6

COMMERCIALANDINDUSTRIALTEMPERATURERANGES

IDT2305

3.3VZERODELAYCLOCKBUFFER

ZERO DELAY AND SKEW CONTROL

All outputs should be uniformly loaded in order to achieve Zero I/O Delay. Since the CLKOUT pin is the internal feedback for the PLL, its relative

loading can affect and adjust the input/output delay. The Output Load Difference diagram illustrates the PLL's relative loading with respect to the other

outputs that can adjust the Input-Output (I/O) Delay.

For designs utilizing zero I/O Delay, all outputs including CLKOUT must be equally loaded. Even if the output is not used, it must have a capacitive

load equal to that on the other outputs in order to obtain true zero I/O Delay. If I/O Delay adjustments are needed, use the Output Load Difference diagram

to calculate loading differences between the CLKOUT pin and other outputs. For zero output-to-output skew, all outputs must be loaded equally.

REF TO CLKA/CLKB RELAY vs. OUTPUT LOAD DIFFERENCE BETWEEN CLKOUT PIN AND CLKA/CLKB PINS

OUTPUT LOAD DIFFERENCE BETWEEN CLKOUT PIN AND CLKA/CLKB PINS (pF)

1500

1000

500

0

-500

-1000

-1500

-30

-25

-20

-15

-10

-5

05

10

15

20

25

30