Differences Between Molded Inductors and Wound Inductors

2025-03-15

In the field of electronic components, inductors, as crucial components, are widely used in various electronic products. Molded inductors and wound inductors are common types of inductors, and they differ in many aspects.

HONGDA Capacitors has achieved remarkable results in the inductor manufacturing field. Its HDSDRH Series Coil Type Whole Shield Power Inductor and HAPM Series Power Inductor Small Size Molding Type perform outstandingly in the market. Understanding the differences between these two types of inductors can help electronic engineers and relevant practitioners make more suitable choices according to different application requirements.

I. Introduction to HONGDA Inductor Products

(I) HDSDRH Series Inductors

The HDSDRH Series Coil Type Whole Shield Power Inductor by HONGDA Capacitors has significant performance advantages.

Features：

1. Inductance: 1~1000uH

2. Tolerance: K:±10%; M:±20%; N:±30%

3. DCR: 0.005~10 Ω

4. Rated Current: 0.1~10 A

5. Profile Feature: Lead-Free

This series of inductors is widely used in smartphones, tablets, laptops, televisions, power supplies, base stations, and various communication devices, providing strong support for the efficient operation of these devices.

Please check the datasheet link for more details:

https://www.hongdacapacitors.com/res/Inductors/hdsdrh-series-power-inductor-coil-type--whole-shield-.pdf

(II) HAPM Series Inductors

Hongda Capacitors HAPM Molding type power inductors feature high power handling, low DC resistance, good shielding, high - temp resistance and compact size.

Features：

1.Low profile, high current power supplies.

2.Low loss realized with low DCR

3.Ultra low buzz noise.

Applied in power supplies, auto, telecom, industrial and renewable energy fields.

Cross to Murata, Wurth, TDK, Vishay, Coilcraft...

Please check the datasheet link for more details:

https://www.hongdacapacitors.com/res/Inductors/hapm-series-power-inductor-big-size-molding-type.pdf

II. Appearance and Structure

(I) Molded Inductors

Molded inductors are manufactured using an integrated die - casting process. The winding and magnetic materials are combined into a single unit through high - temperature and high - pressure die - casting. Visually, they usually present a flat rectangular shape with a smooth surface, no obvious leads or winding marks. The overall structure is compact and robust. Their size specifications vary, with common length - to - width ratios ranging from 1:1 to 2:1, and the height also differs for different models, generally within the range of 1 - 5 millimeters.

Due to their integrated structure design, they have good mechanical strength, which can effectively resist external impacts and vibrations, reducing the risk of damage caused by mechanical stress during use.

(II) Wound Inductors

Wound inductors are made by winding wires around a magnetic core. The magnetic core can have various shapes, such as toroidal, E - shaped, and rod - shaped.

The winding method can be single - layer or multi - layer. The leads of wound inductors usually extend from both sides of the magnetic core, and the wound coils are clearly visible on the surface. Their size varies greatly. The volume of small - sized wound inductors may be similar to that of molded inductors, while large - sized wound inductors may be several times larger. The structure of wound inductors is relatively loose, with certain gaps between the windings. This makes the windings at risk of displacement when affected by external forces, which may affect the performance stability of the inductor.

III. Electrical Performance

(I) Inductance Value Range

The inductance value range of molded inductors is relatively narrow, generally between 0.1μH and 100μH. This is determined by their manufacturing process and material characteristics, and it is somewhat difficult to achieve higher inductance values. However, within this range, they can provide relatively stable inductance values, making them suitable for circuits with high requirements for inductance accuracy, such as the power management circuits of portable electronic devices like mobile phones and tablets. The inductance value range of the HDCDRH series inductors is 1.5μH - 330μH, which expands on the common range of molded inductors. The HDSDRH series inductors can also meet the specific inductance value requirements of certain circuits according to different models, better satisfying the needs of some circuits with special inductance value requirements.

The inductance value range of wound inductors is much wider, ranging from a few microhenries to several henries. By adjusting factors such as the number of winding turns, magnetic core material, and shape, different inductance values can be easily achieved. This wide range of inductance values enables wound inductors to be widely used in various circuits, such as power - intensive power circuits, industrial control circuits, and some circuits with special inductance value requirements.

(II) DC Resistance (DCR)

During the manufacturing process of molded inductors, the DC resistance can be effectively reduced by optimizing materials and processes. Their DCR values are usually low, generally between a few milliohms and several tens of milliohms. A low DC resistance means that when current passes through, the power loss generated by the inductor itself is small, which can improve the circuit efficiency and reduce heat generation. This is of great advantage in electronic products with strict power consumption requirements. For example, in the power conversion circuit of a laptop, a molded inductor with a low DCR can reduce energy consumption and extend the battery life.

