11 May 2012

Circuit designers usually try to use capacitors rather than inductors in their circuits because of their smaller size, reduced interference effects, and ease of manufacture.  Coilcraft, Inc. has introduced a type of coil design that has made it easier to make use of coils in circuits where an inductance would work better than capacitance, such as oscillators, tuned circuits, and resonant circuits.

Coilcraft’s new PFL family of coils is especially designed for applications that require ultra-small inductors that can still handle significant current levels.

The PFL series comes in a wide assortment of footprints that would fit in a variety of applications. The new PFL4514 and PFL4517 are the latest additions to the PFL line of miniature power inductors.

These low-profile inductors feature a magnetic shield, which reduces the effects of magnetic coupling between components, and allows for tighter component spacing without electromagnetic interference. The unique PFL design provides the same performance as found in the larger standard-sized inductors, so circuit designers can now increase board density at a low cost without sacrificing any efficiency.

The PFL4514 and PFL4517 are wirewound surface-mount inductors that feature very low profiles.

The PFL4514 Series Shielded Power Inductor requires only 16 mm2 of board space and is 1.4 mm high. The 4.2 A current handling capability compares to much larger inductors. The inductance values of the PFL4514 Series range from 1.0 µH to 22 µH and feature an operating temperature range of -40 to +125°C. The DC resistance of the PFL4514 is relatively low, as low as 80 milli-ohms, making it more suitable for battery-powered devices.

The PFL4517 Series features and even lower DC resistance, which can be as low as 40 milli-ohms. Inductance values ranging from 0.68 µH to 10 µH are offered for the PFL4517. The PFL4517 is taller than the PFL4514 by 0.3 mm, and is designed for higher current levels up to 6.5A.

These low-profile, magnetically shielded inductors share a common footprint for design and prototyping flexibility. These devices have a composite-core construction with relatively heavy gauge windings to provide the high current handling capability and low DC resistance. The parts are halogen-free and RoHS-compliant, with matte tin over nickel terminations that are compatible with 260°C processing.

Coilcraft offers free evaluation samples on its website to qualifying designers, or a combined Designers Kit C451 can be purchased, which contains three samples of both the PFL4514 and PFL4517 in a range of values.