MAXM17505 5V Output
Evaluation Kit
General Description
The MAXM17505 evaluation kit (EV kit) is a demonstration
circuit of the MAXM17505 high-voltage, high-efficiency,
current-mode scheme, synchronous step-down
DC-DC switching power module. The EV kit is
designed for 5V output and delivers up to 1.7A load
current from a wide input-voltage range of 11V to 60V.
The EV kit switches at an optimal 500kHz switching
frequency to allow the use of small component-sizes,
helping to minimize solution-size while maintaining highperformance. The EV kit provides a precision-enable
input, an open-drain RESET output signal, and external
frequency synchronization to provide a simple and reliable
startup sequence and eliminate beat frequency between
regulators. The EV kit also includes optional component
footprints to program different output voltages, an adjustable input undervoltage-lockout, and a soft-start time to
control inrush current during startup. The MAXM17505 IC
data sheet provides a complete description of the part that
should be read in conjunction with this data sheet prior to
modifying the demo circuit.
Evaluates: MAXM17505 in 5V
Output-Voltage Application
Features
●● Highly Integrated Solution with Integrated Shield
Inductor
●● Wide 11V to 60V Input Range
●● Preset 5V Output with a Fixed Resistor Divider on FB
(Feedback Pin)
●● Programmable Output-Voltage Feature (0.9V to 12V)
●● Up to 1.7A Output Current
●● High 93.3% Efficiency (VIN = 12V, VOUT = 5V at 0.74A)
●● 500kHz Switching Frequency
●● Enable/UVLO Input, Resistor-Programmable UVLO
Threshold
●● Adjustable Soft-Start Time
●● Selectable PWM, PFM, or DCM Mode
●● Open-Drain RESET Output
●● External Frequency Synchronization
●● Overcurrent and Overtemperature Protection
●● Low-Profile, Surface-Mount Components
●● Lead(Pb)-Free and RoHS Compliant
Ordering Information appears at end of data sheet.
19-7607; Rev 0; 4/15
●● Fully Assembled and Tested
Evaluates: MAXM17505 in 5V
Output-Voltage Application
MAXM17505 5V Output
Evaluation Kit
Quick Start
Recommended Equipment
●●
MAXM17505 EV kit
●●
11V to 60V DC power supply (VIN)
●●
Dummy load capable of sinking 1.7A
●●
Digital voltmeter (DVM)
●●
100MHz dual-trace oscilloscope
Procedure
The 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) Set the power supply at a voltage between 11V and
60V. Disable the power supply.
2) Connect the positive and negative terminals of the
power supply to IN and PGND PCB pads, respectively.
3) Connect the positive and negative terminals of the
1.7A load to OUT and PGND2 PCB pads, respectively,
and set the load to 0A.
4) Connect the DVM across the OUT PCB pad and the
PGND2 PCB pad.
5) Verify that no shunts are installed across pin 1-2 on
jumper JU1 to enable UVLO (see Table 1 for details).
6) Verify that a shunt is installed across JU3 to disable
the external synchronization (see Table 3 for details).
7) Verify that a shunt is installed across JU2 to enable
PWM mode (see Table 2 for details).
8) Enable the input power supply.
9) Verify the DVM displays 5V.
10) Increase the load up to 1.7A to verify the DVM
continues displaying 5V.
Detailed Description of Hardware
The EV kit is a proven circuit to demonstrate the highvoltage, high-efficiency, and compact solution-size of
the synchronous step-down DC-DC power module. The
output voltage is preset for 5V to operate from 11V to
60V, provideing up to 1.7A load current. The optimal
frequency is set at 500kHz to maximize efficiency and
minimize component size. The EV kit includes jumpers JU1
to enable/disable UVLO of the device, JU2 to configure
in PWM, PFM, or DCM mode in advantage of light-load
efficiency, and JU3 to enable/disable external clock
synchronize (SYNC). The RESET PCB pad is also
available for monitoring output voltage regulation to
enable/disable the application circuit of the load. The
electrolytic capacitor (C8) is required only when the VIN
power supply is situated far from the MAXM17505 circuit.
