General Description
The 840N021 is a LVCMOS/LVTTL clock synthesizer designed for
Ethernet applications. The device generates a 125MHz clock signal
from a 25MHz crystal with excellent phase jitter performance. The
device uses IDT’s fourth generation FemtoClock® NG technology for
an optimum of high clock frequency, low phase noise performance
and low power consumption.The device supports 2.5V or 3.3V
voltage supply and is packaged in a small, lead-free (RoHS 6) 8-lead
TSSOP package. The extended temperature range supports
wireless infrastructure, telecommunication and networking end
equipment requirements. The device is a member of the
high-performance clock family from IDT.

Features
• Fourth generation FemtoClock® NG technology
• 125MHz output clock synthesized from a 25MHz fundamental
mode crystal
• One 2.5V or 3.3V LVCMOS/LVTTL clock output
• Crystal interface designed for a 12pF parallel resonant crystal
• RMS phase jitter @ 125MHz, using a 25MHz crystal
(1.875MHz - 20MHz): 0.156ps (maximum)
• RMS phase jitter @ 100MHz, using a 20MHz crystal
(12kHz - 20MHz): 0.451ps (maximum)
• LVCMOS interface level for the output enable input
• Full 2.5V or 3.3V supply voltage
• Lead-free (RoHS 6) packaging
• -40°C to 85°C ambient operating temperature
• Use replacement part 840N202CKI-dddLF