MAX15015AEVKIT+ - Maxim Integrated Products, Inc.

General Description

The MAX15015A evaluation kit (EV kit) is a fully assem-

bled and tested PCB that evaluates the MAX15015A

PWM/PFM step-down converter, which integrates a

high-side switch and an LDO regulator. The

MAX15015A EV kit operates over a wide input-

voltage range of 4.5V to 40V and provides up to 1A at

the 3.3V output. The LDO regulator provides up to

50mA at the preset 5V output. The MAX15015A fea-

tures undervoltage lockout, overcurrent, and thermal-

shutdown protection.

The MAX15015A normally operates as a PWM converter

and automatically switches to PFM mode at light loads

to improve efficiency. The MAX15015A switching fre-

quency is preset to 500kHz and features a SYNC input

to provide external frequency synchronization for sensi-

tive applications. The EV kit provides PCB pads to eval-

uate the SYNC and ENABLE features of the

MAX15015A. The EV kit board can also be used to eval-

uate the MAX15015B. The MAX15015A can operate

over the automotive temperature range of -40°C to

+125°C.

Features

o3.3V, 1A, 500kHz Step-Down Converter

o5V, 50mA LDO Regulator

oLDO Voltage Adjustable Up to 11V

oIndependent Turn On/Off Control for Step-Down

Converter (EN_SW)

oRegulator Power-On Reset with Adjustable

Timeout Period

o84% High Efficiency at VIN = 12V and IOUT = 1A

oAutomatic PWM/PFM Mode

oOvercurrent and Thermal-Shutdown Protection

oFully Assembled and Tested

Evaluates: MAX15015A/MAX15015B

MAX15015A Evaluation Kit

________________________________________________________________

Maxim Integrated Products

DESIGNATION QTY DESCRIPTION

C1 1

10µF ±10%, 50V X5R ceramic

capacitor (2220)

Murata GRM55DR61H106K

C2, C4, C5, C6,

C15 5

0.1µF ±10%, 50V X7R ceramic

capacitors (0603)

TDK CI608X7R1H104K

C3 1

0.22µF ±10%, 50V X7R ceramic

capacitor (0805)

Murata GRM21BR71H224K

C7 1

47µF ±20%, 6.3V X5R ceramic

capacitor (1206)

TDK C3216X5RUJ476M

C8, C13 2

0.033µF ±10%, 50V X7R ceramic

capacitors (0603)

Murata GRM188R71H333K

C9 1

0.47µF ±10%, 10V X7R ceramic

capacitor (0603)

TDK CI608X7R1A474K

DESIGNATION QTY DESCRIPTION

C10 1

1µF ±10%, 25V X7R ceramic

capacitor (0805)

TDK C2012X7R1E105K

C11 1

10µF ±10%, 16V X7R ceramic

capacitor (1206)

Murata GRM31CR61C106K

C12 1

220pF ±5%, 50V X7R ceramic

capacitor (0603)

TDK C1608X7R1H221J

C14 1

4700pF ±10%, 50V X7R ceramic

capacitor (0603)

Murata GRM188R71H472K

D1 1

150mA, 100V Schotky diode

(SOD-123)

Vishay BAT46W

D2 1 2A, 60V Schotky diode (SMB)

Diode Inc. B260

PART TEMP RANGE IC PACKAGE

MAX15015AEVKIT+ 0°C to +70°C* 36 TQFN-EP**

Ordering Information

Component List

19-0689; Rev 0; 12/06

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Denotes a lead-free and ROHS-complaint EV kit.

This limited temperature range is for the EV kit PCB only.

EP = Exposed paddle.

Component List continued on next page.

Evaluates: MAX15015A/MAX15015B

Quick Start

Recommended Equipment

• 40V adjustable, 2A power supply

• Electronic load capable of sinking up to 1A

• Three digital voltmeters

Procedure

The MAX15015A EV kit is fully assembled and tested.

Follow these steps to verify board operation. Do not

turn on the power supply until all connections are

completed.

1) Connect the positive terminal of the electronic load

to the VOUT PCB pad on the EV kit board. Connect

the ground terminal of the electronic load to the

PGND PC pad.

2) Connect digital voltmeters across the VIN and

PGND pads, VOUT and PGND PC pads, and the

LDO_OUT and GND pads.

3) Verify that shunts are installed on jumpers JU1 and

JU2 (step-down converter and LDO outputs

enabled).

4) Verify that a shunt is not installed at jumper JU3

(LDO_OUT set to 5V).

5) Connect the power supply’s positive terminal to the

VIN PCB pad on the EV kit. Connect the power-

supply ground terminal to the PGND PC pad.

6) Turn on the power supply.

7) Set the power-supply voltage to 12V.

8) Enable the 1A electronic load.

9) Verify that the voltmeters at VOUT and LDO_OUT

measure 3.3V and 5V, respectively.

Detailed Description

The MAX15015A EV kit evaluates the MAX15015A

PWM/PFM step-down converter with an integrated

high-side switch and LDO regulator. The MAX15015A

EV kit operates over a wide input-voltage range of 4.5V

to 40V and requires a 2A power supply.

