Datasheet

ADA4433-1 Data Sheet
Rev. 0 | Page 12 of 16
APPLICATIONS INFORMATION
FULLY DIFFERENTIAL TRANSMISSION MODE
The ADA4433-1 is designed to be used as a fully differential driver.
The differential outputs of the ADA4433-1 allow fully balanced
transmission using twisted or untwisted pair cable. In this
configuration, the differential output termination consists of two
source resistors, one on each output, each equal to half the receiver
input termination. For example, in a 75 Ω system, each output of
the ADA4433-1 is back terminated with 37.5 Ω resistors that are
connected to a differential resistance of 75 Ω at the receiver (see
Figure 22).
Figure 22. Fully Differential Mode
PRINTED CIRCUIT BOARD (PCB) LAYOUT
As with all high speed applications, attention to PCB layout is of
paramount importance. Adhere to standard high speed layout
practices when designing with the ADA4433-1. A solid ground
plane is recommended. Place a 0.1 µF surface-mount, ceramic
power supply decoupling capacitor as close as possible to the
supply pin.
Connect the GND pin to the ground plane with a trace that is as
short as possible. Use controlled impedance traces of the shortest
length possible to connect to the signal I/O pins and do not run the
traces over any voids in the ground plane. A 75 Ω impedance level
is typically used in video applications. All signal outputs of the
ADA4433-1 should include series termination resistors when
driving transmission lines.
When the ADA4433-1 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 need to be terminated
in its characteristic impedance.
INN
INP
ADA4830-1
75Ω
−
+
37.5Ω
37.5Ω
POSITIVE WIRE
NEGATIVE WIRE
DRIVER PCB
ADA4433-1
10597-027