ICS844251I-15 Datasheet, PDF (1/11 Pages) Integrated Circuit Systems – FEMTOCLOCKS™ CRYSTAL-TO-LVDS CLOCK GENERATOR

Integrated
Circuit
Systems, Inc.
PRELIMINARY
ICS844251I-15
FEMTOCLOCKS™ CRYSTAL-TO-LVDS
CLOCK GENERATOR
GENERAL DESCRIPTION
The ICS844251I-15 is an Ethernet Clock
ICS
Generator and a member of the HiPerClocks^TM
HiPerClockS™ _{family of high performance devices from ICS.}
The ICS844251I-15 uses an 18pF parallel
resonant crystal over the range of 23.2MHz -
30MHz. For Ethernet applications, a 25MHz crystal is
used. The device has excellent <1ps phase jitter
performance, over the 1.875MHz - 20MHz integration
range. The ICS844251I-15 is packaged in a small 8-pin
TSSOP, making it ideal for use in systems with limited
board space.
FEATURES
• One Differential LVDS output
• Crystal oscillator interface, 18pF parallel resonant crystal
(23.2MHz - 30MHz)
• Output frequency ranges: 116MHz - 150MHz and
580MHz - 750MHz
• VCO range: 580MHz - 750MHz
• RMS phase jitter @ 125MHz, using a 25MHz crystal
(1.875MHz - 20MHz): 0.46ps (typical)
• 3.3V or 2.5V operating supply
• -40°C to 85°C ambient operating temperature
• Available in both standard and lead-free RoHS-compliant
packages
COMMON CONFIGURATION TABLE
Inputs
Crystal Frequency (MHz) FREQ_SEL M
25
1
25
26.667
1
25
25
0
25
26.667
0
25
Multiplication Value Output Frequency
N
M/N
(MHz)
1
25
625
1
25
666.67
5
5
125
5
5
133.33
BLOCK DIAGRAM
FREQ_SEL ^Pulldown
XTAL_IN
XTAL_OUT
OSC
Phase
Detector
VCO
580MHz - 750MHz
M = ÷25 (fixed)
FREQ_SEL N
0
÷1
1
÷5
PIN ASSIGNMENT
VDDA 1
8 VDD
GND 2
7Q
XTAL_OUT 3
6 nQ
Q
XTAL_IN 4
5 FREQ_SEL
nQ
ICS844251I-15
8-Lead TSSOP
4.4mm x 3.0mm x 0.925mm
package body
G Package
Top View
The Preliminary Information presented herein represents a product in prototyping or pre-production. The noted characteristics are based on
initial product characterization. Integrated Circuit Systems, Incorporated (ICS) reserves the right to change any circuitry or specifications
without notice.
844251BGI-15
www.icst.com/products/hiperclocks.html
REV. A NOVEMBER 23, 2005
1