Maxim Integrated MAX17509 User manual

Evaluates: MAX17509 4.5V–16V,
Dual 3A Synchronous Buck Converter
MAX17509 Evaluation Kit
General Description
The MAX17509 evaluation kit (EV kit) is a fully assembled
and tested circuit board to demonstrate the performance
of the MAX17509, a dual 3A, high-efciency, synchronous
step-down DC-DC converter. The EV kit operates from a
4.5V to 16V input voltage to generate two, independent
3.3V and 1.2V outputs, with each regulator delivering
up to 3A continuous output current. The EV kit is preset
to the default 1MHz switching frequency for optimum
efciency and component sizes, and each regulator
operates 180° out-of-phase to reduce input-voltage ripple
and total RMS input ripple current. The EV kit also
features adjustable input undervoltage-lockout (UVLO),
programmable frequency, external frequency synchro-
nization input, adjustable output voltage ranging from
0.904V to 3.782V and 4.756V to 5.048V with 20mV
resolution, selectable switching slew rate, adjustable soft-
start time with soft-stop option, power-good outputs, and
selectable overcurrent (OC) fault response to promote
design exibility and system reliability.
Features
●Wide Input-Voltage Range (4.5V to 16V)
●3.3V and 1.2V Output Voltages
●Up to 3A Output Current per Regulator
●Two Independent Outputs Operating 180° Out-of-
Phase
●1MHz Switching Frequency
●External Frequency Synchronization Input
●Brickwall and Latchoff Overcurrent Response
(Selectable to Hiccup Response)
●Autoconfigured Internal Compensation
●Power-Good Output Indicator
●Independent Adjustable EN/UVLO Input
●Independent Adjustable Soft-Start Time with Soft-
Stop Option
●Selectable Switching Slew Rate for EMC Compliant
●Low-Profile and Small-Size, Surface-Mount
Components
●Fully Assembled and Tested
19-7670; Rev 0; 6/15
Ordering Information appears at end of data sheet.
Quick Start
Recommended Equipment
●MAX17509 EV kit
●4.5V to 16V, 4A DC input power supply
●Two loads capable of sinking 3A
●Digital voltmeters (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 4.5V and
16V. 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
rst 3A load to OUT1 and PGND PCB pads, respec-
tively, and the second 3A load to OUT2 and PGND
PCB pads, respectively. Set both loads to 0A.
4) Connect the rst DVM across the OUT1 and PGND
PCB pads, and the second across OUT2 and PGND,
respectively.
5) Change the position of SW1 and SW2 to position 1-2
(or 2-3) to enable the respective regulator. SW1 and
SW2 in the middle position will disable the device.
6) Enable the input power supply.
7) Verify that DVM1 displays 3.3V and DVM2 displays
1.2V.
8) Increase the load up to 3A to verify that DVM
continues displaying 3.3V and 1.2V, respectively.
Note that the EV kit is designed to demonstrate com-
pact solution-size so that the output voltage-sensing
is performed near C2 for VOUT1 and C3 for VOUT2.
Therefore, the output voltage is accurate across
those respective components.

