UG-720 EVAL-ADuM3151Z User Guide
DATA I/O STRUCTURES
Each data channel has a variety of structures to help configure,
load, and monitor both the input and output. Figure 3 shows one
of the data paths from an external connection to the DUT pin.
Each channel has the same or a subset of these connections
depending on the particular I/O.
Starting at the external connection, the signal path is
1. Pad layout for a PCB board edge-mounted SMA connector.
2. Two 0805 pads are provided where 100 Ω resistors to
ground can be installed. The combined resistance of 50 Ω
provides a termination for a standard coaxial cable.
3. A 3-pin 100 mil header is provided, where Pin 1 is
connected to ground through a 10 kΩ resistor, and Pin 3 is
connected to VDD through a 10 kΩ resistor. Te mpora ry
pull-up or pull-down can be implemented with a shorting
jumper between Pin 2 and either Pin 1 or Pin 3.
4. A 2-pin 100 mil header provides a signal ground pair that
can be used for clip leads or for shorting a channel to
ground temporarily.
5. There are groupings of three open through holes, consisting
of a signal and two ground connections. These holes can be
used for hardwiring signal wires into the PCB, installing a
header to accept a Tektronix active probe, or installing a
2-pin header to allow adjacent channels to temporarily be
shorted together.
Figure 3 shows four 0603 pad layouts between the signal path
and optional connections. Pads with similar functions are
arranged in vertical rows and their function is labeled on the
PCB.
• LOAD is a connection to load structures located on the
reverse side of the board. These structures consist of
100 kΩ resistors to power and ground to pull high-Z
outputs to a midrange voltage when not being actively
driven. This is useful during debugging because it allows
easy identification floating outputs. The header and
associated resistors identified in Point 3 are also connected
to the signal path by this pad.
• PULL-DOWN is an 0603 pad layout between the signal
path and GND
1
or GND
2
can be used for installing a
permanent pull-down resistor or load capacitor.
• SMA CONNECT is an 0603 pad layout that allows
connection of the data path to the board edge SMA pad
layout and terminations.
• PULL-UP is an 0603 pad layout between the signal path
and V
DD1
or V
DD2
can be used for installing a permanent
pull-up resistor.
Figure 2 shows many of the optional components installed, as well
as how jumpers can be used to temporarily connect channels.
This figure shows a signal connected to the first channel SMA
and then fanned out to the top three channels and monitored by
an active scope probe.
Figure 3. Configuration and Monitoring Structures (Showing a Datapath from an External Connection to the DUT Pin)
1 SMA CONNECT
OR PADS
NOTES:
1. THE NUMBERED COMPONENTS IN THIS DIAGRAM CORRESPOND TO THE DESCRIPTIONS
IN THE DAT
A I/O STRUCTURES SECTION.
3 3-PIN HEADER
FOR 10kΩ LOADS
4 2-PIN HEADER
GND/SIGNAL
2 TERMINA
TION
2 POSITIONS
5 OPEN HOLES FOR SOLDERED WIRES
OR 200mil TEKTRONIC HEADER,
GND/GND/SIGNAL
12437-003
Rev. 0 | Page 4 of 9
