描述 Description

The 843N571I is a PLL based clock synthesizer for use in Ethernet

applications. The 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. Using IDT’s latest FemtoClock NG PLL

technology, the 843N571I achieves <0.3ps RMS phase jitter

performance.

843N571I can synthesize 100MHz, 125MHz, 156.25MHz and a low

frequency 33.33MHz CPU clock from a single device. Six LVCMOS

outputs also serve as additional buffering of the 25MHz crystal

reference.

Features

? Fourth generation FemtoClock? Next Generation (NG) technology

? Seven single-ended LVCMOS outputs, 30? output impedance

? Three LVPECL output pairs

One differential LVPECL (QA, nQA) output pair: 156.25MHz

Two selectable differential LVPECL output pairs (QB, nQB and

QC, nQC): 100MHz and 125MHz

? One single-ended LVCMOS (QD0) 33.33MHz CPU clock

? Selectable external crystal or single-ended input source

? Crystal oscillator interface designed for 25MHz, parallel resonant

crystal

? FemtoClock NG frequency multiplier provides low jitter, high

frequency output

? FemtoClock NG VCO frequency: 2.5GHz

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

(12kHz – 20MHz): 0.283ps (typical)

? Power supply noise rejection PSNR: -80dB

? 3.3V supply voltage

? -40C to 85C ambient operating temperature

? Lead-free (RoHS 6) packaging