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.

App note: Interfacing AT84AD001B dual 8-bit 1 Gsps ADC and AVR ATmega128L


e2v’s application note interfacing their 1 Gsps 8-bit ADC to AVR. Link here (PDF)

With its smart feature (3-wire serial interface), e2v’s AT84AD001B dual 8-bit 1 Gsps ADC provides you with digital control over various functions offered with the dual ADC: calibration, gain and offset adjustments, DMUX ratio selection, analog and clock input mode, and partial or full standby mode.

This digital control via the 3-wire serial interface can be managed using Atmel’s ATmega128L AVR. The aim of this application note is to provide you with the relevant information for interfacing these two devices.

App note: Designing VCNL3020 into an application


An app note from Vishay: Designing VCNL3020 into an application (PDF!)

The VCNL3020 is a proximity sensor with I2C interface. It combines an infrared emitter, PIN photodiode, and signal processing IC in a single package with a 16 bit ADC. With a range of up to 20 cm (7.9″), this stand-alone, single component greatly simplifies the use and design-in of a proximity sensor in consumer and industrial applications because no mechanical barriers are required to optically isolate the emitter from the detector. The VCNL3020 features a miniature leadless package (LLP) for surface mounting in a 4.9 mm x 2.3 mm package with a low profile of 0.83 mm designed specifically for the low height
requirements of smart phone, mobile phone, digital camera, and tablet PC applications. Through its standard I2C bus serial digital interface, it allows easy access to a “Proximity Signal” measurement without complex calculations or programming. The programmable interrupt function offers wake-up functionality for the microcontroller when a proximity event occurs which reduces processing overhead by eliminating the need for continuous polling.

App note: WM8731 Suggested power-On/Off sequence


Interesting app note from Cirrus Logic on how to minimize popping sound on the output when turning on/off the DAC on their WM8731 digital to analog converter. Link here (PDF)

As with any consumer audio product, it is important that any on/off power noise be kept to a minimum. Generally, this is done with some sort of external mute circuit at the output socket of the application. Although effective, this does increase the BOM (bill of materials) cost, which in many cases is a critical factor.

With this in mind, the WM8731 DAC signal path may be powered-on in such a way that power on/off noise is kept to a minimum with no need for an external muting circuit, reducing the BOM cost.

App note: CS3001/2/11/12 & CS3003/4/13/14 Chopper-stabilized Operational Amplifiers



Cirrus Logic’s app note, discussing their own designed chopper amps. Link here (PDF)

The chopper-stabilized amplifiers designed at Cirrus Logic are unique. These amplifiers offer performance benefits that combine the best features of bipolar amplifiers with the best features of chopper amplifiers. The intent of this application note is to understand Cirrus Logic’s unique technology and to see how it can be applied in various measurement applications.

App note: Output buffer options for Si53X/55X/57X/59X XO/VCXO devices


SiLabs’ application note: Output buffer options for Si53X/55X/57X/59X XO/VCXO devices (PDF!)

The Si53x/55x/57x/59x XO/VCXO devices can be ordered with one of four different output buffer types: CMOS, LVPECL, LVDS, or CML. Each output type has its own particular benefits and disadvantages. This document describes each buffer type, proper biasing and termination schemes, and related technical trade-offs.

App note: WM9712 Jack plug auto-detection, hookswitch detection and microphone headset detection


App note on Cirrus Logic’s WM9712 jack plug auto-detection by monitoring the connected headphone resistance. Link here (PDF)

This application note describes two operations associated with using headset. The first is the facility to automatically switch between a mono ear speaker and stereo headphones for use in a Smartphone, PDA etc. The second operation is a method which can be used to detect if stereo headphones have been attached or if a mono headset with microphone has been attached.