General Description

The 813N252DI-02 device uses IDT's fourth generation

FemtoClock® NG technology for optimal high clock frequency and

low phase noise performance, combined with a low power

consumption and high power supply noise rejection. The

813N252DI-02 is a PLL based synchronous multiplier that is

optimized for PDH or SONET to Ethernet clock jitter attenuation and

frequency translation.

The813N252DI-02 is a fully integrated Phase Locked loop utilizing a

FemtoClock NG Digital VCXO that provides the low jitter, high

frequency SONET/PDH output clock that easily meets OC-48 jitter

requirements. This VCXO technology simplifies PLL design by

replacing the pullable crystal requirement of analog VCXOs with a

fixed 27MHz generator crystal. Jitter attenuation down to 10Hz is

provided by an external loop filter. 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

device requires the use of an external, inexpensive fundamental

mode 27MHz crystal. The device is packaged in a space-saving

32-VFQFN package and supports industrial temperature range.

Features

• Fourth generation FemtoClock® NG technology

• 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, HCSL

• Accepts input frequencies from 8kHz to 155.52MHz including

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

125MHz and 155.52MHz

• Crystal interface optimized for a 27MHz, 10pF parallel resonant

crystal

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

fundamental mode crystal

• Customized settings for jitter attenuation and reference tracking

using an external loop filter connection

• FemtoClock NG frequency multiplier provides low jitter, high

frequency output

• Absolute pull range: ±100ppm

• Power supply noise rejection (PSNR): -85dB (typical)

• FemtoClock NG VCXO frequency: 2500MHz

• RMS phase jitter @ 156.25MHz, using a 27MHz crystal

(12kHz – 20MHz): 0.6ps (typical)

• RMS phase jitter @ 125MHz, using a 27MHz crystal

(12kHz – 20MHz): 0.65ps (typical)

• 3.3V supply voltage

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

• Available in lead-free (RoHS 6) package