PRELIMINARY
ICS843246
Integrated
Circuit
Systems, Inc.
FEMTOCLOCKS™ C RYSTAL-TO-3.3V LVPECL
FREQUENCY SYNTHESIZER W/INTEGRATED FANOUT BUFFER
GENERAL DESCRIPTION
FEATURES
The ICS843246 is a Crystal-to-3.3V LVPECL • Six LVPECL outputs
ICS
HiPerClockS™
Clock Synthesizer/Fanout Buffer designed for
• Crystal oscillator interface
Fibre Channel and Gigabit Ethernet appli-
cations and is a member of the HiperClockS™
family of High Performance Clock Solutions
• Output frequency range: 53.125MHz to 333.3333MHz
• Crystal input frequency range: 25MHz to 33.333MHz
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.
• 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
• Available in both standard and lead-free RoHS-compliant
packages
SELECT FUNCTION TABLE
Inputs
Function
FB_SEL N_SEL1 N_SEL0 M Divide N Divide
M/N
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
20
20
20
20
24
24
24
24
2
4
10
5
5
4
8
2.5
8
3
4
6
6
4
12
2
BLOCK DIAGRAM
PIN ASSIGNMENT
VCCO
VCCO
1
24 Q3
Q0
2
3
4
23
22
21
20
nQ3
Q4
nQ4
Q5
nQ2
Q2
nQ1
nQ0
Pullup
PLL_BYPASS
5
Q1
Q1
6
19 nQ5
nQ0
Q0
PLL_BYPASS
VCCA
7
8
9
10
11
12
N_SEL1
VEE
VEE
N_SEL0
XTAL_OUT
XTAL_IN
18
17
16
15
14
13
1
0
nQ1
Output
Divider
XTAL_IN
OSC
PLL
Q2
VCC
FB_SEL
XTAL_OUT
nQ2
ICS843246
24-Lead, 300-MIL SOIC
7.5mm x 15.33mm x 2.3mm
body package
Q3
Feedback
Divider
nQ3
M Package
TopView
Pulldown
Pullup
Q4
FB_SEL
N_SEL1
nQ4
24-LeadTSSOP
4.40mm x 7.8mm x 0.92mm
body package
Pullup
N_SEL0
Q5
G Package
TopView
nQ5
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