an1789

Application Note 1789
ISL8225MEVAL2Z Evaluation Board User Guide
The ISL8225M is a complete, dual step-down switching mode
DC/DC module. The dual outputs can easily be paralleled for
single-output, high-current use. It is easy to apply this
high-power, current-sharing DC/DC power module to
power-hungry datacom, telecom and FPGA applications. All
that is needed in order to have a complete, dual 15A design
ready for use are the ISL8225M, a few passive components
and VOUT setting resistors.
Specifications
The ease of use virtually eliminates design and manufacturing
risks while dramatically improving time to market. Need more
output current? Simply parallel up to six ISL8225M modules to
scale up to an 180A solution.
• fSW = 500kHz
The ISL8225M has a thermally enhanced, compact QFN
package that operates at full load and over-temperature
without requiring forced-air cooling. Easy access to all pins,
with few external components, reduces PCB design to a
component layer and a simple ground layer.
The ISL8225MEVAL2Z evaluation board allows for a single
6-phase paralleled output, which delivers high current up to
90A. The input voltage is 4.5V to 20V and the default output
voltage on this board is set at 1.2V. The current level for this
board is 90A with no extra cooling required.
Related Resources
This board has been configured and optimized for the following
operating conditions:
• VIN = 4.5V to 20V
• VO = 1.2V
• IO = 90A
Key Features
• Up to 300W output for 3 modules parallel operation
• Up to 90A load capability for 3 modules parallel operation
• 4.5V to 20V input range
• 0.6V to 5.5V output range
• 1.5% output voltage accuracy
• Up to 95% conversion efficiency
• Lower output ripple and input ripple due to multiple phases
interleave
Recommended Equipment
• 0V to 20V power supply with at least 10A source current
capability
See how-to
video at
intersil.com/
evid02
• Electronic load capable of sinking current up to 90A
(multiple electronic current loads can be used in parallel to
sink more current)
Related Literature
• Digital multimeters (DMMs)
• 100MHz quad-trace oscilloscope
• ISL8225M datasheet
Ordering Information
PART NUMBER
ISL8225MEVAL2Z
+
VIN
+
V
4.5V TO 20V
-
DESCRIPTION
6-Phase, 90A Evaluation Board
LOAD
(0A~90A)
Note 1
-
+
V
VOUT
-
NOTE:
1. Multiple loads can be paralleled to
reach 90A (i.e. Two 45A loads
paralleled together).
FIGURE 1. ISL8225MEVAL2Z BOARD IMAGE
December 1, 2014
AN1789.1
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2012, 2014. All Rights Reserved
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
Application Note 1789
Quick Start
Board Setting
The inputs are J3 (VIN) and J4 (GND). The outputs are J1 and
J5 (VOUT), J2 and J6 (GND) and J6 (VOUT2). Please refer to
Figure 1. This 90A evaluation board can be easily modified to
30A (one module) or 60A (two modules) operation.
If low current applications are needed, this 90A evaluation board
can be easily programmed to 30A and 60A use.
30A Application (1 Module)
1. Connect a power supply capable of sourcing at least 10A to
the input (VIN J3 and GND J4) of the ISL8225MEVAL2Z
evaluation board, with a voltage between 4.5V to 20V.
Connect an electronic load or the device to be powered to the
output (VOUT (J1, J5) and GND (J2, J6)) of the board. All
connections, especially the low voltage, high current VOUT
lines, should be able to carry the desired load current and
should be made as short as possible. Duplicated tab
connections on VOUT (J1, J5) and GND (J2, J6) to carry large
current.
EN -- Open, EN2-- OFF, EN3 -- OFF
2. Ensure the jumpers for EN2 and EN3 are in the “ON” position
and EN is open. Turn on the power supply. If the board is
working properly, the green LED will illuminate; if not, the red
LED will illuminate (recheck the wire/jumper connections in
this case). Measure the output voltage, VOUT, which should be
at 1.2V.
In this mode, only modules 1 and 2 (or 3) are running and
module 3 (or 2) is disabled.
