ICS844246 Datasheet, PDF (1/13 Pages) Integrated Circuit Systems – FEMTOCLOCKS™ CRYSTAL-TO-LVDS FREQUENCY SYNTHESIZER W/INTEGRATED FANOUT BUFFER

Integrated
Circuit
Systems, Inc.
PRELIMINARY
ICS844246
FEMTOCLOCKS™ CRYSTAL-TO-LVDS
FREQUENCY SYNTHESIZER W/INTEGRATED FANOUT BUFFER
GENERAL DESCRIPTION
The ICS844246 is a Crystal-to-LVDS Clock
ICS
Synthesizer/Fanout Buffer designed for Fibre
HiPerClockS™ _{Channel and Gigabit Ethernet applications and}
is a member of the HiperClockS™ family of
High Performance Clock Solutions from ICS.
The output frequency can be set using the frequency
select pins and a 25MHz crystal for Ethernet fre-
quencies, or a 26.5625MHz crystal for a Fibre Channel.
The low phase noise characteristics of the ICS844246
make it an ideal clock for these demanding applications.
FEATURES
• Six LVDS 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): 0.39ps (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
Inputs
FB_SEL N_SEL1 N_SEL0
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
M Divide
20
20
20
20
24
24
24
24
Function
N Divide
2
4
5
8
3
4
6
12
• Available in both standard and lead-free RoHS-compliant
packages
M/N
10
5
4
2.5
8
6
4
2
BLOCK DIAGRAM
PIN ASSIGNMENT
PLL_BYPASS ^Pullup
XTAL_IN
XTAL_OUT
OSC
1
Output
PLL
0
Divider
Q0
nQ0
Q1
nQ1
Q2
nQ2
VDDO 1
VDDO 2
nQ2 3
Q2 4
nQ1 5
Q1 6
nQ0 7
Q0 8
PLL_BYPASS 9
VDDA 10
VDD 11
FB_SEL 12
24 Q3
23 nQ3
22 Q4
21 nQ4
20 Q5
19 nQ5
18 N_SEL1
17 GND
16 GND
15 N_SEL0
14 XTAL_OUT
13 XTAL_IN
Feedback
Q3
ICS843246
24-Lead, 300-MIL SOIC
Divider
nQ3
7.5mm x 15.33mm x 2.3mm
body package
FB_SEL ^Pulldown
Q4
M Package
Top View
N_SEL1 ^Pullup
nQ4
24-Lead TSSOP
Pullup
N_SEL0
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.
844246AM
www.icst.com/products/hiperclocks.html
REV. A SEPTEMBER 29, 2005
1