- 您现在的位置：买卖IC网 > PDF目录9091 > LTC6946IUFD-2#TRPBF (Linear Technology)IC INTEGER-N PLL W/VCO 28QFN PDF资料下载
参数资料
| 型号： | LTC6946IUFD-2#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 15/30页 |
| 文件大小： | 0K |
| 描述： | IC INTEGER-N PLL W/VCO 28QFN |
| 软件下载： | PLLWizard™ PLLWizard™, with .NET 2.0 installer |
| 标准包装： | 2,500 |
| 类型： | 时钟/频率合成器（RF/IF），分数-N，整数-N， |
| PLL： | 是 |
| 输入： | 时钟 |
| 输出： | 时钟 |
| 电路数： | 1 |
| 比率 - 输入:输出： | 1:1 |
| 差分 - 输入:输出： | 是/是 |
| 频率 - 最大： | 4.91GHz |
| 除法器/乘法器： | 是/是 |
| 电源电压： | 3.15 V ~ 5.25 V |
| 工作温度： | -40°C ~ 105°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-WFQFN 裸露焊盘 |
| 供应商设备封装： | 28-QFN（4x5） |
| 包装： | 带卷 (TR) |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页当前第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页
LTC6946
22
6946fa
APPLICATIONS INFORMATION
4. Select loop filter components CI and CP based on BW
and RZ. A reliable loop can be achieved by using the
following equations for the loop capacitors (in Farads):
CI =
3.5
2 π BW RZ
(8)
CP =
1
7 π BW RZ
(9)
DESIGN AND PROGRAMMING EXAMPLE
This programming example uses the DC1705A with the
LTC6946-3. Assume the following parameters of interest:
fREF = 20MHz at 7dBm into 50Ω
fSTEP = 125kHz
fRF = 2.4GHz
From the Electrical Characteristics table:
fVCO = 3.825GHz to 5.744GHz
KVCO% = 4.0%Hz/V to 6.0%Hz/V
Determining Divider Values
Following the Loop Filter Design algorithm, first deter-
mine all the divider values. Using Equations 2, 3, 4 and 5
calculate the following values:
O = 2
R = 20MHz/(125kHz 2) = 80
fPFD = 250kHz
N = 2 2.4GHz/250kHz = 19200
fVCO = 4.8GHz
Also, from Equation 1 or Table 7 determine B:
B = 8 and BD[3:0] = 0
The next step in the algorithm is to determine the open-
loop bandwidth. BW should be at least 10× smaller than
fPFD. Wider loop bandwidths could have lower integrated
phase noise, depending on the VCO phase noise signature,
while narrower bandwidths will likely have lower spurious
power. Use a factor of 15 for this design example:
BW =
250kHz
15
= 16.7kHz
Loop Filter Component Selection
Now set loop filter resistor, RZ, and charge pump current,
ICP. Because the KVCO varies over the VCO’s frequency
range, using the KVCO geometric mean gives good results.
Using an ICP of 11.2mA, RZ is determined:
K VCO = 4.8 10
9 0.04 0.06 = 235MHz / V
RZ =
2 π 16.7k 19200
11.2m 235M
RZ = 765Ω
Now calculate CI and CP from Equations 7 and 8:
CI =
3.5
2 π 16.7k 765
= 44nF
CP =
1
7 π 16.7k 765
= 3.6nF
Status Output Programming
This example will use the STAT pin to alert the system
whenever the LTC6946 generates a fault condition. Pro-
gram x[5], x[4], x[3], x[1], x[0] = 1 to force the STAT pin
high whenever any of the UNLOCK, ALCHI, ALCLO, THI
or TLO flags asserts:
Reg01 = h3B
Power Register Programming
For correct PLL operation all internal blocks should be
enabled, but PDREFO should be set if the REFO pin is
not being used. OMUTE may remain asserted (or the
MUTE pin held low) until programming is complete. For
PDREFO = 1 and OMUTE = 1:
Reg02 = h0A
相关PDF资料 |
PDF描述 |
|---|---|
| LTC6946IUFD-1#TRPBF | IC INTEGER-N PLL W/VCO 28QFN |
| X9410WV24IZ | IC XDCP DUAL 64-TAP 10K 24-TSSOP |
| X9410WV24IT1 | IC XDCP DUAL 64-TAP 10K 24-TSSOP |
| M83723/78W20397 | CONN PLUG 39POS STRAIGHT W/PINS |
| ADF4106SCPZ-EP-R7 | IC PLL FREQ SYNTHESIZER 20LFCSP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC6946IUFD-3#PBF | 功能描述:IC INTEGER-N PLL W/VCO 28-QFN RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 时钟发生器，PLL，频率合成器 系列:- 标准包装:2,000 系列:- 类型:PLL 频率合成器 PLL:是 输入:晶体 输出:时钟 电路数:1 比率 - 输入:输出:1:1 差分 - 输入:输出:无/无 频率 - 最大:1GHz 除法器/乘法器:是/无 电源电压:4.5 V ~ 5.5 V 工作温度:-20°C ~ 85°C 安装类型:表面贴装 封装/外壳:16-LSSOP（0.175"，4.40mm 宽） 供应商设备封装:16-SSOP 包装:带卷 (TR) 其它名称:NJW1504V-TE1-NDNJW1504V-TE1TR |
| LTC6946IUFD-3#TRPBF | 功能描述:IC INTEGER-N PLL W/VCO 28QFN RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 时钟发生器，PLL，频率合成器 系列:- 标准包装:1,000 系列:Precision Edge® 类型:时钟/频率合成器 PLL:无 输入:CML，PECL 输出:CML 电路数:1 比率 - 输入:输出:2:1 差分 - 输入:输出:是/是 频率 - 最大:10.7GHz 除法器/乘法器:无/无 电源电压:2.375 V ~ 3.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:16-VFQFN 裸露焊盘，16-MLF? 供应商设备封装:16-MLF?（3x3） 包装:带卷 (TR) 其它名称:SY58052UMGTRSY58052UMGTR-ND |
| LTC6946-x | 制造商:LINER 制造商全称:Linear Technology 功能描述:16-Bit, 20Msps Low Noise Dual ADC |
| LTC694C | 制造商:LINER 制造商全称:Linear Technology 功能描述:Microprocessor Supervisory Circuits |
| LTC694C-3.3 | 制造商:LINER 制造商全称:Linear Technology 功能描述:3.3V Microprocessor Supervisory Circuits |
发布紧急采购，3分钟左右您将得到回复。