MAXM17505ALJ+T - Maxim Integrated

General Description

The Himalaya series of voltage regulator ICs and power

modules enable cooler, smaller, and simpler power supply

solutions. The MAXM17505 is an easy-to-use, step-down

power module that combines a switching power supply

controller, dual n-channel MOSFET power switches, fully

shielded inductor, and the compensation components in

a low-profile, thermally-efficient, system-in-package (SiP).

The device operates over a wide input voltage range of

4.5V to 60V and delivers up to 1.7A continuous output

current with excellent line and load regulation over an output

voltage range of 0.9V to 12V. The device only requires five

external components to complete the total power solution.

The high level of integration significantly reduces design

complexity, manufacturing risks, and offers a true plug-

and-play power supply solution, reducing time-to-market.

The device can be operated in the pulse-width modu-

lation (PWM), pulse-frequency modulation (PFM), or

discontinuous conduction mode (DCM) control schemes.

The MAXM17505 is available in a low-profile, highly

thermal-emissive, compact, 29-pin 9mm x 15mm x

2.8mm SiP package that reduces power dissipation in

the package and enhances efficiency. The package is

easily soldered onto a printed circuit board and suitable

for automated circuit board assembly. The device can

operate over the industrial temperature range from -40°C

to +125°C.

Applications

●Industrial Power Supplies

●Distributed Supply Regulation

●FPGA and DSP Point-of-Load Regulator

●Base Station Point-of-Load Regulator

●HVAC and Building Control

Benets and Features

●Reduces Design Complexity, Manufacturing Risks,

and Time-to-Market

• Integrated Switching Power Supply Controller and

Dual-MOSFET Power Switches

• Integrated Inductor

• Integrated Compensation Components

• Integrated Thermal-Fault Protection

• Integrated Peak Current Limit

●Saves Board Space in Space-Constrained

Applications

• Complete Integrated Step-Down Power Supply in a

Single Package

• Small Prole 9mm x 15mm x 2.8mm SiP Package

• Simplied PCB Design with Minimal External BOM

Components

●Offers Flexibility for Power-Design Optimization

• Wide Input Voltage Range from 4.5V to 60V

• Output-Voltage Adjustable Range from 0.9V to 12V

• Adjustable Frequency with External Frequency

Synchronization (100kHz to 1.8MHz)

• Soft-Start Programmable

• Autoswitch PWM, PFM, or DCM Current-Mode

Control

• Optional Programmable EN/UVLO

Ordering Information appears at end of data sheet.

19-7443; Rev 2; 11/16

4.5V TO 60V

SGND PGND PGND

OUT

SYNC

MAXM17505

OUT

OPTIONAL

3.3V, 3.5A

OUT

EP3

RESET

EN MODE RT

EP1

MAXM17505 4.5V to 60V, 1.7A High-Efciency, DC-DC Step-

Down Power Module with Integrated Inductor

Typical Application Circuit

EVALUATION KIT AVAILABLE

IN to PGND (Note 2) .............................................-0.3V to +65V

EN to SGND (Note 2) ............................................ -0.3V to +65V

VCC .............................................-0.3V to min (VIN + 0.3V, 6.5V)

FB, RESET, SS, CF, MODE,

SYNC, RT to SGND .........................................-0.3V to +6.5V

OUT to PGND (VIN < 25V) .........................-0.3V to (VIN + 0.3V)

OUT to PGND (VIN ≥ 25V) .................................... -0.3V to +25V

LX to PGND................................................-0.3V to (VIN + 0.3V)

BST to PGND ........................................................-0.3V to +70V

BST to VCC ...........................................................-0.3V to +65V

BST to LX .............................................................-0.3V to +6.5V

Operating Temperature Range ......................... -40°C to +125°C

Junction Temperature ...................................................... +125°C

Storage Temperature Range ............................ -65°C to +125°C

Lead Temperature (soldering, 10s) .................................+245°C

Junction-to-Ambient Thermal Resistance (θJA) ...........30.8°C/W

Electrical Characteristics

(VIN = VEN = 24V, RRT = 40.2kΩ (500kHz) to SGND, VPGND = VMODE = VSYNC = VSGND = 0V, VCC = LX = SS = RESET = OUT = open,

VBST to VLX = 5V, VFB = 1V, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages are

referenced to SGND, unless otherwise noted.) (Note 4)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

