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.
Most circuit designers are familiar with diode dynamiccharacteristics such as charge storage, voltage dependentcapacitance and reverse recovery time. Less commonlyacknowledged and manufacturer specifi ed is diode forwardturn-on time. This parameter describes the timerequired for a diode to turn on and clamp at its forwardvoltage drop. Historically, this extremely short time, unitsof nanoseconds, has been so small that user and vendoralike have essentially ignored it. It is rarely discussed andalmost never specifi ed. Recently, switching regulator clockrate and transition time have become faster, making diodeturn-on time a critical issue. Increased clock rates aremandated to achieve smaller magnetics size; decreasedtransition times somewhat aid overall effi ciency but areprincipally needed to minimize IC heat rise. At clock speedsbeyond about 1MHz, transition time losses are the primarysource of die heating.
Abstract: Using a wafer-level package (WLP) can reduce the overall size and cost of your solution.However when using a WLP IC, the printed circuit board (PCB) layout can become more complex and, ifnot carefully planned, result in an unreliable design. This article presents some PCB designconsiderations and general recommendations for choosing a 0.4mm- or 0.5mm-pitch WLP for yourapplication.
This product integration guide provides application circuit information for theSmartMesh® LTP5903PC wireless embedded network manager. This guide is acompanion to the 020-0039 SmartMesh LTP5903PC Datasheet, whichdescribes overall product behavior, including detailed information about normaloperating conditions, electrical and mechanical specifications, hardware andsoftware interfaces, and connector pinouts.
The above title is not happenstance and was arrived at afterconsiderable deliberation. As a linear IC manufacturer, it isour goal to encourage users to design and build switchingregulators. A problem is that while everyone agrees thatworking switching regulators are a good thing, everyonealso agrees that they are difficult to get working. Switchingregulators, with their high efficiency and small size, areincreasingly desirable as overall package sizes shrink.Unfortunately, switching regulators are also one of themost difficult linear circuits to design. Mysterious modes,sudden, seemingly inexplicable failures, peculiar regulationcharacteristics and just plain explosions are commonoccurrences. Diodes conduct the wrong way. Things gethot that shouldn’t. Capacitors act like resistors, fusesdon’t blow and transistors do. The output is at ground, andthe ground terminal shows volts of noise.
提出一種基于凌陽單片機的步進電機加減速的控制方法。采用凌陽科技推出的16位結構工控單片機SPMC75F2413A為控制器，由Allegro公司生產的兩相步進電機專用驅動器件SLA7042M構成步進電機的驅動電路，在傳統的3段直線加減速控制算法基礎上增加至7段S形曲線加減速過程，控制步進電機的啟動和停止。實驗結果表明，該控制方法克服了直線加減速中不連續、易造成系統沖擊的問題，整個系統實現柔性控制，電機啟動、停止連續性能提高30%。
Abstract:
The method of controlled stepping motor is referred based on SPMC75F2413A MCU， which adopts the 16 knots SPMC75F2413A MCU as the controller. The special-purpose actuation chip SLA7042M of two stepping motor produced by Allegro Corporation constituted to actuation electric circuit. The purpose of increasing to seven section of S shape curve based on the traditional three sections of straight line is to control the start and stop process of stepping motor. The experimental results show that the control method solves easy to pull-out and overshot problems. The overall system realizes flexible control， and the performance of motor start or stop continuity is increased 30%
AVR Studio 4.12 includes new device support and numerous overall enhancements;new breakpoint system, integrated AVR GCC development and improved docking system!See release notes for more details.
