Vishay Custom Magnetics has introduced the SGCM05339, a space-grade, surface-mount common mode choke designed for EMI filtering and noise suppression in high-reliability applications.
It targets GaN and SiC switching stages and other power electronics where fast edges and high di/dt drive stringent EMC and screening requirements.
Key features and benefits
The Vishay SGCM05339 common mode choke is built around a compact nanocrystalline core in a self-shielded construction, optimized for harsh space, aerospace, and defense environments. Its overmolded, ruggedized package is intended for use where vibration, thermal cycling, and contamination resistance are critical.
Key characteristics include:
- Nanocrystalline core in a self-shielded design for reduced stray fields and improved EMC behavior in dense layouts.
- Overmolded construction for mechanical robustness and stable electrical performance over life.
- High common mode impedance over an extended frequency range, providing broadband EMI attenuation around fast-switching GaN and SiC edges.
- Heat rating current capability up to 14.43 A (typical), supporting high-current power stages without excessive temperature rise.
- Wide continuous operating temperature range from -55 °C to +130 °C, suitable for many space and military thermal profiles.
- Dielectric withstand voltage of 1000 VRMS and minimum insulation resistance of 10 GΩ at 500 VDC, supporting isolation and safety margins in isolated power architectures.
- Outgassing compliant per ASTM-E595, addressing contamination and materials constraints in space hardware.
- Multiple screening options including MIL-STD-981 Family 04 Class S and Class B, and EEE-INST-002, allowing alignment with program-specific quality flows.
The device can be customized by turn count, wire gauge, temperature class, and screening options, enabling optimization of impedance, current capability, and qualification level for specific platforms.
Typical applications
The SGCM05339 is positioned as a common mode choke for power conversion stages where wide bandgap devices or high-current operation make EMI control challenging.
Typical use cases include:
- GaN and SiC switching stages in power converters, where very fast voltage transitions increase radiated and conducted emissions.
- Low profile, high current power supplies on space and defense platforms that must balance height constraints with EMI and thermal performance.
- DC/DC converters in distributed power systems for satellites, avionics, and defense systems.
- Power converters for solar panels, including spaceborne solar power conditioning units, where common mode noise can couple into sensitive telemetry or communication lines.
In these applications, the choke is placed in series with line pairs (e.g. input or output of a converter) to attenuate common mode noise components while minimally affecting differential mode power transfer.
Technical highlights
Within the SGCM05339 family, Vishay specifies the following electrical ranges:
- Inductance per winding: 320 µH to 10 400 µH.
- Typical common mode impedance: 540 Ω to 3600 Ω.
- Maximum DC resistance per winding: 0.0029 Ω to 0.1318 Ω.
- Typical heat rating current: 2.02 A to 14.43 A, defined as the series DC current causing approximately ΔT=30 ∘C\Delta T = 30\,^\circ\text{C}ΔT=30∘C.
- Peak impedance frequency: 2.06 Hz to 31.74 Hz (per datasheet definition for this family).
- Maximum leakage inductance: 0.35 µH to 7.75 µH.
In practice, the combination of relatively low DC resistance and high heat rating current makes the part suitable for continuous operation in higher power rails without excessive conduction loss. The wide inductance and impedance span allows engineers to trade off between stronger common mode attenuation and acceptable insertion loss, depending on the conducted EMI limits and the converter’s waveform characteristics.
The specified dielectric strength and insulation resistance support designs where the choke forms part of an isolation barrier or sits between noisy and quiet reference domains, although exact creepage and clearance distances should be taken from the detailed manufacturer datasheet.
Availability and part numbers
SGCM05339 is currently released as a single series identifier for this space-grade, surface-mount common mode choke. According to Vishay, samples and production quantities are available with typical lead times of 8 to 12 weeks, subject to screening and customization options.
Engineers should consult the SGCM05339 product page and datasheet for:
- Detailed electrical tables for each inductance/impedance option in the series.
- Mechanical outline, recommended pad layout, and 3D models.
- Ordering codes covering screening level, temperature class, and any custom variants.
For program-specific screening (e.g. MIL-STD-981 Class S vs Class B or particular EEE-INST-002 flow), coordination with Vishay sales/FAE is usually required to confirm part numbers and lot-level documentation.
Design-in notes for engineers
When designing in the SGCM05339, several practical aspects are worth consideration:
- Selecting inductance and impedance: choose the inductance per winding and typical common mode impedance based on your converter’s switching frequency, edge rates, and EMI test margins. Higher impedance values improve attenuation but may increase size and leakage inductance.
- Thermal design: use the specified heat rating current as a reference, but verify temperatures in your own environment. Conservative derating below the maximum 14.43 A rating is recommended for long-life space missions.
- Layout and self-shielding: the self-shielded design helps contain magnetic fields, but placement near sensitive analog or RF circuits should still be minimized. Short, symmetric routing of the differential pair through the common mode choke improves EMC performance.
- Isolation and safety: the 1000 VRMS dielectric withstand voltage and minimum 10 GΩ insulation resistance are useful input parameters for insulation coordination. Always cross-check creepage, clearance, and insulation system requirements against mission or safety standards.
- Screening and qualification: early in the project, align the chosen screening option (e.g. MIL-STD-981 Family 04 Class S) with customer or agency requirements to avoid later requalification. Screening impacts both cost and lead time.
- Customization: for non-standard EMI targets or mechanical constraints, customization of turn count, wire gauge, and temperature class allows tailoring the choke’s impedance profile and current handling. Engaging with the manufacturer during early architecture trades can reduce later board spins.
For GaN and SiC designs in particular, it is important to consider how very fast dv/dt and di/dt may excite parasitics around the choke; co-design with snubbers, gate drive layout, and shielding is recommended to extract full benefit from the SGCM05339’s broadband common mode performance.
Source
This article is based on technical information provided by Vishay Intertechnology in their official new product introduction material for the SGCM05339 series, complemented by general application context for power and EMI design.