AL128 datasheet(41/45 Pages) ETC

41 / 45 page

AL128

April 2, 1999

The high frequency clock reference or crystal should be handled carefully. Jitter and noise on the clock

will degrade the video performance. Keep the clock paths to the AL128 as short as possible to reduce

noise pickup.

Locate phase locked loop components close to the relevant AL128 pins. Isolate these components

from noise.

9.5 Analog Signal Interconnect

The AL128 should be located closely to the output connectors to minimize noise and reflections. Keep

the critical analog traces as short and wide as possible.

High frequency digital signals, especially pixel clocks and data signals should never overlap any of the

analog signal circuitry and should be kept as far away as possible.

The AL128 should have no inputs left floating. Each of the unused analog input pins should be

connected to GND. All of the digital input pins are internally pulled down.

The analog output traces should also not cross the AL128 and VDD power planes to maximize high-

frequency power supply rejection.

9.6 Component Placement

The suggested component placement is as follows:

Remarks:

1. PLL crystal/oscillator circuits should be placed at the lower left corner and close to

AL128 to avoid noise interference.

Analog Power

PLL

XTAL

RGB input

AL128

AL422

Al128-15

Layout considerations

TV output

(separated

and

shielded)

AL128 Datasheet(PDF) 41 Page - List of Unclassifed Manufacturers