843204I-01 Datasheet, PDF (6/14 Pages) Integrated Device Technology – FemtoClock® Crystal-to-3.3V LVPECL Frequency Synthesizer

843204I-01 DATA SHEET
APPLICATION INFORMATION
POWER SUPPLY FILTERING TECHNIQUES
As in any high speed analog circuitry, the power supply
pins are vulnerable to random noise. The 843204I-01 pro-
vides separate power supplies to isolate any high switching
noise from the outputs to the internal PLL.V , V , and V should
CC CCA
CCO_x
be individually connected to the power supply plane through vias,
and bypass capacitors should be used for each pin. To achieve
optimum jitter performance, power supply isolation is required.
Figure 1 illustrates how a 10Ω resistor along with a 10µF and a
.01μF bypass capacitor should be connected to each V .
CCA
3.3V
V
CC
.01μF 10Ω
V
CCA
.01μF
10μF
FIGURE 1. POWER SUPPLY FILTERING
CRYSTAL INPUT INTERFACE
The 843204I-01 has been characterized with 18pF parallel
resonant crystals. The capacitor values shown in Figure 2 below
were determined using an 18pF parallel resonant crystal and
were chosen to minimize the ppm error.
X1
18pF Parallel Crystal
C1
27pF
XTAL_IN
C2
27pF
XTAL_OUT
FIGURE 2. CRYSTAL INPUt INTERFACE
FEMTOCLOCKS™ CRYSTAL-TO-
6
3.3V LVPECL FREQUENCY SYNTHESIZER
REVISION A 11/5/15