NB6N11SMNGEVB
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4
CML Outputs
Likewise, CML outputs need to be terminated to V
CC
via
a 50
W
resistor. If no internal resistors are provided on the
device, 0402 chip resistor pads are provided on the bottom
side of the evaluation board to terminate the CML driver. If
internal resistors are provided, the V
T
pins should be wired
to V
CC
.
For CML lab setup and test, operation with negative
supply voltages is recommended to enable the 50
W
internal
impedance in the oscilloscope, or other measuring
instrument, to be used as a CML output termination; (V
CC
= 0 V, SMAGND = 0 V, and V
EE
/DUTGND =
−
5.0 V,
−
3.3 V,
−
2.5 V, or
−
1.8 V).
LVDS Outputs
LVDS outputs are typically terminated with 100
W
across
the Q/Q output pair. The 100
W
can be added on the
QFN16EVB, but it is not provided on the board, since there
are several user dependent LVDS output measurement
techniques.
For LVDS lab setup and test, a single supply is typically
used, ie. V
CC
= 3.3 V and DUTGND = 0 V.
Installing the SMA Connectors
Each configuration indicates the number of SMA
connectors needed to populate an evaluation board for a
given device. Each input and output requires one SMA
connector. Install all the required SMA connectors onto the
board and solder the center signal conductor pin to the board
on J1 through J16. Please note that the alignment of the
signal connector pin of the SMA connector to the metal trace
on the board can influence lab results. The launch and
reflection of the signals are largely influenced by imperfect
alignment and soldering of the SMA connector.
Validating the Assembled Board
After assembling the evaluation board, it is recommended
to perform continuity checks on all soldered areas before
commencing with the evaluation process. Time Domain
Reflectometry (TDR) is another highly recommended
validation test.
