GENERAL DESCRIPTION

The 873996 is a Zero Delay/Multiplier/Divider with hitless input clock

switching capability and a member of the family of low jitter/phase

noise devices from IDT. The 873996 is ideal for use in redundant,

fault tolerant clock trees where low phase noise and low jitter are

critical. The device receives two differential LVPECL clock signals

from which it generates 6 LVPECL clock outputs with “zero” delay.

The output divider and feedback divider selections also allow for

frequency multiplication or division.

The 873996 Dynamic Clock Switch (DCS) circuit continuously

monitors both input clock signals. Upon detection of a failure (input

clock stuck LOW or HIGH for at least 1 period), INP_BAD for that

clock will be set HIGH. If that clock is the primary clock, the DCS will

switch to the good secondary clock and phase/frequency alignment

will occur with minimal output phase disturbance.

The low jitter characteristics combined with input clock monitor-ing

and automatic switching from bad to good input clocks make the

873996 an ideal choice for mission critical applications that utilize

1G or 10G Ethernet or 1G/4G/10G Fibre Channel.

FEATURES

• Six differential 3.3V LVPECL outputs

• Selectable differential clock inputs

• CLKx, nCLKx pair can accept the following differential

input levels: LVPECL, LVDS, LVHSTL, HCSL, SSTL

• Input clock frequency range: 49MHz to 213.33MHz

• Output clock frequency range: 49MHz to 640MHz

• VCO range: 490MHz to 640MHz

• External feedback for “zero delay” clock regeneration

with confi gurable frequencies

• Output skew: 100ps (maximum)

• RMS phase jitter (1.875MHz - 20MHz): 0.6ps (typical) assuming a low phase noise reference clock input

• 3.3V supply voltage

• 0°C to 70°C ambient operating temperature

• Available in lead-free (RoHS 6) package