INPUT SUPPLY (VIN)

IN Input Voltage Range VIN 4.5 60 V

Input Shutdown Current IIN_SH VEN = 0V 10.5 13 μA

Input Quiescent Current

IQ_PFM_HIB MODE = RT = open 125 μA

IQ_DCM MODE = VCC 1.16 1.8 mA

IQ_PWM Normal switching mode, no load 9.5 mA

LOGIC INPUTS

EN Threshold VENR VEN rising 1.192 1.215 1.26 V

VENF VEN falling 1.068 1.09 1.131 V

Enable Pullup Resistor RENP Pullup resistor between IN and EN pins 3.15 3.3 3.45 MΩ

LDO

VCC Output Voltage Range VCC 6V < VIN < 60V, 1mA < IVCC < 25mA 4.75 5 5.25 V

VCC Current Limit IVCC_MAX VIN = 6V, VCC = 4.3V 26.5 60 100 mA

VCC Dropout VCC_DO VIN = 4.5V, IVCC = 20mA 4.2 V

VCC UVLO VCC_UVR VCC rising 4.05 4.2 4.3 V

VCC_UVF VCC falling 3.65 3.8 3.9

OUTPUT SPECIFICATIONS

Line Regulation Accuracy VIN = 6.5V to 60V, VOUT = 5V 0.1 mV/V

Load Regulation Accuracy Tested with IOUT = 0A and 1A 1 mV/A

MAXM17505 4.5V to 60V, 1.7A High-Efciency, DC-DC Step-

Down Power Module with Integrated Inductor

www.maximintegrated.com Maxim Integrated

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Note 1: SGND and PGND are internally connected.

Note 2: See Pin Description for the connection of the backside exposed pad.

Note 3: Data taken using Maxim's evaluation kit, MAXM17505EVKIT#.

Absolute Maximum Ratings (Notes 1, 2)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these

or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect

device reliability.

Package Thermal Characteristics (Note 3)

Electrical Characteristics (continued)

(VIN = VEN = 24V, RRT = 40.2kΩ (500kHz) to SGND, VPGND = VMODE = VSYNC = VSGND = 0V, VCC = LX = SS = RESET = OUT =

open, VBST to VLX = 5V, VFB = 1V, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages

are referenced to SGND, unless otherwise noted.) (Note 4)

Note 4: All limits are 100% tested at TA = +25°C. Maximum and minimum limits are guaranteed by design and characterized over

temperature.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

FB Regulation Voltage VFB_REG

MODE = SGND 0.887 0.910 V

MODE = open 0.890 0.915 0.936

FB Input Bias Current IFB 0V < VFB < 1V, TA = +25°C -50 +50 nA

FB Undervoltage Trip Level to

Cause Hiccup VFB_HICF 0.56 0.58 0.65 V

Hiccup Timeout 32,768 Cycles

SOFT-START (SS)

