
ICS843253AGI-45 REVISION A JULY 20, 2009
1
2009 Integrated Device Technology, Inc.
FemtoClock Crystal-to-3.3V LVPECL
Frequency Synthesizer
ICS843253I-45
General Description
The ICS843253I-45 is a two LVPECL output and
one LVCMOS output Synthesizer optimized to
generate Ethernet reference clock frequencies and
is a member of the HiPerClocks family of high
performance clock solutions from IDT. Using a
25MHz, 18pF parallel resonant crystal, the following frequencies
can be generated: 25MHz, 125MHz, and 156.25MHz. The
ICS843253I-45 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 ICS843253I-45 is
packaged in a small 16-pin TSSOP package.
Features
Two differential LVPECL output pairs and
one LVCMOS reference clock output
Crystal oscillator interface designed for a 25MHz, 18pF parallel
resonant crystal
A 25MHz crystal generates output frequencies of: 25MHz,
125MHz and 156.25MHz
VCO frequency: 625MHz
RMS Phase Jitter @ 156.25MHz, (1.875MHz – 20MHz) using a
25MHz crystal: 0.46ps (typical)
Full 3.3V supply mode
-40°C to 85°C ambient operating temperature
Available in both standard (RoHS 5) and lead-free (RoHS 6)
packages
HiPerClockS
ICS
Block Diagram
OSC
Phase
Detector
VCO
625MHz
Feedback Divider
÷25
÷4
÷5
25MHz
QA
nQA
QB
nQB
REF_OUT
CLK_ENA
XTAL_IN
XTAL_OUT
CLK_ENB
Pullup
Pin Assignment
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
REF_OUT
VCC
VCCA
VCCOA
nQA
QA
VEE
CLK_ENA
CLK_ENB
VEE
QB
nQB
VCCOB
XTAL_IN
XTAL_OUT
VEE
ICS843253I-45
16-Lead TSSOP
4.4mm x 5.0mm x 0.925mm package body
G Package