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 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
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.
More to know about MOSFET gate threshold voltages, an application note from Vishay. Link here (PDF)
The question of how to turn on a MOSFET might sound trivial, since ease of switching is a major advantage of field-effect transistors. Unlike bipolar junction transistors, these are majority carrier devices. One does not have to worry about current gain, tailoring the base current to match the extremes of hfe and variable collector currents, or providing negative drives. Since MOSFETs are voltage driven, many users assume that they will turn on when a voltage, equal to or greater than the threshold, is applied to the gate. However, the question of how to turn on a MOSFET or, at a more basic level, what is the minimum voltage that should be applied to the gate, needs reappraisal with more and more converters being controlled digitally. While digital control offers the next level of flexibility and functionality, the DSPs, FPGAs, and other programmable devices with which it is implemented are designed to operate with low supply voltages. It is necessary to boost the final PWM signal to the level required by the MOSFET gate. This is where things begin to go wrong, because of the misconceptions about what really turns on a MOSFET. Many digital designers look at the gate threshold voltage and jump to the conclusion that, just as with their digital logic, the MOSFET will change state as soon as the threshold is crossed.
Another very interesting bit of technology. The combination of so much functionality into such a small part is a real touch-stone as to where things are heading.
A quick look at the antenna design to see if I could sort down the details and then some die-decap to analyze the silicon a bit. The RF section is especially interesting. In the video I call out a section as being an inductor… on second thought as I type this it might even be a transformer?
Another small board, this time for a INA219. The INA219 is a high-side current shunt and power monitor with an I2C interface.
For testing I used Rei VILO library with a MSP430G2553 and Energia, and I measured the power consumption for this simple circuit.