19-4282; Rev 0; 9/08
MAX15023 Evaluation Kit
General Description
The MAX15023 evaluation kit (EV kit) is a fully assem-
bled and tested PCB that contains all the components
necessary to evaluate the performance of the
MAX15023 dual, synchronous step-down controller.
The MAX15023 EV kit requires a 9V to 16V DC power
supply, which provides up to 5A for normal operation.
The EV kit provides 1.2V/10A and 3.3V/5A at the out-
puts. Each step-down controller operates 180° out-of-
phase to reduce input-voltage ripple and total RMS
input ripple current.
The converters’ switching frequency is programmed to
500kHz. The EV kit includes individual enable control
PCB pads for each converter and power-good outputs
for both converters that can be configured for power-
supply sequencing of the outputs.
o
9V to 16V Input Range
o
Optional 4.5V to 5.5V Input Range for MAX15023
o
1.2V/10A (VOUT1)
o
3.3V/5A (VOUT2)
o
500kHz Switching Frequency
o
Independent Enable Inputs
o
Independent Power-Good Outputs
o
Configurable for Power-Supply Sequencing
Operation
o
Lead-Free and RoHS Compliant
o
Fully Assembled and Tested
Features
Evaluates: MAX15023
Ordering Information
PART
MAX15023EVKIT+
TYPE
EV Kit
+Denotes
lead-free and RoHS compliant.
Component List
DESIGNATION
C1
C2–C5, C13,
C29
C6
QTY
1
DESCRIPTION
330µF ±20%, 25V electrolytic
capacitor (10mm x 10.2mm)
Panasonic EEEFC1E331P
Not installed, ceramic capacitors
(0603)
22pF ±5%, 50V C0G ceramic
capacitor (0603)
Murata GRM1885C1H220J
3300pF ± 5%, 50V C0G ceramic
capacitors (0805)
Murata GRM2165C1H332J
1µF ±10%, 25V X5R ceramic
capacitor (0603)
Murata GRM188R61E105K
390pF ±5%, 50V C0G ceramic
capacitor (0603)
Murata GRM1885C1H391J
33pF ±5%, 50V C0G ceramic
capacitor (0603)
Murata GRM1885C1H330J
4.7µF ±10%, 6.3V X5R ceramic
capacitor (0603)
Murata GRM188R60J475K
DESIGNATION
C14, C25, C26
QTY
3
DESCRIPTION
10µF ±10%, 25V X5R ceramic
capacitors (1206)
Murata GRM31CR6E106K
Not installed, ceramic capacitors
(0805)
22µF ±20%, 6.3V X5R ceramic
capacitors (1206)
Murata GRM31CR0J226M
0.22µF ±10%, 16V X7R ceramic
capacitors (0603)
Murata GRM188R71C224K
1500µF ±20%, 2.5V aluminum
electrolytic capacitor (10.3mm x
10.3mm)
Nichicon PCF0E152MCL1GS
2200pF ±5%, 50V C0G ceramic
capacitors (0805)
Murata GRM2165C1H222JA
Not installed, capacitor (1206)
3-pin headers
0.8µH, 12A inductor
Coilcraft MSS1048-801NL
0
C15, C23
C16, C17, C18,
C22
0
1
4
C7, C9
2
C19, C20
2
C8
1
C21
1
C10
1
C24, C27
C28
JU1, JU2, JU3
L1
2
0
3
1
C11
1
C12
1
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX15023 Evaluation Kit
Evaluates: MAX15023
Component List (continued)
DESIGNATION
L2
QTY
1
DESCRIPTION
3.3µH, 6.3A inductor
Coilcraft MSS1048-332NL
30V, 11.6A n-channel MOSFETs
(8 SO)
Fairchild FDS8880
30V, 8.6A/6.3A n-channel MOSFET
(8 SO)
Fairchild FDS6982AS
Uninsulated banana jacks
10Ω ±5% resistors (0603)
Not installed, resistors (0603)
200kΩ ±1% resistors (0603)
47kΩ ±5% resistors (0603)
12.1kΩ ±1% resistors (0603)
30.1kΩ ±1% resistor (0603)
16.2kΩ ±1% resistor (0603)
22.1kΩ ±1% resistor (0603)
33kΩ ±1% resistor (0603)
1.62kΩ ±1% resistor (0603)
20kΩ ±1% resistor (0603)
45.3kΩ ±1% resistor (0603)
DESIGNATION
