
FEMTOCLOCK CRYSTAL-TO-
3.3V LVPECL CLOCK GENERATOR
ICS843251-04
IDT / ICS 3.3V LVPECL CLOCK GENERATOR
1
ICS843S51AG-04 REV. A JANUARY 12, 2009
General Description
The ICS843251-04 is a 10Gb/12Gb Ethernet Clock
Generator and a member of the HiPerClocksTM
family of high performance devices from IDT. The
ICS843251-04 can synthesize 10 Gigabit Ethernet
and 12 Gigabit Ethernet with a 25MHz crystal. It can
also generate SATA and 10Gb Fibre Channel reference clock
frequencies with the appropriate choice of crystals. The
ICS843251-04 has excellent phase jitter performance and is
packaged in a small 8-pin TSSOP, making it ideal for use in
systems with limited board space.
Features
One differential 3.3V LVPECL output
Crystal oscillator interface designed for
18pF parallel resonant crystal
Crystal input frequency range: 19.33MHz – 30MHz
Output frequency range: 145MHz – 187.5MHz
VCO range: 580MHz – 750MHz
RMS phase jitter @ 156.25MHz, (1.875MHz – 20MHz):
0.39ps (typical)
Full 3.3V supply mode
0°C to 70°C ambient operating temperature
Available in both standard (RoHS 5) and lead-free (RoHS 6)
packages
Configuration Table with 25MHz Crystal
Configuration Table with Selectable Crystals
HiPerClockS
ICS
Inputs
Output
Frequency
(MHz)
Application
Crystal Frequency
(MHz))
Feedback Divide
VCO Freq.(MHz)
N Output Divide
25
30
750
4
187.5
12 Gigabit Ethernet
25
625
4
156.25
10 Gigabit Ethernet
Inputs
Output
Frequency
(MHz)
Application
Crystal Frequency
(MHz))
Feedback Divide
VCO Freq.(MHz)
N Output Divide
20
30
600
4
150
SATA
21.25
30
637.5
4
159.375
10 Gigabit Fibre Channel
24
25
600
4
150
SATA
25.5
25
637.5
4
159.375
10 Gigabit Fibre Channel
30
25
750
4
187.5
12 Gigabit Fibre Channel
Pin Assignment
1
2
3
4
8
7
6
5
Q
nQ
FREQ_SEL
VCC
VCCA
VEE
XTAL_OUT
XTAL_IN
Block Diagram
OSC
Phase
Detector
VCO
580MHz-750MHz
DIV. N
÷4
0 = ÷25 (default)
1 = ÷30
XTAL_IN
XTAL_OUT
FREQ_SEL
nQ
Q
ICS843251-04
8 Lead TSSOP
4.40mm x 3.0mm x 0.925mm
package body
G Package
Top View