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I recently saw a question posted on LinkedIn about whether purely reactive components produce noise like resistors do. This, of course, would be Johnson Noise, also known as Thermal Noise. I do not recall any mention of such noise in reactive components (inductors and capacitors) in my studies, other than the that attributed to the resistances associated with these components. And there is not much written about this subject. The few times I have seen anything written about this, it is stated th ...
Maxim Integrated has recently introduced the MAX11300 (SPI interface) and MAX11301 (I2C interface) Programmable Mixed Signal I/O (PIXI™) Devices. They contain a 12-bit ADC, 12-bit DAC, 2.5V (0.24%) internal reference and temperature sensor and sport impressive specifications. These FPAAs (Field Programmable Analog Arrays) should be welcomed by the analog community, but it should be recognized that these devices are by no means the first FPAA products available and it might be argued that t ...
nickgray

Reference Designs

Posted by nickgray Oct 21, 2013
I once worked for a company that provided circuit designs and even application notes based upon construction of a single copy of a circuit, generally at the request of a customer. This is fine if the usual disclamers are given. However, that company did not give any disclaimers at all and customers rightfully complained when they designed the circuit into their prototype systems and the circuit did not work properly. It was my job to help customers with these and other problems and most of the t ...
In a world enamored with all things digital, analog just refuses to die. It seems as though analog may be old-fashioned. After all, everything we have and use today is digital. Our cameras, telephones, television, communications systems, and everything else seems to have gone digital. Doesn’t this make analog irrelevant? The truth is, the natural world is analog. Digital is black and white, like flipping a light switch on and off, while analog is shades of grey, like the rising and setting ...
During the recent DesignCon of January 2013 engineering students expressed their desire for role models. I do not believe there is a shortage of role models so much as a lack of introducing role models to them. I do not pretend to know of all role models, but I certainly believe that people like Jim Williams, Bob Pease and Bob Widlar are among the present day role models of analog electrical engineering. Unfortunately, they are now all deceased. Jim Williams began as an engineering technician an ...
I often get questions about changing a bipolar supply circuit (using positive and negative supplies) to a circuit that uses no negative supply. Operational amplifiers do not care whether or not they have a negative supply, but do require a certain range of total supply voltages. So, for +15V / -15V performance, it would seem that we may need a positive supply voltage of +30V and ground. However, the input should be near halfway between the two supply voltages, or in the vicinity of +15V with a s ...
Many things can be accomplished with either analog or digital techniques, but any given application can best be done with one or the other, usually. There are places for analog and places for digital and there really should be no argument about that.   ...
nickgray

High Gain Circuits

Posted by nickgray Mar 5, 2010
High gain circuits generally require multiple stages of precision amplifiers. However, lower precision components can often be used if provision is made for adjusting offsets and sometimes adjusting gain. Injecting a little current into an input node of an amplifier can be quite effective in correcting for a large offset voltage. The real problem with a large offset voltage is that it is nearly always accompanied with a large temperature coefficient of offset, meaning the offset voltage can chan ...