Maxim Integrated MAX17572 Quick Start Manual

MAX17572 3.3V Output
Evaluation Kit

Evaluates: MAX17572 in 3.3V

Output-Voltage Application

General Description

The MAX17572 3.3V output evaluation kit (EV kit)
provides a proven design to evaluate the MAX17572

high-voltage, high-efciency, synchronous step-down
DC-DC converter. The EV kit is preset for 3.3V output at
load currents up to 1A and features a 500kHz switching
frequency for optimum efciency and component size.
The EV kit features adjustable input undervoltage lockout,
adjustable soft-start, open-drain active-low RESET signal,
and external frequency synchronization.

Features

● Operates from a 4.5V to 60V Input Supply

● 3.3V Output Voltage

● Up to 1A Output Current

● 500kHz Switching Frequency

● Enable/UVLO Input, Resistor-Programmable UVLO

Threshold

● Adjustable Soft-Start Time

● Open-Drain RESET Output

● External Frequency Synchronization

● Overcurrent and Overtemperature Protection

● Proven PCB Layout

● Fully Assembled and Tested

Quick Start

Recommended Equipment

● MAX17572 3.3V output EV kit

● 4.5V to 60V, 2A DC input power supply

● Load capable of sinking 1A

● Digital voltmeter (DVM)

Procedure

The EV kit is fully assembled and tested. Follow the steps
below to verify the board operation. Caution: Do not turn

on power supply until all connections are completed.

1) Set the power supply at a voltage between 4.5V and
60V. Disable the power supply.

2) Connect the positive terminal of the power supply
to the VIN PCB pad and the negative terminal to

the nearest PGND PCB pad. Connect the positive
terminal of the 1A load to the V
negative terminal to the nearest PGND PCB pad.

3) Connect the DVM across the V
the nearest PGND PCB pad.

4) Verify that shunts are installed across pins 1-2 on
jumper JU1 (see Table 1 for details).

5) Turn on the DC power supply.

6) Enable the load.

7) Verify that the DVM displays 3.3V

PCB pad and the

OUT

PCB pad and

OUT

Ordering Information appears at end of data sheet.

19-8651; Rev 1; 6/17

MAX17572 3.3V Output
Evaluation Kit

Evaluates: MAX17572 in 3.3V

Output-Voltage Application

Detailed Description of Hardware

The MAX17572 3.3V output EV kit provides a proven
design to evaluate the MAX17572 high-voltage, high

efciency, synchronous step-down DC-DC converter. The
EV kit is preset for 3.3V output from 4.5V to 60V input at
load currents up to 1A and features a 500kHz switching
frequency for optimum efciency and component size.
The EV kit includes an EN/UVLO PCB pad and jumper
JU1 to enable the output at a desired input voltage. An
additional RESET PCB pad is available for monitoring
whether the converter output is in regulation.

Soft-Start capacitor selection

The device implements adjustable soft-start operation to
reduce inrush current. A capacitor connected from the SS
pin to GND programs the soft-start time. The selected
output capacitance (C
determine the minimum required soft-start capacitor
as follows:

C 56 10 C V

≥× × ×

SS SEL OUT

The soft-start time (tSS) is related to the capacitor con­nected at SS (CSS) by the following equation:

For example, to program a 2ms soft-start time, a 12nF
capacitor should be connected from the SS pin to GND.

Setting the Undervoltage-Lockout Level

The device offers an adjustable input undervoltage-lockout
level. Set the voltage at which the device turns on with
a resistive voltage-divider connected from VIN to SGND

(see Figure 1). Connect the center node of the divider to

) and the output voltage (V

SEL

6

−

C

=

t

SS

SS

×

5.55 10

−

6

OUT

)

EN/UVLO. Choose R1 to be 3.3MΩ and then calculate
R2 as follows:

R2

−

(V 1.215)

INU

×

1.215 R1

=

where VINU is the voltage at which the device is required
to turn on. Ensure that VINU is higher than 0.8 x V

OUT

.

If the EN/UVLO pin is driven from an external signal source,
a series resistance of minimum 1kΩ is recommended to
be placed between the signal source output and the EN/
UVLO pin, to reduce voltage ringing on the line.

