Evaluation Board Hardware; Setting Up The Evaluation Board; Input And Output Connections; Radiated Emissions - Analog Devices EVAL-ADM2867EEBZ User Manual

UG-1677

EVALUATION BOARD HARDWARE

SETTING UP THE EVALUATION BOARD

The EVAL-ADM2867EEBZ is powered via the VREG_IN
connection on the P1 screw terminal connector. The voltage
connected to VREG_IN on the P1 screw connector can either be
regulated or connected directly to the V
Insert the LK8 jumper into Position A to power the
directly from the VREG_IN terminal.
The on-board ADP7104 voltage regulator accepts a voltage from
3 V to 20 V on the VREG_IN terminal and can supply either a
3.3 V or a 5 V regulated supply to the V
Select the regulated voltage via the LK8 jumper. Insert the
LK8 jumper into Position B to operate the device with a
regulated V supply of 3.3 V. Insert the LK8 jumper into
CC
Position C to operate the device with a regulated V
5.5 V. The V pin is fitted with a 10 μF decoupling capacitor
CC
(C4) and a 0.1 μF decoupling capacitor (C5).
To power the V supply pin of the
IO
terminal block and operate the V
voltage, insert Jumper LK9. To power the V
a separate VIO terminal block, remove Jumper LK9. In this
configuration, the VIO input of the P1 terminal block can be
connected to a separate, low voltage logic supply between 1.7 V
and 5.5 V. A 0.1 μF decoupling capacitor (C7) is fitted at the
connector between the V pin and GND
IO
A footprint for a second 10 μF capacitor (C11) can provide
additional decoupling capacitance to the V
Use the V pin of the ADM2867E
SEL
voltage for the RS-485 transceiver. To configure the device to
output a 3.3 V isolated supply voltage, connect the V
ADM2867E to the GND pins. To configure the device to output
ISO
a 5 V isolated supply voltage, connect the V
ADM2867E to the V pin. The R6 and R7 resistors can be
ISOOUT
inserted or removed as needed to make these connections. Avoid
inserting the R6 and R7 resistors together because this connection
shorts the power and ground pins together.
See Table 2 and Table 3 for more details on the jumper and
power supply connections. The corresponding labeled test points
allow power supply monitoring on the EVAL-ADM2867EEBZ
with the probe referenced to ground.
pin of the ADM2867E.
CC
ADM2867E
pin of the ADM2867E.
CC
supply of
CC
ADM2867E from the VCC
and V supply pins at the same
IO CC
supply pin from
IO
pins of the ADM2867E.
1
pin.
IO
to select the isolated supply
pin of the
SEL
pin of the
SEL
EVAL-ADM2867EEBZ

INPUT AND OUTPUT CONNECTIONS

Digital input and output signals are connected via the P2 and
P3 screw terminal blocks to allow wire connections from the
EVAL-ADM2867EEBZ to a signal generator. The EVAL-
ADM2867EEBZ includes screw terminals for the TxD signal,
receiver data output (RxD) signal, receiver enable ( RE ), and driver
enable (DE) test points. Screw terminals for the driver inversion
function (INVD) and receiver inversion function (INVR) are
also available on P3. Alternatively, jumper connections can
connect these signals to the V
ADM2867E (see Table 2).
Connections to the RS-485 bus are made via the P7 and P8 screw
terminal blocks. The EVAL-ADM2867EEBZ has four bus input
and output signals: Signal A for noninverting input signals, Signal B
for inverting input signals, Signal Y for noninverting output signals,
and Signal Z for inverting output signals. The bus cables also
include a common ground connection and can be connected to the
P8 screw terminal block of the EVAL-ADM2867EEBZ. Test points
are available on the EVAL-ADM2867EEBZ and are appropriately
labeled for all digital and bus input and output signals.

RADIATED EMISSIONS

The EVAL-ADM2867EEBZ is a 2-layer printed circuit board
(PCB) that meets the EN 55032 Class B radiated emissions
requirements under full load while operating at the maximum
data rate. Advances in the isolated dc-to-dc converter eliminate
the need for complex mitigation techniques, such as edge guarding
and embedded stitching capacitance. Two 0402, surface-mount
ferrite beads are used to suppress high frequency noise and
minimize the amount of noise radiated by the ADM2867E.
The recommended ferrite beads have a high impedance in the
100 MHz to 1 GHz frequency range (see Table 1). The EVAL-
ADM2867EEBZ is populated with the BLM15HD182SN1 ferrite
beads on E1 and E2.
Table 1. Recommended Surface-Mount Ferrite Beads
Manufacturer
Murata Electronics
Taiyo Yuden
Rev. 0 | Page 4 of 12
User Guide
pin or GND pins of the
IO 1
Part Number
BLM15HD182SN1
BKH1005LM182-T