5秒后页面跳转
AN-07 PDF预览

AN-07

更新时间: 2024-10-27 23:30:31
品牌 Logo 应用领域
其他 - ETC /
页数 文件大小 规格书
8页 135K
描述
SY89429/30V Frequency Synthesis

AN-07 数据手册

 浏览型号AN-07的Datasheet PDF文件第2页浏览型号AN-07的Datasheet PDF文件第3页浏览型号AN-07的Datasheet PDF文件第4页浏览型号AN-07的Datasheet PDF文件第5页浏览型号AN-07的Datasheet PDF文件第6页浏览型号AN-07的Datasheet PDF文件第7页 
SY89429/30V  
FREQUENCY  
SYNTHESIS  
APPLICATION NOTE  
AN-07  
Introduction  
General Requirements  
Micrel-Synergy’s SY89429/30V frequency synthesizers  
Operating the SY89429/30V is very simple. Very few low  
are designed to be used in various clock subsystems. The cost external components are required. These low cost  
Primary function of the product is to synthesize clock external components provide the tuning capability needed  
frequencies required for systems needing a high quality, to optimize and minimize jitter characteristics in each  
low jitter clock source.  
individual system application. To achieve the best possible  
The cost of other clock sources, either crystal or SAW performance in jitter and power supply noise rejection, basic  
oscillators, increase dramatically as precision/frequency high speed design guidelines should be followed.  
requirements of digital systems push into the 100+ MHz  
Power Supply Requirements  
arena. Many low cost CMOS frequency synthesizers  
appeared in the market in the last few years. Unfortunately,  
these products have relatively high jitter and limited operating  
frequency range. Therefore, their applications are limited to  
lower precision/lower frequencies.  
SY89429/30V, designed with Micrel-Synergy’s high  
performance ASSET™ Bipolar technology and differential  
ECL circuit technology throughout, is a perfect low cost  
alternative to the expensive crystal or SAW oscillators. Unlike  
other frequency synthesizers, SY89429/30V has extremely  
low jitter and high supply noise rejection that ECL is famous  
for.  
Because the devices are programmable between 25MHz  
to 950MHz using a 16MHz crystal, different system  
frequency requirements can all use the same device. This  
may dramatically reduce inventory costs and management  
of additional products otherwise required to achieve these  
various frequencies. This programmability also makes board/  
system speed grading possible as part of the normal  
production flow without multiple oscillators. This provides  
higher overall yield and lower manufacturing cost.  
In addition to cost savings, there are many other benefits  
to using the SY89429/30V. Normal system production testing  
can incorporate frequency margining that is unavailable to  
fixed frequency designs as in crystal or SAW oscillators.  
This capability leads directly to higher product quality and  
reliability. Furthermore, SY89429/30V can be programmed  
in small steps (1MHz steps with a 16.000MHz crystal).  
Other precise frequencies can be programmed as well. See  
section titled “Advanced Frequency Control Applications.”  
This ability to provide any frequency eliminates the need for  
the high cost custom oscillator alternatives.  
SY89429/30V is designed to operate with a single positive  
supply of either +3.3V or +5V. The FOUT and /FOUT (the  
differential PECL outputs) will interface to PECL inputs using  
the same supply voltage. However, SY89429/30V can also  
be used in a true ECL systems. For this application, please  
refer to the section titled “True ECL Design.”  
Power Supply Filtering Techniques  
As in any high speed integrated circuits, power supply  
filtering is very important. A 0.1µF high frequency by-pass  
capacitor should be used between all separate power supply  
pins and ground. VCC1, VCC_QUIET, VCC_TTL and VCC_OUT  
should be individually connected to the power supply plane  
through vias, and a by-pass capacitor should be used for  
each pin. To achieve optimum jitter performance, better  
power supply isolation is required. In this case a ferrite  
bead along with a 1µF and a 0.01µF by-pass capacitor  
should be connected to each power supply pin. Figure 4  
shows the connections of the power supply filtering using  
ferrite beads.  
Termination for PECL Outputs  
The differential PECL outputs, FOUT and /FOUT, are  
open emitter outputs. Therefore, terminating resistors or  
current sources must be used for functionality. These outputs  
are designed to drive 50transmission lines. Matched  
impedance techniques should be used to maximize operating  
frequency and minimize wave-form distortion. There are a  
few simple termination schemes. Figure 1 shows three  
simple termination circuits for a +5V system.  
Interface for Inputs  
Throughout this application note we refer to a frequency  
range of 25MHz to 950MHz. This is only for simplicity  
reasons and make the application note applicable to both  
devices.  
The VCO range for SY89429V and SY89430V are  
different. That is, SY89429V has an internal VCO range of  
400MHz to 800MHz and an external output frequency of  
25MHz to 400MHz. SY89430V has an internal VCO range  
of 400MHz to 950MHz and an external output frequency of  
50MHz to 950MHz.  
The SY89429/30V is designed to interface with TTL  
compatible signals. All inputs except XTAL1 and XTAL2 are  
TTL compatible. These inputs have internal pull up resistors.  
Therefore, any inputs can be left open—open inputs are  
logical “1” state. Although inputs can be left open, it is  
recommended that open inputs be connected to a power  
supply line. These inputs can be connected to a power  
supply line (VCC for a logical “1”) or a ground line (VEE for a  
logical “0”) directly or through series resistors. Alternatively,  
these inputs can also be driven directly from any TTL  
compatible signals. XTAL1 and XTAL2 inputs should only  
be connected to a crystal.  
Rev.: E  
Amendment:/0  
Issue Date: February 2000  
1

与AN-07相关器件

型号 品牌 获取价格 描述 数据表
AN0750-521P ETC

获取价格

AN0625-521P
AN0875-521P ETC

获取价格

AN0625-521P
AN08AG1-16.000MHZ MMD

获取价格

Parallel - Fundamental Quartz Crystal, 16MHz Nom, ROHS COMPLIANT, MICRO MINIATURE PACKAGE-
AN08AG1-16.000MHZ-T MMD

获取价格

Parallel - Fundamental Quartz Crystal, 16MHz Nom, ROHS COMPLIANT, MICRO MINIATURE PACKAGE-
AN08CH1-40.000MHZ MMD

获取价格

暂无描述
AN08CH1-40.000MHZ-T MMD

获取价格

Parallel - Fundamental Quartz Crystal, 40MHz Nom, ROHS COMPLIANT, MICRO MINIATURE PACKAGE-
AN08EE1-40.000MHZ MMD

获取价格

Parallel - Fundamental Quartz Crystal, 40MHz Nom, ROHS COMPLIANT, MICRO MINIATURE PACKAGE-
AN08EE1-40.000MHZ-T MMD

获取价格

Parallel - Fundamental Quartz Crystal, 40MHz Nom, ROHS COMPLIANT, MICRO MINIATURE PACKAGE-
AN08FG1-40.000MHZ MMD

获取价格

Parallel - Fundamental Quartz Crystal, 40MHz Nom, ROHS COMPLIANT, MICRO MINIATURE PACKAGE-
AN08FG1-40.000MHZ-T MMD

获取价格

Parallel - Fundamental Quartz Crystal, 40MHz Nom, ROHS COMPLIANT, MICRO MINIATURE PACKAGE-