AD9513/PCBZ Analog Devices Inc, AD9513/PCBZ Datasheet - Page 20

• Manufacturer Part Number: AD9513/PCBZ
• Description: 800MHz 3-Chan Clock Distribution EB
• Manufacturer: Analog Devices Inc

Specifications of AD9513/PCBZ

• Main Purpose: Timing, Clock Distribution
• Utilized Ic / Part: AD9513
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD9513
Table 16. OUT0 Divide or OUT2 Divide
S9
0
1/3
2/3
1
0
1/3
2/3
1
0
1/3
2/3
1
0
1/3
2/3
1
1
DIVIDER PHASE OFFSET
The phase offset of OUT1 and OUT2 can be selected (see Table 13
to Table 15). This allows the relative phase of the outputs to be set.
After a SYNC operation (see the Synchronization section), the
phase offset word of each divider determines the number of
input clock (CLK) cycles to wait before initiating a clock output
edge. By giving each divider a different phase offset, output-to-
output delays can be set in increments of the fast clock period, t
Figure 24 shows four cases, each with the divider set to divide = 4.
By incrementing the phase offset from 0 to 3, the output is
offset from the initial edge by a multiple of t
DIVIDER OUTPUT
Duty cycle is the clock signal high time divided by the total period.
Figure 24. Phase Offset—Divider Set for Divide = 4, Phase Set from 0 to 2
CLOCK INPUT
PHASE = 0
PHASE = 1
PHASE = 2
PHASE = 3
DIV = 4
CLK
S10
0
0
0
0
1/3
1/3
1/3
1/3
2/3
2/3
2/3
2/3
1
1
1
1
0
3 × t
1
OUT0
Divide (Duty Cycle
S2 ≠ 2/3
1
2 (50%)
3 (33%)
4 (50%)
5 (40%)
6 (50%)
8 (50%)
9 (44%)
10 (50%)
12 (50%)
15 (47%)
16 (50%)
18 (50%)
24 (50%)
30 (50%)
32 (50%)
CLK
t
CLK
2
3
t
2 × t
4
CLK
CLK
5
6
7
1
8
)
9
CLK
OUT2
Divide (Duty Cycle
S2 = 2/3
7 (43%)
11 (45%)
13 (46%)
14 (50%)
17 (47%)
19 (47%)
20 (50%)
21 (48%)
22 (50%)
23 (48%)
25 (48%)
26 (50%)
27 (48%)
28 (50%)
29 (48%)
31 (48%)
10
.
11
12
13
14
1
CLK
5
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.
1
)
For example:
For Divide = 4:
The outputs can also be described as:
Setting the phase offset to Phase = 4 results in the same relative
phase as Phase = 0° or 360°.
The resolution of the phase offset is set by the fast clock period
(t
divide ratio, up to a phase offset of 15.
Phase offsets can be related to degrees by calculating the phase
step for a particular divide ratio:
Using some of the same examples:
CLK
CLK = 491.52 MHz
t
Phase Offset 0 = 0 ns
Phase Offset 1 = 2.0345 ns
Phase Offset 2 = 4.069 ns
Phase Offset 3 = 6.104 ns
Phase Offset 0 = 0°
Phase Offset 1 = 90°
Phase Offset 2 = 180°
Phase Offset 3 = 270°
Phase Step = 360°/Divide Ratio
Divide = 4
Phase Step = 360°/4 = 90°
Unique Phase Offsets in Degrees Are Phase = 0°, 90°,
Divide = 9
Phase Step = 360°/9 = 40°
Unique Phase Offsets in Degrees Are Phase = 0°, 40°, 80°,
CLK
) at CLK. The maximum unique phase offset is less than the
180°, 270°
120°, 160°, 200°, 240°, 280°, 320°
= 1/491.52 = 2.0345 ns