UG-043 EVAL-ADuM4160EBZ User Guide
Rev. B | Page 4 of 8
In addition, the ground and power planes can be capacitively
linked via C15 to C18 at the option of the user. This linking can
provide plane-to-plane noise bypassing through several paths to
reduce radiated emissions from the ADuM5000 power supply.
Two large screw holes along the top edge of the PCB provide
connection to the upstream ground plane and the downstream
ground plane. These holes allow grounding of the PCB to the
system in multiple configurations. The floating planes are
designed with 0.4 mm of setback to all vias and other board
planes. If the floating structures are employed for noise reduction,
the PCB must not be used for high voltage testing. When this
type of structure is required in the final design, build it on an
inner layer of the PCB to avoid creepage and clearance issues.
SPEED SELECTION
The ADuM4160 and ADuM3160 work at a fixed USB trans-
mission speed, either low speed or full speed. The SPU pin and
the SPD pin on the upstream and downstream sides of the device
set the speed and must be set by jumpers on the evaluation
board. For proper operation, set both speed jumpers to the
same speed setting.
Table 3. Speed Selection Jumpers
SPU (JP4) SPD (JP5) Speed
Short SPU Full Short SPD full Full (12 Mbps)
Short SPU Low Short SPD low Low (1.5 Mbps)
PULL-UP CONTROL
The PIN pin allows control of enumeration and disconnect by the
peripheral. When PIN is logic high, the pull-up on the upstream
side of the ADuM4160 or the ADuM3160 is applied to the data
line appropriate for the USB speed mode, which allows enum-
eration and data transmission. When PIN is logic low, the
upstream pull-up is disconnected, making the upstream port
behave as though the port were not present.
This function allows the peripheral to delay communication
with the host by delaying application of the upstream pull-up
resistor until it is ready to enumerate on the bus. If this func-
tionality is not required, tie PIN to V
DD2
, and when power is
applied to both the downstream power supplies, the pull-up is
applied to the upstream side.
Jumper JP6 provides control of PIN. A 10 kΩ resistor pulls the
PIN input high. When a shunt is placed across JP6, it is pulled
low, which provides a default state of high to PIN, allowing
immediate enumeration.
Table 4. PIN Pull-Up Control
PIN (JP6) Upstream Pull-Up State
Short Disconnected
Open Connected
SERIES RESISTORS
The two USB speeds supported by the ADuM4160 and
ADuM3160 require different series resistance values at the
transceiver terminals.
For full speed operation, the R1, R2, R3, and R4 resistors must
be populated with 24 Ω, 1% resistors. These 24 Ω resistors are
installed in the base configuration of the evaluation board and,
if the evaluation board is operating at full speed, no changes are
required.
When the ADuM4160 operates at low speeds, it is recom-
mended to modify the evaluation board from the as received
configuration. For low speed operation, replace the R1, R2, R3,
and R4 resistors with 0 Ω, 0805 sized, SMT shunts. If impedance is
not critical, the 24 Ω resistors do not significantly affect the low
speed performance, and they can be left in place for both speed
modes.
TEST POINTS
Positions for eight test points are included on the evaluation
board. No headers are provided in the default configuration.
Mounting holes for a ground signal pair are provided. The holes
fit a standard square pin spaced at 100 mil or 200 mil on center.
This configuration was chosen to match the dimensions of the
Tektronix® high frequency active probes or standard headers. To
obtain an appropriate scope header use a 3-pin SIP (2.54 mm
spacing) wire wrap header and remove the center pin. The
signal pin can be trimmed to match the spacing of the probe. If
another type of connection is required, insert wires into the
holes provided for these connections.
OPTIONAL COMPONENTS
Options for installing common-mode chokes and external ESD
protection on the DD+/DD− and UD+/UD− data lines are avail-
able on the EVA L -ADUM4160EBZ evaluation board. Positions
for 1206-sized Wurth WE-CNSW chokes are provided at
Position FL1 and Position FL2. Positions for ESD diode packs
(NUP2202 from ON Semiconductor®) are provided at Position D1
and Position D2. In addition, pads for surface-mount ferrite
inductors are provided at Position R6 to Position R10. These
positions are included on the PCB as a convenience to the end
user and are not necessary for operation. To make use of
common-mode chokes, remove the R11, R12, R13, and R14
shunts.
