IPC-TM-650 EN 2022 试验方法.pdf - 第427页

1.0 Scope This test method is to determine the dielectric constant and dissipation factor of raw printed wiring board material at 1 MHz. 2.0 Applicable Documents None 3.0 Test Specimens Each specimen shall be 50.8 ± 0.07…

IPC-2541-1

Figure

1 Test Pattern

IPC-2541-2

Figure

2 Test Circuit

IPC-TM-650

Number

2.5.4.1

Subject

Conductor

Temperature Rise Due to Current Changes in

Conductors

Date

8/97

Revision

age3of3

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1.0

Scope

This

test method is to determine the dielectric

constant and dissipation factor of raw printed wiring board

material at 1 MHz.

2.0

Applicable Documents

None

3.0

Test Specimens

Each

specimen shall be 50.8 ± 0.076

mm [2.0 ± 0.003 in] in diameter by thickness of laminate or

substrate material. Remove copper of metal-clad specimens

by etching using standard commercial practices. At least

three specimens are required.

4.0

Equipment/Apparatus

4.1 Meter

1 MHz Digital LCR Meter, Hewlett Packard

Mdl 4271A or equivalent.

4.2

Test Fixture

Hewlett

Packard Mdl 16022A test fixture

or equivalent.

4.3

Specimen Holder

special specimen holder made as

shown in Figure 1. This holder is designed to be compatible

with the H/P test fixture, Mdl 16022A.

4.0

Procedure

5.1 Preparation

5.1.1

Prepare

the specimens as specified in paragraph 3.0.

5.1.2 Calculate

the effect thickness (inches) =

0.01942 x Mass

Density

Mass

= Measured weight in grams

Density = Grams per cubic cm (as per ASTM-D-792,

Method 1A)

5.1.3

Coat

both sides of specimens with one uniform coat-

ing of silver conductive paint.

5.1.4

Air-dry

the specimens until dry to touch, then oven-dry

at 50°±2°C for 1/2 hour and cool in a desiccator.

5.1.5

Punch

or machine a 25.4 mm [1.0 in] diameter disc

from the 50.8 mm [2.0 in] specimens. (Assure that there is no

carry over of the paint from one side to the other.)

5.1.6 Condition

the 25.4 mm [1.0 in] specimens for a mini-

mum of 40 hours at 23°±5°C at a relative humidity of 50%.

5.2

Testing

5.2.1

Turn

meter on and allow to warm up for 60 minutes

minimum.

5.2.1.1

Set

the controls on the meter as follows:

Function – C-D

Range – Manual

Trigger – Internal

Rate – FCW

Test Signal Level – Low

5.2.1.2

Connect

the cables for the test fixture to the appro-

priate connectors.

5.2.2

Plug

the special specimen holder into the test fixture.

5.2.3

The

digital display on the meter will show the capaci-

tance value and the dissipation factor of the unknown dielec-

tric specimen.

5.3

Calculation

5.3.1 Dielectric Constant

The

dielectric constant shall be

determined by using the following formula:

K =

0.225

K = Dielectric constant

C = Capacitance reading from Mdl 4271A Meter

A = Area of a 1-inch disc (square inches)

t = Effective thickness (inches)

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062

IPC-TM-650

TEST

METHODS MANUAL

Number

2.5.5.2

Subject

Dielectric

Constant and Dissipation Factor of

Printed Wiring Board Material—Clip Method

Date

12/87

Revision

Originating Task Group

N/A

Material

in this Test Methods Manual was voluntarily established by Technical Committees of the IPC. This material is advisory only

and its use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of this

material. Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.

Equipment referenced is for the convenience of the user and does not imply endorsement by the IPC.

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5.3.2

Dissipation Factor

The

dissipation factor value is

read directly from the digital display.

5.4

Report

The

report shall contain the following:

1. Measurement of effective thickness of specimens tested.

2. Capacitance values of the specimens tested.

3. Calculated dielectric constants and averaged measure-

ment.

4. Dissipation factor values and averaged measurement.

6.0 Notes

6.1

The

dielectric constant is defined as the ratio of the

capacitance with the test material between the two plates to

the capacitance of air between two plates.

6.2

The

dissipation factor of a dielectric material is the rela-

tionship between the permittivity (capacitance of material) and

conductivity (ability to conduct or the reciprocal of the electri-

cal resistivity) measured at a given frequency.

IPC-2552-1

Figure

1 Special Test Fixture for Dielectric Constant and Dissipation Factor Measurements

IPC-TM-650

Number

2.5.5.2

Subject

Dielectric

Constant and Dissipation Factor of Printed Wiring

Board Material—Clip Method

Date

12/87

Revision

age2of2

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