The MAX15015A EV kit step-down converter is config-

ured to 3.3V and provides up to 1A (typ). The

MAX15015A step-down converter switching frequency

is set to 500kHz, and can be synchronized to a SYNC

input signal operating below 600kHz. The MAX15015A

normally operates as a PWM converter and automati-

cally switches to PFM mode at light loads to improve

efficiency. The EV kit features PCB pads to evaluate the

SYNC, EN_SW, and the EN_SYS features of the

MAX15015A.

MAX15015A Evaluation Kit

2 _______________________________________________________________________________________2 _______________________________________________________________________________________

DESIGNATION QTY DESCRIPTION

JU1, JU2, JU3 3 2-pin headers

L1 1 27µH, 2.8A inductor

Sumida CDRH124NP-270MC

R1, R2 2 332kΩ ±1% resistors (0603)

R3 0 Not installed, resistor (0603)

R4, R11 2 10kΩ ±5% resistors (0402)

R5 1 1Ω ±5% resistor (0603)

R6 1 2.26kΩ ±1% resistor (0603)

R7 1 4.53kΩ ±1% resistor (0603)

R8 1 133Ω ±1% resistor (0603)

R9 1 7.5kΩ ±1% resistor (0603)

R10 1 61.9kΩ ±1% resistor (0603)

R12 1 63.4kΩ ±1% resistor (0603)

TP1 1 PC mini red test point

U1 1

MAX15015AATX+

(36-pin, 6mm x 6mm x 0.8mm,

TQFN)

— 3 Shunts (JU1, JU2, JU3)

— 1 MAX15015AEVKIT+ PCB

SUPPLIER PHONE WEBSITE

Diodes Inc. 805-446-4800 www.diodes.com

Murata 770-436-1300 www.murata.com

Sumida 847-545-6700 www.sumida.com

TDK 847-803-6100 www.component.tdk.com

Vishay 203-268-6261 www.vishay.com

Component List (continued)

Component Suppliers

Note: Indicate that you are using the MAX15015A when con-

tacting these component suppliers.

The LDO regulator has a default 5V output and can be

configured for a 2.5V output after installing the shunt on

jumper JU3. An open-drain RESET output changes

from low to high whenever the LDO voltage rises to

92.5% of its regulated output. When LDO_OUT

exceeds its rising threshold voltage, RESET remains

low for the reset timeout period, and then goes high.

The RESET signal can be monitored at test point TP1

on the EV kit and is pulled up to LDO_OUT by resistor

R11. The reset timeout period is set by capacitor C8.

The MAX15015A features configurable soft-start, inde-

pendent undervoltage lockout (UVLO) for the step-

down converter and regulator, cycle-by-cycle current

limit, hiccup-mode-output short-circuit protection, and

thermal shutdown. The step-down converter UVLO is

configurable by choosing the appropriate R2 and R3

resistor values.

Jumper Selection

Enabling VOUT and LDO_OUT

The MAX15015A features input pads EN_SW and

EN_SYS that can be used to enable the VOUT and

LDO_OUT outputs. The EV kit also provides jumpers

JU1 and JU2 to configure the EN_SW and EN_SYS,

respectively. See Table 1 for jumpers JU1 and JU2

configurations.

The MAX15015A EV kit shutdown current can be evalu-

ated by removing jumper JU1.

LDO_OUT Selection

Jumper JU3 sets the linear regulator output voltage to

2.5V or 5V. See Table 2 for LDO jumper configuration.

To configure LDO_OUT to other output voltages, refer

to the

Setting the LDO Linear Regulator Output Voltage

section in the MAX15015A data sheet.

Configuring the Output Voltage (VOUT)

The MAX15015A EV kit step-down converter output

voltage is configured to 3.3V by resistors R7 and R9.

The EV kit’s output voltage (VOUT) can be reconfigured

in the range of 1.26V to 28V by replacing these resis-

tors. To select a new value for resistor R7, refer to the

Setting the Output Voltage

section in the MAX15015A

data sheet. Use the following equation to reconfigure

the output voltage to the desired value:

where VOUT is the desired output voltage in volts.

Reconfiguring the MAX15015A EV kit for a new output

voltage may require replacing inductor L1 and capaci-

tors C1 and/or C7. To select a new value for inductor L1

and capacitors C1 and C7, refer to the

Inductor

Selection, Output Capacitor Selection,

and

Input

Capacitor Selection

sections, respectively, in the

MAX15015A data sheet.

Configuring the Undervoltage

Lockout (UVLO)

The MAX15015A step-down converter and LDO regula-

tor turns on when the input voltage (VIN) is above the

MAX15015A minimum 4.1V threshold (shunts on JU1

and JU2 must be installed). The converter turn-on

threshold can be reconfigured to a desired value

greater than 4.1V by selecting resistors R2 and R3. To

reconfigure the converter’s turn-on threshold, use the

following equation:

where VEN_SW is the desired turn-on threshold in volts.

