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| ブランド名: | ZXY |
| モデル番号: | zxy |
| MOQ: | 交渉可能 |
| 価格: | 交渉可能 |
| パッケージの詳細: | カートン |
| 支払条件: | T/T |
The compact flat filter SMD common-mode choke is a surface-mount passive electronic component primarily used to suppress high-frequency electromagnetic interference (EMI) and radio frequency interference (RFI) in circuits. Its core function is to conduct the desired useful signal (differential-mode signal) while effectively attenuating and filtering out unwanted noise shared between the two conductors (common-mode noise). Benefiting from its flat, miniature SMD package structure, it is highly suitable for space-constrained modern high-density PCB designs. Widely used in switching power supplies, data cables (e.g., USB), communication equipment, automotive electronics, and various consumer electronics, it serves as a critical component for enhancing electromagnetic compatibility (EMC) and system stability.
Key Features Analysis:
Function: Filters common-mode electromagnetic interference to improve electromagnetic compatibility (EMC).
Structure: Surface-mount device (SMD) with a flat, miniaturized design that saves PCB space.
Applications: Noise suppression in power supplies, data cables, communications, automotive electronics, and other fields.
1. Suppressing Common-Mode Noise (Primary Function)
Issue: In high-speed or high-current switching circuits (such as switching power supplies and data transmission lines), two conductors (e.g., power lines, USB D+ and D-) simultaneously generate unwanted high-frequency noise with identical amplitude and phase, known as “common-mode noise.” This noise is a primary source of electromagnetic interference (EMI), leading to degraded system performance or interference with other devices.
Solution: Common-mode chokes present high impedance to common-mode noise. When common-mode noise currents flow through them, the magnetic fields from both windings combine in phase, generating significant inductive reactance. This reactance obstructs, reflects, and absorbs the noise energy, converting it into dissipated heat. This effectively suppresses the transmission of common-mode noise into circuits or its emission to the external environment.
2. Enabling Lossless Passage of Differential Signals
For useful differential signals requiring transmission (i.e., signals with equal amplitude but opposite phase on two wires, such as data signals), the magnetic fields generated internally cancel each other out, presenting extremely low inductive reactance (nearly short-circuited). Consequently, differential signals pass through with minimal attenuation.
3. Achieves Electromagnetic Compatibility (EMC) Compliance
Through the aforementioned filtering action, it significantly reduces electromagnetic radiation emitted by equipment while enhancing the device's immunity to external interference. This is crucial for products to pass stringent EMC certifications such as FCC and CE.
4. Protecting Sensitive Circuits
It prevents external high-frequency interference or surge noise on power lines from entering downstream sensitive circuits (such as CPUs, sensors, communication chips), thereby improving system stability and reliability.
In summary, its function resembles that of an “intelligent traffic cop”:
For common-mode noise (the troublemakers): Firmly intercept and block passage.
For differential-mode signals (legitimate traffic):
Maintains clear pathways and enables swift passage.
Thanks to its surface-mount (SMD) technology and compact, low-profile package, it efficiently performs these functions within extremely limited spaces. This makes it an indispensable filtering component in modern high-density, miniaturized electronic devices.
| Feature / Parameter | Description & Significance |
| Common Mode Impedance (Z<sub>cm</sub>) | The total opposition to common mode current flow (resistance + reactance) at a specific frequency (e.g., 100MHz). Higher impedance means better noise suppression. This is the most critical spec for EMI filtering. |
| Rated Current | The maximum continuous DC current that can flow through the windings without causing performance degradation or saturation. Exceeding this can lead to overheating and loss of inductance. |
| DC Resistance (DCR) | The inherent resistance of the wire windings. A lower DCR minimizes voltage drop and power loss (I²R loss), which is crucial for power line efficiency. |
| Rated Voltage | The maximum continuous voltage that can be applied between the coil and the core (isolation voltage). Important for safety and reliability. |
| Operating Temperature Range | The range of ambient temperatures within which the inductor will perform to its specifications. Typically from -40°C to +85°C / +125°C. |
| Self-Resonant Frequency (SRF) | The frequency at which the inductor's parasitic capacitance resonates with its inductance. Effective filtering occurs below the SRF. Performance degrades rapidly above it. |
| Insertion Loss | A measure of the signal attenuation (loss) introduced by the filter. It is the ratio of power without the filter to power with the filter. Higher insertion loss in the target frequency band means better filtering performance. |
| Leakage Inductance | The small amount of uncoupled inductance that behaves as a series differential mode inductor. It can provide additional attenuation of differential mode noise. |
| Saturation Current | The current level at which the core's magnetic properties saturate, causing a sharp drop in inductance. The inductor stops functioning effectively as a filter beyond this point. |
| Isolation / Withstanding Voltage | The maximum voltage that can be applied between the coils and the core (or between coils for isolated types) for a short time without breakdown. Critical for safety and noise isolation. |
| Package Size | The physical dimensions of the component (e.g., 1210, 1812, 3020). Smaller sizes save PCB space but may trade off performance (current rating, impedance). |
| Shielding | Shielded: Contains the magnetic field, prevents crosstalk. Unshielded: Can be susceptible to and cause crosstalk but is often lower cost. Most SMD types are shielded. |
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|
| ブランド名: | ZXY |
| モデル番号: | zxy |
| MOQ: | 交渉可能 |
| 価格: | 交渉可能 |
| パッケージの詳細: | カートン |
| 支払条件: | T/T |
The compact flat filter SMD common-mode choke is a surface-mount passive electronic component primarily used to suppress high-frequency electromagnetic interference (EMI) and radio frequency interference (RFI) in circuits. Its core function is to conduct the desired useful signal (differential-mode signal) while effectively attenuating and filtering out unwanted noise shared between the two conductors (common-mode noise). Benefiting from its flat, miniature SMD package structure, it is highly suitable for space-constrained modern high-density PCB designs. Widely used in switching power supplies, data cables (e.g., USB), communication equipment, automotive electronics, and various consumer electronics, it serves as a critical component for enhancing electromagnetic compatibility (EMC) and system stability.
