ICS845252I Datasheet, PDF (1/17 Pages) Integrated Device Technology – FemtoClock™ Crystal-to-CML Clock Generator

FemtoClock™ Crystal-to-CML Clock
Generator
ICS845252I
DATA SHEET
General Description
The ICS845252I is a 3.3V/2.5V CML clock generator
ICS
designed for Ethernet applications. The device
HiPerClockS™ _{synthesizes either a 50MHz, 62.5MHz, 100MHz,}
125MHz, 156.25MHz, 250MHz or 312.5MHz clock
signal with excellent phase jitter performance. The
clock signal is distributed to two low-skew differential CML outputs.
The device is suitable for driving the reference clocks of Ethernet
PHYs. The device supports 3.3V and 2.5V voltage supply and is
packaged in a small, lead-free (RoHS 6) 32-lead VFQFN package.
The extended temperature range supports telecommunication,
wireless infrastructure and networking end equipment requirements.
The device is a member of the HiPerClockS™ family of High
Performance Clock Solutions from IDT.
Features
• Clock generation of: 50MHz, 62.5MHz, 100MHz, 125MHz,
156.25MHz, 250MHz and 312.5MHz
• Two differential CML clock output pairs
• Crystal interface designed for 25MHz,
18pF parallel resonant crystal
• RMS phase jitter @ 125MHz, using a 25MHz crystal
(1.875MHz – 20MHz): 400fs (typical), 3.3V
Offset
Noise Power
100Hz.................... -102.4 dBc/Hz
1kHz.................... -119.4 dBc/Hz
10kHz................... -124.8 dBc/Hz
100kHz................... -125.7 dBc/Hz
• LVCMOS interface levels for the control inputs
• Full 3.3V and 2.5V supply voltage
• Available in lead-free (RoHS 6) 32 VFQFN package
• -40°C to 85°C ambient operating temperature
Block Diagram
XTAL_IN
XTAL_OUT
OSC
REF_CLK ^Pulldown
0
Phase
f_{REF Detector}
1
VCO
490-680
MHz
REF_SEL ^Pulldown
FBSEL ^Pulldown
nBYPASS ^Pullup
FSEL1:0 ^{Pulldown, Pulldown}
nOE ^Pulldown
÷20,
÷25 (default)
0
÷2 (default),
÷4,
1 _÷5,
÷10
Pin Assignment
Q0
nQ0
Q1
nQ1
32 31 30 29 28 27 26 25
nQ0 1
24 nc
Q0 2
23 nc
VDD 3
22 REF_SEL
nOE 4
21 FSEL1
nc 5
20 FSEL0
nc 6
19 ^nc
nc 7
18 VDD
nc 8
17 nc
9 10 11 12 13 14 15 16
ICS845252I
32 lead VFQFN
5.0mm x 5.0mm x 0.925mm package body
K Package
Top View
ICS845252AKI REVISION A SEPTEMBER 30, 2009
1
©2009 Integrated Device Technology, Inc.