App note: STM32 cross-series timer overview

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STM32 timer overview application note (PDF!) from ST:

The STM32 devices are built-in with various types of timers, with the following features for
each:

  • General-purpose timers are used in any application for output compare (timing and delay generation), one-pulse mode, input capture (for external signal frequency measurement), sensor interface (encoder, hall sensor)…
  • Advanced timers: these timers have the most features. In addition to general purpose
    functions, they include several features related to motor control and digital power
    conversion applications: three complementary signals with deadtime insertion,
    emergency shut-down input.
  • One or two channel timers: used as general-purpose timers with a limited number of
    channels.
  • One or two channel timers with complementary output: same as previous type, but
    having a deadtime generator on one channel. This allows having complementary
    signals with a time base independent from the advanced timers.
  • Basic timers have no input/outputs and are used either as timebase timers or for
    triggering the DAC peripheral.
  • Low-power timers are simpler than general purpose timers and their advantage is the ability to continue working in low-power modes and generate a wake-up event.
  • High-resolution timers are specialized timer peripherals designed to drive power conversion in lighting and power source applications. It is however also usable in other fields that require very fine timing resolution. AN4885 and AN4449 are practical examples of high-resolution timer use.

App note: HVArc Guard® surface-mount capacitors for low-power voltage multiplier applications

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Application note on Vishay’s arc resistant SMD capacitors, Link here (PDF)

Voltage multipliers can generate very high voltages due to an inverter circuit that feeds a step-up transformer, which is connected to the multiplier circuit. An example of a typical voltage multiplier, which is simply a circuit comprised of capacitors and diodes that charge and discharge in alternating half cycles of the applied AC voltage. Applications for voltage multipliers include flyback converters, where a high voltage is produced from a low battery or supply voltage in medical X-ray systems, air ionizers, and oscilloscopes, and instrumentation requiring a high-voltage power supply.

When a high voltage potential is applied at > 1000 V, an arc-over between the terminals, or from terminal to case will occur. To eliminate any arc-over, an overcoating can be applied to the board, or additional board layout spacing can be added to isolate the high-voltage section from other sections of the board. Although coatings add cost to the process and the design, they are required in some applications to meet electrical safety standards.

App note: AC film capacitors in connection with the mains

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An application note from Vishay about choosing the right filter capacitors that are placed directly on mains. Link here (PDF)

To help reducing emission and increasing the immunity of radio interference, electromagnetic interference suppression film capacitors (EMI capacitors) are playing a major role in all kind of applications. These capacitors are put directly parallel over the mains at the input of the appliances.

Because of the high energy availability and the severe environment of surge voltages and pulses, applications of capacitors in connection with the mains must be chosen carefully. Two kinds of connections and thus two kinds of applications can be distinguished. One is where the capacitor is directly connected in parallel with the mains without any other impedance or circuit protection, and another where the capacitor is connected to the mains in series with another circuitry.

App note: Modern PRTD temperature sensors and high-resolution Delta-Sigma ADCs enable wide range high-accuracy temperature measurements

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Modern PRTD temperature sensors and high-resolution Delta-Sigma ADCs enable wide range high-accuracy temperature measurements application note from Maxim:

Many modern industrial, medical, and commercial applications require temperature measurements in the extended temperature range with accuracies of ±0.3°C or better, performed with reasonable cost and often with low power consumption. This article explains how platinum resistance temperature detectors (PRTDs) can perform measurements over wide temperature ranges of -200°C to +850°C, with absolute accuracy and repeatability better than ±0.3°C, when used with modern processors capable of resolving nonlinear mathematical equation quickly and cost effectively. This article is the second installment of a series on PRTDs. For the first installment, please read application note 4875, “High-Accuracy Temperature Measurements Call for Platinum Resistance Temperature Detectors (PRTDs) and Precision Delta-Sigma ADCs.”

A similar version of this article appeared in the June 21, 2012 issue of EDN magazine.

App note: The 2-Channel serial audio interface: A tutorial

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A pretty older application note about the serial audio interface by Cirrus Logic. Link here (PDF)

It may come as a surprise to those trying to make their initial investigation into audio systems design that there is a de-facto standard for transferring audio data within a system. Despite the differing naming conventions used within the industry, these apparently different interfaces are essentially identical. For the sake of simplicity, we will use the term Serial Audio Interface (SAI) in this discussion. The Serial Audio Interface is by far the most common mechanism used to transfer two channels of audio data between devices within a system; for instance, from the analogto-digital converter to the Digital Signal Processor (DSP) and then the digital-to-analog converter.

App note: The LM4935 headset and push-button detection guide

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Another headset plug-in detection from Texas Instruments. Link here (PDF)

The headset detect circuitry can differentiate between mono, stereo, mono with microphone, and stereo with microphone headsets. It can operate while the LM4935 is placed into low current standby mode, which promotes extended battery life. In standby mode, it consumes no extra current, if the headset has not been inserted into the headset jack.

App note: Differences between ATmega328/P and ATmega328PB

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Differences between ATmega328/P and ATmega328PB (PDF!) application note from Atmel:

This application note assists the users of Atmel® ATmega328 variants to understand the differences and use Atmel ATmega328PB.
ATmega328PB is not a drop-in replacement for ATmega328 variants, but a new device. However, the functions are backward compatible with the existing ATmega328 functions. Existing code for these devices will work in the new devices without changing existing configuration or enabling new functions. The code that is available for your existing ATmega328 variants will continue to work on the new ATmega328PB device.
The ATmega328PB is the first 8-bit Atmel AVR® device to feature the successful Atmel QTouch® Peripheral Touch Controller (PTC).
For differences in errata, typical, and electrical characteristics between ATmega328 variants and ATmega328PB, refer to the specific device datasheets.

App note: MSP430 32-kHz crystal oscillators

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MSP430 32-kHz crystal oscillators (PDF!) application note from Texas Instruments:

Selection of the right crystal, correct load circuit, and proper board layout are important for a stable crystal oscillator. This application report summarizes crystal oscillator function and explains the parameters to select the correct crystal for MSP430
ultralow-power operation. In addition, hints and examples for correct board layout are given. The document also contains detailed information on the possible oscillator tests to ensure stable oscillator operation in mass production.