General Description

The 844441 is a low jitter, high performance clock generator and a

member of the FemtoClock® family of silicon timing products. The

844441 is designed for use in applications using the SAS and SATA

interconnect. The 844441 uses an external, 25MHz, parallel

resonant crystal to generate four selectable output frequencies:

75MHz, 100MHz, 150MHz, and 300MHz. This silicon based

approach provides excellent frequency stability and reliability. The

844441 features down and center spread spectrum (SSC) clocking

techniques.

Features

• Designed for use in SAS, SAS-2, and SATA systems

• Center (±0.17) Spread Spectrum Clocking (SSC)

• Down (-0.23 or -0.5) SSC

• Better frequency stability than SAW oscillators

• One differential 2.5V LVDS output

• Crystal oscillator interface designed for 25MHz

(CL = 12pF) frequency

• External fundamental crystal frequency ensures high reliability

and low aging

• Selectable output frequencies: 75MHz, 100MHz, 150MHz,

300MHz

• Output frequency is tunable with external capacitors

• RMS phase jitter @ 100MHz, using a 25MHz crystal

(12kHz – 20MHz): 1.1936ps (typical)

• 2.5V operating supply

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

• Lead-free (RoHS 6) packaging