RRx

EN SW

23 15 1=⎡

⎣

⎢⎤

⎦

⎥

−

VOUT

1 244 1

=⎡

⎣

⎢⎤

⎦

⎥

−

Evaluates: MAX15015A/MAX15015B

MAX15015A Evaluation Kit

_______________________________________________________________________________________ 3

Table 1. EN_SYS and EN_SW

Configuration

EV KIT FUNCTION

JU1 SHUNT

POSITION

JU2 SHUNT

POSITION VOUT LDO_OUT

Not installed Not installed Off Off

Not installed Installed Off Off

Installed Not installed Off On

Installed Installed On On

Table 2. LDO Configuration (JU3)

JU3 SHUNT

POSITION

SET_LDO PIN

CONNECTION

LDO_OUT

OUTPUT

VOLTAGE

Not installed Connected to GND 5V

Installed Connects to feedback

resistors R10 and R12 2.5V

Linear Regulator Operation

The MAX15015A linear regulator operates in either a

preset voltage mode or an adjustable mode. In preset

voltage mode, LDO_OUT is 5V. Select the preset volt-

age mode by removing the shunt at JU3. In adjustable

mode, LDO_OUT is set to 2.5V by resistors R10 and

R12 (shunt installed at JU3). To reconfigure LDO_OUT

voltage to a different voltage (1.5V to 11V ), replace

resistors R10 and R12 with new values. Use the follow-

ing equation to select a new resistor value:

where VLDO_OUT is the desired LDO_OUT voltage.

Synchronization Input (SYNC)

The EV kit’s SYNC PCB pad can be used to synchro-

nize the MAX15015A switching frequency with an exter-

nal digital-clock signal in the range of 400kHz to

600kHz. When SYNC is driven with an external digital

clock, the MAX15015A synchronizes to the rising edge

of the external clock.

The square-wave clock source must provide the follow-

ing signal qualities:

• Logic-low = 0 to 0.8V

• Logic-high = 2.2V to 5.5V

• Input frequency = 400kHz to 600kHz. Refer to the

MAX15015A data sheet for more information on the

SYNC pin.

• Duty cycle = 50%

To use external synchronization, connect the external

square-wave clock to the SYNC and GND pads.

Compensation Network

The MAX15015A IC provides the flexibility of externally

compensating its internal error amplifier to achieve

stability for various applications. The MAX15015A is

compensated by choosing values for resistors R6–R9,

and capacitors C12, C13, and C14. To reconfigure the

compensation network for specific requirements, refer

to the

Compensation Design

section in the MAX15015A

data sheet.

Evaluating the MAX15015B

The MAX15015A EV kit board can also evaluate the

MAX15015B step-down converter. The MAX15015A IC

must be removed and replaced with the MAX15015B.

When using the MAX15015B, LDO_OUT has a 3.3V

default output (JU3 not installed).

VLDO OUT

10 12

1 244 1

=⎡

⎣

⎢⎤

⎦

⎥

−

Evaluates: MAX15015A/MAX15015B

MAX15015A Evaluation Kit

4 _______________________________________________________________________________________

Evaluates: MAX15015A/MAX15015B

_______________________________________________________________________________________ 5

GND

VIN

PGND

JU1

C10

1μF

0.033μF

C11

10μF

C13

0.033μF

C12

220pF

C14

4700pF

0.1μF

SYNC

EN_SW

EN_SYS D1

27μH

0.1μF

10kΩ

332kΩ

OPEN

SS DRAIN DRAIN

EN_SYS

EN_SW

N.C.

34 REG

0.47μF

25 DVREG

5SGND

SGND

PGND

20 21

IN_SW

PGND

C-

C+

BST

LX 17

LX 18

CT 6

SYNC

332kΩ

R11

10kΩ

R10

61.9kΩ

4.53kΩ

R12

63.4kΩ

2.26kΩ

133Ω

7.5kΩ

1Ω

MAX15015A

0.22μF

N.C.

N.C. COMP FB

35 31 32

JU2

VIN

10μF

50V

VOUT

LDO_OUT

VOUT

PGND

GND

47μF

6.3V

VIN

C15

0.1μF

RESET 4

LDO_OUT 11

IN_LDO 13

SET_LDO 10

VOUT

0.1μF

TP1

JU3

MAX15015A Evaluation Kit

_______________________________________________________________________________________ 5

Figure 1. MAX15015A EV Kit Schematic

Evaluates: MAX15015A/MAX15015B

MAX15015A Evaluation Kit

6 _______________________________________________________________________________________

Figure 2. MAX15015A EV Kit Component Placement Guide—

Component Side

Figure 3. MAX15015A EV Kit PCB Layout—Component Side

Figure 4. MAX15015A EV Kit PCB Layout—GND Layer 2 Figure 5. MAX15015A EV Kit PCB Layout—Power Layer 3

Evaluates: MAX15015A/MAX15015B

MAX15015A Evaluation Kit

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are

implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________

Figure 6. MAX15015A EV Kit PCB Layout—Solder Side