参数资料
型号: ICS810001BK-21
厂商: INTEGRATED DEVICE TECHNOLOGY INC
元件分类: 时钟及定时
英文描述: 810001 SERIES, PLL BASED CLOCK DRIVER, 1 TRUE OUTPUT(S), 0 INVERTED OUTPUT(S), QCC32
封装: 5 X 5 MM, 0.95 MM HEIGHT, MO-220VHHD-2, VFQFN-32
文件页数: 6/22页
文件大小: 485K
代理商: ICS810001BK-21
810001BK-21
www.icst.com/products/hiperclocks.html
REV. A AUGUST 12, 2005
14
Integrated
Circuit
Systems, Inc.
ICS810001-21
FEMTOCLOCKSDUAL VCXO VIDEO PLL
PRELIMINARY
DESCRIPTION OF THE PLL STAGES
The ICS843002-21 is a two stage device, a VCXO PLL fol-
lowed by a low phase noise FemtoClock frequency multiplier.
The VCXO uses an external pullable crystal which can be
pulled ±100ppm by the VCXO PLL circuitry to phase lock it to
the input reference frequency. There are two VCXO crystal
ports in order to provide VCXO frequency versatility. For HDTV
applications, this allows the use of a 26.973027MHz crystal
for the generation of 74.175MHz, or a 27.00MHz crystal for
the generation of 74.25MHz, for example.
The VCXO output frequency can be output directly from the
device, or it can be passed to the FemtoClock frequency
multiplier which will multiply it up to a higher frequency.
VCXO PLL LOOP RESPONSE CONSIDERATIONS
Loop response characteristics of the VCXO PLL is affected
by the VCXO feedback divider value (bandwidth and damping
factor), and by the external loop filter components (bandwidth,
damping factor, and 2nd frequency response). A practical range
of VCXO PLL bandwidth is from about 1Hz to about 1kHz.
The setting of VCXO PLL bandwidth and damping factor is
covered later in this document. A PC based PLL bandwidth
calculator is also under development. For assistance with loop
bandwidth suggestions or value calculation, please contact
ICS applications.
Table 3A shows frequency translation configuration examples.
Note that in the first two V3:V0 selections the VCXO PLL feed-
back divider is the same value of 1000. This means the VCXO
PLL loop response (bandwidth and damping factor) will be the
same for all of these settings.
The same is true for V3:V0 = 0010 through 0110. This means
the device can be configured to translate between 74.175MHz,
74.25MHz, and 27MHz (from any one to another, all nine com-
binations) and it will maintain the same loop response char-
acteristics. This is also true for V3:V0 = 1000 through 1010.
For high VCXO PLL feedback divider values, the phase de-
tector rate, and therefore loop filter charge pulse rate, is greatly
reduced. To prevent output clock wander, low leakage capaci-
tors should be used. In addition, when loop bandwidth is low
(say below 20Hz), capacitors with low microphonic sensitiv-
ity should be used. PPS film type capacitors are one type that
perform well in this environment. Below 5Hz, shielding should
be considered to prevent excessive phase wander (low fre-
quency phase jitter or clock phase deviation).
SETTING THE VCXO PLL LOOP RESPONSE
The VCXO PLL loop response is determined both by fixed device
characteristics and by other characterizes set by the user. This
includes the values of R
S, CS, CP and RSET as shown in the
External VCXO PLL Components figure on this page.
The VCXO PLL loop bandwidth is approximated by:
WHERE:
R
S = Value of resistor RS in loop filter in Ohms
I
CP = Charge pump current in amps (see table on page 12)
K
O = VCXO Gain in Hz/V
Feedback Divider = 1 to 11011 (as determined by inputs
V3:V0)
The above equation calculates the “normalized” loop bandwidth
(denoted as “NBW”) which is approximately equal to the - 3dB
bandwidth. NBW does not take into account the effects of
damping factor or the second pole imposed by C
P. It does,
however, provide a useful approximation of filter performance.
To prevent jitter on the clock output due to modulation of the
VCXO PLL by the phase detector frequency, the following general
rule should be observed:
(Phase Detector) = Input Frequency ÷ Pre-Divider)
The PLL loop damping factor is determined by:
WHERE:
C
S = Value of capacitor CS in loop filter in Farads
NBW (VCXO PLL) =
R
S x ICP x KO
2
π x Feedback Divider
NBW (VCXO PLL)
(Phase Detector)
20
DF = x
R
S
2
I
CP x CS x KO
Feedback Divider
ICS810001-21
FEMTOCLOCKS DUAL VCXO VIDEO PLL
TSD
IDT / ICS FEMTOCLOCKS DUAL VCXO VIDEO PLL
ICS810001-21
14
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相关代理商/技术参数
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ICS810001BK-21T 制造商:ICS 制造商全称:ICS 功能描述:FEMTOCLOCKS-TM DUAL VCXO VIDEO PLL
ICS810001BK-22LF 功能描述:IC CLK SYNC DL VCXO PLL 32 VFQFN RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 专用 系列:HiPerClockS™, FemtoClock™ 标准包装:1,500 系列:- 类型:时钟缓冲器/驱动器 PLL:是 主要目的:- 输入:- 输出:- 电路数:- 比率 - 输入:输出:- 差分 - 输入:输出:- 频率 - 最大:- 电源电压:3.3V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:28-SSOP(0.209",5.30mm 宽) 供应商设备封装:28-SSOP 包装:带卷 (TR) 其它名称:93786AFT
ICS810001BK-22LFT 功能描述:IC CLK SYNC DL VCXO PLL 32 VFQFN RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 专用 系列:HiPerClockS™, FemtoClock™ 标准包装:1,500 系列:- 类型:时钟缓冲器/驱动器 PLL:是 主要目的:- 输入:- 输出:- 电路数:- 比率 - 输入:输出:- 差分 - 输入:输出:- 频率 - 最大:- 电源电压:3.3V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:28-SSOP(0.209",5.30mm 宽) 供应商设备封装:28-SSOP 包装:带卷 (TR) 其它名称:93786AFT
ICS810001DK-21LF 功能描述:IC CLK GEN SYNC VCXO DL 32VFQFN RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 专用 系列:HiPerClockS™, FemtoClock™ 标准包装:1 系列:- 类型:时钟/频率发生器,多路复用器 PLL:是 主要目的:存储器,RDRAM 输入:晶体 输出:LVCMOS 电路数:1 比率 - 输入:输出:1:2 差分 - 输入:输出:无/是 频率 - 最大:400MHz 电源电压:3 V ~ 3.6 V 工作温度:0°C ~ 85°C 安装类型:表面贴装 封装/外壳:16-TSSOP(0.173",4.40mm 宽) 供应商设备封装:16-TSSOP 包装:Digi-Reel® 其它名称:296-6719-6
ICS810001DK-21LFT 功能描述:IC CLK GEN SYNC VCXO DL 32VFQFN RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 专用 系列:HiPerClockS™, FemtoClock™ 标准包装:1,500 系列:- 类型:时钟缓冲器/驱动器 PLL:是 主要目的:- 输入:- 输出:- 电路数:- 比率 - 输入:输出:- 差分 - 输入:输出:- 频率 - 最大:- 电源电压:3.3V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:28-SSOP(0.209",5.30mm 宽) 供应商设备封装:28-SSOP 包装:带卷 (TR) 其它名称:93786AFT