R21
R24, R25
R28, R29
TP1–TP6
U1
—
—
QTY
1
2
2
6
1
3
1
DESCRIPTION
10kΩ ±1% resistor (0603)
1.5Ω 5% resistors (1210)
Panasonic ERJ-P14J1R5U
49.9Ω ±1% resistors (0805)
PC mini red test points
Dual, synchronous step-down
controller (24 TQFN-EP*)
Maxim MAX15023ETG+
Shunts (JU1, JU2, JU3)
PCB: MAX15023 Evaluation Kit+
N1, N2, N3
3
N4
PGND (x3), VIN,
VOUT1, VOUT2
R1, R6
R2, R7, R11
R3, R8
R4, R5
R9, R10
R13
R14
R15
R17
R18
R19
R20
1
6
2
0
2
2
2
1
1
1
1
1
1
1
*EP
= Exposed pad.
Component Suppliers
SUPPLIER
Coilcraft, Inc.
Fairchild
Semiconductor
PHONE
WEBSITE
847-639-6400 www.coilcraft.com
888-522-5372 www.fairchildsemi.com
Murata Electronics
770-436-1300 www.murata-northamerica.com
North America, Inc.
Nichicon USA
Panasonic Corp.
858-824-1515 www.nichicon-us.com
800-344-2112 www.panasonic.com
Note:
Indicate that you are using the MAX15023 when contacting
these component suppliers.
Quick Start
Required Equipment
Before beginning, the following equipment is needed:
• MAX15023 EV kit
•
•
•
Adjustable 9V to 16V, 5A DC power supply
Two electronic loads
Two voltmeters
2) Connect a voltmeter to the VOUT1 and PGND pads.
3) Connect a voltmeter to the VOUT2 and PGND pads
4) Connect a 10A electronic load to the VOUT1 and
PGND banana jack connectors.
5) Connect a 5A electronic load to the VOUT2 and
PGND banana jack connectors.
6) Connect a DC power supply to the VIN and PGND
banana jack connectors and set the voltage to 12V.
Procedure
The MAX15023 EV kit is fully assembled and tested.
Follow the steps below to verify board operation.
Caution: Do not turn on the power supply until all
connections are completed.
1) Install shunts across pins 1-2 of jumpers JU1
(VOUT1 enabled), JU2 (VOUT2 enabled), and JU3
(VIN input source for U1).
7) Enable the power-supply output.
8) Enable the electronic loads connected at VOUT1
and VOUT2 and set to 10A and 5A, respectively.
9) Verify that voltmeters at VOUT1 and VOUT2 mea-
sure 1.2V and 3.3V, respectively.
2
_______________________________________________________________________________________
MAX15023 Evaluation Kit
Detailed Description of Hardware
The MAX15023 evaluation kit (EV kit) is a fully assem-
bled and tested PCB that contains all the components
necessary to evaluate the performance of the
MAX15023 dual, synchronous step-down controller.
The MAX15023 EV kit is designed to operate from a
single DC power supply that provides 9V to 16V and
5A of current. The MAX15023 controller can also be
operated using a separate 4.5V to 5.5V power source
applied at the VCC and SGND PCB pads.
When oper-
ating the MAX15023 EV kit using separate power-
supply sources at the VIN and PGND connectors
and VCC PCB pads, apply power at the VIN and
PGND connectors first and then at the VCC and
SGND PCB pads.
Converter 1 (VOUT1) is configured for 1.2V and pro-
vides up to 10A of output current. VOUT1’s source and
sink current limits are set to 14A (typ) and 7A (typ),
respectively, with resistor R14. Converter 2 (VOUT2) is
configured for 3.3V and provides up to 5A of output cur-
rent. VOUT2’s source and sink current limits are set to
7A (typ) and 3.5A (typ), respectively, with resistor R15.
