PCB layout 基本規(guī)範(fàn)項(xiàng)次 項(xiàng)目 備註1 一般PCB 過板方向定義： PCB 在SMT 生產(chǎn)方向?yàn)槎踢呥^迴焊爐(Reflow), PCB 長(zhǎng)邊為SMT 輸送帶夾持邊. PCB 在DIP 生產(chǎn)方向?yàn)镮/O Port 朝前過波焊爐(Wave Solder), PCB 與I/O 垂直的兩邊為DIP 輸送帶夾持邊.1.1 金手指過板方向定義： SMT: 金手指邊與SMT 輸送帶夾持邊垂直. DIP: 金手指邊與DIP 輸送帶夾持邊一致.2 SMD 零件文字框外緣距SMT 輸送帶夾持邊L1 需≧150 mil. SMD 及DIP 零件文字框外緣距板邊L2 需≧100 mil.3 PCB I/O port 板邊的螺絲孔(精靈孔)PAD 至PCB 板邊, 不得有SMD 或DIP 零件(如右圖黃色區(qū)).PAD
上傳時(shí)間： 2014-12-24
上傳用戶：jokey075
|Introduction Basic Concept Tips to layout Power circuit Type of Power circuit Basic Concept Maximum Current calculation Resistance of Copper ideal power supply & noise Capacitor & Inductor Power consumption Function of power circuit
標(biāo)簽： PCB 電源設(shè)計(jì)
上傳時(shí)間： 2014-01-04
上傳用戶：kao21
This document provides practical, common guidelines for incorporating PCI Express interconnect layouts onto Printed Circuit Boards (PCB) ranging from 4-layer desktop baseboard designs to 10- layer or more server baseboard designs. Guidelines and constraints in this document are intended for use on both baseboard and add-in card PCB designs. This includes interconnects between PCI Express devices located on the same baseboard (chip-to-chip routing) and interconnects between a PCI Express device located “down” on the baseboard and a device located “up” on an add-in card attached through a connector. This document is intended to cover all major components of the physical interconnect including design guidelines for the PCB traces, vias and AC coupling capacitors, as well as add-in card edge-finger and connector considerations. The intent of the guidelines and examples is to help ensure that good high-speed signal design practices are used and that the timing/jitter and loss/attenuation budgets can also be met from end-to-end across the PCI Express interconnect. However, while general physical guidelines and suggestions are given, they may not necessarily guarantee adequate performance of the interconnect for all layouts and implementations. Therefore, designers should consider modeling and simulation of the interconnect in order to ensure compliance to all applicable specifications. The document is composed of two main sections. The first section provides an overview of general topology and interconnect guidelines. The second section concentrates on physical layout constraints where bulleted items at the beginning of a topic highlight important constraints, while the narrative that follows offers additional insight.
標(biāo)簽： pci PCB 設(shè)計(jì)規(guī)范
上傳時(shí)間： 2013-10-15
上傳用戶：busterman
We provide complete power solutions with a full lineup of power managementproducts. This brochure provides an overview of our high performance DC/DC switching regulatorcontrollers for applications including datacom, telecom, industrial, automotive, medical, avionicsand control systems. We make power design easier with our industry-leading field applicationengineering support; a broad selection of demonstration boards with schematics, layout filesand parts lists; SwitcherCAD® software for simulation, application notes and comprehensivetechnical documentation.
上傳時(shí)間： 2013-10-15
上傳用戶：lz4v4
Advancements in board assembly, PCB layout anddigital IC integration have produced a new generationof densely populated, high performance systems. Theboard-mounted point-of-load (POL) DC/DC power suppliesin these systems are subject to the same demandingsize, high power and performance requirements asother subsystems. The rigorous new POL demands aredifficult to meet with traditional controller or regulatorICs, or power modules.
上傳時(shí)間： 2014-12-24
上傳用戶：lbbyxmraon
Piezoelectric motors are used in digital cameras for autofocus,zooming and optical image stabilization. Theyare relatively small, lightweight and effi cient, but theyalso require a complicated driving scheme. Traditionally,this challenge has been met with the use ofseparatecircuits, including a step-up converter and an oversizedgeneric full-bridge drive IC. The resulting high componentcount and large board space are especially problematicin the design of cameras for ever shrinking cell phones.The LT®3572 solves these problems by combining astep-up regulator and a dual full-bridge driver in a 4mm× 4mm QFN package. Figure 1 shows a typical LT3572Piezo motor drive circuit. A step-up converter is usedto generate 30V from a low voltage power source suchas a Li-Ion battery or any input power source within thepart’s wide input voltage range of 2.7V to 10V. The highoutput voltage of the step-up converter, adjustable upto 40V, is available for the drivers at the VOUT pin. Thedrivers operate in a full-bridge fashion, where the OUTAand OUTB pins are the same polarity as the PWMA andPWMB pins, respectively, and the OUTA and OUTB pinsare inverted from PWMA and PWMB, respectively. Thestep-up converter and both Piezo drivers have their ownshutdown control. Figure 2 shows a typical layout
上傳時(shí)間： 2013-11-18
上傳用戶：hulee
The LTC®4099 high effi ciency USB power manager andLi-Ion/Polymer battery charger seamlessly managespower distribution from multiple sources in portableapplications. It is differentiated from other USB powermanagers by its bidirectional I2C port that allows the hostmicroprocessor to control and monitor all aspects of theUSB power management and battery charging processes.In addition, a programmable interrupt generation functionalerts the host microprocessor to changes in device statusand provides unprecedented control of power managementfunctions. This high degree of confi gurability allowspost-layout changes in operation, even changes in thefi eld, and it allows a single qualifi ed device to be usedin a variety of products, thus reducing design time andeasing inventory management.
