ICS843246 Datasheet, PDF (1/15 Pages) Integrated Circuit Systems – FEMTOCLOCKS™ CRYSTAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER W/INTEGRATED FANOUT BUFFER

Integrated
Circuit
Systems, Inc.
PRELIMINARY
ICS843246
FEMTOCLOCKS™ CRYSTAL-TO-3.3V LVPECL
FREQUENCY SYNTHESIZER W/INTEGRATED FANOUT BUFFER
GENERAL DESCRIPTION
The ICS843246 is a Crystal-to-3.3V LVPECL
ICS
Clock Synthesizer/Fanout Buffer designed for
HiPerClockS™ _{Fibre Channel and Gigabit Ethernet appli-}
cations and is a member of the HiperClockS™
family of High Performance Clock Solutions
from ICS. The output frequency can be set using the fre-
quency select pins and a 25MHz crystal for Ethernet
frequencies, or a 26.5625MHz crystal for a Fibre Channel.
The low phase noise characteristics of the ICS843246
make it an ideal clock for these demanding applications.
FEATURES
• Six LVPECL outputs
• Crystal oscillator interface
• Output frequency range: 53.125MHz to 333.3333MHz
• Crystal input frequency range: 25MHz to 33.333MHz
• RMS phase jitter at 125MHz, using a 25MHz crystal
(1.875MHz to 20MHz): 0.41ps (typical)
• Full 3.3V or 3.3V core, 2.5V output supply mode
• 0°C to 70°C ambient operating temperature
• Industrial temperature information available upon request
SELECT FUNCTION TABLE
• Available in both standard and lead-free RoHS-compliant
packages
Inputs
Function
FB_SEL N_SEL1 N_SEL0 M Divide N Divide M/N
0
0
0
20
2
10
0
0
1
20
4
5
0
1
0
20
5
4
0
1
1
20
8
2.5
1
0
0
24
3
8
1
0
1
24
4
6
1
1
0
24
6
4
1
1
1
24
12
2
BLOCK DIAGRAM
PIN ASSIGNMENT
PLL_BYPASS ^Pullup
XTAL_IN
XTAL_OUT
OSC
1
Output
PLL
0
Divider
Q0
nQ0
Q1
nQ1
Q2
nQ2
VCCO 1
VCCO 2
nQ2 3
Q2 4
nQ1 5
Q1 6
nQ0 7
Q0 8
PLL_BYPASS 9
VCCA 10
VCC 11
FB_SEL 12
24 Q3
23 nQ3
22 Q4
21 nQ4
20 Q5
19 nQ5
18 N_SEL1
17 VEE
16 VEE
15 N_SEL0
14 XTAL_OUT
13 XTAL_IN
FB_SEL ^Pulldown
N_SEL1 ^Pullup
N_SEL0 ^Pullup
Feedback
Divider
Q3
ICS843246
24-Lead, 300-MIL SOIC
nQ3
7.5mm x 15.33mm x 2.3mm
body package
Q4
M Package
Top View
nQ4
24-Lead TSSOP
4.40mm x 7.8mm x 0.92mm
Q5
body package
nQ5
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.
843246AM
www.icst.com/products/hiperclocks.html
REV. A SEPTEMBER 29, 2005
1