Key Features Analysis:
Function: Filters common-mode electromagnetic interference to improve electromagnetic compatibility (EMC).
Structure: Surface-mount device (SMD) with a flat, miniaturized design that saves PCB space.
Applications: Noise suppression in power supplies, data cables, communications, automotive electronics, and other fields.
1. Suppressing Common-Mode Noise (Primary Function)
Issue: In high-speed or high-current switching circuits (such as switching power supplies and data transmission lines), two conductors (e.g., power lines, USB D+ and D-) simultaneously generate unwanted high-frequency noise with identical amplitude and phase, known as “common-mode noise.” This noise is a primary source of electromagnetic interference (EMI), leading to degraded system performance or interference with other devices.
Solution: Common-mode chokes present high impedance to common-mode noise. When common-mode noise currents flow through them, the magnetic fields from both windings combine in phase, generating significant inductive reactance. This reactance obstructs, reflects, and absorbs the noise energy, converting it into dissipated heat. This effectively suppresses the transmission of common-mode noise into circuits or its emission to the external environment.
2. Enabling Lossless Passage of Differential Signals
For useful differential signals requiring transmission (i.e., signals with equal amplitude but opposite phase on two wires, such as data signals), the magnetic fields generated internally cancel each other out, presenting extremely low inductive reactance (nearly short-circuited). Consequently, differential signals pass through with minimal attenuation.
3. Achieves Electromagnetic Compatibility (EMC) Compliance
Through the aforementioned filtering action, it significantly reduces electromagnetic radiation emitted by equipment while enhancing the device's immunity to external interference. This is crucial for products to pass stringent EMC certifications such as FCC and CE.
4. Protecting Sensitive Circuits
It prevents external high-frequency interference or surge noise on power lines from entering downstream sensitive circuits (such as CPUs, sensors, communication chips), thereby improving system stability and reliability.
In summary, its function resembles that of an “intelligent traffic cop”:
For common-mode noise (the troublemakers): Firmly intercept and block passage.
For differential-mode signals (legitimate traffic):
Maintains clear pathways and enables swift passage.
Thanks to its surface-mount (SMD) technology and compact, low-profile package, it efficiently performs these functions within extremely limited spaces. This makes it an indispensable filtering component in modern high-density, miniaturized electronic devices.
| Feature / Parameter | Description & Significance |
| Common Mode Impedance (Z<sub>cm</sub>) | The total opposition to common mode current flow (resistance + reactance) at a specific frequency (e.g., 100MHz). Higher impedance means better noise suppression. This is the most critical spec for EMI filtering. |
| Rated Current | The maximum continuous DC current that can flow through the windings without causing performance degradation or saturation. Exceeding this can lead to overheating and loss of inductance. |
| DC Resistance (DCR) | The inherent resistance of the wire windings. A lower DCR minimizes voltage drop and power loss (I²R loss), which is crucial for power line efficiency. |
| Rated Voltage | The maximum continuous voltage that can be applied between the coil and the core (isolation voltage). Important for safety and reliability. |
| Operating Temperature Range | The range of ambient temperatures within which the inductor will perform to its specifications. Typically from -40°C to +85°C / +125°C. |
| Self-Resonant Frequency (SRF) | The frequency at which the inductor's parasitic capacitance resonates with its inductance. Effective filtering occurs below the SRF. Performance degrades rapidly above it. |
| Insertion Loss | A measure of the signal attenuation (loss) introduced by the filter. It is the ratio of power without the filter to power with the filter. Higher insertion loss in the target frequency band means better filtering performance. |
| Leakage Inductance | The small amount of uncoupled inductance that behaves as a series differential mode inductor. It can provide additional attenuation of differential mode noise. |
| Saturation Current | The current level at which the core's magnetic properties saturate, causing a sharp drop in inductance. The inductor stops functioning effectively as a filter beyond this point. |
| Isolation / Withstanding Voltage | The maximum voltage that can be applied between the coils and the core (or between coils for isolated types) for a short time without breakdown. Critical for safety and noise isolation. |
| Package Size | The physical dimensions of the component (e.g., 1210, 1812, 3020). Smaller sizes save PCB space but may trade off performance (current rating, impedance). |
| Shielding | Shielded: Contains the magnetic field, prevents crosstalk. Unshielded: Can be susceptible to and cause crosstalk but is often lower cost. Most SMD types are shielded. |