3. The ISL8225MEVAL2Z is manufactured with a VOUT default
value of 1.2V; if different output voltages are desired, board
resistors can be exchanged to provide the desired VOUT. Please
refer to Table 1 on page 2 for R2/R64 resistor values, which can
be used to produce different output voltages.
For 12V VIN and VOUT more than 1.5V, the switching frequency
will need to be adjusted, as shown in Table 1. The resistor RFSET
can be adjusted for the desired frequency. No frequency
adjustments are necessary for VOUT below 1.5V. For 5V VIN, the
frequency does not need to be adjusted and the module default
frequency can be used at any allowed VOUT. If the output voltage
is set to more than 1.8V, the output current will need to be
derated to allow for safe operation. Please refer to the derating
curves in the ISL8225M datasheet.
TABLE 1. VALUE OF BOTTOM RESISTOR FOR DIFFERENT OUTPUT
VOLTAGES (R1 = 1k)
VOUT
(V)
R2 /R64
(Ω)
FREQUENCY
(kHz)
RFSET (Ω)
(VIN = 12V)
0.6
0/0
Default
Default
0.8
3010/1500
Default
Default
1.0
1500750
Default
Default
1.2
1000/500
Default
Default
1.5
665/332
Default
Default
2.5
316/158
650
249k
3.3
221/110
800
124k
5.0
137/68.1
950
82.5k
5.5
121/60.4
950
82.5k
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2
In this mode, only module 1 is running and modules 2 and 3 are
disabled.
60A Application (2 Modules)
EN -- Open, EN2-- ON, EN3 -- OFF
Or:
EN -- Open, EN2-- OFF, EN3 -- ON
90A Application (3 Modules)
EN -- Open, EN2-- ON, EN3 -- ON
In this mode, all modules are running.
Disable All Modules and Use the EN Pin to
Start the Modules
EN -- Connected
In this mode, all modules are disabled and EN can be used to
control all modules to startup.
Evaluation Board Information
The evaluation board size is 150mm x 130mm. It is a 6-layer
board, containing 2 oz. copper on the top and bottom layers and
1 oz. copper on all internal layers. The board can be used as a
90A reference design. Refer to “Layout” section beginning on
page 7. The board is made of FR4 material and all components,
including the solder attachment, are lead-free.
Current Sharing Check
The evaluation board allows the user to measure the current
sharing accuracy. Four 0Ω resistors (i.e. R59~R62 for M1
Channel 2 in Figure 2) are put serially on each output with two on
each side of the evaluation board. To measure the output current
of each phase, please remove all four resistors and put looped
wires or sensing resistors on correct positions.
Although the assembled resistors have zero resistance, there is
still small resistance (< 50mΩ) on each resistor. At large output
current, the efficiency can be decreased by 1~3% due to the
power loss on those 0Ω resistors. The efficiency curves are shown
in Figures 16 and 17 with 0Ω resistors, while Figures 18 and 19
show the efficiency curves by replacing those resistors with short
copper straps.
AN1789.1
December 1, 2014
Application Note 1789
Thermal Considerations and Current Derating
For high current applications, board layout is very critical in order
to make the module operate safely and deliver maximum
allowable power. To carry large currents, the board layout needs
to be designed carefully to maximize thermal performance. To
achieve this, select enough trace width, copper weight and the
proper connectors.
This evaluation board is designed for running 90A at 1.2V at
room temperature without additional cooling systems needed.
However, if the output voltage is increased or the board is
operated at elevated temperatures, then the available current is
derated. Refer to the derated current curves in the ISL8225M
datasheet to determine the output current available.
For layout of designs using the ISL8225M, the thermal
performance can be improved by adhering to the following
design tips:
1. Use the top and bottom layers to carry the large current.
VOUT1, VOUT2, Phase 1, Phase 2, PGND, VIN1 and VIN2
should have large, solid planes. Place enough thermal vias to
connect the power planes in different layers under and
around the module.
