

2.29

-8.132

2.68

-6.811

1.13

-24.289

1.63

-12.412

1.91

-10.097

2.30

-8.091

2.69

-6.783

1.14

-23.686

1.64

-12.308

1.92

-10.032

2.31

-8.051

2.70

-6.755

1.15

-23.127

1.65

-12.207

1.93

-9.968

2.32

-8.011

2.71

-6.728

1.16

-22.607

1.66

-12.107

1.94

-9.904

2.33

-7.972

2.72

-6.700

1.17

-22.120

1.67

-12.009

1.95

-9.842

2.34

-7.933

2.73

-6.673

1.18

-21.664

1.68

-11.913

1.96

-9.780

2.35

-7.894

2.74

-6.646

1.19

-21.234

1.69

-11.818

1.97

-9.720

2.36

-7.856

2.75

-6.620

1.20

-20.828

1.70

-11.725

1.98

-9.660

2.37

-7.818

2.76

-6.594

1.21

-20.443

1.71

-11.634

1.99

-9.601

2.38

-7.781

2.77

-6.567

1.22

-20.079

1.72

-11.545

2.00

-9.542

2.39

-7.744

2.78

-6.541

1.23

-19.732

1.73

-11.457

2.01

-9.485

2.40

-7.707

2.79

-6.516

1.24

-19.401

1.74

-11.370

2.02

-9.428

2.41

-7.671

2.80

-6.490

1.25

-19.085

1.75

-11.285

2.03

-9.372

2.42

-7.635

2.81

-6.465

1.26

-18.783

1.76

-11.202

2.04

-9.317

2.43

-7.599

2.82

-6.440

1.27

-18.493

1.77

-11.120

2.05

-9.262

2.44

-7.564

2.83

-6.415

1.28

-18.216

1.78

-11.039

2.06

-9.208

2.45

-7.529

2.84

-6.390

1.29

-17.949

1.40

-15.563

2.07

-9.155

2.46

-7.494

2.85

-6.366

1.30

-17.692

1.41

-15.385

2.08

-9.103

2.47

-7.460

2.86

-6.341

1.31

-17.445

1.42

-15.211