PRELIMINARY
FEMTOCLOCKS™ CRYSTAL-TO-LVDS
FREQUENCY SYNTHESIZER W/INTEGRATED FANOUT BUFFER
ICS844246I
GENERAL DESCRIPTION
FEATURES
The ICS844246I is a Crystal-to-LVDS Clock
• Six LVDS outputs
ICS
HiPerClockS™
Synthesizer/Fanout Buffer designed for Fibre
Channel and Gigabit Ethernet applications and is
a member of the HiperClockS™ family of High
Performance Clock Solutions from IDT. The output
• Crystal oscillator interface
• Output frequency range: 53.125MHz to 333.3333MHz
• Crystal input frequency range: 25MHz to 33.333MHz
frequency can be set using the frequency select pins and a
25MHz crystal for Ethernet frequencies, or a 26.5625MHz
crystal for a Fibre Channel. The low phase noise character-
istics of the ICS844246I make it an ideal clock for these
• 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
• -40°C to 85°C ambient operating temperature
demanding applications.
• Available in both standard (RoHS 5) and lead-free (RoHS 6)
packages
SELECT FUNCTION TABLE
Inputs
Function
FB_SEL N_SEL1 N_SEL0 M Divide N Divide
M/N
10
5
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
5
4
8
2.5
8
3
4
6
6
4
12
2
BLOCK DIAGRAM
PIN ASSIGNMENT
Q0
VDDO
1
24
23
22
Q3
2
3
VDDO
nQ2
nQ3
Q4
nQ0
Pullup
PLL_BYPASS
4
Q2
nQ1
Q1
nQ0
nQ4
Q5
nQ5
N_SEL1
GND
21
20
19
18
17
16
15
14
13
5
6
7
8
Q1
1
nQ1
Q0
Output
Divider
XTAL_IN
9
PLL_BYPASS
VDDA
GND
OSC
PLL
Q2
0
10
11
12
N_SEL0
XTAL_OUT
XTAL_IN
XTAL_OUT
VDD
FB_SEL
nQ2
Q3
Feedback
Divider
ICS844246I
24-Lead TSSOP, E-Pad
4.40mm x 7.8mm x 0.90mm
body package
nQ3
Pulldown
FB_SEL
Q4
G Package
Top View
Pullup
nQ4
N_SEL1
Pullup
N_SEL0
Q5
nQ5
The Preliminary Information presented herein represents a product in pre-production.The noted characteristics are based on initial product characterization
and/or qualification.Integrated DeviceTechnology, Incorporated (IDT) reserves the right to change any circuitry or specifications without notice.
IDT™ / ICS™ LVDS FREQUENCY SYNTHESIZER W/FANOUT BUFFER
1
ICS844246BGI REV. A NOVEMBER 14, 2007