2. Phase 1 and Phase 2 pads are switching nodes that generate
switching noise. Keep these pads under the module. For
noise-sensitive applications, it is recommended to keep
phase pads only on the top and inner layers of the PCB; do not
place phase pads exposed to the outside on the bottom layer
of the PCB. To improve the thermal performance, the phase
pads can be extended in the inner layer, as shown in Phase 1
and 2 pads on layer 3 (Figure 11) for this 90A evaluation
board. Make sure that layer 2 and layer 4 have the GND layers
to cover the extended areas of phase pads at layer 3 to avoid
noise coupling.
3. To avoid noise coupling, we recommend adding 1nF
capacitors on all COMP and ISHARE pins of each module for
multiple module operations.
5. If the ambient temperature is high or the board space is
limited, airflow is needed to dissipate more heat from the
modules. A heat sink can also be applied to the top side of the
module to further improve the thermal performance (heat
sink recommendation: Aavid Thermalloy, part number
375424B00034G, www.aavid.com).
Remote Sensing
The ISL8225MEVAL2Z board allows the user to apply the remote
sensing function to loads in order to achieve good output
regulation accuracy. To make use of this function, remove
resistors R7 and R8 and connect the kelvin sensing lines through
the jumper JP4 (RS) to the point of load.
Phase-shift Programming
In current sharing mode, the phase-shift is needed to interleave
the different phases to lower the input and output ripples. As
shown in Table 2, there are different sharing modes from
2-phase (180° phase-shift) and 4-phase (90° phase-shift) to
6-phase (60° phase-shift). The master module sends the CLKOUT
signal to the SYNC pin of the second module with the phase-shift
to its own clock signal. Then the second module synchronizes to
the CLKOUT signal of the master module and sends its CLKOUT
signal to the third module’s SYNC pin. The individual 2 phases of
each module are set to be 180° phase-shift by default. This
evaluation board is set to mode 5B with 60° phase-shift between
phases.
If the MODE pin is not tied to VCC (5A or 5B), all VMON pins of
different modules can be tied together, except the VMON pin of
the master phase. If mode 7A is needed to allow for 90°
phase-shift, the MODE pin has to tie to VCC. In this case, the
VMON pin of the associated module needs to be separated by
connecting a 953Ω resistor and a 22nF capacitor to SGND, as
shown in the ISL8225M datasheet.
4. Place the modules evenly on the board and leave enough
space between modules. If the board space is limited, try to
put the modules with low power loss closely together (i.e. low
VOUT or IOUT) while still separating the module with high power
loss.
TABLE 2. ISL8225M 3-MODULE BOARD OPERATION MODES
1ST
MODULE (I = INPUT; O = OUTPUT; I/O = INPUT AND OUTPUT, BI-DIRECTION)
MODES OF OPERATION
ISHARE (I/O)
OPERATION
REPRESENTS
MODE
WHICH
OF 2ND
VSEN2+ CLKOUT/REFIN CHANNEL(S) 2ND CHANNEL WRT
CURRENT
(I)
WRT 1ST (I OR O)
1ST (O)
MODULE
OPERATION
MODE
OF 3RD
MODULE
OUTPUT
MODE
EN2
(I)
EN3
(I)
VSEN2(I)
MODE
(I)
5A
0
0
VCC
GND
-
60°
Both Channels
180°
-
-
2-Phase
5B
1
1
VCC
GND
-
60°
Both Channels
180°
5B
5B
6-Phase
7A
1
0
VCC
VCC
VCC
90°
Both Channels
180°
5A or 7A
-
4-Phase
8
Cascaded Module Operation MODEs 5A+5A+7A+5A+5A+5A/7A, No External Clock Required
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3
12-Phase
AN1789.1
December 1, 2014
C11
C08
IN
OPEN
C07
330UF
47UF
C05
C06
OPEN
VOUT
VOUT
TP9
R40
0
RS
-
0
R8
DNP
C08A
330UF
C04
R7
+
1K
E
47UF
0
TP10
OPEN
R2
R39
C03
0
1K
R53
C02
R1
0
GND
E
C01
21
0
JP4
OPEN
C40
22
R38
OPEN
C12
IN
J2
0
C35
COMP
GND
0.01UF
GND_S1
S1
1000PF
J6
EGND
R13
C6
100PF
CLKOUT1
OPEN
C10
OUT
S1
DNP
VMON
C29
OUT
1000PF
C4
0
R18
C5
1000PF
1K
R6
JP8
3
3 4
0
PGOOD
OUT
DNP
R10
PHASE2U1
PHASE1U1
R5
3K
S3
R60
1000PF
22UF
CIN4
DNP
1
DNP
C7
C19
19
20
2
100PF
R14
249K
C32
22UF
CIN3
CIN2
22UF
22UF
CIN1
0
R47
VOUT1
18
17
16
VCC1
VOUT
ISHARE
IN
S1
SGND1
E
E
S1
DRAWN BY:
TIM KLEMANN
RELEASED BY:
UPDATED BY:
S1
TIM KLEMANN
DATE:
ENGINEER:
DATE:
TITLE:
08/23/2012
JIAN YIN
DATE:
11/01/2012
TESTER
2
MASK#
E
FILENAME:
FIGURE 2. ISL8225MEVAL2Z BOARD SCHEMATIC
DATE:
ISL8225M
EVALUATION BOARD
SCHEMATIC
HRDWR ID
ISL8225MEVAL2Z
SHEET
REV.
