This document was developed under the Standard Hardware and Reliability Program (SHARP) TechnologyIndependent Representation of Electronic Products (TIREP) project. It is intended for use by VHSIC HardwareDescription Language (VHDL) design engineers and is offered as guidance for the development of VHDL modelswhich are compliant with the VHDL Data Item Description (DID DI-EGDS-80811) and which can be providedto manufacturing engineering personnel for the development of production data and the subsequent productionof hardware. Most VHDL modeling performed to date has been concentrated at either the component level orat the conceptual system level. The assembly and sub-assembly levels have been largely disregarded. Under theSHARP TIREP project, an attempt has been made to help close this gap. The TIREP models are based upon lowcomplexity Standard Electronic Modules (SEM) of the format A configuration. Although these modules are quitesimple, it is felt that the lessons learned offer guidance which can readily be applied to a wide range of assemblytypes and complexities.
Industrial systems demand semiconductors that are precise, flexibleand reliable. Linear Technology offers a broad line of high performanceanalog ICs that simplify system design with rugged devices featuringparameters fully guaranteed over the -40°C to 85°C temperature range.We back this up with knowledgeable applications support, long productlife cycles and superior on-time delivery.
The MAX5713/MAX5714/MAX5715 4-channel, low-power,8-/10-/12-bit, voltage-output digital-to-analog converters(DACs) include output buffers and an internal referencethat is selectable to be 2.048V, 2.500V, or 4.096V. TheMAX5713/MAX5714/MAX5715 accept a wide supplyvoltage range of 2.7V to 5.5V with extremely low power(3mW) consumption to accommodate most low-voltageapplications. A precision external reference input allowsrail-to-rail operation and presents a 100kI (typ) load toan external reference.
Abstract: A perfect voltage reference produces a stable voltage independent of any external factors. Real-world voltagereferences, of course, are subject to errors caused by many external factors. One causeof these major errors istemperature. Without care, it is easy to operate a voltage reference outside its operating temperature range. Thisapplication note describes how references respond to temperature changes, and how self-heating can cause a voltagereference to operate outside its recommended temperature range. Once understood, this knowledge can then be used toavoid making this design error.
Abstract: A laser module designer can use a fixed resistor, mechanical pot, digital pot, or a digital-to-analogconverter (DAC) to control the laser driver's modulation and bias currents. The advantages of a programmablemethod (POT or DAC) are that the manufacturing process can be automated and digital control can be applied(e.g., to compensate for temperature). Using POTs can be a more simple approach than a DAC. There can be aslight cost advantage to using a POT, but this is usually not significant relative to other pieces of the design.Using a DAC can offer advantages, including improved linearity (translating to ease of software implementationand ability to hit the required accuracy), increased board density, a wider range of resolutions, a betteroptimization range, ease of use with a negative voltage laser driver, and unit-to-unit consistency
The purpose of this application note is to show an example of how a digital potentiometer can be used in thefeedback loop of a step-up DC-DC converter to provide calibration and/or adjustment of the output voltage.The example circuit uses a MAX5025 step-up DC-DC converter (capable of generating up to 36V,120mWmax) in conjunction with a DS1845, 256 position, NV digital potentiometer. For this example, the desiredoutput voltage is 32V, which is generated from an input supply of 5V. The output voltage can be adjusted in35mV increments (near 32V) and span a range wide enough to account for resistance, potentiometer and DCDCconverter tolerances (27.6V to 36.7V).
The LTC®1966 is a true RMS-to-DC converter that uses aDS computational technique to make it dramatically simplerto use, significantly more accurate, lower in powerconsumption and more flexible than conventional logantilogRMS-to-DC converters. The LTC1966 RMS-to-DCconverter has an input signal range from 5mVRMS to1.5VRMS (a 50dB dynamic range with a single 5V supplyrail) and a 3dB bandwidth of 800kHz with signal crestfactors up to four.
High input impedance and a wide input range are twohighly desirable features in a precision analog-to-digitalconverter, and the LTC®2449 delta-sigma ADC has both.With just a few external components, the LTC2449 formsan exceptional measurement system with very high inputimpedance and an input range that extends 300mV beyondthe supply rails.
Digital-to-analog converters (DACs) are prevalent inindustrial control and automated test applications.General-purpose automated test equipment often requiresmany channels of precisely controlled voltagesthat span several voltage ranges. The LTC2704 is ahighly integrated 16-bit, 4-channel DAC for high-endapplications. It has a wide range of features designed toincrease performance and simplify design.
Designers of signal receiver systems often need to performcascaded chain analysis of system performancefrom the antenna all the way to the ADC. Noise is a criticalparameter in the chain analysis because it limits theoverall sensitivity of the receiver. An application’s noiserequirement has a signifi cant infl uence on the systemtopology, since the choice of topology strives to optimizethe overall signal-to-noise ratio, dynamic range andseveral other parameters. One problem in noise calculationsis translating between the various units used by thecomponents in the chain: namely the RF, IF/baseband,and digital (ADC) sections of the circuit.
