Power Inductor TFM Series
Table of contents
Product summary
A summary of the TFM series is shown in Figure 1. Starting with the TFM-ALM series, various lines of products are available, each with further improved characteristics.
| Series | TFM-ALM | TFM-ALC | TFM-BLD | TFM-BLE | TFM-ALMA | TFM-ALVA |
|---|---|---|---|---|---|---|
| Applications | Commercial Grade |
Automotive Grade |
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| Product summary |
Thin-film type inductors which use metallic magnetic materials. By employing our original pattern forming technology as well as metallic magnetic materials with improved saturation magnetic flux densities, these products have achieved rated currents on the order of several A despite being compact and low-profile. The risk of short-circuits is prevented by a structure which includes insulation between the coil conductors, for greater reliability. |
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| Characteristics improved compared to earlier products by optimizing internal pattern. | Their characteristics have been enhanced even further over the ALM series by changing their metal materials and optimizing their internal patterns. | The terminal electrodes have an L shape, which enables narrower pitch mounting than five-surface electrode products. | Magnetic materials technology and structural designs achieve lower resistance and higher current than the BLD series. | These products are compatible with quality requirements for in-vehicle mounting, and are guaranteed to support temperatures of 150°C. | The characteristics of their metal materials have been improved over the ALMA series for enhanced withstanding voltage performance. | |
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Product structures
The TFM series consists of inductors which are produced using thin-film processing. Since their coils are formed by Cu plating, they support highly flexible designs, and their use of resin electrodes also allows them to lessen stresses such as those from heat and board deflection.
Terminal electrode
Stresses are lessened
with the resin electrode type
Comparison of stress simulations under conditions of thermal stress (150°C)
Insulating film
Product features
The features of each TFM series are shown in Figure 3. The TFM-ALMA and TFM-ALVA series consist of products with automotive specifications, which support temperatures of 150℃.
| Series | TFM-ALM | TFM-ALC | TFM-BLD | TFM-BLE | TFM-ALMA | TFM-ALVA |
|---|---|---|---|---|---|---|
| Appearance | 
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| Operating temperature range | -40 – 125°C (including self-heating) |
-55 – 150°C (including self-heating) |
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| Magnetic material | Metallic magnetic material | |||||
| Terminal electrode specifications | Resin electrode (conductive resin layer + plating) | |||||
| Features | Standard specification Compatible with high current |
Compact High efficiency |
Compact Low-profile |
Low resistance Compatible with high current High efficiency |
Automotive specifications Compact Compatible with high current |
Automotive specifications 40 V guaranteed |
The TFM series has an extensive lineup ranging from high-current types with improved DC superimposition characteristics that are effective for improving power supply efficiency in the high load range to low core loss types that are effective for improving power supply efficiency in the light load range.
Input / output conditions Vin=3.7V Vout=1.2V
Drive conditions Fsw=3.4MHz
For products with automotive specifications, by developing new metallic magnetic materials, we expanded the lineup with products that can be used in automotive battery lines, something that was difficult with compact power inductors.
Achieves rated voltage of 40 V using proprietary materials technology and responds to market needs for miniaturization and high-density mounting
Applications
Example applications which use the TFM series are shown in Figure 6. Since the inductors in the TFM series are compact and can support large currents, they are ideal for applications requiring high-density mounting such as smartphones and automotive ECUs.
| Application | Block diagram |
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| Smartphone | 
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| Automotive ECU | 
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List of products
A list of products by series and shape is shown in Figure 8. Detailed information can be viewed and samples can be purchased by clicking on the product type name.
- Commercial grade
- Automotive grade
| Size (mm) |
Height (mm) |
TFM-ALM | TFM-ALC | TFM-BLD | TFM-BLE | TFM-ALMA | TFM-ALVA |
|---|---|---|---|---|---|---|---|
| 1.4x1.2 | 0.8 Max. |  |
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| 1.6x0.8 | 0.8 Max. |  |
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| 2.0x1.2 | 0.8 Max. |  TFM201208ALC |
 TFM201208BLD |
 TFM201208BLE |
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| 1.0 Max. |  TFM201210ALMA |
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| 2.0x1.6 | 1.0 Max. | 
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 TFM201610ALVA |
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| 1.2 Max. | TFM201612ALMA |
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| 2.5x2.0 | 1.2 Max. |  |
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| 3.2x2.5 | 1.2 Max. |  |
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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 characteristic with switching devices for voltage conversion (see Figure 8).
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.
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
Contact Information
Related Links
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