Charging Current ISS VSS = 0.5V 4.7 55.3 μA

RT AND SYNC

Switching Frequency fSW

RRT = 210kΩ 90 100 110

kHzRRT = 9.76kΩ 1800

RRT = open 450 500 550

SYNC Frequency Range 1.1 x

fSW

1.4 x

fSW kHz

SYNC Pulse Width 50 ns

SYNC Threshold VIH 2.1 V

VIL 0.8

MODE

MODE Threshold

VM_DCM MODE = VCC (DCM mode) VCC - 1.6

VVM_PFM MODE = open (PFM mode) VCC/2

VM_PWM MODE = GND (PWM mode) 1.4

CURRENT LIMIT

Average Current-Limit Threshold IAVG_LIMIT VOUT = VFB = 0.8V, fSW = 200kHz 2.4 A

RESET

RESET Output Level Low IRESET = 10mA 0.4 V

RESET Output Leakage Current VRESET = 5.5V, TA = TJ = +25°C -0.1 +0.1 µA

FB Threshold for RESET

Assertion VFB_OKF VFB falling 90.5 92 94.6 %

FB Threshold for RESET

Deassertion VFB_OKR VFB rising 93.8 95 97.8 %

RESET Deassertion Delay After

FB Reaches 95% Regulation 1024 Cycles

THERMAL SHUTDOWN

Thermal-Shutdown Threshold Temperature rising +165 °C

Thermal-Shutdown Hysteresis 10 °C

MAXM17505 4.5V to 60V, 1.7A High-Efciency, DC-DC Step-

Down Power Module with Integrated Inductor

www.maximintegrated.com Maxim Integrated

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(VIN = 4.5V to 60V, VOUT = 0.9V to 12V, IOUT = 0A to 1.7A, TA = +25°C, unless otherwise noted.)

100

0 500 1000 1500

EFFICIENCY (%)

OUTPUT CURRENT (mA)

EFFICIENCYvs. OUTPUT CURRENT

VOUT = 5V, PWM MODE

toc04

MODE = SGND

VIN =12V,

fSW = 500kHz

VIN =24V,

fSW = 500kHz

VIN =36V,

fSW = 500kHz

VIN =48V,

fSW = 500kHz

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0 500 1000 1500

EFFICIENCY (%)

OUTPUT CURRENT (mA)

EFFICIENCYvs. OUTPUT CURRENT

VOUT = 12V, PFM MODE

toc01

MODE = OPEN

VIN = 24V,

fSW = 1.2MHz

VIN = 36V,

= 1.2MHz

VIN = 48V,

= 1.2MHz

fSW fSW

100

0 500 1000 1500

EFFICIENCY (%)

OUTPUT CURRENT (mA)

EFFICIENCYvs. OUTPUT CURRENT

VOUT = 2.5V, PFM MODE

toc07

MODE = OPEN

VIN = 5V,

fSW = 350kHz

VIN =12V,

fSW = 350kHz

VIN = 24V,

fSW = 350kHz

VIN =36V,

fSW = 350kHz

VIN =48V,

fSW

= 277kHz

100

0 500 1000 1500

EFFICIENCY (%)

OUTPUT CURRENT (mA)

EFFICIENCYvs. OUTPUT CURRENT

VOUT = 12V, PWM MODE

toc02

MODE = SGND

VIN =24V,

fSW = 1.2MHz VIN = 36V,

fSW = 1.2MHz

VIN = 48V,

fSW = 1.2MHz

100

0 500 1000 1500

EFFICIENCY (%)

OUTPUT CURRENT (mA)

EFFICIENCYvs. OUTPUT CURRENT

VOUT = 5V, PFM MODE

toc03

MODE=OPEN

VIN = 12V,

fSW = 500kHz

VIN =24V,

fSW = 500kHz

VIN =36V,

fSW = 500kHz

VIN =48V,

fSW = 500kHz

100

0 500 1000 1500

EFFICIENCY (%)

OUTPUT CURRENT (mA)

EFFICIENCYvs. OUTPUT CURRENT

VOUT = 2.5V, PWM MODE

toc08

MODE = SGND

VIN =5V,

fSW = 350kHz

VIN =12V,

fSW = 350kHz

VIN =24V,

fSW = 350kHz

VIN =36V,

fSW = 350kHz

VIN =48V,

fSW = 277kHz

100

0 500 1000 1500

EFFICIENCY (%)

OUTPUT CURRENT (mA)

EFFICIENCYvs. OUTPUT CURRENT

VOUT = 3.3V, PFM MODE

toc05

MODE = OPEN

VIN =12V,

fSW = 400kHz

VIN =24V,

fSW =400kHz

VIN =36V,

fSW =400kHz

VIN =48V,

fSW =360kHz

100

0 500 1000 1500

EFFICIENCY (%)

OUTPUT CURRENT (mA)

EFFICIENCYvs. OUTPUT CURRENT

VOUT = 3.3V, PWM MODE

toc06

MODE = SGND

VIN =12V,

fSW = 400kHz

VIN =24V,

fSW =400kHz

VIN =36V,

fSW =400kHz

VIN =48V,

fSW =360kHz

Maxim Integrated

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MAXM17505 4.5V to 60V, 1.7A High-Efciency, DC-DC Step-

Down Power Module with Integrated Inductor

Typical Operating Characteristics

(VIN = 4.5V to 60V, VOUT = 0.9V to 12V, IOUT = 0A to 1.7A, TA = +25°C, unless otherwise noted.)