上傳時(shí)間： 2013-10-22
上傳用戶：18602424091
保定眾邦公司開發(fā)生產(chǎn)的零序電流互感器是用于電力電纜上的一種互感器，它的一次繞組為穿過互感器內(nèi)孔的三相一次導(dǎo)體電纜（或是單相電纜），它的一次電流是一次三相電流的矢量和（在三相平衡時(shí)為0），當(dāng)發(fā)生系統(tǒng)單相接地時(shí)或三相平衡時(shí)，矢量和不為0，零序電流互感器的二次有電流輸出，可以供給保護(hù)裝置，實(shí)現(xiàn)保護(hù)和監(jiān)控。由于電纜自身絕緣，零序電流互感器外殼也是絕緣的，所以零序電流互感器可以使用在任一電壓等級(jí)的電纜上
標(biāo)簽： 零序電流互感器
上傳時(shí)間： 2014-12-24
上傳用戶：wentian_e
鐘是現(xiàn)代人類日常生活必不可少的工具，語音時(shí)鐘更是現(xiàn)在電子時(shí)鐘多功能化發(fā)展的一個(gè)方向。語音電子鐘具有突出的播報(bào)時(shí)間的功能，它被廣泛用在生活中的各種場(chǎng)合。本設(shè)計(jì)就是從日常生活中常見的事物入手，通過對(duì)語音電子鐘的設(shè)計(jì)，讓我認(rèn)識(shí)到單片機(jī)已經(jīng)深入到我們生活的每個(gè)領(lǐng)域。 本文從語音電子鐘的設(shè)計(jì)原理、設(shè)計(jì)方案入手，詳細(xì)介紹了系統(tǒng)硬件設(shè)計(jì)、軟件設(shè)計(jì)及調(diào)試。在語音電子鐘的設(shè)計(jì)中，要處理好以下幾個(gè)關(guān)鍵：D/A（數(shù)/模）轉(zhuǎn)換，語音識(shí)別，人機(jī)接口，程序設(shè)計(jì)。D/A（數(shù)/模）和語音識(shí)別技術(shù)關(guān)系到時(shí)間的正確播報(bào)，人機(jī)接口是播報(bào)時(shí)間和調(diào)整時(shí)間的關(guān)鍵。利用凌陽SPCE061A單片機(jī)在語音識(shí)別和處理方面的優(yōu)點(diǎn)，結(jié)合實(shí)踐，設(shè)計(jì)出有特色的語音電子鐘。
上傳時(shí)間： 2013-10-30
上傳用戶：feitian920
MFC 六大技術(shù)之簡(jiǎn)化仿真（Console 程序） 第㆓篇【欲善工事先利其器】提供給對(duì) Visual C++ 整合環(huán)境全然陌生的朋友㆒個(gè)導(dǎo)引。 這㆒篇當(dāng)然不能取代 Visual C++ User's Guide 的㆞位，但對(duì)整個(gè)軟件開發(fā)環(huán)境有全盤以 及概觀性的介紹，可以讓初學(xué)者迅速了解手㆖掌握的工具，以及它們的主要功能。 第㆔篇【淺出 MFC 程序設(shè)計(jì)】介紹㆒個(gè) MFC 程序的生死因果。已經(jīng)有 MFC 程序經(jīng) 驗(yàn)的朋友，不見得不會(huì)對(duì)本篇感到驚艷。根據(jù)我的了解，太多㆟使用 MFC 是「只知道 這么做，不知道為什么」；本篇詳細(xì)解釋 MFC 程序之來龍去脈，為初入 MFC 領(lǐng)域的 讀者奠定扎實(shí)的基礎(chǔ)。說不定本篇會(huì)讓你有醍醐灌頂之感。
標(biāo)簽： MFC 簡(jiǎn)體中文
上傳時(shí)間： 2013-12-16
上傳用戶：qq527891923
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