ICS84330CI Datasheet, PDF (8/20 Pages) Integrated Circuit Systems – 720MHZ, LOW JITTER, CRYSTAL-TO-3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER

ICS84330CI Data Sheet
720MHZ, CRYSTAL-TO-LVPECL FREQUENCY SYNTHESIZER
Applications Information
Power Supply Filtering Technique
As in any high speed analog circuitry, the power supply pins are
vulnerable to random noise. To achieve optimum jitter performance,
power supply isolation is required. The ICS84330CI provides
separate power supplies to isolate any high switching noise from the
outputs to the internal PLL. V_CC and V_CCA should be individually
connected to the power supply plane through vias, and 0.01µF
bypass capacitors should be used for each pin. Figure 2 illustrates
this for a generic V_CC pin and also shows that V_CCA requires that an
additional 10 resistor along with a 10F bypass capacitor be
connected to the V_CCA pin.
3.3V
V_CC
.01µF _10Ω
V_CCA
.01µF
10µF
Figure 2. Power Supply Filtering
Recommendations for Unused Input and Output Pins
Inputs:
LVCMOS Control Pins
All control pins have internal pullups or pulldowns; additional
resistance is not required but can be added for additional protection.
A 1k resistor can be used.
Outputs:
TEST Output
The unused TEST output can be left floating. There should be no
trace attached.
LVPECL Outputs
The unused LVPECL output pair can be left floating. We recommend
that there is no trace attached. Both sides of the differential output
pair should either be left floating or terminated.
50
40
30
20
10
0
200
300
400
500
600
700
Output Frequency (MHz)
Figure 3. Cycle-to-Cycle Jitter vs. fOUT (using a 16MHz crystal)
Spec Limit
N=1
ICS84330CVI REVISION A JANUARY 7, 2011
8
©2011 Integrated Device Technology, Inc.