General Description

The ICS871004I-04 is a high performance 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 jitter attenuator may be required to

attenuate high frequency random and deterministic jitter components

from the PLL synthesizer and from the system board. The

ICS871004I-04 has three PLL bandwidth modes: 200kHz, 700kHz

and 1700kHz. The 200kHz mode provides the maximum jitter

attenuation, but it also results in higher PLL tracking time. In this

mode, the spread spectrum modulation may also be attenuated. The

700kHz bandwidth provides an intermediate bandwidth that can

easily track tri-angular spread profiles, while providing good jitter

attenuation. The 1700kHz bandwidth provides the best tracking skew

and will pass most spread profiles, but the jitter attenuation will not be

as good as the lower bandwidth modes. The ICS871004I-04 can be

set for different modes using the F_SELx pins as shown in Table 3C.

The ICS871004I-04 uses IDT’s 3RD Generation FemtoClock? PLL

technology to achieve the lowest possible phase noise. The device is

packaged in a 24 Lead TSSOP package, making it ideal for use in

space constrained applications such as PCI Express add-in cards.

特性 Features

? Four differential HCSL output pairs

? One differential clock input

? CLK, nCLK can accept the following differential input levels:

LVPECL, LVDS, HSTL, HCSL

? Output frequency range: 98MHz to 640MHz

? Input frequency range: 98MHz to 128MHz

? VCO range: 490MHz - 640MHz

? Cycle-to-cycle jitter: 7.5ps (typical)

? Three bandwidth modes allow the system designer to make jitter

attenuation/tracking skew design trade-offs

? Full 3.3V supply mode

? -40°C to 85°C ambient operating temperature

? Available in lead-free (RoHS 6) package