ADA4430-1

Rev. C | Page 16 of 20

PRINTED CIRCUIT BOARD LAYOUT

As with all high speed applications, attention to printed circuit

board layout is of paramount importance. Standard high speed

layout practices should be adhered to when designing with the

ADA4430-1. A solid ground plane is recommended, and a 0.1 μF

surface-mount, ceramic power supply, decoupling capacitor should

be placed as close as possible to the supply pin.

The GND pin should be connected to the ground plane with a

trace that is as short as possible. Controlled impedance traces of

the shortest length possible should be used to connect to the signal

I/O pins and should not pass over any voids in the ground plane. A

75 Ω impedance level is typically used in video applications. All

signal outputs of the ADA4430-1 should include series termination

resistors when driving transmission lines.

When the ADA4430-1 receives its inputs from a device with

current outputs, the required load resistor value for the output

current is most often different from the characteristic impedance of

the signal traces. In this case, if the interconnections are sufficiently

short (less than 2 inches), the trace does not have to be

terminated in its characteristic impedance.