App note: How to maintain USB signal integrity when adding ESD protection

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Introducing the eye diagram method in this app note from ON Semiconductors in determining signal integrity of USB lines. Link here (PDF)

The Universal Serial Bus (USB) has become a popular feature of PCs, cell phones and other electronic devices. USB makes data transfer between electronic devices faster and easier. USB 2.0 transfers data at up to 480 Mbps. At these data rates, any small amount of capacitance added will cause disturbances to the data signals. Designers are left with the challenge of finding ESD protection solutions that can protect these sensitive lines without adding signal degrading capacitance. This document will discuss USB 2.0 and evaluate the importance of low capacitance ESD protection devices with the use of eye diagrams.

App note: Low-side self-protected MOSFET

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Integrated fault protected MOSFET app note from ON Semiconductors. Link here (PDF)

The ever increasing density and complexity of automotive and industrial control electronics requires integration of components, wherever possible, so as to conserve space, reduce cost, and improve reliability. Integration of protection features with power switches continues to drive new product development. The often open environments of automotive and industrial electronics, subject to severe voltage transients, high power and high inductance loads, numerous external connections, and human intervention force the requirement of fault protection circuitry. Advancements in power MOSFET processing technology afford an economical marriage of protection features, such as current limitation, and standard MOSFET power transistor switches. This paper describes the technology and operation of ON Semiconductor’s HDPlus monolithic low-side smart MOSFET family.

App note: Hot plug insertion startup time delay for eFuse

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App note from ON semiconductors about time delay on start up in conjunction with eFuse to compensate voltage spikes that can falsely trigger them. Link here (PDF)

The eFuse protection devices are used for limiting the system load current in the event of an overload or a short circuit. Many applications employ ON Semiconductor eFuses at the power input stage of the system between the main power input connector and DC−DC converters or power regulators. Such applications often tend to experience a voltage spikes and transients during a hot-plug events, especially when the long cables are used at the power input.

Although ON Semiconductor eFuses are extremely immune to voltage transients and eFuses with the Overvoltage clamp feature provide a fast response when limiting the output voltage during transients, sometimes various applications require a time delay between the hot-plug input voltage application and enabling of the eFuse in order for the input voltage to be stabilized before turning on the eFuse.

App note: The four benefits brought by using NCP12600

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App note discussing extended features of NCP12600, NCP12600 is a multi-mode controller for offline power supplies by ON Semiconductor. Link here (PDF)

Beside the novel multi−mode structure it embarks, the NCP12600 packs a lot of features such as an efficient short−circuit protection architecture, a start−up sequence with a slow switching frequency ramp−up, a fast reset when latched and an auto−recovery scheme when line cycle dropout occurs in latched versions. Let’s discover these novelties in the present application note.

App note: Application of SiC MOSFETs

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App note from ON Semiconductors about Silicon Carbide MOSFETs, their difference and gains over Silicon MOSFETs. Link here (PDF)

Among the Wide Band Gap materials silicon carbide (SiC) is by far the most mature one. The raw wafer quality has greatly improved over the last years with significant reduction of micro pipes and dislocations. Silicon carbide devices can work at high temperatures, are very robust and offer both low conduction and switching losses. The high thermal conductivity makes SiC also a perfect choice for high power applications, when good cooling is required. Compared to silicon switches, silicon carbide MOSFETs inherit some specific characteristics like the shift of gate threshold a designer should be aware of. This effect will be explained in this application note.

App note: Interfacing to analog switches: Driving the control input of an analog switch with 1.8 V or lower − Is it safe?

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ON Semiconductor’s analog switches let you drive with an input control voltage lower than Vcc. Link here (PDF)

Analog switches are everywhere today. Due to their small size and low current consumption, they are popular in portable devices where they are effective in a variety of subsystems including audio and data communications, port connections, and even test. They can be used to facilitate signal routing, allow multiple data types to share an interface connector, or permit temporary access to internal processors during manufacturing. Analog switches are often used to give portable system designers a convenient method of increasing their features or accessibility without duplicating any circuitry. Understanding the key specifications and tradeoffs can make the difference between a temporary fix and a truly optimized solution.

App note: Consideration of self-pollution reduction for electronic systems

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App note from ON Semiconductors discussing how locally generated EMI affects its own system and how to prevent it. Link here (PDF)

This application note will address the problem of Electro Magnetic Interference (EMI) self pollution in which one part of an electrical systems such as cell phones and consumer electrical products emit radiation that interferes with the operation of other parts of the system.

App note: Current sensing power MOSFETs

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SENSEFET App note from ON Semiconductors incorporate a current sense inside a power MOSFET, these devices are straight forward calculating for sense resistance and voltage but have trade-offs for smaller current sensing. Link here (PDF)

Current sensing power MOSFETs provide a highly effective way of measuring load current in power conditioning circuits. Conceptually simple in nature, these devices split load current into power and sense components, and thereby allow signal level resistors to be used for sampling. Since this technique results in higher efficiency and lower costs than competing alternatives, understanding how to use SENSEFET product is an important design issue.

Getting accustomed to these devices is relatively, but not completely, straightforward. They are conceptually simple, but have their own unique set of characteristics and subtle properties. The following discussion examines both, and starts with a description of how SENSEFET devices work.

App note: Improve flicker performance of direct AC driven LED fixtures with self valley fill

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Application note from ON Semiconductors on LED lighting flicker caused by its own AC supply by adding an improved self valley fill circuit. Link here (PDF)

To provide power to LED loads from AC input, SwitchMode Power Supplies (SMPS) are generally used since LED need to be driven by regulated current. Consequently, LED lighting solution have to inherit the design complexity of a typical SMPS which includes designing the magnetic component, handling of Electromagnetic Interferences (EMI) as well as implementing Power Factor Correction (PFC). Direct-AC Drivers (DACD) for LEDs provides a new way to drive the LED load from an AC input with much simpler system architecture while satisfying EMI and power factor (PF) requirements with minimal effort. However, its drawback is flickering of light output at the zero crossing of AC line voltage due to loss of current to the LED load.

Though flicker is not always obvious, it can still cause headaches for a small percentage of people exposed to flickering lights for long periods. This is a major issue for offices, schools, stores and other brightly lit commercial and industrial spaces where people spend a lot of time.