ICS844008I-15 Datasheet, PDF (1/12 Pages) Integrated Circuit Systems – FEMTOCLOCKS™ CRYSTAL-TO-LVDS FREQUENCY SYNTHESIZER

Integrated
Circuit
Systems, Inc.
PRELIMINARY
ICS844008I-15
FEMTOCLOCKS™ CRYSTAL-TO-
LVDS FREQUENCY SYNTHESIZER
GENERAL DESCRIPTION
The ICS844008I-15 is an 8 output LVDS
ICS
Synthesizer optimized to generate PCI Express
HiPerClockS™ _{reference clock frequencies and is a member}
of the HiPerClocks^TM family of high performance
clock solutions from ICS. Using a 25MHz
parallel resonant crystal, the following frequencies can be
generated based on F_SEL pin: 100MHz or 125MHz. The
ICS844008I-15 uses ICS’ 3^rd generation low phase noise
VCO technology and can achieve <1ps typical rms phase
jitter, easily meeting PCI Express jitter requirements. The
ICS844008I-15 is packaged in a 32-pin LQFP package.
FEATURES
• Eight LVDS outputs
• Crystal oscillator interface
• Supports the following output frequencies:
100MHz or 125MHz
• VCO: 500MHz
• RMS phase jitter @ 125MHz, using a 25MHz crystal
(1.875MHz - 20MHz): 0.42ps (typical)
• Full 3.3V supply modes
• -40°C to 85°C ambient operating temperature
• Available in both standard and lead-free RoHS compliant
packages
FREQUENCY SELECT FUNCTION TABLE
PIN ASSIGNMENT
Input
Frequency
(MHz)
25MHz
25MHz
Input
F_SEL
0
1
M Divider
Value
20
20
N Divider
Value
4
5
M/N Divider
Value
5
4
Output
Frequency
(MHz)
125
100
BLOCK DIAGRAM
nPLL_SEL ^Pulldown
Q0
nQ0
Q1
1
nQ1
32 31 30 29 28 27 26 25
Q0 1
24 Q7
nQ0 2
23 nQ7
VDD 3 ^{ICS844008I-15} 22 VDD
Q1
4
32-Lead LQFP
7mm x 7mm x 1.4mm
21
Q6
nQ1 5
package body
20 nQ6
GND 6
Y Package
19 GND
Q2 7
Top View
18 Q5
nQ2 8
17 nQ5
9 10 11 12 13 14 15 16
25MHz
XTAL_IN
VCO
Q2
XTAL_OUT
OSC
Phase
Detector
500MHz
(w/25MHz
0
Reference)
÷4
÷5
nQ2
Q3
nQ3
M = ÷20 (fixed)
Q4
nQ4
Pullup
OE1
Q5
nQ5
Q6
nQ6
Q7
MR ^Pulldown
F_SEL ^Pullup
OE2 ^Pullup
nQ7
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.
844008AYI-15
www.icst.com/products/hiperclocks.html
REV. A FEBRUARY 2, 2006
1