Common-mode filtering for signal lines
The TDK ACT45B-110-2P-TL003 is a two-line common-mode choke from the ACT45B series, designed to suppress conducted noise on signal lines in automotive and industrial applications. It presents 600 Ohms of common-mode impedance at 10 MHz, which is the frequency band where most switching noise from DC-DC converters and digital buses couples onto signal pairs. Rated for 250 mA continuous current with a maximum DC resistance of 600 mOhm, the insertion loss at rated current stays within the thermal budget of the ferrite core.
Automotive-grade reliability and temperature range
Qualified to AEC-Q200, the ACT45B-110-2P-TL003 meets the stress and lifetime requirements for under-hood and passenger-cabin electronics. The 11 µH inductance at 100 kHz provides low-frequency common-mode attenuation below the 10 MHz resonance peak, filling the gap between bulk ferrite beads and higher-frequency chip filters. This dual-band characteristic suits CAN bus, LIN bus, and sensor signal lines where both switching noise and low-frequency ripple need suppression.
The tape-and-reel packaging supports automated pick-and-place for volume production. The two-line configuration with four pads means each signal pair passes through the choke with the common-mode impedance in series with the return path. Layout should keep the differential pair traces close together before and after the choke to minimize loop area and preserve the common-mode rejection ratio.