Magnetics for LM258X Flyback Regulator

Category: Coilcraft Inc, Electronics, Transformers

Magnetics for LM258X Flyback Regulators Overview

The provided datasheet details standard flyback regulator transformers designed to be used with National Semiconductor’s LM2585, LM2586, LM2587, and LM2588 SIMPLE SWITCHER® switching regulators. These transformers have been developed for efficient power conversion in switch-mode power supply systems. The availability of both surface mount (SM) and through-hole (PC) configurations allows for versatile application across different types of electronic assemblies.

Key Specifications

A highlight of the datasheet is the presentation of transformers with a variety of turns ratios and their respective electrical characteristics. Important specifications include volt-time product, primary and secondary inductance (max and min), leakage inductance, direct current resistance (DCR), and peak inductor current (Ipk). The datasheet also lists the part numbers for easy reference. As an example, part T1 (SM) and T1 (PC) are provided with their corresponding volt-time product, leakage inductance, DCR, turns ratio, and output specifications. Certain transformers, like T7, also come in both surface mount and through-hole variations.

Performance and Reliability

The transformers feature 500 V isolation between windings, ensuring safe operation under various conditions. They can operate within an ambient temperature range from -40°C to +85°C and have a storage temperature range for components of the same values, but for packaging, it is slightly broader, from -55°C to +80°C. The products exhibit resistance to soldering heat, with surface mount parts capable of withstanding up to three 30-second reflows at a maximum of +235°C.

Additional Information

The datasheet advises referring to Document 362, “Soldering Surface Mount Components,” before soldering, emphasizing the importance of proper assembly techniques. The transformers are constructed with ferrite core material. The Mean Time Between Failures (MTBF) offered by the transformers is quite significant at over 26 million hours, indicating high reliability. For cleaning, only pure water or alcohol is recommended to avoid damaging the components.

Conclusion and References

As the datasheet concludes with general recommendations and precautions for handling and usage, it also states that all specifications are subject to change and recommends users to check Coilcraft’s website for the latest information. The datasheet reflects Coilcraft’s commitment to providing detailed, accurate information to facilitate correct component selection and usage. Contact information, including email and web addresses, is provided for further inquiries.