App note: Package-related thermal resistance of LEDs


App note from OSRAM on thermal resistance for LEDs and IREDs (IR emitting diodes). Link here (PDF)

In order to achieve the expected reliability, lifetime and optimal performance of LEDs, especially for high-power LEDs, appropriate thermal management is of the utmost importance. One of the key parameters for good thermal management is the temperature of the active semiconductor layer designated as the junction temperature. The manufacturer’s recommended maximum junction temperature should therefore not be exceeded during operation, in order to prevent damage to the component. Ideally, the junction temperature should be kept as low as possible for the given application.

Due to the design principle of the LEDs, the junction temperature of the LED can not be measured directly.

App note: Increasing accuracy in feedback circuits and voltage dividers with thin film chip resistor arrays


App note from Vishay on using chip resistors to achieve long-term stability. Link here (PDF)

Thin film chip resistor arrays consist of several resistors of equal or different values combined in one package. During the manufacturing processes and the device’s lifecycle, all the particular resistors virtually experience identical conditions, which allow the specification of their relative tolerances, relative temperature coefficients, and even a relative resistance drift. These relative parameters provide precise and stable resistance ratios and far better long-term stability of feedback circuits and voltage dividers compared to discrete resistors.

App note: Custom magnetics – What are they and when do you need them?


Consideration factors before going to custom magnetic request from manufacturer, an app note from Vishay. Link here (PDF)

There are many manufacturers that claim they build custom magnetics. However, there is often confusion as to what constitutes custom magnetics and whether or not a designer actually needs them or can afford them. This article will clarify what custom magnetics are, help designers determine if they are needed, and explain how to engage with a custom magnetics supplier.

App note: Simplify home audio systems With the PCM9211 – A versatile audio interface transceiver


A digital interface PCM9211 from Texas Instruments app note. Link here (PDF)

Large-screen HDTVs are selling in huge volumes over last few years, primarily driven by amazing improvements in picture quality & form factor (thinner screens). The form factor constraints from having skinny screens result in tiny built-in speakers that are undersized, under-powered and are typically aimed at wrong direction. Hence sound bars have exploded in popularity as complementary audio system by providing a sound experience that more closely matches the TV’s life-like pictures. In addition, with release of HDMI 2.1 specification we finally have a nocompromise audio solution for HDMI as part of the eARC [enhanced Audio Return Channel]. This tech note reviews eARC and simplified Sound Bar design using PCM9211 and how to interface eARC signals with PCM9211.

App note: Noise suppression for wireless headphones


Wireless headphone interference investigation from muRata. Link here

Recently, the popularity of wireless headsets has been growing as the number of situations where people “play sports while listening to music” increases.

Bluetooth is frequently used for communication between smartphones and headsets. However, audio can skip due to communication errors, so countermeasures are required.

This is an extremely important point of user evaluation and a difficult issue to resolve.
Here we depict an actual case to explain the interference mechanism in the device which causes the audio to skip, and key points for improvement to introduce useful countermeasures for solving the problem.
We hope that you will use it as a guide to help your design work proceed more smoothly.

App note: The Phytochrome system – Why use far-red?


App note from Würth Elektronik on why plants evolved to use far-red wavelengths and why it is essential for them. Link here (PDF)

The light requirement of plants is now known to be far more complex than originally thought leading to the development of numerous LED technologies that produce a variety of different light spectra, both monochromatic and polychromatic.

Far-red encompasses wavelengths 700 – 800 nm, a region of light that is on the edge of visibility in humans. However, these wavelengths have been proven to result in faster growth, increased biomass and better sensory characteristics (e.g. smell, taste, texture, color).

App note: CeraLink® Capacitors


Compact and high capacitance ceramic capacitors from TDK electronics. Link here (PDF)

CeraLink is a family of very compact capacitors for stabilizing voltages in the DC link. They are therefore suitable for use as either snubber or DC link capacitors. These products are based on PLZT ceramics and are designed to provide engineers with compact components optimized for fast switching converters, converters with very tight space requirements and converters that need to withstand high operating temperatures. The basic component is a ceramic chip which either is manufactured with lead frames or which can be combined modularly to form capacitors with higher capacitance values.

App note: Linear regulator specifications


Thorough items on a linear regulator datasheet provides valuable details about its proper usage discussed in this App note from ROHM semiconductor. Link here (PDF)

A linear regulator data sheet includes a specifications table that lists output voltage values and precision. Besides, very important information such as maximum ratings, operating conditions and characteristic graphs are described in the table.

App note: Connecting LDOs in parallel


App note from ROHM semiconductor on combining LDOs for higher load capacity. Link here (PDF)

When you want to increase the output current capacity of an LDO, or when the power dissipation of a single LDO is insufficient, you might think of connecting LDOs in parallel if you need to disperse the dissipation using two LDOs. This application note provides some hints on how to connect LDOs in parallel.

App note: Basics and low-cost solution proposals to move from legacy USB2.0 connector to USB Type-C™ connector with STM32 devices


App note from STMicroelectronics about interfacing STM32 legacy USB 2.0 to USB Type-C. Link here (PDF)

This application note is a guideline to introduce this USB Type-C connector onto platform to replace legacy USB2.0 connectors. It introduces some basis of the two new standards USB Type-C™ and the USB Power Delivery.