GENERAL DESCRIPTION

The 874005-04 is a high performance Differential-to-LVDS 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 874005-04 has 2 PLL bandwidth modes: 300kHz and

2MHz. The 300kHz mode will provide maximum jitter attenuation,

but higher PLL tracking skew and spread spectrum modulation

from the motherboard synthesizer may be attenuated. The 2MHz

bandwidth provides the best tracking skew and will pass most

spread profi les. The 874005-04 supports Serdes reference clock

frequencies of 100MHz, 125MHz and 250MHz.

The 874005-04 uses IDT’s 3rd Generation FemtoClockTM PLL

technology to achive 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.

FEATURES

• Five differential LVDS output pairs

• One differential clock input

• Supports 100MHz, 125MHz, and 250MHz Serdes reference

clocks

• CLK and nCLK supports the following input types:

LVPECL, LVDS, LVHSTL, SSTL, HCSL

• Output frequency range: 98MHz - 320MHz

• Input frequency range: 98MHz - 128MHz

• PCI Express (2.5 Gb/S) and Gen 2 (5 Gb/s) jitter compliant

• RMS phase jitter @ 100MHz (1.875MHz – 20MHz):

0.88ps (typical)

• VCO range: 490MHz - 640MHz

• Cycle-to-cycle jitter: 35ps (maximum) QA = QB = ÷4

• 3.3V operating supply

• Two bandwidth modes allow the system designer to make jitter

attenuation/tracking skew design trade-offs

• 0°C to 70°C ambient operating temperature

• Available in lead-free (RoHS 6) package