840N021 Datasheet, PDF (1/13 Pages) Integrated Device Technology – FemtoClock NG Crystal-to-LVCMOS/LVTTL Clock

FemtoClock® NG
Crystal-to-LVCMOS/LVTTL Clock
840N021
DATA SHEET
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.
Frequency Table
f_XTAL (MHz)
20
25
Q Output Frequency (MHz)
100
125
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
Function Table
Input
OE
0
1 (default)
Output Enable
Output Q is disabled in high-impedance state
Output Q is enabled.
NOTE: OE is an asynchronous control.
Block Diagram
XTAL_IN
PFD
FemtoClock^® NG
OSC
&
VCO
÷5
Q
XTAL_OUT
LPF
490-637.5MHz
÷25
Pullup
OE
Pin Assignment
VDDA 1
OE 2
XTAL_OUT 3
XTAL_IN 4
8 VDD
7Q
6 GND
5 DNU
840N021
8-lead TSSOP
4.40mm x 3.0mm x 0.925mm
package body
G Package
Top View
840N021 REVISION A 8/14/15
1
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