Philips TDA8783 - Manual (Page 22)

2002 Oct 23 22
Philips Semiconductors Product specification
40 Msps, 10-bit analog-to-digital
interface for CCD cameras
TDA8783
Power and grounding recommendations
Care must be taken to minimize noise when designing a
printed-circuit board for applications such as PC cameras,
surveillance cameras, camcorders and digital still
cameras.
For the front-end integrated circuit, the basic rules of
printed-circuit board design and implementation of analog
components (such as classical operational amplifiers)
must be taken into account, particularly with respect to
power and ground connections.
The connections between CCD interface and CDS input
should be as short as possible and a ground ring
protection around these connections can be beneficial.
Decoupling capacitors are necessary on all supply pins as
shown in Fig.16.
Separate analog and digital supplies provide the best
performance. If it is not possible to do this on the board,
then decouple the analog supply pins effectively from the
digital supply pins. The decoupling capacitors must be
placed as close as possible to the IC package.
In a two-ground system, in order to minimize the noise
from package and die parasitics, the following
recommendations must be implemented:
•
The ground pin associated with the digital outputs must
be connected to the digital ground plane and special
care should be taken to avoid feedthrough in the analog
ground plane. The analog and digital ground planes
must be connected with an inductor as close as possible
to the IC package, in order to have the same DC voltage
on the ground planes.
•
The digital output pins and their associated lines should
be shielded by the digital ground plane, which can be
used as return path for the digital signals.