ICS843246I Datasheet, PDF (1/17 Pages) Integrated Device Technology – FEMTOCLOCKS™ CRYSTAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER W/INTEGRATED FANOUT BUFFER

FEMTOCLOCKS™ CRYSTAL-TO-3.3V LVPECL FREQUENCY
SYNTHESIZER W/INTEGRATED FANOUT BUFFER
ICS843246I
GENERAL DESCRIPTION
The ICS843246I is a Crystal-to-3.3V LVPECL 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 IDT. The output
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 characteristics
of the ICS843246I make it an ideal clock for these demanding
applications.
FEATURES
• Six LVPECL outputs
• Crystal oscillator interface
• VCO range: 490MHz to 680MHz
• 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
Core/Output
3.3V/3.3V
3.3V/2.5V
SELECT FUNCTION TABLE
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
• -40°C to 85°C ambient operating temperature
• Available in both standard (RoHS 5) and lead-free (RoHS 6)
packages
BLOCK DIAGRAM
PLL_BYPASS ^Pullup
XTAL_IN
XTAL_OUT
OSC
FB_SEL ^Pulldown
N_SEL1 ^Pullup
N_SEL0 ^Pullup
1
Output
PLL
0
Divider
Feedback
Divider
PIN ASSIGNMENT
Q0
nQ0
Q1
nQ1
Q2
nQ2
Q3
VCCO ₁
24 Q3
VCCO 2
23 nQ3
nQ2 3
22 Q4
Q2 4
21 nQ4
nQ1 5
20 Q5
Q1 6 19 nQ5
nQ0 7
18 N_SEL1
Q0 8
17 VEE
PLL_BYPASS 9
16 ^VEE
VCCA 10 15 N_SEL0
VCC _{11 14} XTAL_OUT
FB_SEL 12 13 XTAL_IN
nQ3
ICS843246I
Q4
24-Lead TSSOP, E-Pad
4.40mm x 7.8mm x 0.9mm
nQ4
body package
G Package
Q5
Top View
nQ5
IDT^™ / ICS^™ 3.3V LVPECL FREQUENCY SYNTHESIZER
1
ICS843246BGI REV. A AUGUST 2, 2007