3.9 electronic testing - philadelphia university electronic... · 3.9 electronic testing ......

Dr. Tarek A. TutunjiEngineering Skills, Philadelphia University

3.9 Electronic Testing

Dr. Tarek A. Tutunji

Philadelphia University, Jordan


Preview In the previous sequences, seven design steps were

discussed.

In this sequence, Electronic Testing will be presented.


Company Goal Ultimate goal of any company is to maximize its long-

term profit

Quality “fit to use” is a tool to reach its goal

Electronic testing is essential to quality improvement


What is Electronic Testing The Process of verifying the functionality of electronic

assemblies

The objective of testing is to identify defective products before they reach the consumer


Design Engineer vs. Test Engineer The Design Engineer is responsible for designing the

product and building the Prototypes to meet customer demand

The Test Engineer is responsible for formulating the test procedure and writing the data sheets in order to verify the functionality of the manufactured product during assembly


Levels of Tests PCB test

Modules test

System test

Module 1 Module 2

System

PCB2PCB1 PCB4PCB3


PCB Test In-circuit test

Test for Shorts, Open, and Polarity

Functional test

Full operation test to simulate the conditions that the PCB will face in the field

Signals at Output ports and crucial Test Points are usually measured

80% of failures are due to Shorts and Open

10% of failures are due to failed components


PCB Testing


Modules Test Two or more PCBs tested together as an integrated

unit

Testing at this stage usually checks interface and output signals only

Module 1 Module 2

System

PCB2PCB1 PCB4PCB3


System Test Complete System Check before Shipping

The in-depth functional tests of individual circuits is not repeated, but system is required to function under normal power for hours or days


Burn-in vs. ESS Testing Burn-in test applies thermal, mechanical, and

electrical stresses within the limits that product will face in the field while testing product functionality

Environmental Stress Screening (ESS) test applies extreme conditions beyond the field stresses while testing product functionality


Testing Strategy Identify the equipment needed for the test such as

scopes, function generators, DVM, Computers, test boxes, … etc

Define the Attributes to be tested. What is to be tested? Voltage, Power, Current, Frequency, … etc

Define the specifications. What are the pass and fail levels of each attribute tested

All the above should be part of a well-defined and documented test procedure


Testing Strategy Well Organized Data Sheets should be used to record

the test results of each electronic assembly

It should include the part and serial number of the assembly tested

These are essential for Quality Management Control and Failure Analyses


Testing Under Stress The test should be carried under different stresses

such as

Thermal Cycle

Thermal Stress

Mechanical Vibration

Mechanical Shock

Electrical Power Cycling


Testing Under Stress The Functional Test should be carried out while the

assembly is under the stresses

It is advisable to combine different stresses simultaneously in order to induce possible field failures


Testing Under Stress


Automatic Testing Use Automatic Test Equipment rather than manual

testing in order to continuously monitor any functionality failure

This involves the use of PC, DAQ cards, and interface units to connect to the electronic assembly under test

It also involves sophisticated programming. In many cases C++ or LABVIEW is used


Automatic Testing


Conclusion Testing Electronic Assemblies is an essential part in

production

Automatic testing gives much better detection than manual testing

Although expensive and time consuming, but the tests are vital to assure product quality. It is much cheaper to catch a failed component at production than in the field

3.9 electronic testing - philadelphia university electronic... · 3.9 electronic testing ......

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