How To Test An Integrated Circuit? A Best Guide

Do you know how your favorite electronics are made? Transistors made from diodes and resistors on a silicon chip provide the basis of electronic circuits. Individual components are often linked together using aluminum wires located directly on the surface of the chip.

This procedure results in the development of integrated circuits. These ICs may contain a few hundred or a few million transistors. Remember that integrated circuits (ICs) are the brains behind most of the high-tech devices you use today, including your digital watch, video gaming console, computer, and more.

How Does IC Work?

An integrated circuit, or IC, is a microelectronic device that combines several smaller components onto a single silicon chip. N-type and P-type semiconductors and P-N junctions are created on the device by diffusion or permeation processes; silicon-based materials are widely utilized.

To perform intermediate or final products of electronic operations, two or more components, including at least one active component, and some or all of the interconnections are integrated with the substrate or on the substrate to form a semiconductor integrated circuit or IC.

Two General Methods for Checking ICs in a Circuit

Once the IC’s operation principle has been grasped, the following procedures can be carried out to definitively ascertain whether or not the IC in the electronic circuit is functioning correctly.

Before analyzing the internal circuit schematic, one must have a firm grasp on the IC’s function in the circuit, its underlying structural concept, primary electrical properties, etc. As an added bonus, it’s helpful to have information about the DC voltage, waveform, and forward and reverse resistance values of each pin connected to the ground before making any pre-inspection assessment.

The next step is to evaluate the piece based on the fault phenomenon and pinpoint the offending component using its physical position. Different forms of expert opinion may be required to establish whether or not the gadget is indeed broken.

Evaluation of the IC’s performance in the circuit before soldering it to the PCB

This approach makes IC quality hard to gauge without expensive testing gear. When comparing a broken integrated circuit to a working one, it is common practice to utilize the DC resistance method to determine the forward and reverse resistance values of each ground-connected pin. Inserting a suspect IC in place of a typical device of the same type is another option for testing its reliability. If the circumstances permit, quantitatively, using the integrated circuit tester to examine the main parameters is the safest bet.

Online checking and judging

What is meant by “online checking and judgment,” in this context, is the evaluation of the integrated circuit while it is still linked to the printed circuit board.

An online evaluation is the best way to update the integrated circuits in home appliances. Some examples of these scenarios are described below.

DC Working Voltage Measurement

This technique is used to evaluate the quality of an IC by measuring the DC working voltage value at each pin connected to the ground and then comparing the measured value to the nominal value. One of the most popular maintenance approaches is measuring voltage to determine an integrated circuit’s quality. However, care must be taken to distinguish between defective and non-faulty voltage errors.

Don’t immediately assume the integrated circuit is broken just because the DC operating voltage of a single pin doesn’t match the voltage value specified in the schematic or maintenance technical data. Initially, they should be ruled out.

Check the reliability of provided nominal voltage

This is because the voltages in some manuals, diagrams, and other information often don’t correspond to reality. Therefore, you should look for further comparable data. It may be essential to examine the component’s schematic and external circuitry to arrive at a theoretical calculation or estimate that will indicate whether or not the voltage is incorrect.

Distinguish the provided rated voltage and working voltage

Injecting a signal into the integrated block causes large fluctuations in the voltage at each pin; testing whether or not the voltage is average requires moving the band or record switch at this time. If the voltage is typical, it indicates that the nominal voltage corresponds to a given operating voltage, and the working voltage is defined according to a given circumstance.

Keep an eye on the pin voltage as it fluctuates due to the peripheral circuit’s changeable parts

A single pin or a peripheral circuit associated with the pin may be connected to a movable potentiometer or switch, causing the measured voltage to be different from the nominal voltage. The pin voltages of these potentiometers and switches are drastically variable and situated at various points on the circuit board. Therefore, when a voltage difference arises at two pins, it is essential to consider the position of the pin or the potentiometer and switch connected to the pin. Turning or pulling on a pin can reveal whether or not its voltage is close to its nominal value. 

Prevent Errors Due To Measurement

Errors can occur if the multimeter has a different internal resistance or the DC voltage is off. As a rule, DC voltage testing is performed using equipment with an internal resistance of more than 20K/V. A multimeter’s reading will be lower than the listed voltage if its internal resistance is less than 20K/V. It’s also important to remember that the large-range files will have a more pronounced deviation impact, so be aware that the voltage recorded at various voltage levels will be different.

Judging The Importance Of The Pin Voltage To The Normal Operation Of The IC

An important factor in determining whether or not an integrated circuit is suitable is whether or not its pin voltage is operating normally when the measured voltage of a pin does not match the average value.

Examining the voltage at IC pins

If the IC’s voltage at each pin is within the typical range, then the IC is healthy. If the IC pin’s voltage is out of whack, troubleshooting should begin at its farthest point from average. In addition, imported pumps should examine their outer parts for defects. The IC has been damaged if there is no error.