When R4 is open, the device switches at 500kHz switch-
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ing frequency. On the bottom layer, additional footprints of
optional components are included to ease board modification
for different input/output configurations.
Soft-Start Input (SS)
The device utilizes an adjustable soft-start function to
limit inrush current during startup. The soft-start time is
programmed by the value of the external capacitor from
SS to GND (C1). The selected output capacitance (CSEL)
and the output voltage (VOUT) determine the minimum
value of C1, as shown by the following equation:
C1 ≥ 28 × 10 −3 × C SEL × VOUT
where C1 is in nF and CSEL is in µF
The soft-start time (tSS) is calculated by the equation
below:
t SS = C1/ 5.55
where tSS is in ms and C1 is in nF.
Programmable Undervoltage Lockout (UVLO)
The EV kit offers an adjustable input undervoltage-lockout
level by resistor dividers connected between the IN, EN/
UVLO, and GND pins. For normal operation, a shunt
should not be installed across pins 1-2 on JU1 to enable
the output through an internal pullup 3.3MΩ resistor from
the EN/UVLO pin to the IN pin. To disable the output,
install the shunt across pins 1-2 on JU1 to pull EN/UVLO
pin to GND. See Table 1 for JU1 jumper setting details.
The EV kit also provides an optional R3 PCB footprint to
program a UVLO threshold voltage at which an input-voltage
level device turns on. The R3 resistor can be calculated
by the following equation:
R3 =
4009.5
(VINU − 1.215)
where VINU is the input voltage at which the device is
required to turn on, and R3 unit is in kΩ.
Mode Selection (MODE)
Table 1. UVLO Enable/Disable
Configuration (JU1)
SHUNT
POSITION
EN PIN
MAXM17505_OUTPUT
Installed
Connected to GND
Disable
Not installed*
Connected to VIN
Enable
*Default position.
Maxim Integrated │ 2
Evaluates: MAXM17505 in 5V
Output-Voltage Application
MAXM17505 5V Output
Evaluation Kit
The device’s MODE pin can be used to select among
PWM, PFM, or DCM modes of operation in advance of
constant frequency or high efficiency at light-loads. The
logic state of the MODE pin is latched when VCC and EN/
UVLO voltage exceed the respective UVLO rising thresholds and all internal voltages are ready to allow LX switching.
The changes on the MODE pin are ignored during normal
operation. Refer to the MAXM17505 IC data sheet for
more information on the PWM, PFM, and DCM modes of
operation. Table 2 shows EV kit jumper settings that can
be used to configure the desired mode of operation.
greater than 160ns, and the maximum external clock
low pulse amplitude should be less than 0.8V. Table 3
describes the connection of the SYNC pin.
Setting VOUT with a Resistive
Voltage-Divider at FB
External Clock Synchronization (SYNC)
The EV kit is preset for 5V and offers an adjustable output
voltage range as low as 0.9V up to 12V at 1.7A maximum
load. The adjustable output voltage can be programmed
by the set of resistor-dividers R1 and R2. Refer to Table
1 (Selection Component Values) on the MAXM17505 IC
data sheet to select optimal component values for each
specific input voltage range from 4.5V to 60V and an
output voltage from 0.9V to 12V. To obtain an output voltage other than the default-setting outputs in Table 1, only
seven component (R1, R2, C1-C4, and C8) values need to
modified by the equation provided in the Setting the Output
Voltage section of the IC data sheet.
Table 2. MODE Description (JU2)
Table 3. SYNC Description (JU3)
The internal oscillator of the device can be synchronized
to an external clock signal to eliminate beat frequency
between regulators through the SYNC pin. The external
synchronization clock frequency must be between 1.1fSW
and 1.4fSW, where fSW is the frequency of operation set
by R5. The minimum external clock high pulse width and
amplitude should be greater than 50ns and 2.1V, respectively.
