ANALOG DEVICES UG-402 Service Manual
Evaluation Board User Guide
10653-001
One Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.com
UG-402
iCoupler ADuM3070 Isolated Switch Regulator
With Integrated Feedback Evaluation Board
FEATURES
2 independent ADuM3070 circuits including 2.5 kV rms
isolated dc-to-dc converters
Single supply
5 V in to 5 V out (regulated)
Reconfigurable to 5 V in to 3.3 V out or 3.3 V in
to 3.3 V out
Double supply
5 V in to 15 V out (regulated) and 7.5 V out (unregulated)
Reconfigurable to 5 V in to 12 V out (regulated) and 6 V
out (unregulated)
Footprints for Coilcraft and Halo transformer options
Multiple switching frequency options
SUPPORTED iCoupler MODELS
ADuM3070
GENERAL DESCRIPTION
The EVA L-ADuM3070EBZ demonstrates two separate
applications for the ADuM3070 isolated switch regulator with
integrated feedback. It has two independent power supply
circuits: a double supply and a single supply. The switching
frequency can be set from 200 kHz to 1000 kHz. The board
supports a variety of I/O configurations and multiple transformer options. It is equipped with two ADuM3070 isolators.
ADUM3070 EVALUATION BOARD
PLEASE SEE THE LAST PAGE FOR AN IMPORTANT
WARNING AND LEGAL TERMS AND CONDITI ONS.
Figure 1. Double Supply (Top) and Single Supply (Bottom) Configurations
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UG-402 Evaluation Board User Guide
TABLE OF CONTENTS
Features .............................................................................................. 1
Supported iCoupler Models ............................................................ 1
General Description ......................................................................... 1
ADuM3070 Evaluation Board ........................................................ 1
Revision History ............................................................................... 2
Single Supply ..................................................................................... 3
Terminals ....................................................................................... 3
Transformer Selection .................................................................. 3
Switching Frequency Options ..................................................... 3
Other Input and Isolated Output Supply Options ................... 4
REVISION HISTORY
5/12—Revision 0: Initial Version
Schematic........................................................................................5
Double Supply ....................................................................................6
Terminals ........................................................................................6
Transformer Selection ..................................................................7
Switching Frequency Options......................................................7
Other Secondary Isolated Supply Configurations ....................8
Schematic........................................................................................8
Evaluation Board Layout ..................................................................9
Ordering Information .................................................................... 10
Bill of Materials ........................................................................... 10
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Evaluation Board User Guide UG-402
10653-002
10653-003
SINGLE SUPPLY
Two independent and isolated circuits comprise the ADuM3070
evaluation board. The lower half of the board, shown in Figure 2,
is for a single power supply configuration (see the ADuM3070
data sheet for applications information about the ADuM3070 in
this configuration).
Figure 2. Single Supply Configuration
The single supply is configured as a 5 V secondary isolated
supply with a 5 V primary input supply, which can provide up
to 2.5 W of regulated, isolated power. It can be reconfigured for
a 3.3 V secondary isolated supply with a 5 V or 3.3 V primary
input supply (see the Other Input and Isolated Output Supply
Options section). Figure 9 shows the single supply schematic.
TERMINALS
The single supply has terminal blocks on Side 1 (the primary/
power supply input side) and Side 2 (the secondary/power supply
output side). A 4.3 mm isolation barrier separates Side 1 and
Side 2. Figure 3 shows these terminal locations.
Tabl e 1 summarizes the functions of the terminal connections.
They are described in detail in the Input Power Connections
and Output Power Connections sections.
V
supplies the voltage to the transformer primary and to the
DD1
ADuM3070 supply voltage, V
for additional information about the V
and V
are bypassed by a 47 µF ceramic capacitor (C1) and a
DDA
(see the ADuM3070 data sheet
DDA
pin function). V
DDA
DD1
0.1 µF local bypass capacitor (C2) located close to the ADuM3070.
R7, R8, C5, and C6 are provided for an optional and unpopulated
snubber, which can be used to reduce radiated emissions.
Power is transferred to Side 2 by a regulated push-pull converter
comprising the ADuM3070 (U1), an external transformer (T1
or T2), and other components (see the ADuM3070 data sheet
for an explanation of this circuit functionality).
Output Power Connections
An output load can be connected to P3 (labeled +5V/3.3V on the
silkscreen and not labeled on the schematic), which is the isolated, regulated 5 V output supply. Connect the return of the
load to P4, which is the Side 2 ground reference. P4 is labeled
GND ISO on the silkscreen and GND2 on the schematic. This
supply can provide up to 500 mA in the default 5 V primary
input supply, 5 V secondary isolated supply configuration.
Figure 5 through Figure 8 in this user guide show how the
power supply’s efficiency varies with load current, switching
frequency, and temperature.
