基于ADF4154的芯片简介及应用电路设计

字数:9500,页数:25

摘要
 简要介绍N分频合成器ADF4154芯片的功能、内部结构、引脚排列以及典型的电路设计，ADF4154是一在无线接受器和发射器的上边频和下边频上实现本机震荡器的N分频频率合成器。它由一个低噪音数字锁相频率检波器（PFD），一个精确的充电泵，一个可编程的基准分频器。它有一个基于允许可编程的N分频校对机部分的Σ-Δ。INT FRAC和MOD寄存器定义B分配公式：N = (INT + (FRAC/MOD)). 另外，四位的参考计数器（R计数器）允许在PFD输入端选择REFIN的频率输入。一个外部环路滤波器和压控震荡器VCO可以实现一个完整的锁相环路PLL。
    ADF4154一个重要的特征是一个内在的快锁模式定时器，用户可以编写一个预定的定时值代替外在时间，从而使PLL工作在宽带宽模式下。
使用一个简单的三线串行借口控制寄存节点。2.7—3.3V电源提供装置的运转，且在不使用情况下低功耗运行。
关键字：
独立VP    双模前置分频  充电泵  三线串行接口  数字锁定检测             定时快锁模式

 Abstract
It briefly introduced The Fractional-N Frequency Synthesizer ADF4154 microcontroller function, internal structure, pin array and typical apply circuit. The ADF4154 is a fractional-N frequency synthesizer that implements local oscillators in the up conversion and down conversion sections of wireless receivers and transmitters. It consists of a low noise digital phase frequency detector (PFD), a precision charge pump, and a programmable reference divider. There is a Σ-Δ based fractional interpolator to allow program-mable fractional-N division. The INT, FRAC, and MOD regis-ters define an overall N divider (N = (INT + (FRAC/MOD))). In addition, the 4-bit reference counter (R counter) allows selectable REFIN frequencies at the PFD input. A complete phase-locked loop (PLL) can be implemented if the synthesizer is used with an external loop filter and a voltage controlled oscillator (VCO).
A key feature of the ADF4154 is the fast-lock mode with a built-in timer. The user can program a predetermined count-down time value so that the PLL will remain in wide bandwidth mode, instead of having to control this time externally.
Control of all on-chip registers is via a simple 3-wire interface. The device operates with a power supply ranging from 2.7 V to 3.3 V, and can be powered down when not in use.
KEY WORD：
Separate VP  dual-modulus prescaler   charge pump   3-wire serial interface
Digital lock detect  fractional-N synthesizer Fast-lock mode with built-in timer 
                     
   目  录

1、ADF4154芯片简介...............................................................2
2、ADF4154芯片封装与引脚功能.....................................................4
3、ADF4154特性...................................................................5
    3、1 ADF4154电气特性.........................................................5
    3、2 ADF4154时间特性.........................................................7
    3、3 ADF4154最大额定值.......................................................8
    3、4 ADF4154典型性能特性.....................................................8
4、DF4154内部结构与工作原理.....................................................10 
4、1 基准输入极.................................................................10
4、2 RF输入极...................................................................11
4、3 RF R 计数器................................................................11
4、4相位频率检波器和充电泵......................................................12
4、5 MUXOUT（多路复用输出）和LOCK DETECT........................................13
4、6寄存器......................................................................14
     4、6、1  N分频寄存器 R0....................................................16
     4、6、2  R分配寄存器 R1....................................................16
     4、6、3  4位射频R 寄存器...................................................17
4、6、4  控制寄存器 R2..........................................................17
4、6、5  噪音和迹寄存器 R3......................................................18
5、DF4154电路设计...............................................................20
循环滤波器布局..................................................................20
滤波器设计构思..................................................................21
接口连接........................................................................21
ADSP-2181接口...................................................................22
PCB 芯片比例设计方针............................................................22
外形轮廓........................................................................23
6、总结.........................................................................23
7、参考资料.....................................................................24

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