General Description

The 813N252I-04 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® NG 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

• Fourth generation FemtoClock® Next Generation (NG)

technology

• One LVPECL output pair and one LVDS output pair

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 NG frequency multiplier provides low jitter, high

frequency output

• Absolute pull range: 100ppm

• FemtoClock NG VCO frequency: 625MHz

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

(12kHz – 20MHz): 0.3ps (typical)

• 3.3V supply voltage

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

• Available in lead-free (RoHS 6) package