ICS8430-71B Datasheet, PDF (8/16 Pages) Integrated Circuit Systems – 700MHZ, LOW JITTER, CRYSTAL INTERFACE / LVCMOS-TO-3.3V LVPECL FREQUENCY SYNTHESIZER

Integrated
Circuit
Systems, Inc.
PRELIMINARY
ICS8430B-71
700MHZ, LOW JITTER, CRYSTAL INTERFACE/
LVCMOS-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
APPLICATION INFORMATION
POWER SUPPLY FILTERING TECHNIQUES
As in any high speed analog circuitry, the power supply pins
are vulnerable to random noise. The ICS8430B-71 provides
separate power supplies to isolate any high switching
noise from the outputs to the internal PLL. V_CC, V_CCA, and V_CCO
should 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 pin.
3.3V
V
CC
.01μF 10Ω
V
CCA
.01μF
10μF
FIGURE 1. POWER SUPPLY FILTERING
CRYSTAL INPUT INTERFACE
A crystal can be characterized for either series or parallel
mode operation. The ICS8430B-71 has a built-in crystal
oscillator circuit. This interface can accept either a series or
parallel crystal without additional components and generate
frequencies with accuracy suitable for most applications.
Additional accuracy can be achieved by adding two small
capacitors C1 and C2 as shown in Figure 2.
X1
18pF Parallel Crystal
XTAL_OUT
C1
18p
XTAL_IN
C2
22p
Figure 2. CRYSTAL INPUt INTERFACE
8430BY-71
www.icst.com/products/hiperclocks.html
8
REV. A SEPTEMBER 20, 2005