The DC resistance of wound inductors is relatively high, especially when using thinner wires for winding. Their DCR values can range from several tens of milliohms to several hundred milliohms. A high DC resistance will cause the inductor to generate significant power consumption when a large current passes through, making the inductor heat up severely. This not only reduces the circuit efficiency but also may affect the normal operation of surrounding electronic components. However, in some circuits with low current requirements and high inductance value requirements, the high DCR of wound inductors does not become a key factor limiting their application.

(III) Saturation Current

Saturation current is an important indicator for measuring the performance of inductors. Molded inductors usually have a relatively high saturation current due to their magnetic material and structure characteristics. In a large - current environment, the decrease in their inductance value is relatively small, and they can maintain good performance stability. For example, in the power circuit of an engine control unit (ECU) in automotive electronics, there may be sudden large - current situations. Molded inductors can operate stably under such conditions to ensure the normal operation of the ECU.

The saturation current of wound inductors is relatively low. When the current exceeds a certain value, the inductance value will drop rapidly. This is because the magnetic core of the wound inductor is easily saturated in a large - current environment, resulting in a decrease in magnetic permeability and thus a reduction in the inductance value. When designing a circuit, special attention needs to be paid to the saturation current of wound inductors to avoid situations where the inductor performance fails due to excessive current during actual use.

IV. Application Scenarios

(I) Consumer Electronics Field

In consumer electronic products such as mobile phones and tablets, due to high requirements for volume and performance, molded inductors are widely used. In the power management chip (PMIC) circuit of a mobile phone, molded inductors are used in the DC - DC conversion circuit. They can provide stable inductance values in a limited space, helping to achieve efficient power conversion. At the same time, their low DCR and high saturation current characteristics can meet the power consumption and large - current requirements of the internal circuits of mobile phones. Both the HDSDRH series inductors and the HAPM series inductors are very suitable for such consumer electronic products, providing stable power support for devices such as mobile phones, tablets, and laptops and ensuring their stable operation.

Wound inductors are also used in the consumer electronics field, mainly in some circuits with high inductance value requirements and relatively less strict volume requirements. For example, in the audio amplification circuits of some high - end audio devices, wound inductors can use their high inductance values to filter and couple audio signals, enhancing the sound quality.

(II) Industrial Control and Power Electronics Field

In the industrial control field, such as in devices like frequency converters and servo drives, wound inductors are widely used. These devices usually need to handle large amounts of power and current. Wound inductors can meet the special inductance requirements of different circuits with their high inductance values and wide inductance value ranges. In the main circuit of a frequency converter, wound inductors are used for filtering and energy storage, helping to stabilize the DC bus voltage and reduce the impact of current fluctuations on the device.

Molded inductors are also gradually being applied in the industrial control field, especially in some occasions with high requirements for device volume and stability. In the power circuits of miniaturized industrial sensors, molded inductors can provide stable inductance values and good anti - interference performance, ensuring the accurate measurement and reliable operation of sensors. Both the HDSDRH series inductors and the HAPM series inductors can also play important roles in the industrial control field. Their stable performance and wide operating temperature range can adapt to the complex working conditions of the industrial environment and provide guarantee for the stable operation of industrial equipment in the power supply part.

(III) Communication Field

In communication devices such as base stations and various communication terminals, the requirements for inductor performance are also very strict. Both the HDSDRH series inductors and the HAPM series inductors can well meet the needs of communication devices with their stable performance and good electromagnetic shielding characteristics.

In the power supply and signal processing circuits of base stations, inductors can help stabilize the current, filter out clutter, and ensure the stable transmission of communication signals. In communication terminal devices such as smartphones and wireless routers, the two series of inductors can also play important roles, ensuring the stable operation of devices in complex electromagnetic environments.

V. Development Trends

With the continuous development of electronic technology, the requirements for inductor performance are getting higher and higher. Both molded inductors and wound inductors are constantly undergoing technological innovation and improvement.

Molded inductors will develop towards higher inductance values, lower DC resistance, and higher saturation currents in the future. By researching and developing new magnetic materials and optimizing manufacturing processes, it is expected to further break through the limitations of the existing inductance value range and meet the continuous upgrading requirements of electronic products. In terms of the manufacturing process, more attention will be paid to automation and refinement to improve production efficiency and product quality consistency.

Wound inductors will be improved in terms of increasing winding accuracy, reducing DC resistance, and increasing saturation current. At the same time, with the continuous emergence of new magnetic core materials, wound inductors will be able to achieve higher performance indicators. In terms of applications, wound inductors will continue to play important roles in high - power and special inductance value - required fields and will continuously expand new application scenarios, such as the high - voltage power systems of new energy vehicles.

In practical applications, it is necessary to select the appropriate inductor type according to specific circuit requirements, cost budgets, and product design needs.  If you have any questions regarding inductor selection and application, please feel free to contact us. Share your circuit requirements and application scenarios, and we will provide you with professional solutions and reasonable product recommendations.

Contact information: max@hongdacap.com.hk MP/whatsapp:+86 18188830464