D
Application Note 1789
VOUT2
COMP1
ISHARE
VMON1
S3
R61
V1SEN2+
23
S1
S1
Q1
2N7002-7-F
1
EN
0
0
TP8
VSEN1-
CLKOUT
15
R56
COMP2
MODE
VMON2
SYNC
470UF
CINA
2
3
4
5
EN/FF1
GRN
RED
LED1
SSL_LXA3025IGC
IN
EN/FF2
EN/FF
OUT
R59
VCC1
0
OUT
0
R11
E
J5
IN
24
E
3.32K
IN
1000PF
R62
R9B
25
PGOOD
R9
3.32K
PGOOD
VCC
IN
R12
SGND
IN
6
VCC1
VIN1
14
V1SEN2+
S1
C8
VOUT
OUT
1
VSEN1+
13
DNP
7
PGND
S1
IN
M1
PHASE1
IN
R16
499
COMP
26
VSEN2+
ISL8225MIRZ
N/C
12
MODE1
VIN2
PHASE2
E
VCC1
8
9
470UF
CINB
4
11
DNP
499
S1
VSEN2-
TP4
IN
R82
0
10
GND
R15
R64
E
PGND
VCC1
0
TP1
OUT
J1
1.2V @ 90A
VOUT
S1
R42
E
GND
J4
VMON
S1
1000PF
J3
OUT
IN
0
MODE1
S1
4.7UF
S1
VIN
OUT
C1
TP6
R10B
TP3
OUT
1000PF
4.5V TO 20V
VIN
R22
IN
TP7
VCC1
OPEN
C18
VIN
SYNC
IN
RFSET
SYNC
OPEN
SYNC
TP5
IN
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ISL8225MEVAL2Z Board Schematics
AN1789.1
December 1, 2014
DNP
DNP
COMP2
C13
100PF
CLKOUT2
S2
C016
330UF
OPEN
47UF
C015
C013
OPEN
C012
OPEN
47UF
C011
R87
47UF
DNP
C0
C42
R86
C010
R70
DNP
C47
OPEN
E
R52
IN
1000PF
VMON1
OUT
0
ISHARE
S2
DATE:
ENGINEER:
RELEASED BY:
DATE:
TITLE:
UPDATED BY:
DATE:
DRAWN BY:
OUT
OUT
OPEN
DNP
R3
S2
VOUT
0
0
R4
OUT
C30
0
OPEN
S2
OPEN
R20
R20B
C25
C16
1000PF
0
R27
0
DNP
E
R69
OPEN
S2
C15
E
C17
EGND
0
C37
IN
S2
1000PF
R19
OFF
VCC2
PGOOD
21
1000PF
PHASE2U2
DNP
R57
19
1
R72
R66
VCC2
20
J8
2
0
R65
22
COMP1
18
17
16
EN2
ON
OUT
0
C36
22UF
22UF
CIN8
22UF
CIN7
PHASE1U2
VOUT1
VMON1
ISHARE
CLKOUT
3
0
S2
TIM KLEMANN
TIM KLEMANN
08/23/2012
11/01/2012
TESTER
MASK#
