基于AD9540的芯片简介及电路设计

字数:15600,页数:37

摘要
简要的介绍了基于AD9540的超低抖动多时钟输出设计的电路，在设计中主要介绍了AD9540的引脚功能、内部结构、电气特性、工作原理、工作特性、工作模式、寄存器工作方式、软硬件控制、应用电路以及引脚封装。AD9540芯片是为应用于时钟产品的模拟器件特别是为数据转换要求较高情况下支持时间较为准确而设计的。该芯片具有高效率的PLL电路，包括可变的200MHz的相频检波器，以及一个数字控制的充电泵，它也提供一个稳定的、655MHz模式的带有可编程转换时间的PECL跟随输出驱动器。外部VCO的值已达到2.7GHz，并且也具有非常高的分辨率，所有的信息可通过一系列写速度达25Mb/s的I/O口装载到AD9540里面去。AD9540的频率分频器可支持扩展频谱工作状态。
关键字：数据转换   分频器   分辨率   PLL电路   充电泵   VCO

Abstract
It is a low jitter clock circuit designing,it has introduced the pin function,internal configuration,electric charator,theory of operation,mode of operation,application circuit and pin package.The AD9540 is Analog Devices’ first dedicated clocking product specifically designed to support the extremely stringent clocking requirements of the highest performance data converters. The device features high performance PLL circuitry including a flexible 200MHz phase frequency detector and a digitally controlled charge pump current.The device also provides a low jitter,655MHz CML-mode, PECL-compliant output driver with programmable slew rates.External VCO rates up to 2.7GHz are supported. Extremely fine tuning resolution is another feature supported by this device.Information is loaded into the AD9540 via a serial I/O port that has a device write-speed of 25Mb/s.The AD9540 frequency divider block can also be programmed to support a spread spectrum mode of operation.
Key words: data conversion   divider   resolution   PLL circuit   charge pump   VCO
 
目录
   摘要..............................................................................1
1. 芯片简介..........................................................................2
   1.1 概述..........................................................................2
   1.2 应用..........................................................................2
   1.3 内部结构图....................................................................2
2. 电气特性..........................................................................3
2.1 电气特性表.......................................................................3
2.2 电路测量条件.....................................................................8
3. 最大值比率........................................................................9
4. 引脚结构与功能描述...............................................................10
5. 典型工作特性.....................................................................12
6. 典型应用电路描述.................................................................17
7. 简单描述.........................................................................18
7.1 PLL电路.........................................................................18
7.2 CML驱动器.......................................................................18
7.3 DDS和DAC........................................................................19
8. 工作模式.........................................................................20
8.1 可选的时钟频率和边缘延迟........................................................20
8.2 多路设备同步模式................................................................20
8.3 自动同步........................................................................20
8.4 硬件手控同步....................................................................21
8.5 软件手控同步....................................................................21
9. 串行端口工作.....................................................................21
9.1 命令字..........................................................................22
9.2 串行接口端口管脚描述............................................................23
9.3 MSB/LSB转换器...................................................................23
10. 寄存器地址表及其描述............................................................24
           10.1 寄存器地址表........................................................24
10.2控制寄存器功能描述..............................................................27
           10.2.1 控制寄存器1功能描述...............................................27
           10.2.2 控制寄存器2功能描述...............................................30
11 外部尺寸.........................................................................34
12 定购指南.........................................................................34
13  总结............................................................................35
参考文献............................................................................35