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Evaluates: MAX17509 4.5V–16V,
Dual 3A Synchronous Buck Converter
MAX17509 Evaluation Kit
Detailed Description of Hardware
The EV kit is a proven circuit to demonstrate the high-
efciency and compact solution-size of the synchronous
step-down DC-DC regulators. The EV kit operates from
a 4.5V to 16V input voltage to generate two independent
3.3V and 1.2V outputs, with each regulator delivering up
to 3A continuous output current. The switching frequency
is set to 1MHz to balance efciency and component
size. The EV kit includes switches SW1,2 to enable/
disable the device, test point TP1 to optionally synchro-
nize to an external clock source (SYNC), and LED1,2
connected to PGOOD1,2 to indicate the status of the
outputs. Additional footprints of optional components are
included to ease board modication for different input/
output congurations. Table 1 displays the resistor
programming options. When the output voltage is changed,
refer to the MAX17509 IC data sheet’s recommendation on
the inductance and capacitance selection criteria.
Table 1. Summary of Resistor Programming
Index 1% RES. R13
MODE
R1
SS1
R2
SS2
R5, R8
COARSE_
R6, R7
FINE_
(kΩ) MODE PHASE
SHIFT FSW OC SSTOP1 TSS1 (ms)
LX-
SLEW SSTOP2 TSS2 (ms)
COARSE
VOUT (V)
FINE
VOUT (V)
0475 (OPEN
or VCC)
TWO SINGLE-PHASE
INDEPENDENT OUTPUTS
180°
500kHz
BRICKWALL AND LATCHOFF
DISABLE
1
MAXIMUM
DISABLE
1
0.650
0.000
1 200 1.0MHz 4 4 0.019
2115 1.5MHz 8 8 0.037
3 75 2.0MHz 16 16 0.966 0.057
4 53.6
0°
500kHz
ENABLE
1
ENABLE
1 1.281 0.078
5 40.2 1.0MHz 4 4 1.597 0.097
6 30.9 1.5MHz 8 8 1.912 0.115
7 24.3 2.0MHz 16 16 2.228 0.135
8 19.1
DUAL-PHASE, SINGLE OUTPUT
180°
500kHz
HICCUP
DISABLE
1
MINIMUM
DISABLE
1 2.543 0.157
9 15 1.0MHz 4 4 2.859 0.176
10 11.8 1.5MHz 8 8 3.174 0.194
11 9.09 2.0MHz 16 16 3.490 0.213
12 6.81 500kHz
ENABLE
1
ENABLE
14.756
(7V VIN) 0.235
13 4.75 1.0MHz 4 4 4.756
(9V VIN) 0.254
14 3.01 1.5MHz 8 8 4.756
(12V VIN) 0.272
15 GND 2.0MHz 16 16 4.756
(16V VIN) 0.291

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Evaluates: MAX17509 4.5V–16V,
Dual 3A Synchronous Buck Converter
MAX17509 Evaluation Kit
Regulator Enable and Adjustable UVLO
The device can be self-enabled by connecting EN_ to
AVCC, and can optionally be programmed to turn on at
the input-voltage threshold by connecting EN_ to the
resistor-divider between IN_ to GND. The EV kit has
SW1 and SW2 to enable regulator 1 and 2, respectively,
through the input supply or AVCC. Moving the switches
to position 1 enables the device at a 4.1V input UVLO
threshold, while moving to position 3 connects EN_ to
AVCC. Moving a switch to position 2 will disable the
respective regulator. The adjustable-input UVLO threshold
of a regulator can be programmed with top feedback
resistor RU connected between IN_ and EN_, and bottom
feedback resistor RB connected between EN_ and GND.
The adjustable-input UVLO threshold of regulator 1 can
be programmed with the resistor-dividers R15 (RU1) and
R3 (RB1), and regulator 2 with R16 (RU2) and R10 (RB2).
Choose RU_ and then calculate RB_ with the following
equation:
RB_ = RU_ x1.262
VINU - 1.262
Where VINU is the input threshold voltage at which the
device is required to turn on. Ensure that VINU is higher
than 0.93 x VOUT.
Mode/Phase Shift/ Switching Frequency
(MODE)
The MODE pin sets the device as a single-phase, dual-
output/dual-phase, or single-output, while also setting the
phase-shift and switching frequency. The EV kit operates
in a single-phase, dual-output conguration, each with
up to 3A output current. Each regulator operates with
180° out-of-phase and 1MHz switching frequency. The
phase-shift mode can be selected to be either 0° or 180°
out-of-phase in the dual-output mode only. The device is
also capable of conguring different switching frequency
options: 0.5MHz, 1MHz, 1.5MHz, and 2MHz for input voltage
up to 6V.
Soft-Start/Soft-Stop Options and Over-Current
Response (SS1)
The SS1 pin sets regulator 1’s soft-start timing among 1,
4, 8, and 16ms, as well as its soft-stop option. The SS1 pin
also sets options to attempt regulation following an under
and overcurrent event. The two options for fault response
due to UC/OC protection are: (1) hiccup and (2) Brickwall
and latchoff. The EV kit is set to 8ms soft-start timing,
with soft-stop enabled for regulator 1, and Brickwall-and-
latchoff overcurrent response for both regulators.
Soft-Start/Soft-Stop Options and Switching
Slew rate (SS2)
The SS2 pin sets regulator 2’s soft-start timing among 1,
4, 8, and 16ms, as well as its soft-stop option. The SS2
pin also sets the switching slew rate of both regulators
to either maximum or minimum. The EV kit is set to 8ms
soft-start timing, with soft-stop enabled, for regulator 2,
and maximum switching slew rate for both regulators.
External Clock Synchronization (SYNC)
The SYNC pin allows frequency-synchronization to
external clock. The EV kit provides a SYNC test point (TP1)
that allows connecting an external clock for frequency
synchronization with frequency within the 900kHz
to 1.3MHz range before regulation starts for stable
operation of 1MHz internal switching frequency at the
12VIN range, and within 0.7–2.75 of the internal switching
frequency, with a limit of 450kHz to 2.2MHz for the 5VIN
range. The minimum external clock high pulse width
should be greater than 30ns. The minimum voltage
should be below 0.6V, with the maximum level being
above 1.8V (e.g., 0 to 5V).

