ICS845204 Datasheet, PDF (7/13 Pages) Integrated Device Technology – CRYSTAL-TO-MLVDS PCI EXPRESS™ CLOCK SYNTHESIZER W/SPREAD SPECTRUM

ICS845204
CRYSTAL-TO-MLVDS CLOCK SYNTHESIZER W/SPREAD SPECTRUM
Parameter Measurement Information, continued
ADVANCE INFORMATION
V_DD
DC Input M-LVDS
out
➤
out
V_OS/∆ V_OS
V_DD
DC Input M-LVDS
100
out
➤
100
V_OD/∆ V_OD
out
Offset Voltage Setup
Differential Output Voltage Setup
Application Information
Power Supply Filtering Technique
As in any high speed analog circuitry, the power supply pins are
vulnerable to random noise. The ICS845204 provides separate
power supplies to isolate any high switching noise from the outputs
to the internal PLL. V_DD, V_DDA and V_DDO 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 0.01µF
bypass capacitor should be connected to each V_DDA pin.
3.3V
V_DD
.01µF _10Ω
V_DDA
.01µF
10µF
Figure 1. Power Supply Filtering
Recommendations for Unused Input and Output Pins
Inputs:
LVCMOS Control Pins
All control pins have internal pull-ups or pull-downs; additional
resistance is not required but can be added for additional
protection. A 1kΩ resistor can be used.
Outputs:
M-LVDS Outputs
All unused M-LVDS output pairs can be either left floating or
terminated with 100Ω across. If they are left floating, there should
be no trace attached.
IDT™ / ICS™ M-LVDS CLOCK SYNTHESIZER
7
ICS845204AK SEPTEMBER 25, 2007