Evaluating the ORCA ORSO42G5 with the
Lattice Semiconductor
High-Speed SERDES Board
12
2. Some newer test equipment provides adjustable bias voltage on the internal 50
Ω
input terminations. This
equipment may be directly connected to the SERDES Tx output, as shown below.
For this connection, the adjustable termination voltage should be set to the V
DDOB
supply voltage used on the High-
Speed SERDES Board (1.5V, if internal supply is being used). This is the best means of observing the Tx data out-
put signals for DC coupled applications, since it eliminates any possible signal degradation caused by bias tee and
DC blocking elements.
References
Bias Tee Model 5575A, Picosecond Pulse Labs, Boulder CO, www.picosecond.com.
50
50
Evaluation Board
SERDES TX Output
V
DDOB
Vterm =
V
DDOB
High Speed Equipment
with Adjustable Term
Input Voltage
