ICS844021I-01 Datasheet, PDF (1/10 Pages) Integrated Circuit Systems – FEMTOCLOCKS™ CRYSTAL-TO- LVDS CLOCK GENERATOR

Integrated
Circuit
Systems, Inc.
PRELIMINARY
ICS844021I-01
FEMTOCLOCKS™ CRYSTAL-TO- LVDS
CLOCK GENERATOR
GENERAL DESCRIPTION
ICS
The ICS844021I-01 is an Ethernet Clock
Generator and a member of the HiPerClocks^TM
HiPerClockS™ _{family of high performance devices from ICS. The}
ICS844021I-01 uses an 18pF parallel resonant
crystal over the range of 24.5MHz - 34MHz. For
Ethernet applications, a 25MHz crystal is used. The
ICS844021I-01 has excellent <1ps phase jitter performance,
over the 1.875MHz - 20MHz integration range. The
ICS844021I-01 is packaged in a small 8-pin TSSOP, making
it ideal for use in systems with limited board space.
FEATURES
• (1) Differential LVDS output
• Crystal oscillator interface, 18pF parallel resonant crystal
(24.5MHz - 34MHz)
• Output frequency range: 122.5MHz - 170MHz
• VCO range: 490MHz - 680MHz
• RMS phase jitter @ 125MHz, using a 25MHz crystal
(1.875MHz - 20MHz): 0.45ps (typical)
• 3.3V or 2.5V operating supply
• -40°C to 85°C ambient operating temperature
COMMON CONFIGURATION TABLE - Gb ETHERNET
Inputs
Crystal Frequency (MHz) M
25
20
26.666
20
33.33
20
N
Multiplication
Value M/N
4
5
4
5
4
5
Output Frequency
(MHz)
125
133.33
166.66
BLOCK DIAGRAM
OE ^Pullup
XTAL_IN
OSC
Phase
Detector
VCO
490MHz - 680MHz
N = ÷4 (fixed)
Q0
nQ0
XTAL_OUT
M = ÷20 (fixed)
PIN ASSIGNMENT
VDDA 1
GND 2
XTAL_OUT 3
XTAL_IN 4
8 VDD
7 Q0
6 nQ0
5 OE
ICS844021I-01
8-Lead TSSOP
4.40mm 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.
844021AGI-01
www.icst.com/products/hiperclocks.html
REV. A MARCH 29, 2005
1