Adjusting Output Voltage

Set the output voltage with a resistive voltage-divider
connected from the positive terminal of the output capacitor

(V

) to SGND (see Figure 2). Connect the center node

OUT

of the divider to the FB pin. Use the following procedure to
choose the resistive voltage-divider values:

Calculate resistor R3 from the output to the FB pin as
follows:

R3C=

Where C

OUT_SEL

(in µF) is the actual derated value of
the output capacitance used and R3 is in kΩ. The minimum
allowable value of R3 is (5.6 x V
If the value of R3 calculated using the above equation.
is less than (5.6 x V
least (5.6 x V

OUT

OUT

).

R4

R4 is in kΩ.

1850

OUT_SEL

), where R3 is in kΩ.

OUT

), increase the value of R3 to at

×

R3 0.9

=

(V 0.9)

OUT

−

Table 1. Regulator Enable (EN/UVLO) Description (JU1)

SHUNT POSITION EN/UVLO PIN MAX17572_ OUTPUT

1-2* Connected to VIN Enabled

Not installed

2-3 Connected to SGND Disabled

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Connected to the center node of resistor-divider

R1 and R2

Enabled, UVLO level set through the

R1 and R2 resistors

Maxim Integrated

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2

MAX17572 3.3V Output

3.20

3.25

3.30

3.35

3.40

3.45

3.50

0.00

0.20

0.40 0.60 0.80 1.00

OUTPUT VOLTAGE (V)

LOAD CURRENT (A )

LOAD AND LINE REGULATION

(3.3V OUT PUT, PWM MODE)

VIN= 36V

VIN= 48V

VIN= 24V

V

IN

= 12V

toc01

20

30

40

50

60

70

80

90

100

0.0 0.2 0.4 0.6 0.8 1.0

EFFI CIENCY (%)

LOAD CURRENT (A )

EFFICIENCY vs. LOAD CURRENT

(3.3V OUT PUT, PWM MODE)

VIN= 48V

VIN= 36V

VIN= 24V

VIN= 12V

MODE = SGND

toc02

R1

SGND

VIN

EN/UVLO

R2

R3

SGND

V

OUT

FB

R4

Evaluation Kit

Evaluates: MAX17572 in 3.3V

Output-Voltage Application

Figure 1. Setting the Input Undervoltage Lockout

EV Kit Performance Report

Figure 2: Adjusting Output Voltage

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Maxim Integrated

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3

MAX17572 3.3V Output

100μS/div

50mV/di v

LOAD CURRENT STEPPED FROM NO LOAD TO 0.5A

(3.3V OUTPUT, PWM MODE)

V

OUT

(AC)

500mA/di v

I

LOAD

toc04

GAIN (dB)

FREQUE NCY (Hz)

BODE PLOT

(3.3V OUTPUT, 1A L OAD CURRENT)

CROSSO VER FREQ UENCY = 42.9kHz,
PHASE MARGIN = 64. 5°

PHASE

GAIN

PHASE (°)

toc03

CROSSO VER FREQUENCY = 42.9kHz,
PHASE MARGIN = 64. 5°

PHASE

GAIN

40

-30

-20

-10

0

10

20

30

80

10

3

-20

0

20

40

60

10

5

10

4

100μS/div

50mV/di v

LOAD CURRENT STEPPED FROM 0.5A TO 1A

(3.3V OUTPUT, PWM MODE)

V

OUT

(AC)

500mA/di v

toc05

I

LOAD

Evaluation Kit

EV Kit Performance Report (continued)

Evaluates: MAX17572 in 3.3V

Output-Voltage Application

Component Suppliers

SUPPLIER WEBSITE

Coilcraft, Inc. www.coilcraft.com
Murata Americas www.murata.com
Panasonic Corp. www.panasonic.com
Vishay www.vishay.com
Onsemi www.onsemi.com

Ordering Information

PART TYPE

MAX17572EVKITA# EV KIT

www.maximintegrated.com

Maxim Integrated

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4

MAX17572 3.3V Output

No. Description Quantity Designator

Part Number

22uF 10%, 10V ,X7R,Ceramic capacitor (1210)

