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AD9512 参数 Datasheet PDF下载

AD9512图片预览
型号: AD9512
PDF下载: 下载PDF文件 查看货源
内容描述: 1.2 GHz的时钟分配IC , 1.6 GHz的输入,分频器,延迟调整,五路输出 [1.2 GHz Clock Distribution IC, 1.6 GHz Inputs, Dividers, Delay Adjust, Five Outputs]
分类和应用: 时钟
文件页数/大小: 48 页 / 1007 K
品牌: ABCO [ ABCO ELECTRONICS CO.LTD ]
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AD9512  
DIVIDERS  
Example 2:  
Each of the five clock outputs of the AD9512 has its own  
divider. The divider can be bypassed to get an output at the  
same frequency as the input (1×). When a divider is bypassed, it  
is powered down to save power.  
Set Divide Ratio = 8  
high_cycles = 3  
low_cycles = 3  
All integer divide ratios from 1 to 32 may be selected. A divide  
ratio of 1 is selected by bypassing the divider.  
Divide Ratio = (3 + 1) + (3 + 1) = 8  
Note that a Divide Ratio of 8 may also be obtained by setting:  
high_cycles = 2  
Each divider can be configured for divide ratio, phase, and duty  
cycle. The phase and duty cycle values that can be selected  
depend on the divide ratio that is chosen.  
low_cycles = 4  
Setting the Divide Ratio  
The divide ratio is determined by the values written via the SCP  
to the registers that control each individual output, OUT0 to  
OUT4. These are the even numbered registers beginning at 4Ah  
and going through 52h. Each of these registers is divided into  
bits that control the number of clock cycles the divider output  
stays high (high_cycles <3:0>) and the number of clock cycles  
the divider output stays low (low_cycles <7:4>). Each value is 4  
bits and has the range of 0 to 15.  
Divide Ratio = (2 + 1) + (4 + 1) = 8  
Although the second set of settings produces the same divide  
ratio, the resulting duty cycle is not the same.  
Setting the Duty Cycle  
The duty cycle and the divide ratio are related. Different divide  
ratios have different duty cycle options. For example, if Divide  
Ratio = 2, the only duty cycle possible is 50ꢀ. If the Divide  
Ratio = 4, the duty cycle can be 25ꢀ, 50ꢀ, or 75ꢀ.  
The divide ratio is set by  
Divide Ratio = (high_cycles + 1) + (low_cycles + 1)  
Example 1:  
The duty cycle is set by  
Duty Cycle = (high_cycles + 1)/[(high_cycles + 1) + (low_cycles + 1)]  
See Table 12 for the values of the available duty cycles for each  
divide ratio.  
Set the Divide Ratio = 2  
high_cycles = 0  
low_cycles = 0  
Divide Ratio = (0 + 1) + (0 + 1) = 2  
Table 12. Duty Cycle and Divide Ratio  
4Ah to 52h  
4Ah to 52h  
Divide Ratio  
Duty Cycle (%)  
Divide Ratio  
Duty Cycle (%)  
LO<7:4>  
HI<3:0>  
LO<7:4>  
HI<3:0>  
2
3
3
4
4
4
5
5
5
5
6
6
6
6
6
50  
67  
33  
50  
75  
25  
60  
40  
80  
20  
50  
67  
33  
83  
17  
0
0
1
1
0
2
1
2
0
3
2
1
3
0
4
0
1
0
1
2
0
2
1
3
0
2
3
1
4
0
7
7
7
7
7
7
8
8
8
8
8
8
8
9
9
57  
43  
71  
29  
86  
14  
50  
63  
38  
75  
25  
88  
13  
56  
44  
2
3
1
4
0
5
3
2
4
1
5
0
6
3
4
3
2
4
1
5
0
3
4
2
5
1
6
0
4
3
Rev. A | Page 25 of 48