The switching frequency for both converters is set to
500kHz by resistor R17 and each converter operates
180° out-of-phase to reduce input-voltage ripple and
total RMS input ripple current.
The EV kit includes individual PCB pads for enable
control of each converter and test points to monitor the
converters’ power-good status. Jumpers JU1 and JU2
are also available to configure the outputs for power-
supply sequencing.
input using the power source applied at the VCC and
SGND PCB pads. Note that the power source applied
to the VCC PCB pad has a 4.5V to 5.5V input-voltage
range.
When operating the MAX15023 EV kit using a
separate power source at the VCC PCB pad, apply
power to the VIN and PGND connectors PCB pad
first and then the VCC and SGND PCB pads.
See
Table 1 for the MAX15023 bias input configuration
Evaluates: MAX15023
Table 1. MAX15023 Bias Input
Configuration
SHUNT
POSITION
1-2
2-3
IN PIN
Connected to VIN
Connected to VCC
MAX15023 IC INPUT
RANGE (V)
9 to 16
4.5 to 5.5
Configuring the Output Voltages
(VOUT1, VOUT2)
VOUT1 and VOUT2 output voltages can be reconfig-
ured between 0.6V to 0.85 x VIN. Resistors R9 and R10
set VOUT1 output voltage and resistors R20 and R21
set VOUT2 output voltage. To configure the EV kit’s out-
put voltages, refer to the
Setting the Output Voltage
section in the MAX15023 IC data sheet for instructions
on selecting new resistor values.
Capacitors C5, C6, and C7 and resistors R11 and R13
provide a compensation network for VOUT1 on the
MAX15023 EV kit. Capacitors C9, C10, and C11 and
resistors R18 and R19 provide a compensation network
for VOUT2 on the MAX15023 EV kit.
Refer to the
Inductor Selection, Input Capacitor
and
Compensation
sections in the MAX15023 IC data sheet
to verify whether other components need replacement for
proper operation after reconfiguring the output voltages.
Converters’ Input Source
The power source is connected to the VIN and PGND
banana jack connectors for the dual converters. The
MAX15023 EV kit converters’ performance is optimized
over the 9V to 16V input-voltage range. The MAX15023
EV kit could operate below the 9V minimum input-volt-
age range and at higher output currents; however, per-
formance might be degraded due to the limitation of
the components used in the EV kit circuit.
Cycle-by-Cycle Peak
Current-Limit Thresholds
The MAX15023 IC employs a current-sensing algorithm
using the on-resistance of the low-side MOSFET as a
current-sensing element to limit the inductor current.
The inductor current is sensed in each converter by
sensing the voltage drop across the on-resistance
(R
(DSON)
) of the respective low-side MOSFETs (N2, N3,
and N4-A). VOUT1 source and sink current limits are
14A (typ) and 7A (typ), respectively. VOUT2 source
and sink current limits are 7A (typ) and 3.5A (typ),
respectively.
MAX15023 IC Bias Input
The MAX15023 EV kit features an option to select the
bias input for the MAX15023 IC controller when config-
uring the EV kit to operate with an input source less
than 6V. Jumper JU3 selects the input-voltage source
for the MAX15023 IC controller. Place a shunt across
pins 1-2 to power the MAX15023 IC using the power
source applied at the VIN and PGND PCB pads. Place
a shunt across pins 2-3 to power the MAX15023 IC
_______________________________________________________________________________________
3
MAX15023 Evaluation Kit
Evaluates: MAX15023
Resistors R14 and R15 set VOUT1 and VOUT2 source
current-limit voltage thresholds (V
ITH_
) to 80mV and
110mV, respectively. The sink current-limit voltage
threshold is approximately half the source current-limit
voltage threshold. Use the following equation to recon-
figure the source current-limit voltage threshold:
V
×
10
R
ILIM _
(
Ω
)
=
ITH _
50
×
10
−
6
where V
ITH_
is the source current-limit voltage threshold
in volts and R
ILIM_
is R14 or R15 in ohms.