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Evaluates: MAX17509 4.5V–16V,
Dual 3A Synchronous Buck Converter
MAX17509 Evaluation Kit
Programmable Output Voltage
The device generates an independently adjustable output
voltage in the ranges of 0.904V to 3.782V and 4.756V to
5.048V in 20mV steps. The EV kit provides 3.3V on regu-
lator 1 and 1.2V on regulator 2. The target output voltage
(VOUT) is determined by the sum of COARSE voltage
(COARSE_) and FINE voltage (FINE_), which can be
programmed by connecting resistors from COARSE
and FINE pins to GND. The COARSE-resistor value is
selected according to the closest COARSE_ voltage less
than or equal to the target output voltage from Table 1.
The FINE resistor value is chosen by the index number,
calculated by the following equation:
OUT OUTCOARSE
VV
Index 0.02

−


=



Where VOUTCOARSE is the COARSE_ closest to the
value of VOUT; Index is the index number selected for
the FINE resistor value from Table 1. Table 2 summarizes
the resistor setting and the optimal inductor and output
capacitor selection for typical output voltages for typical
12VIN range. Consult the MAX17509 IC data sheet’s
recommendation on the inductance and capacitance
value, as well as the guideline for the 5VIN range.
Table 2. Summary of Resistor Setting and the Optimal Inductor and Output Capacitor
Selection for Typical Output Voltages
VOUT (V) COARSE INDEX FINE
INDEX
COARSE
RESISTOR (kΩ)
FINE
RESISTOR (kΩ)
6 ≤ VIN ≤ 16V, FSW = 1MHz
LMIN (μH) COUTMIN (μF)
0.9 2 13 115 4.75 1 100
1.0 3 2 75 115 1.2 82
1.2 3 12 75 6.81 1.2 68
1.5 4 11 53.6 9.09 1.5 55
2.0 6 5 30.9 40.2 2.2 41
2.5 7 14 24.3 3.01 2.2 33
3.0 9 7 15.0 24.3 2.2 18
3.3 10 7 11.8 24.3 2.2 18
5.0 (7V VIN)
5.0 (9V VIN)
5.0 (12V VIN)
5.0 (16V VIN)
12
13
14
15
13
6.81
4.75
1.8
18
4.75 2.7
3.01 3.9
GND 4.7

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Evaluates: MAX17509 4.5V–16V,
Dual 3A Synchronous Buck Converter
MAX17509 Evaluation Kit
EV Kit Performance Report
1.185
1.190
1.195
1.200
1.205
1.210
0.0 0.5 1.0 1.5 2.0 2.5 3.0
VOUT (V)
OUTPUT CURRENT (A)
LOAD REGULATION
VOUT = 1.2V toc04
VIN = 5V
VIN =12V
VIN =16V
60
65
70
75
80
85
90
95
100
01000 2000 3000
EFFICIENCY (%)
OUTPUT CURRENT (mA)
VOUT1 = 3.3V
EFFICIENCY vs. OUTPUT CURRENT toc01
EN2 = 0V
VIN = 16V
VIN = 5V
VIN = 12V
60
65
70
75
80
85
90
0 1000 2000 3000
EFFICIENCY (%)
OUTPUT CURRENT (mA)
VOUT2 = 1.2V
EFFICIENCYvs. OUTPUT CURRENT
toc02
EN1 = 0V
VIN =16V
VIN =12V
VIN = 5V
3.250
3.255
3.260
3.265
3.270
3.275
3.280
0.0 0.5 1.0 1.5 2.0 2.5 3.0
V
OUT
(V)
OUTPUT CURRENT (A)
LOAD REGULATION
V
OUT
= 3.3V
toc03
V
IN
= 16V
V
IN
= 5V
V
IN
= 12V

