General Description

The 813N252I-09 is a PLL based synchronous multiplier that is

optimized for PDH or SONET to Ethernet clock jitter attenuation and

frequency translation. The device contains two internal frequency

multiplication stages that are cascaded in series. The first stage is a

VCXO PLL that is optimized to provide reference clock jitter

attenuation. The second stage is a FemtoClock™ frequency multiplier

that provides the low jitter, high frequency Ethernet output clock that

easily meets Gigabit and 10 Gigabit Ethernet jitter requirements.

Pre-divider and output divider multiplication ratios are selected using

device selection control pins. The multiplication ratios are optimized

to support most common clock rates used in PDH, SONET and

Ethernet applications. The VCXO requires the use of an external,

inexpensive pullable crystal. The VCXO uses external passive loop

filter components which allows configuration of the PLL loop

bandwidth and damping characteristics. The device is packaged in a

space-saving 32-VFQFN package and supports industrial

temperature range.

Features

• Two LVPECL output pairs

Each output supports independent frequency selection at 25MHz,

125MHz, 156.25MHz and 312.5MHz

• Two differential inputs support the following input types: LVPECL,

LVDS, LVHSTL, SSTL, HCSL

• Accepts input frequencies from 8kHz to 155.52MHz including

8kHz, 1.544MHz, 2.048MHz, 19.44MHz, 25MHz, 77.76MHz,

125MHz and 155.52MHz

• Attenuates the phase jitter of the input clock by using a low-cost

pullable fundamental mode VCXO crystal

• VCXO PLL bandwidth can be optimized for jitter attenuation and

reference tracking using external loop filter connection

• FemtoClock frequency multiplier provides low jitter, high frequency

output

• Absolute pull range: 50ppm

• FemtoClock VCO frequency: 625MHz

• RMS phase jitter @ 125MHz, using a 25MHz crystal

(12kHz – 20MHz): 0.25ps (typical) and 0.35ps (maximum)

• 3.3V supply voltage

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

• Available in lead-free (RoHS 6) package