Tag Archives: app notes

App note: Bluetooth® multi-speaker audio application

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App note from Microchip about wireless multi-speaker connectivity solution. Link here (PDF)

Microchip’s Multi-Speaker Bluetooth Audio solution utilizes Microchip proprietary technology to connect a master speaker to one or multiple slave speakers through a modified Bluetooth protocol. Multi-speaker functionality is implemented using Microchip’s BM6x family of modules. One (master) speaker can either be connected to an audio streaming Bluetooth device (smartphone, tablet, laptop, etc.) or its own auxiliary input (AUX/LINE-In jack), and re-transmit either of the two audio sources to one or more speakers acting as a slave.

App note: Add authentication security to automotive endpoints

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App note about end device security from Maxim Integrated, by adding DS28E40 Deep Cover 1-Wire authenticator to keep the system devices in-check. Link here

The increasing electronic content in vehicles presents new attack surfaces to hackers. Digital authentication can reduce the risk of theft and counterfeiting of genuine and approved components. In mission-critical automotive applications, such as advanced driver-assistance systems (ADAS) and electric vehicle (EV) batteries, low-quality counterfeits can introduce safety risks if their performance is degraded, compared with approved components. On the other hand, stolen components may not be calibrated to operate properly after installation in a different vehicle. By adding a single authentication IC, designers can authenticate a component with only one signal between an electronic control unit (ECU) and endpoint component. Endpoints that can benefit from authentication cover a broad range of applications in vehicles, such as optical cameras, headlamps, EV batteries, occupancy sensors, and even steering wheels, just to name a few.

App note: High-impedance and low-noise op amps enable dry electrodes in medical systems

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App note from Maxim Integrated which introduces their buffer op-amp designed for wearable sensors on medical monitoring. Link here

The use of wearable sensors for fitness and health monitoring is growing tremendously. Over the past decade, wearable technology has gained much attention from the tech industry for commercial reasons and has generated interest of physicians due to its potential benefits in the health of their patients. Wearable devices use biomedical sensors to monitor not only activity parameters such as step count or walking/running speed or elevation, but also physiological parameters such as heart electrical activities or blood pressure.

App note: Low temperature soldering

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A study and actual test using LTS (Low Temperature Soldering) on SMT devices from Nexperia. Link here (PDF)

New generation Low Temperature Solder (LTS) pastes for Surface Mount Technology (SMT) is proposed for low temperature applications such as computing. LTS pastes are commonly build on near-eutectic SnBi alloying system and therefore show reduced melting temperatures which reduces the reflow temperatures as well as the energy consumption during SMT by up to 40%. This translates into reduced CO2 emissions and reduced manufacturing cost. Additionally, such effect can improve the yield impact created by high temperature (HT) warpage. HT warpage is widely recognized seen as main driver to reduce the reflow temperature for SMT. New product markets such as ultra-mobile computing and the Internet of Things (IoT) drive the need for smaller and thinner packages and boards which can suffer warpage by reflow temperatures of current solder systems like SAC. By lowering the peak temperature during reflow, warpage is reduced, resulting in higher SMT yields.

App note: Resistor Equipped Transistors (RETs)

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Introduction and application of resistor equipped transistors from Nexperia. Link here (PDF)

Bipolar transistors are controlled via the base current applied. Because of high temperature dependency of the voltage drop across the base-emitter path, it is required to add at least a series resistors at the base for stable and safe operation of a transistor in most applications This is required to keep base current at a desired level.
To reduce the number of components and to make board designs less complex, Resistor-Equipped Transistors (RET) have been introduced. These are single or dual transistors with resistors integrated on the same die. The integrated resistors have higher tolerances than commonly used external resistors. This fact makes RETs most suitable for switching applications where the transistor operates either in on-state or off-state. This is the reason also, why RETs are often referred to as digital transistors.

App note: Protecting charger interfaces and typical battery charging topologies

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Nexperia’s app note presenting ideas to protect USB port on devices. Link here (PDF)

This application note describes a complete solution for battery charging in mobile devices. This includes how to charge a Li-Ion battery with typical battery charger topologies, particularly with external bypass transistors and ways to effectively protect against overvoltage and overcurrent from the charger connector.