When there is no signal, the voltage at each pin of the IC in a TV, for instance, can vary. In a video recorder, the voltage of each pin of the IC is different under different working modes; if the pin voltage that should not change is found to vary substantially and the one that should change is always stable, the IC can be judged to be damaged. The IC’s judgment should be more reserved in this situation.

As stated above, the IC has no circuit defect; however, the measured value is off from the nominal value. A test condition should be defined to accurately record measured empirical data before conducting a DC voltage or DC resistance test on an integrated block. Each potentiometer is typically set to its midpoint, and the source uses the standard signal at a fixed intensity.

Of course, it would be more indicative if the settings for each function switch could be re-recorded. Suppose the observed individual pin voltages are still outside the nominal value after excluding the causes above. In that case, further analysis is required, although one of two things may be happening. The failure of the integrated circuit is the cause of one of the failures. The peripheral circuit of the integrated block is responsible for the second. Repairing IC household equipment requires first determining which of these two problems occurred.

AC Voltage Measurement

A multimeter with a dB plughole can be used to approximately measure the AC operating voltage of the IC, which can be used to understand the variations in the IC’s AC signal. Place the AC voltage block of the multimeter into the wall outlet, then insert the positive end of the test pen into the dB jack. For a multimeter without a dB plughole, a 0.1 to 0.5 uF DC blocking capacitor must be connected in series with the positive pen. This technique can be used for ICs with a low operating frequency, like video amplification stages and field scanning circuits. The measured data can only be interpreted as a close approximation or a presence/absence because these circuits’ natural frequencies and waveforms are distinct.

What Causes Defects on Integrated Circuits?

There are numerous causes for why your ICs don’t function properly. These are the typical causes you should be aware of:

Electrical Overstress

This flaw, also known as EOS, appears when a gadget is subjected to higher voltages than it can handle. Due to electrostatic discharge, that exposure may be advantageous or negligent due to improper use.

In such cases, it could be harder to find the harm. Identifying problems might require more creative approaches. However, failure analyzers can identify too many currents by using precise techniques and equipment to isolate heat.

Error due to packaging-related damage

Chips and cracks in the integrated circuit’s packaging can reduce their dependability and result in operational issues. Additionally, moisture collected through fissures and cleaning agents could short internal components. That will malfunction and could harm the packing during shipping or incorrect handling.

Damages induced by ESD

A division of EOS is ESD. Damages caused by ESD include contact damage, leakage, gate oxide rupture, and damage to the resistor-metal interface. These mistakes happen when machinery or individuals improperly handle devices throughout IC production, transit, and application. This sensitivity is further increased by high-speed circuit operation and decreasing chip sizes, among other things.

ESD detection could be a common concern for IC designers. Keep in mind that ESD causes more than one-third of field errors in the semiconductor industry. IC designers need effective failure analysis testing and strong circuit protection to reduce these errors.

Faults on the manufacturing

Remember that contaminants and imperfections cause stability issues in the finished chip in the bulk silicon, crystal defects, and design issues throughout the production of the integrated circuit.

The heat conductivity of the die may be reduced by minor clearances between the substrate and the die. Under regular operation, that problem could cause a die to overheat and crack, leading to an early failure.

Additionally, due to high bonding pressure, small holes at the bond wire and dire interface may severely impact an IC’s reliability.

Imperfections on the open circuit

The open circuit could have a variety of flaws, including surface blemishes and cracks, shoddy wire bonding, and improperly etched metal traces. It is more difficult to find other faults, like alignment issues with dice and drilling between metal layers.

How Can a Multimeter Be Used to Test an IC?

This section will assist you in determining whether an integrated circuit you are working with is functioning. To complete this process, you will need a multimeter, which can be purchased at any electronics retailer.

Integral circuits are one of the many electronic components that a digital multimeter may test.

But be sure to perform a thorough visual examination before you use a multimeter. Remember that your integrated circuit could malfunction if it sustains any physical damage. Therefore, it is imperative to perform a comprehensive visual inspection to detect chippings, charring, and cracks.

Here’s how to examine your integrated circuit (IC) for a potential short circuit issue.

• Your digital multimeter’s continuity function should be selected.
• All the pins on one side of the integrated circuit should be connected. Reconnect it to one of your digital multimeter’s test probes.
• Examine each pin of an integrated circuit with the remainder of the multimeter test probe. If you find continuity in more than 50% of the pins, your IC will likely be shorted.

Conclusion

Remember that integrated circuits, like any other circuit components, might malfunction while in use. The reliability of these tiny components can be affected by several factors, including electrostatic discharge, physical damage, and manufacturing faults.

Please let us know if you have any further questions or if this post has helped answer any of your issues. Leave a comment below and tell us what you think.

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