GENERAL DESCRIPTION

The 9DB306 is a high performance 1-to-6 Differential-toLVPECL Jitter Attenuator designed for use in PCI Express?

systems. In some PCI Express systems, such as those found

in desktop PCs, the PCI Express clocks are generated from a

low bandwidth, high phase noise PLL frequency synthesizer. In

these systems, a zero delay buffer may be required to attenuate

high frequency random and deterministic jitter components from

the PLL synthesizer and from the system board. The 9DB306

has 2 PLL bandwidth modes. In low bandwidth mode, the PLL

loop BW is about 500kHz and this setting will attenuate much of

the jitter from the reference clock input while being high enough

to pass a triangular input spread spectrum profi le. There is also

a high bandwidth mode which sets the PLL bandwidth at 1MHz

which will pass more spread spectrum modulation.

For serdes which have x30 reference multipliers instead of x25

multipliers, 5 of the 6 PCI Express outputs (PCIEX1:5) can be

set for 125MHz instead of 100MHz by confi guring the appropriate

frequency select pins (FS0:1). Output PCIEX0 will always run at

the reference clock frequency (usually 100MHz) in desktop PC PCI

Express Applications

FEATURES

? Six differential LVPECL output pairs

? One differential clock input

? CLK and nCLK supports the following input types:

LVPECL, LVDS, LVHSTL, SSTL, HCSL

? Maximum output frequency: 140MHz

? Input frequency range: 90MHz - 140MHz

? VCO range: 450MHz - 700MHz

? Output skew: 135ps (maximum)

? Cycle-to-Cycle jitter: 30ps (maximum)

? RMS phase jitter @ 100MHz, (1.5MHz - 22MHz): 3ps (typical)

? 3.3V operating supply

? 0°C to 70°C ambient operating temperature

? Available in lead-free (RoHS 6) package

? Industrial temperature information available upon request