- 您现在的位置：买卖IC网 > PDF目录248541 > 514EAAXXXXXXBAG (SILICON LABORATORIES) 250 MHz, OTHER CLOCK GENERATOR, PDSO6 PDF资料下载
参数资料
| 型号： | 514EAAXXXXXXBAG |
| 厂商： | SILICON LABORATORIES |
| 元件分类： | XO, clock |
| 英文描述： | 250 MHz, OTHER CLOCK GENERATOR, PDSO6 |
| 封装： | 3.20 X 5 MM, ROHS COMPLIANT PACKAGE-6 |
| 文件页数： | 7/32页 |
| 文件大小： | 267K |
| 代理商： | 514EAAXXXXXXBAG |
第1页第2页第3页第4页第5页第6页当前第7页第8页第9页第10页第11页第12页第13页第14页第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页第31页第32页
Si514
Preliminary Rev. 0.9
15
3. All-Digital PLL Applications
The Si514 uses a high resolution divider M that enables fine frequency adjustments with resolution better than
0.026 parts per billion. Fine frequency adjustments are useful when making frequency corrections that compensate
for changing ambient conditions, long term aging or when locking the Si514 to an input clock reference. Figure 3
shows a typical implementation using a system IC such as an FPGA to control the output of the Si514 in a phase-
locked application. Refer to “AN575: An Introduction to FPGA-Based ADPLLs” for more information.
Figure 3. All-Digital PLL Application Using Si514 with Dual CMOS Output
Since small frequency changes must be within ±1000 ppm of the center frequency, HS_DIV and LS_DIV remain
constant. The below expression can be used to calculate a new M2 divider value based on a desired output
frequency shift, where FOUT is in ppm.
Some systems, particularly those that use feedback control, can simplify the computation by implementing an
approximate frequency change based on toggling a bit position or adding/subtracting a bit to the existing M_Frac
value. Since M ranges approximately ±10% between 65.04065041 and 78.17385866, the effect of changing
M_Frac by a single bit depends only slightly on the absolute value of M.
For M=71 near the midpoint of the range, toggling M_Frac[0] changes the output frequency by 0.026 ppb. Each
higher order bit doubles the influence such that toggling M_Frac[1] is 0.052 ppb, M_Frac[2] is 0.1 ppb, etc. Figure 4
shows this trend across multiple registers generalized to M_Frac[N]. Coarse changes greater than ±1.7 ppm are
possible but most applications require finer transitions. Toggling each bit involves incrementing or decrementing
the bit position. Writing M_Int[8:3] in register 9 completes the operation.
Figure 4. Output Frequency Change When Toggling M_Frac[N], M=71
I2C Control
Any Frequency
DSPLL
CLK_OUT
FB
Si514
FPGA
÷
I2C
Master
Command
Conversion
Loop
Filter
PD
÷
SCL
SDA
Fin
M2
M1 1 FOUT 10
6
–
–
=
M_Int[8:0] = 000100111
M = 71.000000000000
M_Frac[28:0] = 00000000000000000000000000000
M_Frac[23:16] = 00000000
M_Frac[15:8] = 00000000
M_Frac[7:0] = 00000000
0.026ppb
6.7ppb
1.7ppm
相关PDF资料 |
PDF描述 |
|---|---|
| 514FACXXXXXXAAGR | 125 MHz, OTHER CLOCK GENERATOR, PDSO6 |
| 514GCCXXXXXXAAGR | 125 MHz, OTHER CLOCK GENERATOR, PDSO6 |
| 514JBBXXXXXXBAGR | 170 MHz, OTHER CLOCK GENERATOR, PDSO6 |
| 514MBAXXXXXXAAG | 250 MHz, OTHER CLOCK GENERATOR, PDSO6 |
| 514NACXXXXXXBAG | 125 MHz, OTHER CLOCK GENERATOR, PDSO6 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| 514ECA000121AAG | 制造商:Silicon Laboratories Inc 功能描述:PROGRAMMABLE XO LVPECL 100.00 MHZ - Trays |
| 514ECA000838BAG | 制造商:Silicon Laboratories Inc 功能描述:PROGRAMMABLE XO - Trays |
| 514ECA000838BAGR | 制造商:Silicon Laboratories Inc 功能描述:OSCILLATOR - Tape and Reel |
| 514F | 功能描述:风扇 50x15mm 24VDC 12CFM 1W 5000RPM 30dBA SB RoHS:否 制造商:Sanyo Denki 产品:Fans 电流类型: 电源电压:48 V 气流:636 CFM 轴承类型: 噪声:83 dBA 速度:6400 RPM 功率额定值:264 W 框架尺寸 (mm):172 mm x 150 mm x 102 mm 外壳材料:Aluminum 端接类型:Wire 系列: |
| 514F | 制造商:ebm-papst Inc 功能描述:FAN 50MM 24VDC |
发布紧急采购，3分钟左右您将得到回复。