The minimum external clock low pulse width should be
SHUNT
POSITION
MODE PIN
MAXM17505_MODE
Not
installed
Unconnected
PFM mode of operation
1-2
Connected to VCC
DCM mode of operation
2-3*
Connected to GND
PWM mode of operation
*Default position.
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SHUNT
POSITION
SYNC PIN
MAXM17505_SYNC
1-2*
Connected to SGND
SYNC feature unused
Not
installed
Connected to test
loop on PCB
Frequency can be
synchronized with
an external clock
*Default position.
Maxim Integrated │ 3
Evaluates: MAXM17505 in 5V
Output-Voltage Application
MAXM17505 5V Output
Evaluation Kit
Typical Operating Characteristics
(VIN = 11V - 60V, VOUT = 5V, IOUT = 0 – 1.7A, TA = +25°C, unless otherwise noted.)
EFFICIENCY vs. OUTPUT CURRENT
VOUT = 5V, PFM MODE
toc01
EFFICIENCY vs. OUTPUT CURRENT
VOUT = 5V, PWM MODE toc02
100
90
80
80
80
60
VIN = 48V,
fSW = 500kHz
VIN = 24V,
fSW = 500kHz
50
40
VIN = 36V,
fSW = 500kHz
VIN = 12V,
fSW = 500kHz
0
500
1000
VIN = 12V,
fSW=500kHz
VIN = 24V,
VIN = 48V,
fSW=500kHz fSW = 500kHz
60
40
1500
OUTPUT CURRENT (mA)
0
500
1000
5.4
VIN = 12V,
fSW = 500kHz
5.3
1500
VOUT (V)
5.1
4.9
500
1500
toc05
VIN = 24V,
fSW = 500kHz
4.7
1000
1500
VIN = 36V,
fSW = 500kHz
5
4.6
4.5
OUTPUT CURRENT (mA)
VIN = 48V,
fSW = 500kHz
MODE = SGND
0
500
1000
1500
OUTPUT CURRENT (mA)
LOAD AND LINE REGULATION
VOUT = 5V, DCM MODE
5.5
1000
4.9
4.8
VIN = 24V,
fSW = 500kHz
MODE = OPEN
0
VIN = 12V,
fSW = 500kHz
5.3
5
4.5
500
5.4
VIN = 36V,
fSW = 500kHz
4.6
0
LOAD AND REGULATION
VOUT = 5V, PWM MODE
5.5
5.1
VIN = 48V,
fSW = 500kHz
MODE = VCC
OUTPUT CURRENT (mA)
5.2
4.7
VIN=36V,
VIN = 48V,
fSW = 500kHz fSW = 500kHz
OUTPUT CURRENT (mA)
5.2
4.8
60
40
VIN = 24V,
fSW = 500kHz
VIN = 12V,
fSW = 500kHz
70
50
MODE = SGND
LOAD AND LINE REGULATION
VOUT = 5V, PFM MODE
toc04
5.5
VOUT (V)
VIN = 36V,
fSW = 500kHz
70
50
MODE = OPEN
EFFICIENCY (%)
90
70
EFFICIENCY vs. OUTPUT CURRENT
VOUT = 5V, DCM MODE
toc03
100
90
EFFICIENCY (%)
EFFICIENCY (%)
100
LOAD CURRENT TRANSIENT RESPONSE
VIN = 24V, VOUT = 5V, IOUT = 0.05A–0.85A,
MODE = OPEN
toc07
toc6
5.4
5.3
VIN = 24V,
fSW = 500kHz
VOUT (V)
5.2
5.1
VIN = 48V,
fSW = 500kHz
IOUT
1A/div
VOUT
200mV/div
(AC
COUPLED)
5
4.9
4.8
VIN = 12V,
fSW = 500kHz
4.7
VIN = 36V,
fSW = 500kHz
4.6
4.5
MODE = VCC
0
500
1000
1500
200µs/div
OUTPUT CURRENT (mA)
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Maxim Integrated │ 4
Evaluates: MAXM17505 in 5V
Output-Voltage Application
MAXM17505 5V Output
Evaluation Kit
Typical Operating Characteristics (continued)
(VIN = 11V - 60V, VOUT = 5V, IOUT = 0 – 1.7A, TA = +25°C, unless otherwise noted.)
