AD9522-5 Analog Devices, Inc., AD9522-5 Datasheet - Page 37

• Manufacturer Part Number: AD9522-5
• Description: 12 Lvds/24 Cmos Output Clock Generator
• Manufacturer: Analog Devices, Inc.

ZERO DELAY OPERATION
Zero delay operation aligns the phase of the output clocks with
the phase of the external PLL reference input.
The zero delay function of the AD9522-5 is achieved by feeding
the output of Channel Divider 0 back to the PLL N divider. In
Figure 36, the change in signal routing for zero delay mode is
shown in blue.
Set Register 0x01E[1] = 1b to select the zero delay mode. In the
zero delay mode, the output of Channel Divider 0 is routed back to
the PLL (N divider) through MUX1 (feedback path shown in blue
in Figure 36). The PLL synchronizes the phase/edge of the output
of Channel Divider 0 with the phase/edge of the reference input.
CLK/CLK
REFIN/
REFIN
MUX1
2, 3, 4, 5, OR 6
DIVIDE BY 1,
1
0
DIVIDER
DIVIDER
REG 0x01E[1] = 1
R
N
EXTERNAL VCXO
DELAY
DELAY
R
N
Figure 36. Zero Delay Function
INTERNAL ZERO DELAY CLOCK FEEDBACK PATH
Rev. 0 | Page 37 of 76
PFD
CP
Because the channel dividers are synchronized to each other,
the outputs of the channel dividers are synchronous with the
reference input. Both the R delay and the N delay inside the
PLL can be programmed to compensate for the propagation
delay from the output drivers and PLL components to minimize
the phase offset between the clock output and the reference
input to achieve zero delay.
CHANNEL DIVIDER 0
CHANNEL DIVIDER 1
CHANNEL DIVIDER 2
CHANNEL DIVIDER 3
AD9522-5
OUT0 TO OUT2
OUT3 TO OUT5
OUT6 TO OUT8
OUT9 TO OUT11
FILTER
LOOP
AD9522-5