App note: Trends in integrated circuits that affect ESD protection requirements


A quick lookup on the ESD protection evolution of ICs in this app note from ON Semiconductor. Link here (PDF)

The stunning progress in integrated circuit capability over the last 40 years is most succinctly expressed by Moore’s Law; “Every 2 years the number of transistors that can be economically manufactured in an integrated circuit will double”. The secret to this success has been the shrinking of integrated circuit feature sizes in all three dimensions. To maintain circuit reliability with the smaller dimensions the operating voltage of integrated circuits has been steadily declining. This trend will continue in the future, as documented in the International Technology Roadmap for Semiconductors. As the working voltage for integrated circuits decreases the voltage at which circuit damage can occur also decreases.

The move to smaller geometries has also prompted fundamental changes in IC technologies that have had an adverse effect on the intrinsic ability of the technologies to survive ESD stress. A prime example is the evolution of nMOS transistors in CMOS technologies.

App note: Circuit configuration options for TVS diodes


Different TVS configuration usage app note from ON Semiconductor. Link here (PDF)

Transient Voltage Suppression (TVS) protection is important because EMI and ESD can disturb the operation of the system, produce permanent damage or cause latent damage that will eventually cause a failure. Avalanche TVS diodes and diode arrays are available in a number of different circuit configurations to protect electronic circuits from surge voltages. This document will analyze the attributes and trade-offs of different circuit configurations created with avalanche TVS and diode array protection devices.

App note: How to select an ambient light sensor for your end equipment


Another application note from Texas Instruments about ambient light sensors and how to effectively use them. Link here (PDF)

Generally, when someone thinks of trying to design a system with an ambient light sensor there are four main concerns or problems that need to be addressed. The most important features of an ambient light sensor are spectral response, power, size, and range of lux measurement.

App note: How to isolate signal and power in isolated CAN systems


CAN system isolation app note from Texas Instruments, Link here (PDF)

With the increase in the usage of signal isolation in many industrial and automotive applications, the need for isolated power has also increased. The benefits of isolation are lost if the power supplies on either side of the isolation barrier are simply shorted. At the same time, if the isolated power sub-systems are not designed carefully, it affects the overall system performance like temperature rise due to poor power transfer efficiency, data corruption due to emissions, and so on. To simplify the design process of isolated CAN sub-systems, this document provides various options (discrete and integrated) to isolate CAN signals and power.

App note: Detecting selfie sticks using TI audio jack switches TS3A227E and TS3A225E


Old app note from Texas Instruments on smart phone selfie sticks button detection. Link here (PDF)

Selfie sticks are becoming as common of a smart phone accessory as a pair of headphones. Because of the selfie stick’s increasing popularity, smart phone manufacturers need to be able to accommodate the accessory. This report describes the procedure required for a smart phone to detect when a selfie stick accessory is inserted into a smart phone’s audio jack receptacle using TI audio jack switches TS3A227E and TS3A225E. It shows how these devices respond to common selfie-stick implementations and how to adjust the audio jack switch’s register settings to accommodate both traditional audio accessories as well as the new selfie stick accessory.

App note: EMI-hardened operational amplifiers reduce inaccuracies


EMI reduction built-in on op amps, app note from Texas Instruments. Link here (PDF)

Operational amplifiers (op amps) with electromagnetic interference (EMI) filters can reduce significant errors. These types of errors are not always obvious to the system designers. They often impact the signal chain, in particular the analog-to-digital converter in the form of a loss of digital counts.

App note: How to properly configure unused operational amplifiers


Good read app note from Texas Instruments about configuring unused op amps on multi amp chips. Link here (PDF)

Multi-channel operational amplifiers (op amps) are often implemented in circuits that do not require the use of all channels. Undesired behavior in an unused amplifier channel can negatively impact system performance, as well as the performance of the channels in use. To avoid degradation of both the op amp and system performance, the unused op amp channels must be configured properly.

App note: Current sense amplifiers in class-D audio subsystems


App note from Texas Instruments about output current sensing in class-D amplfiers. Link here (PDF)

Current sensing in audio subsystems are widely used in conjunction with CLASS-D amplifiers for diagnostics or to provide speaker current feedback to the DSP for speaker enhancement to emulate smartamp. The most expensive component in the audio subsystem is the speaker. The impedance of the speakers ranges from 2Ω for subwoofer to a 8Ω for stereo speakers. Exceeding the current flowing through the speakers has a potential to create excessive heat in the voice coil which can lead to permanent damage of the speakers.

App note: Pulsed Over-Current Driving of LEDs


App note from CREE on driving LEDs over its specified current capability. Link here (PDF)

The Applications Engineering team at Cree is often asked whether it is safe to operate Cree XLamp® LEDs with pulsed currents above the maximum data-sheet rating. This question is usually asked in the context of legitimate product requirements such as those posed by emergency-vehicle applications, specialized stroboscopic illumination and even pulsed modulation for general-illumination dimming applications.

The short answer is “it depends.” Multiple variables affect both initial and long-term performance and reliability of an LED. These include thermal resistance, pulse duration, as well as current amplitude, frequency and duty cycle.

App note: Optimizing PCB Thermal Performance for LEDs


Application note from CREE on efficiently designing a conventional FR4 PCB to manage thermal heat and as a cheap alternative to metal core pcbs. Link here (PDF)

One of the most critical design parameters for an LED illumination system is the system’s ability to draw heat away from the LED junction. High operating temperatures at the LED junction adversely affect the performance of LEDs, resulting in decreased light output and lifetime. To properly manage this heat, specific practices should be followed in the design, assembly and operation of LEDs in lighting applications.