App note: Clearing Xilinx FPGA configuration to allow boundary scan testing

Another application note from XJTAG on preparing Xilinx FPGA for proper boundary scan testing. Link here

When Xilinx FPGAs are configured it can restrict the boundary scan access to some signals on the device. One work-around for this problem is to configure the FPGA with a ‘blank’ image that closely matches its unconfigured state, allowing boundary scan testing to occur without any problems.

A second issue that can affect boundary scan testing with FPGAs is that they contain pull resistors. Depending on the design, these may be enabled when the FPGA is unconfigured as well as when it is configured. If these internal resistors are enabled on nets that contain pull resistors mounted on the board, two potential problems can occur:

1. If the internal resistor and external resistor pull in opposite directions, the boundary scan tests may not be able to test the external pull resistor if it is weaker than the internal pull resistor.
2. If the internal and external resistors pull in the same direction, a fault with the external resistor may not be detected because the internal resistor may mask the fault.

By setting the correct configuration options it is possible to disable these internal pull resistors when generating a ‘blank’ FPGA image.

App note: Using a test reset section to initialise JTAG devices

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An app note from XJTAG about applying test reset to put some devices to JTAG compliant mode. Link here

Some JTAG devices require a specific sequence of states to be applied to some signals in order to put the device into a JTAG-compliant mode. This application note describes how a Test Reset section can be used to describe the required sequence and control its application.

App note: Linear power MOSFETS basic and applications

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Some examples of power MOSFETS application from this app note from IXYS Corporation. Link here (PDF)

Applications like electronic loads, linear regulators or Class A amplifiers operate in the linear region of the Power MOSFET, which requires high power dissipation capability and extended Forward Bias Safe Operating Area (FBSOA) characteristics. Such mode of operation differs from the usual way of using Power MOSFET, in which it functions like an “on-off switch” in switched-mode applications. In linear mode, the Power MOSFET is subjected to high thermal stress due to the simultaneous occurrence of high drain voltage and current resulting in high power dissipation. When the thermo-electrical stress exceeds some critical limit, thermal hot spots occur in the silicon causing the device to fail

App note: Depletion-Mode power MOSFETs and applications

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IXYS Corporation’s N-Channel power MOSFET selection and application. Link here (PDF)

Applications like constant current sources, solid-state relays, telecom switches and high voltage DC lines in power systems require N-channel Depletion-mode power MOSFET that operates as a normally “on” switch when the gate-to-source voltage is zero (VGS=0V). This paper will describe IXYS latest N-Channel Depletion power MOSFETs and their application advantages to help designers to select these devices in many industrial applications.

App note: Infrared (IR) Spectroscopy with the SFH 473X – Background & technology

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Infrared spectroscopy by OSRAM and their SFH 473X broadband light emitters. Link here (PDF)

Imagine you can check if the mangos on the market are sweet – without even touching them…

Imagine you can verify if your prescribed medical tablets contain the life-saving compound – or if they are counterfeits…

Imagine you can check the calories of your favorite cheese dish – before eating…

Imagine all this is possible with one fingertip on your smartphone…

The SFH 473X series is precisely designed to support this innovation. This note covers briefly the background of spectroscopy and the case for the SFH 473X series.

App note: Ambient light sensors – General application note

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Different ambient sensors differs on their ability to sense specific wavelength and introduce different ambient levels compared to human eye, here’s a general application note from OSRAM. Link here (PDF)

This application note introduces discusses ambient light sensing. The different types of ambient light sensors are described and related to specific applications.

App note: USB Type C, CC Pin design considerations, high voltage design considerations for Type-C connector pins in systems supporting non-USB standard charging protocol and/or fault cases

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Another app note from Fairchild Semiconductors on USB Type C to USB legacy design considerations. Link here (PDF)

When designing hardware systems with type C connectors, a designer also has to consider all legacy, standard, and nonstandard specifications that exist in the USB connector eco system. With the introduction of the Type C connector and the Configuration channel (CC Pin) new challenges occur trying to ensure overall system robustness. This note addresses some of the concerns with the CC pin in a robust system environment.

App note: USB Type-C design considerations, USB Type-C adapters

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Type-C USB cable adapter design consideration app note from Fairchild Semiconductors. Link here (PDF)

USB is a ubiquitous connector that is used by many customers and in many different applications. With the official release of the USB Type-C connector, many companies are racing to implement this new connector and the supporting infrastructure. The early adopters of this connector will be faced with many challenges as different vendor’s release products that are either non-compliant or designed to earlier versions of the specification.

One specific challenge is with USB Type-C adapter cables and how they are implemented. The adapter cables are critical for new designs because they allow backward compatibility to the existing USB infrastructure. Vendors are making a wide range of adapter cables which can cause detection issues which need to be considered. This application note describes these considerations and possible solutions to the problems faced.

App note: HT45F3630 power tool speed control switch application example

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All in one motor control MCU HT45F3630 from Holtek. Link here (PDF)

Aimed at the motor speed control product application area, HOLTEK has developed the HT45F3630, which is commonly used in electric drills, electric screwdrivers, lawn mowers and other similar product applications. This MCU provides a group of PWM high voltage and large current output pins which can directly drive Power MOS transistors to reduce their switching losses. Additionally, the device includes integrated over current protection and detection functions and an amplifier which allows the input signal to be amplified by 51 times, requiring a lower value current sense resistance value which will increase the overall efficiency and extend the operating time. When an over current event occurs, the PWM switching will be shut off by hardware to achieve immediate protection.