1

C2 MURATA GRM32ER71A226K

33uF,20%,80V,ELECT,10mm

1

C3

PANASONIC EEE-FK1K330P

C4 TDK C2012X7R1A475K085AC

C5 Murata GRM155R71E562K

C6,C7 MURATA GRM155R71H104KE14

C8 MURATA GRM1555C1H470JA01

C9

MURATA GRM1555C1H101JA01D

C10

MURATA GRM188R72A104KA35

ON SEMICONDUCTOR

NSR05F20NXT5G

Sullins: PTC36SAAN

L1 COILCRAFT XAL4040-153ME

RES+,3.32MOHM,1%,0402

1

R1

RES+,604K OHM,1%,0402

1

R2

RES+,86.6K OHM,1%,0402

1

R3

RES+, 32.4KOHM,1%,0402

1

R4

RES+, 4.7OHM,1%,0402

1

R5

RES+,100K OHM,1%,0402

1

R6

RES+,40.2K OHM,1%,0402

1

R7

RES+,1K OHM,1%,0402

1

R8

Buck Converter
MAX17572ATJ+

Evaluation Kit

MAX17572 EV System Bill of Materials

Evaluates: MAX17572 in 3.3V

Output-Voltage Application

1 2.2uF 10%, 100V ,X7R,Ceramic capacitor (1210) 1

2
3
4 4.7uF 10%, 10V ,X7R,Ceramic capacitor (0805) 1
5 5600pF,10%,50V,X7R,0402,Ceramic capacitor(0402) 1
6 0.1uF,10%,50V,X7R, Ceramic capacitor(0402) 2
7 47pF,10%,50V,X7R,0402,Ceramic capacitor(0402) 1
8 100pF,10%,50V,X7R,0402,Ceramic capacitor(0402) 1
9 0.1uF,10%,100V,X7R,0603,Ceramic capacitor(0603) 1

10 Diode PIV=20V; IF=0.5A 1

11 3-pin header (36-pin header 0.1” centers ) 1 JU1
12 INDUCTOR, 15uH, 2.8A 1
13
14
15
16
17
18
19
20

21

22 3 pin headers

1 U1

1 See Jumper Table1 SULLINS STC02SYAN

C1 MURATA GRM32ER72A225KA35

D1

MAX17572ATJ+

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Maxim Integrated

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5

MAX17572 3.3V Output

EN/UVLO

RT/SYNC

Evaluation Kit

MAX17572 EV System Schematic

Evaluates: MAX17572 in 3.3V

Output-Voltage Application

VOUT

3.3V, 1A

21

L1

U1

MAX17572

15UH

C7

111

LX

VIN

22UF

C2

0.1UF

BST

EN/UVLO

2 10

R3

9

EXTVCC

PGND

12

PGND

86.6K

7

FB

VCC

546

8

GND

RT/SYNC

32.4K

R4

VCC604K

3

RESET\

SS

RESET

10K

R6

EP

13

5600PF

C5

www.maximintegrated.com

VIN

VIN

0.1UF

C10

2.2UF

C1

C3

80V

33UF

+

21

PGND

VCC

R1

C4

3.32M

1

JU1

2

4.7UF

40.2K

47PF

C8 R7

R2

3

1K

R8 D1

C9

100PF

SGND

Maxim Integrated

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MAX17572 3.3V Output
Evaluation Kit

MAX17572 EV System PCB Layout

Evaluates: MAX17572 in 3.3V

Output-Voltage Application

MAX17572 3.3V EV Kit—Top Silkscreen MAX17572 3.3V EV Kit—Top

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MAX17572 3.3V EV Kit—Bottom

Maxim Integrated

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MAX17572 3.3V Output
Evaluation Kit

Evaluates: MAX17572 in 3.3V

Output-Voltage Application

Revision History

REVISION

NUMBER

0 9/16 Initial release —

1 6/17

REVISION

DATE

DESCRIPTION

Updated Typical Operating Characteristics, Resistor references in Adjusting
Output Voltage section, Bill of Materials, Schematic, and PCB Layout gures.

PAGES

CHANGED

2–7

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.

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.

©

2017 Maxim Integrated Products, Inc.

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Authorized Distributor

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MAX17572EVKITA#