ICS844246 Datasheet, PDF (1/16 Pages) Integrated Circuit Systems – FEMTOCLOCKS™ CRYSTAL-TO-LVDS FREQUENCY SYNTHESIZER W/INTEGRATED FANOUT BUFFER

PRELIMINARY
FEMTOCLOCKS™ CRYSTAL-TO-LVDS
FREQUENCY SYNTHESIZER W/INTEGRATED FANOUT BUFFER
ICS844246
GENERAL DESCRIPTION
The ICS844246 is a Cr ystal-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 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 character-
istics 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
SELECT FUNCTION TABLE
Inputs
Function
• Available in both standard (RoHS 5) and lead-free (RoHS 6)
packages
FB_SEL N_SEL1 N_SEL0 M Divide N Divide M/N
0
0
0
20
0
0
1
20
2
10
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
BLOCK DIAGRAM
PIN ASSIGNMENT
PLL_BYPASS ^Pullup
XTAL_IN
XTAL_OUT
OSC
FB_SEL ^Pulldown
N_SEL1 ^Pullup
N_SEL0 ^Pullup
1
Output
PLL
0
Divider
Feedback
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
Q3
ICS844246
nQ3
24-Lead TSSOP, E-Pad
4.40mm x 7.8mm x 0.90mm
Q4
body package
G Package
nQ4
Top View
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 Device Technology, Incorporated (IDT) reserves the right to change any circuitry or specifications without notice.
IDT^™ / ICS^™ LVDS FREQUENCY SYNTHESIZER W/FANOUT BUFFER 1
ICS844246BG REV.C NOVEMBER 14, 2007