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Transient Voltage Suppression Diode, TVS Diode, Unidirectional TVS, Bidirectional TVS, TVS Working Principle, TVS Characteristics, TVS Applications, TVS Selection, TVS Parameters, Breakdown Voltage VBR, Reverse Standoff Voltage VRWM - Yinte Electronics

People often ask: What are the common issues in EMS immunity design for EMC? Here are the frequently asked questions:
1. In automotive electronics EMS design, how to choose a suitable microcontroller to reduce electromagnetic radiation? What are the differences in electromagnetic compatibility between different brands and models of microcontrollers?
»»» In automotive electronics EMS design, microcontroller (MCU) selection needs to focus on reducing high-speed switching noise and optimizing clock radiation. Core strategies include:
· Prioritize MCUs with low EMI characteristics: Need to pay attention to...

1. What are the immunity testing requirements for common mode inductors in IEC 61000-4-6 standard?​
2. What are the conducted emission suppression requirements for common mode inductors in information technology equipment per CISPR 22 standard?​
3. What is the classification basis for the insulation system of common mode inductors in UL 1446 standard?​

1. What challenges does common mode inductor design face in millimeter-wave devices?
2. What are the material options for bendable common mode inductors in flexible electronic devices?
3. What are the application prospects of superconducting common mode inductors in extreme environments?

​1. What are possible reasons for severe heating of common mode inductors? How to troubleshoot?​
Answer: Possible reasons:

Excessive differential mode current: Common mode inductors have weak suppression capability for differential mode current. If differential mode current in the circuit exceeds design values, it increases copper loss (I²R) in windings, causing heating.
Core saturation: When common mode current or differential mode current is too high, magnetic flux density in the core exceeds saturation point, permeability drops sharply, and eddy current losses increase dramatically, causing core heating.
· Abnormal winding resistance: Winding wires are too thin, local short circuits or poor contact during winding.

1. What fixture should be used for insertion loss testing of common mode inductors? Why?​
Answer: Insertion loss testing of common mode inductors typically uses 50Ω standard coaxial fixtures (such as BNC or SMA interface fixtures), and in some scenarios, they are used in conjunction with LINE IMPEDANCE STABILIZATION NETWORK (LISN). Reason: According to EMC testing standards (such as CISPR 16, IEC 61000-4-6), the characteristic impedance of the testing system needs to be unified to 50Ω.

​Question 1. How to optimize interference suppression above 10MHz through the combination of common mode inductors and Y capacitors?
Answer: Common mode inductors suppress interference through high common mode impedance from low to medium-high frequencies (e.g., below 1MHz), but at high frequencies (above 10MHz), impedance decreases due to parasitic capacitance (between windings, between windings and core), weakening suppression effect. Y capacitors (usually ceramic capacitors, such as MLCC) have low equivalent series resistance (ESR) and parasitic inductance (ESL), providing low impedance paths in high-frequency bands to divert common mode interference to ground. Optimization methods:
Capacitance selection:

1. What is the optimal distance between common mode inductors and X capacitors? Why?​
Answer:
The optimal distance between common mode inductors and X capacitors is generally recommended to be controlled within 3-5cm. The reason is that common mode inductors mainly suppress common mode interference, while X capacitors mainly filter differential mode interference. The two need to work together to form an EMI filter.
If the distance is too far, parasitic inductance between leads increases, causing impedance matching of the filter network in high-frequency bands (e.g., above 100MHz) to be disrupted, and interference signals may "bypass" the filter through parasitic parameters...

1. What special parameter requirements do common mode inductors need to meet in 5G base station power supplies?​
Answer:
High-frequency response and low parasitic capacitance: Need to maintain high impedance (e.g., above 1000Ω) in frequency bands above 100MHz, parasitic capacitance needs to be <10pF to avoid high-frequency signal leakage.
High saturation current: Meet large current requirements of base station power supplies (e.g., above 10A). Core materials preferably nanocrystalline or iron silicon aluminum to balance saturation characteristics and high-frequency loss.
Wide temperature range: Operating temperature needs to cover -40°C to +85°C, some outdoor base stations require...