Evaluation Board User Guide UG-487
Rev. 0 | Page 3 of 8
PCB EVALUATION GOALS
This board is intended to achieve two goals.
It will allow a user of the ADuM5010 or ADuM6010 to
exercise the functional capabilities of the part. These
include evaluation of bypass, loading, power supply
enable/disable control and setting the adjustable output
voltage level.
This evaluation board demonstrates the EMI mitigation
techniques required to make a low emissions design as
discussed in the AN-0971 Application Note.
CONNECTORS
This evaluation system will be used to evaluate a variety of
different aspects of performance. Connections to a power
supply and instrumentation are critical to performing accurate
measurements without creating artificial ringing, reflections,
ripple, and EMI.
Two types of interconnections are provided, SMA edge con-
nectors and through-hole signal ground pairs. Between these
two options, both temporary and permanent connections to
the board are easily made. When coax connections are desired,
SMA connectors are available for the V
DDP
power input and
V
ISO
output. These connectors were chosen because they are
low profile and provide excellent mechanical connections to
the PCB. Most lab equipment is geared toward use of BNC
connectors, so adaptors will be required to use the on board
connectors.
Power can be directly wired to the PCB via the P6A and P7A
through-hole connectors. These provide a power ground
pair with the power on the Pin 1 hole. These through holes
are on 200mil centers, which match the pin spacing required
for Tektronix active probes. These positions can be used for
scope test points or direct wiring of power and ground.
PART CONFIGURATION STRUCTURES
The ADuM5010 and ADuM6010 have pins that must have
set inputs for the IC to operate properly. The evaluation board
allows all a full range of configuration options. On the primary
side, the PDIS pin must either be tied low to enable the con-
verter, or pulled high to disable the output power and put the
part in a standby state. Connector P3A allows a jumper to be
placed between Pin 1 and Pin 2 to disable the converter, or
between Pin 2and Pin 3 to enable the converter. The header
can be removed if an external logic source controls the disable
function and the signal can be fed directly into Position 2 of
the header.
Control of the V
ISO
voltage is accomplished through a voltage
divider that’s center node is attached to the V
SEL
pin as shown
in Figure 3. There are two options for setting the output voltage
supported on this evaluation board. A 20 kΩ potentiometer is
installed at R1A in series with a 16.5 kΩ resistor at position
R16A making a variable resistance to V
ISO
of 16.5 kΩ to 36 kΩ.
A resistor to ground at position R14A forms the lower leg of
the voltage divider. This will give a range of adjustment of
V
ISO
< 3.3 V to > 5 V.
Alternatively, if a fixed output voltage is desired, R16A can be
removed and a resistor can be installed in R13A that combined
with the existing resistance in R14A will form a fixed voltage
divider to set V
ISO
to a single voltage. Refer to the ADuM5010
or ADuM6010 data sheet for selection of resistor values.
BYPASS ON THE PCB
Several positions and structures are provided to allow optimum
bypass of the evaluation board. Provisions have been made for
optional surface-mount bulk capacitors to be installed near the
power connectors to compensate for long cables to the power
supply or external load. Parallel bypass capacitors are installed
near the ADuM5010 or ADuM6010 consisting of a 0.1 μF and a
10 μF capacitor for V
DDP
and V
ISO
. The 0.1 μF capacitors can be
moved to positions on the back side of the board if required.
The PCB also implements distributed capacitive bypass on the
primary side of the PCB. This consists of power and ground fills
on the top and bottom layers of the PCB on the V
DDP
side of the
board. This is one of the techniques discussed in the EMI
Mitigation section. It has the added benefit of providing added
bypass on the primary side of the converter where the largest
currents flow as well as RF shielding.
PROVISION FOR LOADING
V
ISO
can be loaded three ways.
An external load can be connected via the SMA connector.
A fixed resistor can be installed at R18A.
A surface mount resistor can be installed at R15A.
