Tech Library

[Oct. 2022 ]

Product Overview

Power Inductor SPM Series

The SPM series power inductors are the metal composite type wire-wound inductors that have the coils integrally molded with metallic magnetic powder. Compared to ferrite-base wire-wound inductors, the SPM series inductors realize larger current, lower Rdc, smaller size and superior DC bias characteristic. In addition, they ensure low magnetic flux leakage and are effective as a means to suppress acoustic noise of the coil. This article introduces the structure, features, and application of these products, and other information that helps you in an easy-to-understand way.

Product summary
Product structures
Product features
List of products
What are power inductors?
Contact

Product summary

The SPM series are the inductors that have the coils integrally molded with metallic magnetic powder. TDK offers a large selection of the SPM series inductors, including the low-profile SPM-LR series, the SPM-HZ and SPM-V series for automotive applications, and others.

SPM-CT Series — Figure 1: Product summary

	Commercial Grade	Automotive Grade
Series	SPM series Standard specifications	SPM-CT series For high frequency use	SPM-LR series Low-profile model	SPM-XT series Large model	SPM-HZ series	SPM-DZ series	SPM-V series
Product summary	The inductors that have the coils integrally molded with magnetic powder. These inductors use Fe-base alloy powder to have high saturation characteristics, i.e. allowing for large current.	The inductors that have the coils integrally molded with magnetic powder. These inductors use Fe-base alloy powder to have high saturation characteristics, i.e. allowing for large current. A wider operating temperature range than commercial grade products (DZ,V Series)
Features	Their Curie temperature is high, and they show only small changes in characteristics with changes in ambient environment temperature. With the use of a coil integrally molded with metallic magnetic material, hum noise and magnetic flux leakage are reduced.	Their Curie temperature is high, and they show only small changes in characteristics with changes in ambient environment temperature. With the use of a coil integrally molded with metallic magnetic material, hum noise and magnetic flux leakage are reduced. AEC-Q200 complied.
Large selection of products, ranging from 4 to 10 mm square. High productivity	By using a proprietary alloy powder, low loss in the high-frequency range is achieved.	The low-profile is achieved with the use of L-shaped terminals. Compact forms ranging from 3 to 5 mm square.	Low resistance with no joint terminal (terminal integrated to wire) Compatible with low inductance range. High productivity	Large selection of products, ranging from 4 to 10 mm square. High productivity	Compact, low profile 30 G vibration resistance High productivity	High inductance High DC superimposition characteristics Large selection of products is offered, ranging from 0.1 to 100 μH. 30 G vibration resistance
Applications	LCD-TV,HDD Amusement equipment Other AV equipment	Wireless chargers IJP head drive	Notebook computers Tablet terminals Gaming equipment	Base stations, servers Amusement equipment Industrial equipment	Car accessories Car navigation Car audio	ADAS Start/Stop Engine ECUs	LED ADAS Engine ECUs, etc.

Product structures

Figure 2 shows the structure of each SPM series. The integral mold structure and the welding method for connecting the wire and terminals achieves high reliability.

	Commercial Grade	Automotive Grade
Series	SPM	SPM-CT	SPM-LR	SPM-XT	SPM-HZ	SPM-DZ	SPM-V
Product structures

Product features

Figure 3 shows the features of each SPM series.

Series	SPM	SPM-CT	SPM-LR	SPM-XT	SPM-HZ	SPM-DZ
Appearance
Operating temperature range	-40 to 125°C (including self-temperature rise)	-55 to 155°C (including self-temperature rise)
Magnetic material	Metallic magnetic material
Terminal electrode specifications	Metal terminal + plating	No joint terminal + plating	Metal terminal + plating
Features	Commercial Grade	Automotive Grade
Standard specifications	High frequency & High Q specifications	Low-profile specifications	Large current specifications	Supports use up to 125°C	Compact, low profile	High inductance High DC superimposition characteristics

One of the remarkable features of the SPM series is that they are made with metallic magnetic core. Compared to ferrite cores, metallic magnetic cores have higher magnetic saturation density and better DC bias characteristic. In addition, since their Curie temperature is high, they show only a small change in characteristics with ambient temperature.

Figure 4: Comparison of DC bias characteristic (Metallic magnetic core vs. ferrite core)

Core material characteristics of high magnetic saturation
Superior DC bias characteristic

DC bias characteristic of each core material

Figure 5: Change in DC bias characteristic with ambient temperature

Core material characteristics of high Curie temperature
Change in characteristics with ambient temperature is small.

DC bias characteristic under different temperatures

Since the SPM series inductors are made with wire-wound cores integrally molded with metallic magnetic powder, they do not have a core gap and the acoustic noise is reduced. Also, they have good shielding qualities and the magnetic flux leakage is small.

Figure 6: Integral molding for suppressing acoustic noise

Core gapless (integral molding) for suppressing acoustic noise
Contributes to improve the set quality

Combination core type — Acoustic noise generates from the gap

Integral molding type (SPM) — With the gapless structure, acoustic noise is suppressed

Figure 7: Comparison of magnetic flux leakage

Shielding structure for low magnetic flux leakage
Effective for reducing EMI

Vertical near magnetic field measurement result

List of products

Figure 8 shows the list of products by series and by shape. You can view the detailed information of the product or purchase a sample by clicking the type name.

Commercial grade — Figure 8: List of products

Automotive grade — Figure 8: List of products

What are power inductors?

Power inductors are inductors used for power supply circuit such as DC-DC converters. They are also called power coils or power choke coil. One of the inductors' characteristics is that they store energy by self-induction function. Chopper type DC-DC converters use inductors having such characteristics with switching devices for voltage conversion (see Figure 9).
Depending on the processing method, inductors can be classified into multilayer type, thin-film type, and wire-wound type. Since wire-wound type permits large current to flow, most of the power inductors are wire-wound type. Various wound-type power inductor products with ferrite or soft magnetic metal core are offered. Recently, the multilayer type and thin-film type, with which reduction of size and thickness can be achieved, are being improved to allow for larger current.

Figure 9: DC-DC converter (chopper type / step-down type) and inductor

The voltage is dropped to a desired level in accordance with the duty ratio (the ratio that indicates how long the switch is ON during the switching cycle) setting.

Switching
repeated

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Size (mm)	SPM	SPM-CT	SPM-LR	SPM-XT	SPM-HZ	SPM-DZ	SPM-V
3mm sqr.			3.2x3.0mm SPM3010-LR SPM3012-LR SPM3015-LR SPM3020-LR
4mm sqr.	4.2x4.0mm SPM4030		4.4x4.1mm SPM4010-LR SPM4012-LR SPM4015-LR SPM4020-LR		4.2x4.0mm SPM4030-HZ	4.3x4.0mm SPM4020-DZ
5mm sqr.	5.2x5.0mm SPM5030		5.4x5.1mm SPM5010-LR SPM5012-LR SPM5015-LR SPM5020-LR		5.2x5.0mm SPM5030-HZ		5.3x5.1mm SPM5030VT
6mm sqr.	7.1x6.5mm SPM6530 SPM6550	7.1x6.5mm SPM6550CT			7.1x6.5mm SPM6530-HZ SPM6550-HZ		7.0x6.5mm SPM6545VT
7mm sqr.							7.5x7.0mm SPM7054VT SPM7054VC
10mm sqr.	10.7x10.0mm SPM10040			11.5x10.0mm SPM10040XT	10.7x10.0mm SPM10040-HZ SPM10054-HZ		10.5x10.0mm SPM10065VT
12mm sqr.				12.6x13.0mm SPM12565XT			13.0x12.5mm SPM12565VT