
ICS844004-104
FEMTOCLOCKCRYSTAL-TO-LVDS FREQUENCY SYNTHESIZER
IDT / ICS LVDS FREQUENCY SYNTHESIZER
8
ICS844004AK-104 REV. A SEPTEMBER 15, 2008
Parameter Measurement Information, continued
Differential Output Voltage Setup
Offset Voltage Setup
Application 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 perform-
ance, power supply isolation is required. The ICS844004-104
provides separate power supplies to isolate any high switching
noise from the outputs to the internal PLL. VDD, VDDA and VDDO
should be individually connected to the power supply plane
through vias, and 0.01F bypass capacitors should be used for
each pin. Figure 1 illustrates this for a generic VDD pin and also
shows that VDDA requires that an additional 10 resistor along with
a 10
F bypass capacitor be connected to the V
DDA pin.
Figure 1. Power Supply Filtering
100
out
LVDS
DC Input
VOD/ VOD
V
DD
out
LVDS
DC Input
VOS/ VOS
V
DD
VDD
VDDA
3.3V or 2.5V
10
10F
.01F