ICS843N252-45 Datasheet, PDF (1/16 Pages) Integrated Device Technology – Fourth generation FemtoClock

FemtoClock^® NG Crystal-to-3.3V LVPECL ICS843N252-45
Frequency Synthesizer
DATA SHEET
General Description
The ICS843N252-45 is a 1 LVPECL and 1 LVCMOS output
Synthesizer optimized to generate Ethernet reference clock
frequencies. The device uses IDT’s fourth generation FemtoClock ^®
NG technology for an optimum of high clock frequency and low
phase noise performance, combined with a low power consumption
and high power supply noise rejection. Using a 25MHz parallel
resonant crystal, the following frequencies can be generated:
156.25MHz and 125MHz. With a very low phase noise VCO it is
targeted to achieve 0.4ps or lower typical rms phase jitter, easily
meeting Ethernet jitter requirements. The ICS843N252-45 is
packaged in a small 16-pin TSSOP package.
Features
• Fourth generation FemtoClock^® Next Generation (NG) technology
• One differential 3.3V LVPECL output and one LVCMOS/LVTTL
output
• Crystal oscillator interface designed for a 25MHz parallel resonant
crystal
• A 25MHz crystal generates output frequencies of: 156.25MHz and
125MHz
• VCO frequency: 625MHz
• RMS Phase Jitter @ 156.25MHz, (12kHz – 20MHz) using a
25MHz crystal: 0.33ps (typical)
• RMS Phase Jitter @ 125MHz, (12kHz – 20MHz) using a 25MHz
crystal: 0.39ps (typical)
• Power supply noise rejection PSNR: -60dB (typical)
• Full 3.3V supply mode
• 0°C to 70°C ambient operating temperature
• Available in lead-free (RoHS 6) package
Block Diagram
CLK_ENA ^Pullup
25MHz
XTAL_IN
PFD
FemtoClock^®NG
÷5
OSC
&
VCO
XTAL_OUT
LPF
625MHz
÷4
CLK_ENB ^Pullup
Feedback Divider
÷25
Pin Assignment
QA
QB
nQB
CLK_ENA 1
VEE 2
QA 3
VCCOA 4
nc 5
nc 6
VCCA 7
VCC 8
16 CLK_ENB
15 VEE
14 QB
13 nQB
12 VCC
11 XTAL_IN
10 XTAL_OUT
9 VEE
ICS843N252-45
16-Lead TSSOP
4.4mm x 5.0mm x 0.925mm package body
G Package
ICS843N252GG-45 REVISION A JULY 6, 2011
1
©2011 Integrated Device Technology, Inc.