FIGURE 3. ISL8225MEVAL2Z BOARD SCHEMATIC
DATE:
JIAN YIN
ISL8225M
EVALUATION BOARD
SCHEMATIC
HRDWR ID
REV
Application Note 1789
VOUT2
0
COMP2
VMON2
MODE
SYNC
R49
2
3
4
5
15
EN/FF
R68
23
VSEN1-
OUT
R71
0
0
IN
0
V2SEN2+
24
PGOOD
E
S2
GND_S2
14
13
IN
S2
SGND2
25
V2SEN2+
DNP
S2
VIN1
EN/FF1
PGND
26
VSEN1+
EN/FF2
R17
VCC
12
PHASE1
IN
ISL8225MIRZ
N/C
S2
VCC2
SGND
11
IN
DNP
6
10
VSEN2+
M2
PHASE2
IN
R67
R28B
1
VSEN2-
E
MODE2
VIN2
7
8
E
PGND
R48
OUT
COMP
OUT
0
COMP2
S2
9
22UF
CIN6
5
CIN5
IN
R45
S2
0
C09
C26
E
IN
OUT
R43
S2
VMON
VMON1
OUT
4.7UF
VCC2
R28
DNP
MODE2
C2
VIN
C14
0
100PF
R35
0
C33
R23
0
OPEN
OUT
R54
1000PF
VCC2
OUT
OPEN
R25
CLKOUT1
IN
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ISL8225MEVAL2Z Board Schematics (Continued)
AN1789.1
December 1, 2014
OUT
C3
R44
S3
C28
S3
C22
OPEN
S3
0
R80
330UF
OPEN
C024
47UF
C021
OPEN
VOUT
OPEN
OPEN
C017
C019
OUT
47UF
C44
R24
E
OPEN
DNP
0
0
DNP
E
R81
1000PF
C31
C23
DNP
OUT
1000PF
C27
100PF
C20
OUT
R79
C018
20
19
18
17
16
15
14
13
1000PF
R37
R29
0
ISHARE
OUT
S3
DATE:
ENGINEER:
RELEASED BY:
DATE:
TITLE:
UPDATED BY:
DATE:
DRAWN BY:
CLKOUT3
0
R76
0
OPEN
21
IN
S3
S3
E
22
VMON2
S3
C24
EGND
C39
COMP3
1000PF
3
0
2
J7
R26
1
0
PGOOD
S3
TP11
GND_S3
OUT
R37B
PHASE2U3
PHASE1U3
DNP
OPEN
C9
OUT
OFF
EN3
S3
24
COMP1
EN/FF
ON
R78
VCC3
0
IN
C023
2
3
4
5
6
7
8
9
22UF
22UF
CIN12
22UF
CIN11
DNP
R51
VOUT1
IN
0
S3
TIM KLEMANN
TIM KLEMANN
08/23/2012
11/01/2012
TESTER
MASK#
FIGURE 4. ISL8225MEVAL2Z BOARD SCHEMATIC
DATE:
JIAN YIN
ISL8225M
EVALUATION BOARD
SCHEMATIC
HRDWR ID
REV.