Refer to the
Current-Limit Circuit (LIM_)
and
Setting the
Cycle-by-Cycle, Low-Side Source Peak Current Limit
sections in the MAX15023 IC data sheet for further
instructions on computing the MAX15023 EV kit source
and sink current limits.
VCC linear regulator output or the DC voltage source
supplied at the VCC PCB pad.
The outputs can also be externally controlled, by plac-
ing independent voltage sources greater than 1.3V at
the EN1 and EN2 PCB pads, when shunts are not
installed at jumpers JU1 and JU2. Additional PCB resis-
tor pads R2 and R7 are included to set the individual
channel to a desired turn-on voltage. See Tables 2 and
3 for jumpers JU1 and JU2 settings.
Table 2. JU1 Jumper Selection (EN1)
SHUNT
POSITION
1-2
2-3*
Not installed
EN1 PIN
Connected to VCC
Connected to
PGOOD2
Pulled down to
GND through R8
VOUT1 OUTPUT
Enabled
Enabled (power-
supply sequencing)
Disabled
Switching Frequency
The MAX15023 controller’s switching frequency is set
to 500kHz by resistor R17. Replace resistor R17 with
a new resistor value to program the switching fre-
quency between 200kHz and 1MHz. Use the following
equation to calculate R17 when reconfiguring the
switching frequency:
R17
=
24806
*See the
Power-Supply Sequencing
section.
Table 3. JU2 Jumper Selection (EN2)
SHUNT
POSITION
1-2
2-3*
Not installed
EN2 PIN
Connected to VCC
Connected to
PGOOD1
Pulled down to
GND through R3
VOUT2 OUTPUT
Enabled
Enabled (power-
supply sequencing)
Disabled
(
f
SW
)
1.0663
where f
SW
is in kilohertz and R17 is in kilohms.
When reconfiguring the EV kit controller switching fre-
quency, it might be necessary to change compensation
network components to new values. Refer to the
Compensation
section in the MAX15023 IC data sheet
for computing new compensation component values.
*See the
Power-Supply Sequencing
section.
Power-Good Outputs
(PGOOD1, PGOOD2)
The MAX15023 EV kit provides power-good output test
points (TP1 and TP2) to monitor the PGOOD1 and
PGOOD2 signals. PGOOD1 and PGOOD2 are high
when VOUT1 and VOUT2, respectively, rise 92.5%
above their programmed output voltages. The PGOOD_
signals are pulled up to VCC by resistors R4 and R5.
When VOUT1 and VOUT2 drop below 89.5% of their
nominal regulated voltages, PGOOD1 and PGOOD2 are
pulled low, respectively.
Power-Supply Sequencing
The MAX15023 EV kit outputs can be configured for
power-supply sequencing by utilizing the PGOOD_ out-
puts and configuring jumpers JU1 and JU2 appropri-
ately. Place shunts across pins 1-2 of jumper JU1 and
pins 2-3 of jumper JU2 for power sequencing VOUT1,
and then VOUT2. Place shunts across pins 1-2 of
jumper JU2 and pins 2-3 of jumper JU1 for sequencing
VOUT2, and then VOUT1. See Table 4 for configuring
the outputs for power-supply sequencing operation.
Enable/Power-Supply Sequencing
(JU1, JU2)
Jumpers JU1 and JU2 configure the MAX15023 EV kit’s
VOUT1and VOUT2 outputs, respectively, for indepen-
dent turn-on/off control or power-supply sequencing.
Install shunts across pins 1-2 of jumpers JU1 and JU2
to enable VOUT1 and VOUT2 using the MAX15023
4
Table 4. Power-Supply Sequencing (JU1,
JU2)
SHUNT POSITION
JU1
1-2
2-3
JU2
2-3
1-2
OUTPUT SEQUENCE OPERATION
VOUT1, VOUT2
VOUT2, VOUT1
_______________________________________________________________________________________
MAX15023 Evaluation Kit
Evaluates: MAX15023
Figure 1. MAX15023 EV Kit Schematic
_______________________________________________________________________________________
5
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