General Description

The 843252 is a 2 differential output LVPECL Synthesizer designed

to generate Ethernet reference clock frequencies. Using a 25MHz,

18pF parallel resonant crystal, the following frequencies can be

generated based on the settings of 4 frequency select pins

(SELA[1:0], SELB[1:0]): 625MHz, 312.5MHz, 156.25MHz, and

125MHz.

The two banks have their own dedicated frequency select pins and

can be independently set for the frequencies mentioned above. The

843252 IDT’s 3rd generation low phase noise VCO technology and

can achieve 1ps or lower typical rms phase jitter, easily meeting

Ethernet jitter requirements. The 843252 is packaged in a small

16-pin TSSOP package.

Features

• Two differential LVPECL output pairs

• Using a 25MHz crystal, the two output banks can be

independently set for 625MHz, 312.5MHz, 156.25MHz or 125MHz

• Crystal oscillator interface

• VCO frequency: 490MHz – 680MHz

• RMS Phase Jitter @ 156.25MHz, (1.875MHz – 20MHz) using a

25MHz crystal: 0.47ps (typical)

• Full 3.3V supply mode

• 0°C to 70°C ambient operating temperature

• Industrial temperature available upon request

• Available in lead-free (RoHS 6) package