# SQ/UC Flat Wire Common Mode Inductors: The Core EMI Solution for Power Adapters
What Are Flat Wire Common Mode Inductors?
A common mode choke (Common Mode Inductor) is an indispensable EMI filtering component in power adapters, switching power supplies, and similar equipment. Compared to conventional round-wire common mode inductors, SQ-type and UC-type flat wire common mode inductors are wound with flat copper wire, offering lower DC resistance (DCR), higher current-carrying capacity, and superior high-frequency performance.
Dongguan Chaorong Electronics Co., Ltd. specializes in the R&D and production of SQ and UC flat wire common mode inductors, with products widely used in power adapters and chargers ranging from 5W to 100W.
SQ Type vs. UC Type: How to Choose?
| Parameter | SQ Flat Wire CM Inductor | UC Flat Wire CM Inductor |
|---|---|---|
| Core Shape | Square core | U-shaped/C-shaped core |
| Inductance Range | 1mH–100mH | 0.5mH–50mH |
| Rated Current | 0.5A–10A | 1A–20A |
| Applicable Frequency | 50Hz–1MHz | 50Hz–2MHz |
| Typical Applications | Small-power adapters, LED drivers | High-power EV chargers, industrial power supplies |
Technical Advantages
1. Low DCR Design
Flat wire has a larger cross-sectional area. With the same number of turns, DC resistance is 30%–50% lower than round wire, effectively reducing copper losses and improving power efficiency.2. Excellent Common Mode Rejection Ratio (CMRR)
In the 150kHz–30MHz frequency band, common mode insertion loss can reach 40dB or more, meeting international EMC standards such as IEC 61000-3-2 and EN 55032.3. High-Temperature Stability
Using high-permeability MnZn ferrite cores, the operating temperature range is -40°C to +125°C, suitable for automotive and industrial environments.4. Customization Services
Chaorong Electronics provides full customization of inductance, rated current, and physical dimensions, with small-batch prototyping supported and delivery in 7–14 days.Application Scenarios
- Smartphone/Tablet Chargers: Suppresses switching noise, passing CCC, CE, and UL certifications - Laptop Power Adapters: Meets Class B radiated emission limits - LED Driver Power Supplies: Reduces flicker index and improves lighting quality - Industrial Control Power: Strong anti-interference capability, suitable for harsh EMC environments
Selection Recommendations
When selecting a common mode inductor, the following parameters are critical:
- Rated Current: Should exceed 1.5× the maximum operating current of the circuit - Inductance: Determined by the frequency range to be suppressed; insertion loss at 150kHz should typically be ≥20dB - Temperature Rise: Should not exceed 40°C under full-load operation
For SQ/UC flat wire common mode inductor specifications or custom quotes, contact Dongguan Chaorong Electronics Co., Ltd. (No. 2, Desheng West 1st Street, Gaobu Town, Dongguan, Guangdong). We provide professional technical support within 24 hours.