General Description

The 8433625 is a 3 differential output LVPECL Synthesizer designed

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

26.041666MHz, 18pF parallel resonant crystal, the following

frequencies can be generated based on the settings of 4 frequency

select pins (DIV_SELA[1:0], DIV_SELB[1:0]): 625MHz, 312.5MHz,

156.25MHz, and 125MHz. The 8433625 has 2 output banks, Bank A

with 1 differential LVPECL output pair and Bank B with 2 differential

LVPECL output pairs.

The two banks have their own dedicated frequency select pins and

can be independently set for the frequencies mentioned above. The

8433625 uses 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 8433625 is packaged in a small

24-pin TSSOP package.

特性 Features

? Three 3.3V LVPECL outputs on two banks, A Bank with one

LVPECL pair and B Bank with 2 LVPECL output pairs

? Using a 25MHz or 26.041666 crystal, the two output banks can be

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

? Selectable crystal oscillator interface

or LVCMOS/LVTTL single-ended input

? VCO range: 520MHz – 680MHz

? RMS phase jitter @ 156.25MHz (1.875MHz - 20MHz):

0.3ps (typical)

? Full 3.3V supply mode

? 0°C to 70°C ambient operating temperature

? Available in lead-free (RoHS 6) package