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Evaluates: MAX17509 4.5V–16V,
Dual 3A Synchronous Buck Converter
MAX17509 Evaluation Kit
EV Kit Performance Report (continued)
STARTUP/SOFT-STOP ENABLED
VIN = 12V, VOUT = 1.2V, IOUT = 0A, TSS = 8ms
500mV/div
toc07
4ms/div
LX
VOUT
10V/div
EN
PGOOD 2V/div
5V/div
STARTUP/SOFT-STOP ENABLED
VIN = 12V, VOUT = 1.2V, IOUT = 3A, TSS = 8ms
500mV/div
toc08
4ms/div
LX
VOUT
10V/div
EN
PGOOD 5V/div
5V/div
LOAD SHORT-CIRCUIT SHUTDOWN (LATCH)
VIN = 12V, VOUT = 1.2V
500mV/div
toc09 4µs/div
LX
V
OUT
10V/div
PGOOD
5V/div
I
L
2A/div
SYNCHRONIZATION vs. LX1 and LX2
180°OUT-OF-PHASE
10V/div
toc10
400ns/div
LX2
LX1
10V/div
CLKIN 5V/div
LOAD CURRENT TRANSIENT RESPONSE
VIN = 12V, VOUT = 3.3V, IOUT = 1.5 -3A
1A/div
toc05
40us/div
IOUT
VOUT
200mV/div
(AC
COUPLED)
LOAD CURRENT TRANSIENT RESPONSE
VIN = 12V, VOUT = 1.2V, IOUT = 1.5–3A
1A/div
toc06
40µs/div
IOUT
VOUT
50mV/div
(AC
COUPLED)

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Evaluates: MAX17509 4.5V–16V,
Dual 3A Synchronous Buck Converter
MAX17509 Evaluation Kit
Figure 2. MAX17509 EV Kit Component Placement Guide—
Solder Side
Figure 3. MAX17509 EV Kit PCB Layout—Component Side
Figure 4. MAX17509 EV Kit PCB Layout—PGND Layer 2
Figure 1. MAX17509 EV Kit Component Placement Guide—
Component Side

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Evaluates: MAX17509 4.5V–16V,
Dual 3A Synchronous Buck Converter
MAX17509 Evaluation Kit
Figure 5. MAX17509 EV Kit PCB Layout—PGND Layer 3 Figure 6. MAX17509 EV Kit PCB Layout—Solder Side
#Denotes RoHS compliant.
Ordering Information
PART TYPE
MAX17509EVKIT# EV Kit
Component Information and Schematic
See the following links for component information and
schematic:
●MAX17509 EV BOM
●MAX17509 EV Schematic

Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specications without notice at any time.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. ©2015 Maxim Integrated Products, Inc.
│ 9
Evaluates: MAX17509 4.5V–16V,
Dual 3A Synchronous Buck Converter
MAX17509 Evaluation Kit
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES CHANGED
0 6/15 Initial release —
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.