LOAD CURRENT TRANSIENT RESPONSE
VIN = 24V, VOUT = 5V, IOUT = 0.05A–0.85A,
MODE = SGND
toc08
IOUT
1A/div
VOUT
200mV/div
(AC
COUPLED)
LOAD CURRENT TRANSIENT RESPONSE
VIN = 24V, VOUT = 5V, IOUT = 0.05A–0.85A,
MODE = VCC
toc09
1A/div
IOUT
200mV/div
(AC
COUPLED)
VOUT
200µs/div
200µs/div
CLOSED-LOOP BODE PLOT
VIN = 24V, VOUT = 5V, IOUT = 1.7A,
MODE = SGND
50
1A/div
200mV/div
(AC
COUPLED)
VOUT
PHASE
30
GAIN (dB)
IOUT
150
90
20
60
10
30
0
0
GAIN
-10
-30
-60
-20
-30
CROSSOVER FREQUENCY = 41.8kHz
PHASE MARGIN = 70.98°
-40
200µs/div
toc11
120
40
-50
1k
10k
100k
PHASE MARGIN (°)
LOAD CURRENT TRANSIENT RESPONSE
VIN = 24V, VOUT = 5V, IOUT = 0.85A-1.7A,
MODE = SGND
toc10
-90
-120
-150
1Meg
FREQUENCY (Hz)
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Maxim Integrated │ 5
MAXM17505 5V Output
Evaluation Kit
Evaluates: MAXM17505 in 5V
Output-Voltage Application
Component Suppliers
SUPPLIER
WEBSITE
Murata Americas
www.murata.com
NEC TOKIN America, Inc.
www.nec-tokinamerica.com
Panasonic Corp.
www.panasonic.com
SANYO Electric Co., Ltd.
www.sanyodevice.com
TDK Corp.
www.component.tdk.com
TOKO America, Inc.
www.tokoam.com
Note: Indicate that you are using the MAXM17505 when contacting these component suppliers.
Component List and Schematic
Refer to the following files attached to this data sheet for
component information and schematic:
●● MAXM17505_EV_BOM.xls
●● MAXM17505_EV_Schematic.pdf
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Maxim Integrated │ 6
MAXM17505 5V Output
Evaluation Kit
Figure 1. MAXM17505 EV Kit Component Placement Guide—
Component Side
Evaluates: MAXM17505 in 5V
Output-Voltage Application
Figure 2. MAXM17505 EV Kit Component Placement Guide—
Solder Side
Figure 3. MAXM17505 EV Kit PCB Layout—Component Side
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Maxim Integrated │ 7
MAXM17505 5V Output
Evaluation Kit
Figure 4. MAXM17505 EV Kit PCB Layout—PGND Layer 2
Evaluates: MAXM17505 in 5V
Output-Voltage Application
Figure 5. MAXM17505 EV Kit PCB Layout—PGND Layer 3
Figure 6. MAXM17505 EV Kit PCB Layout—Solder Side
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Maxim Integrated │ 8
Evaluates: MAXM17505 in 5V
Output-Voltage Application
MAXM17505 5V Output
Evaluation Kit
Ordering Information
PART
TYPE
MAXM17505EVKIT#
EV Kit
#Denotes RoHS compliant.
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Maxim Integrated │ 9
Evaluates: MAXM17505 in 5V
Output-Voltage Application
MAXM17505 5V Output
Evaluation Kit
Revision History
REVISION
NUMBER
REVISION
DATE
0
4/15
DESCRIPTION
Initial release
PAGES
CHANGED
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