I frequently design new electronics systems. Sometimes these are variations of something I have done before and at other times they are completely new. If you are new to a particular product area and there is something similar in the marketplace then it is always a good idea to have a look at how other […]
Power supply noise
Power supply noise can come in more than one form. It could be switching noise from a switching regulator or switched mode power supply or noise from a linear regulator. While switching noise is to be expected, linear regulators are often assumed to be “quiet” but they may not be as quiet as you think. […]
Effects of intermodulation distortion in analog circuits
Unless you are an RF designer you probably haven’t thought much about intermodulation distortion. Harmonic distortion is more likely to have been of concern with low frequency circuits such as video and audio. Harmonic distortion, as the name suggests, creates unwanted components which are harmonically related to the signal. So, if you are amplifying 1kHz […]
Level Shifting Digital Logic Signals Part 2
I discussed the problem of level shifting logic signals a while ago but I noticed the recently introduced NXP AXP level shifters so thought it was worth revisiting the subject to see if these new devices will really help solving the problem of interfacing the increasingly varied power supply voltages in digital and mixed-signal circuits. […]
Understanding accelerometers
Accelerometers used to be expensive devices used in aircraft and missiles but now they are very cheap devices found everywhere – for example in your mobile phone. Their use in a mobile phone is not as critical as part of an aircraft navigation system and the accuracy and cost reflect that, with 3 axis devices […]
Choosing inductors or ferrite beads for power supply filtering
I recently came across an interesting article by Analog Devices in their February “Analog Dialogue” called “Ferrite Beads Demystified”. It was interesting beyond its analysis of ferrite beads because it covered one of the issues I have seen in the past with regards to power supply filtering — that of resonance between a power supply […]
Using online design tools
While a lot of manufacturers have “design” tools to help you choose their parts, there are also other useful tools out there. Some, like Appcad, were just tools without trying too hard to sell you anything. Appcad is still available www.hp.woodshot.com and the current version 4.0.0 is really version 3.0.2 with the branding changed. I […]
How to choose transistors
Choosing a transistor can be a daunting task, not because it is necessarily complicated (but it can be!) but because there are so many to choose from. Digi-Key lists over 40,000 MOSFETs for example. Even before you start your search you need to decide on which type of transistor. For a simple, microcontroller driven switch […]
Understanding charge storage in semiconductors
While we are all probably familiar with the concept of capacitors storing charge, remember that semiconductors do so as well. This may not be an issue for your design or it could be a major headache, depending on the application. With bipolar transistors, charge storage in the base when the transistor is saturated will slow […]
How to choose an operational amplifier: what you need to know
Choosing an opamp for a particular task can sometimes be simple but at other times, you will have a lot of conflicting requirements which makes choosing more of a challenge. Also, the number of opamps available now is huge so it can take a while to work your way through the options from different manufacturers. […]