SMD inductance components are used in a small number of circuits. They are only used at the output end of low-voltage DC control power supplies. They can be used together with filter capacitors to form a π-shaped filter circuit of CLC. . The inductive element is composed of a single coil, some with a magnetic core (large inductance), the unit is generally expressed in μH and mH, and the circulating current value is a few milliamps to several hundred milliamps.
What are the identification methods of SMD inductors? SMD Shielded Power Inductor Factory to share with you.
SMD inductor identification method, SMD inductors are available in round, square and rectangular packaging forms, and the color is mostly black. With iron core inductors (or circular inductors), it is easy to identify from the appearance. However, some rectangular inductors are more like chip resistors in terms of appearance. The label of the chip inductor on the circuit board by the inverter manufacturer is marked with the word L. The working parameters of the inductor include inductance, Q value (quality factor), DC resistance, rated current, self-resonant frequency, etc., but the size of the chip inductor is limited, and most of them are only marked with the inductance, and other parameters are not marked, and are often Indirect labeling method - the labeling on the body of the chip inductor is only part of the information of the entire specification and model, that is, most of it is only the inductance information.
1. SMD inductor identification method:
1) From the appearance, such as a square or circular inductor with a magnetic core, the volume is slightly larger, and the magnetic core and coil can be seen;
2) Some chip inductors are the same as chip resistors in appearance, but there are no numbers and letters marked, only a small circle mark, which means inductance components;
3) The serial numbers of components in the circuit are often marked with the letter L, such as L1, DL1, etc.
4) There is an inductance label, such as 100.
5) The AC resistance of an ideal inductor is large, while the DC resistance is zero. The measured resistance value of the inductive element is extremely small, with a resistance value close to zero ohms. With observation and measurement (position and function in the circuit), it can distinguish whether the component is a chip resistor or a chip inductor, and determine the inductive component.
6) Use a special inductance tester to disconnect the component from the circuit and measure its inductance.
2. Fault replacement:
1) Components of the same type can be removed from the waste circuit board and replaced
2) First determine the inductance and circulating current value, replace it with ordinary leaded inductance components, and fix them well
3) Self-winding, making inductance substitutes, there is a certain difficulty in operation
4) If there is no obvious impact on circuit performance, emergency repair can be temporarily short-circuited
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How to choose an inductor according to your needs
When choosing a product, always choose the product based on external needs. The same is true for Integrated molding chip inductance, you need to consider the factors, and then choose the appropriate one-piece chip inductors, shielded chip inductors, and chip power inductors. There are many factors that affect the chip inductor. Let's talk about how to choose the chip inductor according to the needs.
1. Select the inductor according to the needs
When choosing a chip inductor for a portable power application, three most important points need to be considered: size and size, and the third is size. Circuit board space in mobile phones is at a premium, especially as functions such as players, TVs and video are added to the phone. The increase in functionality will also increase the current draw of the battery. Therefore, modules that have traditionally been powered by linear regulators or connected directly to batteries require higher-power solutions. One step towards a higher power solution is to use a magnetic buck converter.
In addition to the size, the main criteria of the inductance are the inductance value at the switching frequency, the DC impedance of the coil, the additional saturation current, the additional RMS current, the communication impedance ESR and the factor. Depending on the application, it is also important that the choice of inductor type is shielded or unshielded.
Similar to DC bias in a capacitor, Vendor A's 2.2µH inductor may be radically different from Vendor B's. The relationship between the inductance value and the DC current of the chip inductor in the relevant temperature range is a very important curve, which must be obtained from the manufacturer. The additional saturation current (ISAT) can be found on this curve. The ISAT is generally defined as the drop in inductance value. DC current when the amount is 30[[%]] of the extra value. Some inductor manufacturers do not have a regular ISAT. They probably gave the DC current when the temperature was 40°C higher than the ambient temperature.
When the switching frequency exceeds 2MHz, it is necessary to pay special attention to the communication loss of the inductor. The ISAT and DCR of the inductors of different manufacturers listed in the standard specification may have very different communication impedances at the switching frequency, resulting in obvious power under light load. difference. This is critical to improving battery life in portable power systems, which spend most of their time in sleep, standby, or low-power mode.
Since chip inductor manufacturers rarely provide ESR and Q factor information, designers should ask them for it. The relationship between the inductance and the current given by the manufacturer is often limited to 25°C, so the relevant data within the operating temperature range should be obtained. The worst case is generally 85°C.
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Specializing in the production of various types of color ring inductors, beaded inductors, vertical inductors, tripod inductors, patch inductors, bar inductors, common mode coils, high-frequency transformers and other magnetic components.
Post time: Sep-02-2022