To use the MSSP port to communicate with 3-wire
devices, the bytes to be output must be aligned
such that the LSB of the address is the 8th bit
(LSB) of a byte to be output. From there, the
bits should fill the byte from right to left
consecutively.
Abstract: Many digital devices incorporate analog circuits. For instance, microprocessors, applicationspecificintegrated circuits (ASICs), and field-programmable gate arrays (FPGAs) may have internalvoltage references, analog-to-digital converters (ADCs) or digital-to-analog converters (DACs). However,there are challenges when you integrate more analog onto a digital design. As with all things in life, inelectronics we must always trade one parameter for another, with the application dictating the propertrade-off of analog function. In this application note, we examine how the demand for economy of spaceand cost pushes analog circuits onto digital substrates, and what design challenges emerge.
Abstract: Perfection is relative and application specific. The perfect race car is not the car we use to commute to work.
We need products for everyday use that are high quality, affordable, and solidly reliable. There will be times when we
must use components that are not perfect, and this is when calibration becomes important. Calibration techniques reduce
tolerances in imperfect manufacturing equipment while maintaining affordability.
Abstract: Specifications such as noise, effective number of bits (ENOB), effective resolution, and noise-free resolution inlarge part define how accurate an ADC really is. Consequently, understanding the performance metrics related to noise isone of the most difficult aspects of transitioning from a SAR to a delta-sigma ADC. With the current demand for higherresolution, designers must develop a better understanding of ADC noise, ENOB, effective resolution, and signal-to-noiseratio (SNR). This application note helps that understanding.
A fully differential amplifi er is often used to converta single-ended signal to a differential signal, a designwhich requires three signifi cant considerations: theimpedance of the single-ended source must match thesingle-ended impedance of the differential amplifi er,the amplifi er’s inputs must remain within the commonmode voltage limits and the input signal must be levelshifted to a signal that is centered at the desired outputcommon mode voltage.
Portable, battery-powered operation of electronic apparatushas become increasingly desirable. Medical, remotedata acquisition, power monitoring and other applicationsare good candidates for battery operation. In some circumstances,due to space, power or reliability considerations,it is preferable to operate the circuitry from a single 1.5Vcell. Unfortunately, a 1.5V supply eliminates almost alllinear ICs as design candidates. In fact, the LM10 opamp-reference and the LT®1017/LT1018 comparators arethe only IC gain blocks fully specifi ed for 1.5V operation.Further complications are presented by the 600mV dropof silicon transistors and diodes. This limitation consumesa substantial portion of available supply range, makingcircuit design diffi cult. Additionally, any circuit designedfor 1.5V operation must function at end-of-life batteryvoltage, typically 1.3V. (See Box Section, “Componentsfor 1.5V Operation.”)
Radio Frequency Integrated Circuit Design
I enjoyed reading this book for a number of reasons. One reason is that itaddresses high-speed analog design in the context of microwave issues. This isan advanced-level book, which should follow courses in basic circuits andtransmission lines. Most analog integrated circuit designers in the past workedon applications at low enough frequency that microwave issues did not arise.As a consequence, they were adept at lumped parameter circuits and often notcomfortable with circuits where waves travel in space. However, in order todesign radio frequency (RF) communications integrated circuits (IC) in thegigahertz range, one must deal with transmission lines at chip interfaces andwhere interconnections on chip are far apart. Also, impedance matching isaddressed, which is a topic that arises most often in microwave circuits. In mycareer, there has been a gap in comprehension between analog low-frequencydesigners and microwave designers. Often, similar issues were dealt with in twodifferent languages. Although this book is more firmly based in lumped-elementanalog circuit design, it is nice to see that microwave knowledge is brought inwhere necessary.Too many analog circuit books in the past have concentrated first on thecircuit side rather than on basic theory behind their application in communications.The circuits usually used have evolved through experience, without asatisfying intellectual theme in describing them. Why a given circuit works bestcan be subtle, and often these circuits are chosen only through experience. Forthis reason, I am happy that the book begins first with topics that require anintellectual approach—noise, linearity and filtering, and technology issues. Iam particularly happy with how linearity is introduced (power series). In therest of the book it is then shown, with specific circuits and numerical examples,how linearity and noise issues arise.
