App note: Transmitting SXGA video signal through 1kft (300m) CAT-5 cable

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An app note from Intersil on utilizing CAT-5 cable for SXGA video transimission. Link here (PDF)

The goal of this application note is to present the most current design methods for transmitting high bandwidth SXGA video signal over long distances of CAT-5 cable (300m or more). The enormous cost benefits of CAT-5 cable will also be discussed; for instance, the average cost of a 100m of CAT-5 cable is $20 while the average cost of a 100m of Coax Cable could easily exceed $240. Furthermore, wiring is reduced from a bulky hard to manage bundle of 3 cables to 1 easily pulled cable. Additionally, CAT-5 cable has a 4th twisted pair available, which can be used for KVM signal, audio, timing or control signal transmission.

App note: Thermal behavior of small-signal discretes on multilayer PCBs

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App note from NXP Semiconductors about multilayer PCB as additional heatsink for flat SMD components mostly power transistors to dissipate heat. Link here (PDF)

This application note illustrates how to improve the power dissipation of discrete components by using multilayer PCBs. It focuses on the impact of using larger copper areas to improve the thermal behavior of applications.

App note: Enhancing cellphone battery performance during GSM pulses through the use of a parallel supercapacitor

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Low ESR and ESL supercapacitor paralleled to cellphone batteries can react more quickly to the demanding power required by GSM pulses. A great appnote read from AVX, link here (PDF)

With the constant addition of features and functionality, battery life and reliability are becoming increasingly vital to those who rely on their smartphones. The transmission signal requires quick pulses of current from the battery, potentially causing the instantaneous voltage of the battery to drop below the phone’s minimum voltage of operation. This may cause the power to the battery to be temporarily interrupted. A series of tests were performed on multiple battery chemistries to determine the beneficial effect of placing an AVX supercapacitor in parallel with the battery, to improve the life of the battery as well as the quality of power provided from it.

App note: Projection with LED light sources

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LEDs are now mostly used in light projection systems due to their low power requirements, long life and robustness. Here’s an app note from OSRAM for proper integrations on these projection LEDs. Link here (PDF)

This application note provides insights into the use of LED light sources for projection applications. An overview of LED projection systems and their benefits is presented, along with a summary of OSRAM Opto Semiconductors LEDs suitable for these applications. Finally, fundamental design issues related to the use of LEDs in projection modules are addressed.

App note: Potting protection for outdoor LED video walls and signs

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LED signs and large LED video panels are always subjected to harsh environment resulting to corrosion to their pcb mountings, here’s an app note from OSRAM about potting these LED panels for protection. Link here (PDF)

This note provides basic information about the potting of flat SMT LEDs in video wall and signage applications. Thereby details on material in use, examples of suitable equipment and the process are presented and described. Additionally, the note gives a short intro into video walls with a typical setup, varying LED type system effects and general challenges. Finally, the results of selected environmental tests are presented, to demonstrate their impact and the aptitude of potting protection method.

App note: PointLED® – It’s nice to be different

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New SMD LED design from OSRAM ideal for mounting on PCB holes for illumination. Link here (PDF)

This application note provides insight into the universally deployable and flexibly mountable light source of the PointLED® product family. A fundamental overview of the LED construction as well as the optical and electrical characteristics and performance of the LED are presented.

App note: How to handle a reed switch

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Proper handling of reed switches to prolong operation and or storage, an application note from HSI sensing. Link here (PDF)

Reed switches consist of two or three metal reed contacts (blades) that are hermetically sealed inside a glass tube. This seal, while strong, may be damaged if proper handling is not used. HSI Sensing has years of experience handling reed switches and have identified several best practices.

App note: Design considerations for mixed-signal, How to design a PCB layout

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Another application note from e2v, this time about PCB design involving mixed-signal (Analog and Digital) components. Link here (PDF)

This application note aims at providing you with some recommendations to achieve improved performance.

The initial assumptions are the following:
• Proper grounding and routing of all signals is essential to ensure accurate signal conversion
• Eliminate the loop area return by using both separate ground plane and power plane
• Circuitry placement on mixed-signal PCBs is a crucial design point

In many cases, engineers have preconceived notions about mixed-signal designs and how analog and digital placement, partitioning and associated design should be performed.

When laying out components for a mixed-signal PCB, certain considerations are critical to achieve optimum performance. Mixed-signal is particularly tricky to design since analog devices possess different characteristics compared to digital components: different power rating, current, voltage and heat dissipation requirements, to name a few.

This study shows how to prevent digital logic ground currents from contaminating analog circuitry on a mixed-signal PCB and particularly ADC component. In our attempt to answer this question, let’s keep in mind two basic principles of electromagnetic compatibility. One is that currents should be returned to their source as locally and compactly as possible, through the smallest possible loop area. The second is that a system should have only one reference plane, if not we would create a dipole antenna.

App note: Dithering in analog-to-digital conversion

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e2V’s application note about dithering, adding noise to improve the dynamic range of ADCs. Link here (PDF)

High-speed ADCs today offer higher dynamic performances and every effort is made to push these state-of-the art performance through design improvements and also through innovative solutions at the system level.

For applications where the performance of the high-speed ADC in the frequency domain is the main critical parameter for the system overall performances, it is possible to improve the ADC response thanks to dither.

Dithering can be defined as adding some white noise, which has the effect of spreading low-level spectral components.

In this application note, the technique of dithering is presented, described and illustrated thanks to test results performed in the 10-bit 2.2Gsps ADC AT84AS008 device.

App note: Power MOSFET in high-side operating modes, possible failure modes, and failure signatures

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App note from Vishay on high-side MOSFET failures investigation leads to one of the following modes of operation:
(a) High-impedance gate drive
(b) Electro-static discharge (ESD) exposure
(c) Electrical over-stressed (EOS) operation

More on it here (PDF)

Power MOSFET failures in high-side applications can often be attributed to a high-impedance gate drive creating a virtual floating gate, which in turn increases the susceptibility of the MOSFET to failure during system-generated ESD and EOS scenarios.