Application Note 1789
VOUT2
VMON1
CLKOUT3
R74
V3SEN2+
IN
E
S3
CLKOUT3
R77
23
VSEN1-
ISHARE
CLKOUT
R58
COMP2
MODE
VMON2
IN
TP2
26
VCC3
V3SEN2+
DNP
EN/FF1
VIN1
EN/FF2
R21
0
R75
VSEN1+
S3
IN
IN
R73
R44B
1
25
ISL8225MIRZ PGOOD
N/C
PGND
VCC3
VSEN2+
M3
PHASE1
DNP
SYNC
10
12
IN
VCC
MODE3
VIN2
VSEN2-
11
IN
OUT
0
PHASE2
E
R50
COMP2
0
E
PGND
VCC3
R46
S3
SGND
22UF
CIN10
6
CIN9
IN
OUT
S3
1000PF
VIN
IN
VMON2
COMP3
0
E
VMON1
C014
4.7UF
R31
OUT
MODE3
DNP
0
C21
R36
0
100PF
R33
0
DNP
R55
C34
VCC3
OUT
OPEN
R30
CLKOUT2
IN
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ISL8225MEVAL2Z Board Schematics (Continued)
AN1789.1
December 1, 2014
Application Note 1789
Layout
OFF
ON
FIGURE 5. TOP ASSEMBLY
FIGURE 6. TOP SILK SCREEN
FIGURE 7. TOP LAYER COMPONENT SIDE
FIGURE 8. LAYER 2
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AN1789.1
December 1, 2014
Application Note 1789
Layout
(Continued)
FIGURE 9. LAYER 3
FIGURE 10. LAYER 4
FIGURE 11. LAYER 5
FIGURE 12. BOTTOM LAYER SOLDER SIDE
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8
AN1789.1
December 1, 2014
Application Note 1789
Layout
(Continued)
FIGURE 13. BOTTOM SILK SCREEN
FIGURE 14. BOTTOM SILK SCREEN MIRRORED
FIGURE 15. BOTTOM ASSEMBLY
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9
AN1789.1
December 1, 2014
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Bill of Materials
PART NUMBER
REF DES
QTY.
VALUE
TOL. VOLTAGE POWER
10TPB330M
C04, C08, C016,
C024, C08A
5
330µF
20%
131-4353-00
TP1
2N7002-7-F
JEDEC TYPE
MANUFACTURER
DESCRIPTION
10
CAP_7343_149
SANYO-POSCAP
Standard solid electrolytic chip tantalum
SMD capacitor
1
CONN
TEK131-4353-00
Tektronix
Scope probe test point PCB mount
Q1
1
SOT23
SOT23
Fairchild
N-Channel EMF effect transistor (Pb-free)
5002
TP2-TP11
10
THOLE
MTP500X
Keystone
Miniature white test point 0.100 pad
0.040 Thole
ECA-1VM471
CINA, CINB
2
470µF
20%
35V
RADIAL
CAPR_708X1398_300_P
Panasonic
Radial capacitor Pb-free
C1-C3
3
4.7µF
10%
16V
805
CAP_0805
Murata
Ceramic capacitor
C0, C02, C05,
C010, C013, C014,
C018
7
47µF
10%
10V
1210
CAP_1210
Murata
Ceramic chip capacitor
CIN1-CIN12
12
22µF
10%
25V
1210
CAP_1210
Murata
Ceramic chip capacitor
H1045-00101-50V10
C6, C7, C13, C14,
C20, C21
6
100pF
10%
50V
603
CAP_0603
Generic
Multilayer capacitor
H1045-00102-16V10
C8
1
1000pF 10%
16V
603
CAP_0603
Generic
Multilayer capacitor
H1045-00102-50V10
C4, C5, C9, C11,
C16-C19, C23-C31,
C40
18
1000pF 10%
50V
603
CAP_0603
Generic
Multilayer capacitor
H1045-00103-50V10
C35
1
0.01µF
10%
50V
603
CAP_0603
Generic
Multilayer capacitor
H1045-OPEN
C10, C12, C15,
C22, C32-C34, C36,
C37, C39, C42,
C44, C47
13
OPEN
5%
OPEN
603
CAP_0603
Generic
Multilayer capacitor
H1082-OPEN
C01, C03, C06,
C07, C09, C011,
C012, C015, C017,
C019, C021, C023
12
OPEN
10%
OPEN
1210
CAP_1210
Generic
Ceramic chip capacitor
R3, R4, R13-R17,
R20, R21,R24,
R25, R28-R31,
R37, R48, R50,
R51, R56-R58,
R86, R87, R10B,
RFSET
