ICS477-05

QUAD PLL WITH VCXO FOR HDTV

VCXO AND SYNTHESIZER

IDT™ / ICS™ QUAD PLL WITH VCXO FOR HDTV

4

ICS477-05

REV H 062404

considered to reduce stray capacitance. (Alternately,

the crystal may be re-specified to a higher load

capacitance. Contact ICS for details.) If the centering

error is more than 25 ppm positive, add identical fixed

centering capacitors from each crystal pin to ground.

The value for each of these caps (in pF) is given by:

External Capacitor =

2 x (centering error)/(trim sensitivity)

Trim sensitivity is a parameter which can be supplied by

your crystal vendor. If you do not know the value,

assume it is 30 ppm/pF. After any changes, repeat the

measurement to verify that the remaining error is

acceptably low (typically less than ±25 ppm).

PCB Layout Recommendations

For optimum device performance and lowest output

phase noise, the following guidelines should be

observed.

1) The 0.01µF decoupling capacitors should be

mounted on the component side of the board as close

to the VDD pins as possible. No vias should be used

between the decoupling capacitors and VDD pins. The

PCB trace to VDD pin should be kept as short as

possible, as should the PCB trace to the ground via.

2) The external crystal should be mounted just next to

the device with short traces. The X1 and X2 traces

should not be routed next to each other with minimum

spaces, instead they should be separated and away

from other traces.

3) To minimize EMI, the 33

Ωseries termination resistor

(if needed) should be placed close to the clock output.

4) An optimum layout is one with all components on the

same side of the board, minimizing vias through other

signal layers. Other signal traces should be routed away

from the ICS477-05. This includes signal traces just

underneath the device, or on layers adjacent to the

ground plane layer used by the device.

Absolute Maximum Ratings

Stresses above the ratings listed below can cause permanent damage to the ICS477-05. These ratings,

which are standard values for ICS commercially rated parts, are stress ratings only. Functional operation of

the device at these or any other conditions above those indicated in the operational sections of the

specifications is not implied. Exposure to absolute maximum rating conditions for extended periods can

affect product reliability. Electrical parameters are guaranteed only over the recommended operating

temperature range.

Item

Rating

Supply Voltage, VDD

7 V

All Inputs and Outputs

-0.5 V to VDD+0.5 V

Ambient Operating Temperature (commercial)

0 to +70

° C

Ambient Operating Temperature (industrial)

-40 to +85

° C

Storage Temperature

-65 to +150

° C

Junction Temperature

125

° C

Soldering Temperature

260

° C