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參數(shù)資料
| 型號(hào)： | AD9522-2/PCBZ |
| 廠商： | Analog Devices Inc |
| 文件頁數(shù)： | 79/84頁 |
| 文件大?。?/td> | 0K |
| 描述： | BOARD EVAL FOR AD9522-2 CLK GEN |
| 設(shè)計(jì)資源： | AD9522 Eval Board Schematic AD9522 BOM |
| 標(biāo)準(zhǔn)包裝： | 1 |
| 主要目的： | 計(jì)時(shí)，時(shí)鐘發(fā)生器 |
| 嵌入式： | 否 |
| 已用 IC / 零件： | AD9522-2 |
| 主要屬性： | 12 LVDS/24 CMOS 輸出，2.2 GHz VCO |
| 次要屬性： | I²C & SPI 接口 |
| 已供物品： | 板 |
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AD9522-2
Rev. 0 | Page 80 of 84
APPLICATIONS INFORMATION
FREQUENCY PLANNING USING THE AD9522
The AD9522 is a highly flexible PLL. When choosing the PLL
settings and version of the AD9522, the following guidelines
should be kept in mind.
The AD9522 has four frequency dividers: the reference (or R)
divider, the feedback (or N) divider, the VCO divider, and the
channel divider. When trying to achieve a particularly difficult
frequency divide ratio requiring a large amount of frequency
division, some of the frequency division can be done by either
the VCO divider or the channel divider, thus allowing a higher
phase detector frequency and more flexibility in choosing the
loop bandwidth.
Within the AD9522 family, lower VCO frequencies generally
result in slightly lower jitter. The difference in integrated jitter
(from 12 kHz to 20 MHz offset) for the same output frequency is
usually less than 150 fs over the entire VCO frequency range
(1.4 GHz to 2.95 GHz) of the AD9522 family. If the desired
frequency plan can be achieved with a version of the AD9522
that has a lower VCO frequency, choosing the lower frequency
part results in the lowest phase noise and the lowest jitter.
However, choosing a higher VCO frequency can result in more
flexibility in frequency planning.
Choosing a nominal charge pump current in the middle of the
allowable range as a starting point allows the designer to increase or
decrease the charge pump current, and thus allows the designer
to fine-tune the PLL loop bandwidth in either direction.
ADIsimCLK is a powerful PLL modeling tool that can be
downloaded from www.analog.com and is a very accurate tool
for determining the optimal loop filter for a given application.
USING THE AD9522 OUTPUTS FOR ADC CLOCK
APPLICATIONS
Any high speed ADC is extremely sensitive to the quality of the
sampling clock of the AD9522. An ADC can be thought of as a
sampling mixer, and any noise, distortion, or time jitter on the
clock is combined with the desired signal at the analog-to-
digital output. Clock integrity requirements scale with the analog
input frequency and resolution, with higher analog input
frequency applications at ≥14-bit resolution being the most
stringent. The theoretical SNR of an ADC is limited by the ADC
resolution and the jitter on the sampling clock. Considering an
ideal ADC of infinite resolution where the step size and
quantization error can be ignored, the available SNR can be
expressed approximately by
π
=
J
At
f
SNR
2
1
20log
(dB)
where:
fA is the highest analog frequency being digitized.
tJ is the rms jitter on the sampling clock.
Figure 70 shows the required sampling clock jitter as a function
of the analog frequency and effective number of bits (ENOB).
fA (MHz)
S
NR
(
d
B)
EN
O
B
10
1k
100
30
40
50
60
70
80
90
100
110
6
8
10
12
14
16
18
t
J
= 100f
s
t
J
= 200f
s
t
J
= 400f
s
t
J
= 1ps
t
J
= 2ps
t
J
= 10p
s
SNR = 20log
1
2πfAtJ
07
22
1-
04
4
Figure 70. SNR and ENOB vs. Analog Input Frequency
See the AN-756 Application Note and the AN-501 Application
Note at www.analog.com.
Many high performance ADCs feature differential clock inputs
to simplify the task of providing the required low jitter clock on
a noisy PCB. Distributing a single-ended clock on a noisy PCB
can result in coupled noise on the sampling clock. Differential
distribution has inherent common-mode rejection that can
provide superior clock performance in a noisy environment.
The differential LVDS outputs of the AD9522 enable clock
solutions that maximize converter SNR performance.
The input requirements of the ADC (differential or single-
ended, logic level termination) should be considered when
selecting the best clocking/converter solution. In some cases,
the LVPECL outputs of the AD9522 may be desirable for
clocking a converter instead of the LVDS outputs of the AD9522.
LVDS CLOCK DISTRIBUTION
The AD9522 provides clock outputs that are selectable as either
CMOS or LVDS level outputs. LVDS is a differential output
option that uses a current mode output stage. The nominal
current is 3.5 mA, which yields 350 mV output swing across a
100 Ω resistor. An output current of 7 mA is also available in
cases where a larger output swing is required. The LVDS output
meets or exceeds all ANSI/TIA/EIA-644 specifications.
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| AD9522-3 | 制造商:AD 制造商全稱:Analog Devices 功能描述:12 LVDS/24 CMOS Output Clock Generator with Integrated 2 GHz VCO |
| AD9522-3/PCBZ | 功能描述:BOARD EVAL FOR AD9522-3 CLK GEN RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評(píng)估演示板和套件 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 主要目的:電信，線路接口單元（LIU） 嵌入式:- 已用 IC / 零件:IDT82V2081 主要屬性:T1/J1/E1 LIU 次要屬性:- 已供物品:板，電源，線纜，CD 其它名稱:82EBV2081 |
| AD9522-3BCPZ | 功能描述:IC CLOCK GEN 2GHZ VCO 64LFCSP RoHS:是 類別:集成電路 (IC) >> 時(shí)鐘/計(jì)時(shí) - 時(shí)鐘發(fā)生器，PLL，頻率合成器 系列:- 標(biāo)準(zhǔn)包裝:1,000 系列:Precision Edge® 類型:時(shí)鐘/頻率合成器 PLL:無 輸入:CML，PECL 輸出:CML 電路數(shù):1 比率 - 輸入:輸出:2:1 差分 - 輸入:輸出:是/是 頻率 - 最大:10.7GHz 除法器/乘法器:無/無 電源電壓:2.375 V ~ 3.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:16-VFQFN 裸露焊盤，16-MLF? 供應(yīng)商設(shè)備封裝:16-MLF?（3x3） 包裝:帶卷 (TR) 其它名稱:SY58052UMGTRSY58052UMGTR-ND |
| AD9522-3BCPZ-REEL7 | 功能描述:IC CLOCK GEN 2GHZ VCO 64LFCSP RoHS:是 類別:集成電路 (IC) >> 時(shí)鐘/計(jì)時(shí) - 時(shí)鐘發(fā)生器，PLL，頻率合成器 系列:- 標(biāo)準(zhǔn)包裝:2,000 系列:- 類型:PLL 時(shí)鐘發(fā)生器 PLL:帶旁路 輸入:LVCMOS，LVPECL 輸出:LVCMOS 電路數(shù):1 比率 - 輸入:輸出:2:11 差分 - 輸入:輸出:是/無 頻率 - 最大:240MHz 除法器/乘法器:是/無 電源電壓:3.135 V ~ 3.465 V 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:32-LQFP 供應(yīng)商設(shè)備封裝:32-TQFP（7x7） 包裝:帶卷 (TR) |
| AD9522-4 | 制造商:AD 制造商全稱:Analog Devices 功能描述:12 LVDS/24 CMOS Output Clock Generator with Integrated 1.6 GHz VCO |
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