IPC-TM-650 EN 2022 试验方法.pdf - 第423页

1.0 Scope To determine if the plated through-holes are suf- ficiently plated to withstand a relatively high current potential. 2.0 Applicable Documents None 3.0 Test Specimen Any plated through-holes on a test coupon or …

Scope

The

purpose of this test is to measure the capaci-

tance effects arising from plastic substrates, adhesives, or

coatings, which may be critical to the reliable functioning of a

circuit.

Applicable Documents

None

Test Specimen

Specimen

thickness for all tests must be

uniform within ±1% of the average thickness. At frequencies

below 1 MHz the specimen shall be large enough to provide

circular electrodes at least 10 cm in diameter and between

1.5 mm to 6.35 mm thick. At frequencies from 1.0 MHz to

1000 MHz, a micrometer electrode holder should be used

with the test specimen.

Equipment/Apparatus

4.1

bridge or resonant circuit capable of measuring the

capacitance and dissipation factor with the required accuracy

at the specified frequency may be used. The inherent accu-

racy of the measurement shall be ± 0.5%, ± 0.2% picofarad,

unless otherwise specified. The electrode material may be thin

foil, evaporated metal, sprayed metal, or air drying conductive

paint.

4.2

The

generating circuit may be any suitable source that

can furnish sufficient current for the specified precision of

measurement or voltage gradient in the dielectric.

Procedure

5.1 Preparation

The

atmospheric conditions surrounding

the specimen prior to and during test must be 23°C, ± 1.1°C

and 50%, ± 4% RH.

5.2

Test

Place

the test specimen in a suitable measuring

cell or holder and measure its capacitance and dissipation

factor with a suitable measuring circuit having required sensi-

tivity and accuracy.

5.3

Evaluation

Record

the shape and dimensions of the

specimen, type and dimensions of electrodes and measuring

cell, test conditions, method of measurement, applied voltage,

voltage gradient, and frequency and capacitance.

5.4

Calculation

C =

4πdo

where:

= capacitance in Farads

Q = total charge in coulombs

V = potential difference between plates in volts

GA = area of plates

4πdo = distance between plates

6 Notes

6.1

Suitable

measurement techniques must be used to mini-

mize errors due to the connections between the measuring

apparatus and the specimen.

6.2

The

AC voltage actually impressed across the specimen

must be as low as possible. When DC polarizing voltages are

required, it must be as specified.

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062

IPC-TM-650

TEST

METHODS MANUAL

Number

2.5.2

Subject

Capacitance

of Insulting Materials

Date

7/75

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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1.0

Scope

determine if the plated through-holes are suf-

ficiently plated to withstand a relatively high current potential.

2.0

Applicable Documents

None

3.0

Test Specimen

Any

plated through-holes on a test

coupon or finished printed wiring boards.

4.0

Apparatus

Power

supply capable of generating 10

amps and having a suitable load resistor.

5.0

Procedure

5.1 Test

Select

a load resistor, such that when the resistor

shunts the positive and ground terminals at a regulated

amperes power supply, a current of 10 amps will flow through

each plated through-hole in the circuit in series with the resis-

tor, for 30 seconds.

5.2

Evaluation

Examine

for breakdown (opens) when the

current is applied to each plated through-hole.

6.0 Notes

The

power supply unit should have a safety

interlock mechanism because of the relatively high current

required for this test.

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062

IPC-TM-650

TEST

METHODS MANUAL

Number

2.5.3

Subject

Current

Breakdown, Plated Through-Holes

Date

8/97

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.

age1of1

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1.0

Scope

This

method is to comparatively determine the

effects of printed conductor materials, conductor cross sec-

tional measurements, substrate materials, and processes on

the temperature D.C. current characteristics of printed wiring

boards on a standard test sample.

The temperature rise must be given for each conductor mate-

rials for a particular value of current, for a specified conductor

cross sectional area, approximate geometry and substrate

material. The results are reported as a plot of temperature

rises versus current for each of the conductor materials, cross

sectional areas, approximate geometry, and a substrate

material.

2.0

Applicable Documents

ASTM B 193

Conductor

Materials, Electrical, Resistivity of

QQ-S-571

Solder,

Tin Alloy, Tin-lead Alloy, and Lead Alloy

3.0

Test Specimens

Standard

test specimen, see Figure 1

Test Pattern. Only one test pattern may be tested at one time,

with current passing through only one conductor at one time.

4.0 Apparatus

4.1

Potentiometer

(0.02% or better accuracy), Leeds and

Northrup type K3 or equivalent.

4.2 Resistors

(0.1 ohm ± 0.01 ohm) (

Caution:

not use

low voltage because of fluctuation.)

4.3

Current

leads, #12 AWG stranded wire.

4.4

Potential

leads, #26 AWG magnet wire.

4.5

Sn60,

Sn62, or Sn63 solder per Federal Specification

QQ-S-571.

4.6

Temperature

chamber capable of maintaining required

temperatures in specification.

4.7

Thermometer

or other temperature measuring device

suitable for measuring laboratory ambient to the nearest 0.5°C

[0.9°F].

4.8 Apparatus

for performing cross sections.

4.9

power supply with range of at least 0-40 volts.

4.10

Digital

Multimeter capable of taking current and voltage

in specification.

5.0

Test

5.1 Preparation

5.1.1

Extraneous

surface coating shall be removed without

affecting the dimensions of the conductor. The sample shall

represent the materials and processes under investigation.

5.1.2

Current

leads shall be secured by soldering to the ter-

minal area. Pretinning of parts prior to soldering is advisable.

5.1.3 Potential

leads shall be secured to the test tabs by

soldering. Pretinning of parts prior to soldering is advisable.

5.1.4

The

ambient air temperature measured at approxi-

mately 101.6 mm [4″] perpendicularly from the center of the

conductor side of the board shall be 25°±5°C [77°±9°F].

The temperature shall be recorded at each measurement.

5.2

Procedure

5.2.1

The test sample shown in Figure 1 shall be suspended

by the four corners, and centrally located within an enclosure

free of forced air movement. The sample shall be so oriented

that the conductors are horizontal.

5.2.2

achieve 3-figure significance in temperature rise

measurements, all potentials should be measured accurately

to four significant figures.

5.2.3

The

resistance of the conductor at the reference tem-

perature (R

)

should be determined with a test current not to

exceed 100 milliamperes applied for as short a time as pos-

sible. (

Caution:

not use low voltage because of fluctua-

tion.)

5.2.4

Pass

the conductor current through an external series

resistor (R

)

having a maximum temperature coefficient of

resistance of 0.00002 per degree C at 25°C. The function of

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062

IPC-TM-650

TEST

METHODS MANUAL

Number

2.5.4.1

Subject

Conductor

Temperature Rise Due to Current

Changes in Conductors

Date

8/97

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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