Small-Footprint Power Inductors Target ADAS Applications

Developed by TDK, these 2.5 x 2.0 x 1.2 mm parts have a rated current of 1.6 A and an inductance of 4.7 µH.

By Murray Slovick, Contributing Editor

In today’s automobiles, electronic control units (ECUs) are increasingly being installed to handle various control tasks and implement in-vehicle information communication, autonomous driving, and other functions. The number of automotive ECUs necessary for advanced driver-assistance systems (ADAS)—and thereby the number of inductors for power circuits used in these units—continues to increase as well. However, as the number of parts grows, mounting space remains limited, creating a concomitant demand for small-footprint electronic parts.

TDK is responding to such market needs with its new TFM2520ALVA inductor, a thin-film metal power inductor that can be connected directly to a 12-V car battery. It has a footprint of just 2.5 mm × 2.0 mm and a height of 1.2 mm. By employing a magnetic metal core, these inductors offer a rated current of 1.6 A and an inductance of 4.7 μH.

The new inductor achieves a rated voltage of 40 V from a part smaller than 9 mm2. (Source: TDK)

Thanks to the material technologies used and a structural design unique to TDK, the inductor achieves a rated voltage of 40 V from a part smaller than 9 mm2. The rated voltage of 40 V is realized by a design that emphasizes voltage resistance.

By using metal magnetic material with high saturation magnetic flux density, inductors for power circuits can be developed with the necessary dc bias characteristics. By way of review, when a dc bias current is applied to an inductor, magnetic permeability decreases as the magnetic material approaches magnetic saturation, which reduces inductance. This is referred to as the dc bias characteristic.

A closed magnetic circuit structure minimizes leakage flux, according to TDK. The new inductor also is said to be able to withstand severe temperature environments with an operating temperature range of −55 to +150°C (including temperature increases attributed to self-heating), and is therefore well-suited for automotive power circuits. Mass production of the AEC-Q200-qualified inductors began last month.

According to TDK, no other thin-film metal inductor featuring a footprint smaller than 9 mm2 is on the market that can be can be used in power circuits with an input directly coupled from a 12-V car battery.

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