The measurement is necessary to determine the EMC characteristics of the IC. Only by accurately understanding the EMC characteristics of IC, can effective preventive measures be taken before production to improve the anti-ESD ability and EMC performance of the product, and avoid problems such as product failure and cost increase caused by ESD interference in the later period.

三、Integrated circuit ESD test and analysis

1、Test environment and electric field generation

l In the test environment, the integrated circuit (IC) is placed in a shape consisting of a ground plane, isolation ring and field source

Into the shielded space. Ground plane: can play the role of grounding protection and shielding electromagnetic interference; Isolation washer: used to determine the distance between the field source and the IC; Field source: is the key component of generating electric field; Through the isolation washer, the field source is positioned at a specific height above the integrated circuit. The field source consists of an electrode to which a test voltage pulse is applied, which in turn generates a defined electric field within which the integrated circuit resides. This setup can provide a controlled and relatively stable electric field environment for integrated circuits to conduct relevant tests.

The L-field source can generate a variety of test pulses that may occur in practice. For example, in practical use, pulse

The rise time of the impulse may vary from 200 picoseconds, 1 nanosecond, and 5 nanoseconds, which makes                

 The test can be closer to the real working scenario and more accurately evaluate the performance of integrated circuits under various actual electric field conditions.

During the test, the electrode voltage is gradually increased until the immunity level of the integrated circuit is reached. pass

In this way, the tolerance capacity of integrated circuits under different electric field strengths can be determined, which provides an important basis for evaluating its reliability and stability.

2. Magnetic field influence in electrostatic discharge events

During electrostatic discharge (ESD) events, structural components may generate additional magnetic fields. For example, when

When ESD occurs, the discharge current forms magnetic fields around the structural components, which may interact with the integrated circuit (IC), thus interfering with the normal operation of the IC.

l The test can be closer to the real working scenario and more accurately evaluate the performance of integrated circuits  under various actual electric field conditions.

During the test,  the electrode voltage is gradually increased until the immunity level of the integrated circuit is reached. pass

In this way, the tolerance capacity of integrated circuits under different electric field strengths can be determined,  which provides an important basis for evaluating its reliability and stability.

2. Magnetic field influence in electrostatic discharge events

During electrostatic discharge (ESD) events,  structural components may generate additional magnetic fields. For example, when

When ESD occurs, the discharge current forms magnetic fields around the structural components,  which may interact with the integrated circuit (IC), thus interfering with the normal operation of the IC.

The measuring device determines EMC parameters that are critical to evaluating the IC's performance and compatibility in electromagnetic environments, including metrics such as immunity, emission level, and more.

3, about the integrated circuit by external electromagnetic field interference

If the electric or magnetic field interferes with the integrated circuit from the outside, changing the layout as a countermeasure is not appropriate. here

In this case, the only useful remedy is to change the mechanical design.

Shielding effect: By changing the mechanical design, effective electromagnetic shielding measures can be added to the IC. For example,

The IC is wrapped in a metal housing or shield, which blocks the entry of external electromagnetic fields, thereby protecting the IC from interference.

Distance and direction adjustment: reasonably adjust the distance and relative direction between the IC and the external electromagnetic field source,

It also belongs to the category of mechanical design. Increasing the distance can reduce the strength of the electromagnetic field, while changing the relative direction may place the IC in a region where the electromagnetic field is weak. If the electromagnetic field around a large transformer is not evenly distributed, the effect of the magnetic field on it can be reduced by adjusting the position and direction of the IC so that it is away from the strong magnetic field area or parallel to the magnetic field direction.

4、Specific countermeasures for radiator strong electric field

For the specific example in Figure 1, the following countermeasures can be taken, where the heat sink above the IC generates a strong electric field:

Increasing the number of contact springs between the electronic module and the radiator can improve the heat transfer between the two.

l Arrange a local shield over the integrated circuit (IC), as shown in Figure 3. This is mainly to reduce the outside

The electromagnetic field interferes with the IC to protect its internal sensitive signals and circuits. If possible, the module is enclosed in all directions with a shield and may be equipped with a through-core filter. This can provide a more comprehensive electromagnetic shielding effect, preventing external electromagnetic fields from entering the inside of the module, but also prevent the electromagnetic radiation generated inside the module from leaking to the outside.

l Move the IC to the side without the electromagnetic field, but doing so will make cooling impossible. This is a kind of

Measures to make trade-offs between electromagnetic compatibility and heat dissipation. When the electromagnetic field interference problem is serious, and other electromagnetic shielding measures are difficult to implement or ineffective, you can consider moving the IC away from the electromagnetic field source. It should be noted that the location may not be conducive to heat dissipation, so it is necessary to consider the IC's operating temperature range, heat dissipation requirements and electromagnetic environment.

Increase the gap between the IC and the heat sink: doing so may have a certain impact on heat dissipation, but in

In some cases, such as when it is necessary to avoid electrical coupling or mechanical interference between the two, it is a feasible method. However, this may lead to a decrease in heat dissipation efficiency, so it needs to be evaluated and optimized according to the specific situation, such as by adding other heat dissipation measures to compensate for the heat loss caused by the increased gap.

To sum up, it can be said that knowing the ESD parameters of a microcontroller in advance is very beneficial in terms of time and cost savings in developing anti-jamming components. This means that the ESD parameters of the microcontroller must be measured. This information will allow the necessary countermeasures to be planned as early as possible during component development to ensure that the entire component is resistant to interference.

Shanghai Leimo EMC Laboratory can test IEC61000 series standards: 30KV static electricity, 1.2/50μS and 8/20μS surge, 10/700μS surge, 10/1000μS surge, ISO7377-2/5A /5b throw load, group pulse 4KV EFT, Performance of semiconductor devices V-I inductance, capacitance test,EMI survey, etc.

Details of testing equipment/testing items are as follows:

Leiditech is committed to becoming a leading brand in the supply of electromagnetic compatibility solutions and components, supplying ESD, TVS, TSS, GDT, MOV, MOSFET, Zener, inductors and other products. Leiditech has an experienced R & D team, can provide personalized customized services according to customer needs, to provide customers with the best quality solutions.