IN Brief:
- ICMS2321-10 and automotive ICMS2321-1A cover inductances from 70µH to 480µH with 1,500VDC dielectric withstand between coils.
- The 30A figure corresponds to approximately 100°C winding temperature rise; ratings at a 40°C rise extend to 20A.
- Samples and production quantities are available now, with Vishay quoting 12-week lead times.
Vishay Intertechnology has introduced two low-profile common-mode choke families for high-current automotive, energy, and industrial electronics, combining heat-rating current of up to 30A with 1,500VDC dielectric withstand between their windings.
The commercial ICMS2321-10 and AEC-Q200-qualified ICMS2321-1A are available in surface-mount and through-hole formats for applications including DC/DC converters, high-voltage inverters, onboard chargers, motor controls, and EMI filters. Vishay also offers custom inductance, impedance, DC resistance, and current values where the standard configurations do not match a particular filter design.
The devices cover inductances from 70µH to 480µH. Common-mode impedance depends on the selected version, ranging from 540Ω to 3,790Ω at 1MHz, 345Ω to 1,920Ω at 10MHz, and 220Ω to 410Ω at 100MHz. That spread allows designers to select a component around the interference spectrum of the converter or load rather than treating common-mode attenuation as one fixed requirement.
The headline 30A current figure needs its thermal condition alongside it. Vishay specifies one heat-rating range of 7A to 20A for an approximate winding temperature rise of 40°C, while a second range of 10A to 30A corresponds to an approximate 100°C rise. The maximum figure therefore cannot be treated as an unrestricted continuous-current rating independent of ambient temperature, enclosure design, airflow, and the exact choke selected.
That distinction is particularly important in compact power converters because winding losses increase with the square of current. A component carrying twice the current produces four times the resistive heating if its resistance remains unchanged, leaving thermal design closely tied to the filter specification.
A common-mode choke uses two coupled windings to discriminate between wanted load current and unwanted interference. Magnetic flux produced by differential current flowing to and from the load largely cancels in the core, while common-mode current travelling in the same direction through both conductors reinforces the magnetic field and encounters a much higher impedance.
The components become increasingly relevant where fast-switching power electronics share wiring with sensitive control, sensing, or communications circuits. High-voltage inverters, DC/DC converters, and motor drives can generate common-mode currents through parasitic capacitances, while attached cables provide paths for conducted emissions and can become efficient radiating structures at higher frequencies.
Wide-bandgap switches make that filter problem more demanding. Silicon carbide and gallium nitride devices can reduce switching loss by operating with faster voltage transitions, but steeper edges increase high-frequency energy and can excite parasitic paths that were less troublesome in slower power stages. A choke has to provide useful attenuation without adding excessive resistance, leakage inductance, or thermal load.
Vishay’s new families are specified for operation at temperatures up to +150°C and use a rugged, self-shielded construction. The automotive ICMS2321-1A adds AEC-Q200 qualification and is being positioned for onboard chargers, where high switching power, vehicle EMC limits, temperature cycling, and vibration all converge in a tightly packaged assembly.
AEC-Q200 qualification provides a component-level reliability framework but does not qualify the complete charger or inverter automatically. Engineers still have to verify the filter with the actual PCB, cable harness, enclosure, switching device, grounding architecture, operating temperature, creepage, clearance, and vehicle-level EMC requirements.
The ICMS2321 range also occupies a different electrical envelope from the smaller Vishay automotive common-mode chokes covered recently by IN Electronics. Those devices reached 14A, whereas the current families extend further into high-current power conversion and add the 1,500VDC inter-winding dielectric requirement. The function overlaps, but the intended power level is materially different.
Surface-mount versions are available on tape and reel for automated placement, while leaded variants support assemblies where through-hole construction remains preferable. Samples and production quantities are available now, with Vishay quoting lead times of 12 weeks.
The design decision is therefore less about selecting the part with the largest current figure than matching impedance, winding resistance, mounting, temperature rise, and dielectric requirements to the converter. At 30A, the choke is already part of the power stage’s thermal architecture, not simply an EMI component added after the circuit has been designed.