PGND PGND
PGND
SHEET 2 OF 2
2/3/2015
MAX17509 EVKIT
EPCB17509
A
1.2
22UF OPEN
1%
11.8K
10UF 10UF0.1UF
2.2UF OPEN
OPEN
1%
42.2K
49.9
30.9K
1% 1%
200K
1%
10K
1% 1%
42.2K
1%
10K
1%
1%
100UF
1K
1%
MAX17509
1%
75K
1%
19.1K
OPEN 0.1UF
1K
G13AP
OPEN
19.1K
OPEN
0.1UF
OPEN
30.9K 6.81K
1%
1UF
OPEN
49.9
1.5UH
0.1UF
2.2UH
1% 1%1%
24.3K
G13AP
C2
R5
C5
IN
LED1
R19
C10
R1
OUT2
R10
R15 R16
R13 R14
LED2
R11
R8
R9R4
C4
U1
C1
R3
C7
C9
TP1
C15 C16
C3
C6
SW2
R12
R17
C12
R2
C8
R7
OUT1
C13
C14
L2
C17
R18
L1
R6
SW1
OUT1
AVCC VCC SYNC
IN AVCC IN
OUT2
VCC
IN
IN
VCC
IN
AVCC
2 1 2 1
11 15141310
4
6
5
4
K A
29
169
23
3
2
214
196
30
33
2532 26
178
6
18
12
7
A
5
K
31
1 24
27
22
20
28
5
6
5
4
6
5
4
EN1
COARSE1
FINE1
SS1 SS2
FINE2
COARSE2
EN2
OUT2
PGND2
PGND2
LX2
LX2
IN2
IN2
BST2
EP PGOOD2 MODE N.C. SYNC VCC AVCC SGND PGOOD1
BST1
IN1
IN1
LX1
LX1
PGND1
PGND1
OUT1
DRAWN BY:
TEMPLATE REV:
REV:
2
B
D
1
C
A
2345
345
678
C
B
A
8 7 6 1
D
DATE:
PROJECT TITLE:
DRAWING TITLE:
SIZE HARDWARE NUMBER:
ENGINEER:
B
B

BILL OF MATERIALS (BOM) 6/16/15 Revision
Remarks QTY Component Manufacturer
(Reference Designators) Per Description Part Number
C2 1CAP CER 22UF 10V 10% X7R 1206 Murata GRM31CR71A226KE15 (10V, X7R, 10%)
C13 11uF ±10%, 16V X7R ceramic capacitor (0603) Murata GRM188R71C105K
C14 12.2uF ±10%, 10V X5R ceramic capacitor (0603) Murata GRM188R71A225K
C9, C10 2CAP CER 0.1UF 25V 10% X7R 0603 Murata GRM188R71E104KA01D
C7, C12 20.1uF 10%, 16V X7R ceramic capacitors (0603) TDK C1608X7R1C104K
C5, C8 210uF ±10%, 25V X7R ceramic capacitors (1206) Murata GRM31CR71E106K
C4 1CAP CER 100UF 6.3V 20% X5R 1206 TDK C3216X5R0J107M160AB
C3, C15, C16, C17 0Not Installed, ceramic capacitors (1206)
C1, C6 0Not Installed, ceramic capacitors (0603)
L2 11.5uH ±20%, 21.45mohm inductor (4mm x 4mm x 2.1mm)
Coilcraft XAL4020-152ME_
Wurth WE-LHMI 74437324015 (1.5uH ±20%, 34.8mOhm inductor)
L1 12.2uH ±20%, 35.2mohm inductor (4mm x 4mm x 2.1mm)
Coilcraft XAL4020-222ME_
Wurth WE-LHMI 74437324022 (2.2uH ±20%, 51mOhm inductor)
LED1, LED2 2LED, YELLOW (0603) LITE-ON LTST-C190YKT
IN, PGND1-PGND3, OUT1, OUT2 6
9020 BUSS EVK KIT PARTS; MAXIM PAD; WIRE; NATURAL;
SOLID; WEICO WIRE; SOFT DRAWN BUS TYPE-S; 20AWG
9020 BUSS
U1 1Maxim MAX17509ATJ+ Maxim MAX17509ATJ+
R1, R2 230.9k ohm ±1%, resistor (0402)
R3, R10 219.1k ohm ±1%, resistor (0402)
R4, R9 210k ohm ±1%, resistor (0402)
R5 111.8k ohm ±1%, resistor (0402)
R6 124.3k ohm ±1%, resistor (0402)
R7 16.81k ohm ±1%, resistor (0402)
R8 175k ohm ±1%, resistor (0402)
R11, R14 21k ohm ±1%, resistor (0402)
R13 1200k ohm ±1%, resistor (0402)
R15, R16 242.2k ohm ±1%, resistor (0402)
R17, R18 249.9 ohm ±1%, resistor (0402)
SW1, SW2 2SWITCH TOGGLE SPDT 0.4VA 20V NKK G13AP
R12 0Not Installed, resistor (0402)
R19 0Not Installed, resistor (0603)
TP1 1TEST POINT “Miniature" (RED) Keystone 5000