26
DNP
1%
603
RES_0603
Generic
Metal film chip resistor (do not populate)
GRM32ER70A476K
GRM32ER71E226KE15L
H2505-DNP-DNP-1
DNP
Application Note 1789
SMD
GRM21BR71C475KA73L
10V
PACKAGE
TYPE
AN1789.1
December 1, 2014
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Bill of Materials (Continued)
PART NUMBER
H2511-00R00-1/16W1
R7-R10, R18, R19,
R22, R23, R26,
R27, R33, R35,
R36, R42-R47,
R49, R52, R54,
R55, R81, R9B,
R20B, R28B, R37B,
R44B
29
0Ω
1%
1/16W
603
RES_0603
Generic
Thick film chip resistor
H2511-01001-1/16W1
R1, R2, R6
3
1kΩ
1%
1/16W
603
RES_0603
Generic
Thick film chip resistor
H2511-03321-1/16W1
R11, R12
2
3.32kΩ
1%
1/16W
603
RES_0603
Generic
Thick film chip resistor
H2511-04990-1/16W1
R64, R82
2
499Ω
1%
1/16W
603
RES_0603
Generic
Thick film chip resistor
H2520-00R00-1/2W5
R38-R40, R53,
R59-R62, R65-R80
24
0Ω
5%
1/2W
2010
RES_2010
Generic
Thick film chip resistor
ISL8225MIRZ
M1-M3
3
QFN
QFN26_670X670_ISL8225M Intersil
Dual 15A DC/DC power module
JUMPER-3-100
J7, J8
2
THOLE
JUMPER-3
Generic
Three pin jumper
JUMPER2_100
JP4, JP8
2
THOLE
JUMPER-1
Generic
Two pin jumper
J1-J6
6
CONN
KPA8CTP
Burndy
Wire connector lug
R5
1
603
RES_0603
ROHM
Metal film chip resistor
LED1
1
SMD
LED_3X2_5MM
Lumex
3mmx2.5mm surface mount red/green
LED
MCR03EZPFX3001
SSL-LXA3025IGC
3kΩ
1%
1/10W
JEDEC TYPE
MANUFACTURER
DESCRIPTION
NOTE:
2. Resistance accuracy of the feedback resistor divider R1/R2 can affect the output voltage accuracy. Please use high accuracy resistance (i.e., 0.5% or 0.1%) to meet the output accuracy requirement.
Application Note 1789
VALUE
11
QTY.
KPA8CTP
TOL. VOLTAGE POWER
PACKAGE
TYPE
REF DES
AN1789.1
December 1, 2014
Application Note 1789
ISL8225MEVAL2Z Efficiency Curves Test conditions at +25°C and no air flow.
Efficiency Curves with Zero-ohm Resistance on the Output
95
3.3VOUT
100
2.5VOUT
3.3VOUT 2.5VOUT
90
1.5VOUT
EFFICIENCY (%)
EFFICIENCY (%)
85
1.2VOUT
75
1VOUT
65
1.2VOUT
1.5VOUT
1VOUT
80
70
55
60
0
10
20
30
40
50
60
70
80
90
100
0
10
20
30
LOAD CURRENT (A)
40
50
60
70
80
90
100
LOAD CURRENT (A)
FIGURE 16. EFFICIENCY CURVES FOR 12V INPUT
FIGURE 17. EFFICIENCY CURVES FOR 5V INPUT
Efficiency Curves by Replacing Zero-ohm Resistance with Thick Copper Strap
95
3.3VOUT
100
2.5VOUT
2.5VOUT
90
1.5VOUT
EFFICIENCY (%)
EFFICIENCY (%)
85
1.2VOUT
75
1VOUT
1.2VOUT 1.5VOUT
1VOUT
80
70
65
55
60
0
10
20
30
40
50
60
70
80
90
LOAD CURRENT (A)
FIGURE 18. EFFICIENCY CURVES FOR 12V INPUT
100
0
10
20
30
40
50
60
70
80
90
100
LOAD CURRENT (A)
FIGURE 19. EFFICIENCY CURVES FOR 5V INPUT
Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is
cautioned to verify that the Application Note or Technical Brief is current before proceeding.
For information regarding Intersil Corporation and its products, see www.intersil.com
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12
AN1789.1
December 1, 2014
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