App note: Understanding data eye diagram methodology for analyzing high speed digital signals


Application note from ON Semiconductors about the Data eye diagram methodology to represent and analyze a high speed digital signal. Link here (PDF)

The eye diagram allows key parameters of the electrical quality of the signal to be quickly visualized and determined. The data eye diagram is constructed from a digital waveform by folding the parts of the waveform corresponding to each individual bit into a single graph with signal amplitude on the vertical axis and time on horizontal axis. By repeating this construction over many samples of the waveform, the resultant graph will represent the average statistics of the signal and will resemble an eye. The eye opening corresponds to one bit period and is typically called the Unit Interval (UI) width of the eye diagram. An ideal digital waveform with sharp rise and fall times and constant amplitude will have an eye diagram.

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


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


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: The 2-Channel serial audio interface: A tutorial


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


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: Inductors


Murata’s application note about inductors and its specifications. Link here (PDF)

Reading a specification for an inductor is considered a simple task, however, there is often some confusion even over the meaning of relatively straight forward parameters.

App note: The LED versus LCD decision


Choosing between two display types, LED and LCD discussed in this application note from Murata. Link here (PDF)

Users of contemporary digital panel meters (DPMs) have a variety of options available to them. While options are nice, they invariably mean more choices have to be made. After determining what meter resolution one requires, the next most basic decision is usually which type of display to use liquid crystal or light emitting diode?
Traditionally, liquid crystal displays (LCDs) have been the obvious choice for outdoor/daylight applications and/or for applications requiring extremely low power consumption (current drains less than 15mA). Light emitting diode (LED) displays, with their comparatively low light intensities and relatively high current drains, have been excluded from these more demanding applications.
Recent DATEL innovations, most notably the introduction of extremely low-power LED displays, have complicated the once straightforward, LED/LCD decision.

App note: EFM32 Energy Modes


Application note from Silicon Labs on their EFM32 energy saving microcontrollers, some interesting points are discussed how these type of microcontrollers can conserve power. Link here (PDF)

In battery powered microcontroller applications, energy saving is essential. By reducing the current consumption, the mean time between battery charging / replacement can be significantly increased. Following these principles will drastically reduce the current consumption:
• Use appropriate Energy Modes
• Exploit low energy peripherals
• Turn off unused modules / peripherals
• Disable clocks to unused modules / peripherals
• Reduce clock frequency
• Lower the operating voltage
The EFM32 supports extensive usage of all these principles.


App note: LCD screens don’t flicker – or do they?


An old application note from Intersil on comparison of CRT and LCD regarding display flicker. Link here (PDF)

When comparing CRT to LCD screens, one of the most popular differences is the issue of flicker. It is a common assumption that CRT screens flicker while LCD screens do not. In truth, both screens have some amount of flicker. The mechanisms are different and methods for correction have varying amounts of success. This appnote presents the cause of flicker in LCD screens and offers a solution for avoiding flicker by using our ISL45041/2 LCD Module Calibrator in LCD panels.