Table 1. Single Supply Terminal Function Descriptions
Terminal Pin Label Description
P1 1 +5V IN Side 1 5 V primary input supply
P2 1 GND Side 1 ground reference
P3 1 +5V/3.3V Side 2 5 V secondary isolated supply
P4 1 GND ISO Side 2 ground reference
Care must be taken to avoid driving the V
output with an
DD2
external voltage because this can result in permanent damage to
the ADuM3070.
Figure 3. Single Supply Terminals
Input Power Connections
Connect 5 V to P1, labeled +5V IN (or +3.3 V for a
3.3 V primary input supply with a 3.3 V secondary isolated
supply). Connect the negative supply to P2, labeled GND
(GND1 on the schematic). These are the only off-board
connections required for the single supply to function.
TRANSFORMER SELECTION
The EVA L-ADuM3070EBZ supports multiple transformer
options. The single supply is equipped with a Halo TGSAD260V6LF (T1) or a Coilcraft JA4631-BL (T2) 1:2 turns ratio
transformer. The Coilcraft footprint is offset to the left of the
Halo footprint. Figure 5 and Figure 7 show the efficiency curves
for the single supply operating with a Coilcraft and a Halo
transformer, respectively.
SWITCHING FREQUENCY OPTIONS
The resistor connected from the ADuM3070 oscillator control
pin (OC) to ground sets the single supply switching frequency.
Figure 4 shows the relationship between this resistance and the
converter switching frequency. The EVA L-ADuM3070EBZ can
be configured with 0 Ω, 0805 resistors to four different preset
switching frequencies. Short-circuiting R10 sets R1 (300 kΩ)
and R2 (150 kΩ) in parallel, and short-circuiting R11 sets R1 and
R3 (100 kΩ) in parallel. Tabl e 2 lists the switching frequencies
that can be selected by short- or open-circuiting R10 and R11.
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UG-402 Evaluation Board User Guide
1500
1400
1300
1200
1100
1000
90
0
800
700
600
500
400
300
200
100
0
0 50 100 150 200 250 30
0 350 400 450 500
f
SW
(kHz)
R
OC
(
Ω)
10653-004
90
80
70
60
50
40
30
20
10
0
0 50045040035030025020015010050
EFFICIENCY (%)
LOAD CURRENT (mA)
f
SW
= 1MHz
f
SW
= 700kHz
f
SW
= 500kHz
f
SW
= 200kHz
10653-005
90
80
70
60
50
40
30
20
10
0
0 50045040035030025020015010050
EFFICIENCY (%)
LOAD CURRENT (mA)
TA= –40°C
T
A
= +25°C
T
A
= +105°C
10653-006
90
80
70
60
50
40
30
20
10
0
0 50045040035030025020015010050
EFFICIENCY (%)
LOAD CURRENT (mA)
f
SW
= 1MHz
f
SW
= 700kHz
f
SW
= 500kHz
f
SW
= 200kHz
10653-007
The user can select a different switching frequency by removing
R10 and R11 and then choosing R1 based on Figure 4. The
board is configured for the 500 kHz setting by default. Figure 5
and Figure 7 show how the switching frequency affects the
supply’s efficiency with either transformer installed. Figure 6
shows how the efficiency curve varies over temperature with a
500 kHz switching frequency.
Table 2. Switching Frequency Selection
R10 R11 ROC Switching Frequency
Open Open 300 kΩ 200 kHz
0 Ω Open 100 kΩ 500 kHz
Open 0 Ω 75 kΩ 700 kHz
0 Ω 0 Ω 50 kΩ 1 MHz
Figure 5. 5 V In to 5 V Out Efficiency with 1:2 Coilcraft Transformer at Various
Switching Frequencies
Figure 4. Switching Frequency vs. R
OTHER INPUT AND ISOLATED OUTPUT SUPPLY OPTIONS
The single supply can be configured to have a 3.3 V secondary
isolated supply with a 3.3 V or 5 V primary input supply. Shortcircuiting R4 by soldering a 0 Ω, 0805 resistor to R9 sets the
output supply for 3.3 V. The voltage at the feedback node (the
FB pin of the ADuM3070) should be the desired output voltage
divided to approximately 1.25 V. Having R9 open-circuited sets
the secondary isolated supply to 5 V, and having it short-circuited
sets the supply to 3.3 V. See the ADuM3070 data sheet for more
details on setting the secondary isolated output supply voltage.
Figure 8 shows how the single supply efficiency curve changes
when it is reconfigured for either of these supply options.
Resistance
OC
Figure 6. 5 V In to 5 V Out Efficiency with 1:2 Coilcraft Transformer at 500 kHz
over Temperature
Figure 7. 5 V In to 5 V Out Efficiency with 1:2 Halo Transformer at Various
Switching Frequencies
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