100

0 500 1000 1500

EFFICIENCY (%)

OUTPUT CURRENT (mA)

EFFICIENCYvs. OUTPUT CURRENT

VOUT = 0.9V, PWM MODE

toc12

MODE = SGND

VIN = 5V,

fSW = 300kHz

VIN =12V,

fSW = 300kHz

VIN = 24V,

fSW = 200kHz

100

0 500 1000 1500

EFFICIENCY (%)

OUTPUT CURRENT (mA)

EFFICIENCYvs. OUTPUT CURRENT

VOUT = 1.2V, PFM MODE

toc09

VIN =5V,

fSW =350kHz

VIN =12V,

fSW = 350kHz

VIN =24V,

fSW = 285kHz

VIN =36V,

fSW = 200kHz

MODE = OPEN

4.5

4.6

4.7

4.8

4.9

5.1

5.2

5.3

5.4

5.5

0 500 1000 1500

VOUT (V)

OUTPUT CURRENT (mA)

LOAD REGULATION

VOUT = 5V, PFM MODE

toc15

MODE = OPEN

VIN =24V,

fSW = 500kHz

VIN =12V,

fSW = 500kHz

VIN =48V,

fSW = 500kHz

VIN =36V,

fSW = 500kHz

100

0 500 1000 1500

EFFICIENCY (%)

OUTPUT CURRENT (mA)

EFFICIENCYvs. OUTPUT CURRENT

VOUT = 1.2V, PWM MODE

toc10

VIN =5V,

fSW = 350kHz

VIN =12V,

fSW = 350kHz

VIN =24V,

fSW = 285kHz

VIN =36V,

fSW = 200kHz

MODE = SGND

100

0 500 1000 1500

EFFICIENCY (%)

OUTPUT CURRENT (mA)

EFFICIENCYvs. OUTPUT CURRENT

VOUT = 0.9V, PFM MODE

toc11

MODE = OPEN

VIN = 5V,

fSW = 300kHz

VIN = 12V,

fSW = 300kHz

VIN = 24V,

fSW = 200kHz

4.5

4.6

4.7

4.8

4.9

5.1

5.2

5.3

5.4

5.5

0 500 1000 1500

VOUT (V)

OUTPUT CURRENT (mA)

LOAD REGULATION

VOUT = 5V, PWM MODE

toc16

MODE = SGND

VIN =12V,

fSW =500kHz

VIN =24V,

fSW =500kHz

VIN =36V,

fSW =500kHz

VIN =48V,

fSW =500kHz

3.000

3.100

3.200

3.300

3.400

3.500

3.600

0 500 1000 1500

VOUT (V)

OUTPUT CURRENT (mA)

LOAD REGULATION

VOUT = 3.3V, PFM MODE

toc13

MODE = OPEN

VIN = 5.0V

fSW =400kHz VIN = 12V

fSW =400kHz

VIN = 24V

fSW =400kHz

VIN = 48V

fSW =360kHz

VIN = 36V

fSW =400kHz

3.0000

3.1000

3.2000

3.3000

3.4000

3.5000

3.6000

0 500 1000 1500

VOUT (V)

OUTPUT CURRENT (mA)

LOAD REGULATION

VOUT = 3.3V, PWM MODE

toc14

MODE = SGND

VIN = 5.0V

fSW =400kHz

VIN = 12V

fSW =400kHz

VIN = 24V

fSW =400kHz VIN = 48V

fSW =360kHz

VIN = 36V

fSW =400kHz

Maxim Integrated

│

www.maximintegrated.com

MAXM17505 4.5V to 60V, 1.7A High-Efciency, DC-DC Step-

Down Power Module with Integrated Inductor

Typical Operating Characteristics (continued)

(VIN = 4.5V to 60V, VOUT = 0.9V to 12V, IOUT = 0A to 1.7A, TA = +25°C, unless otherwise noted.)

OUTPUT VOLTAGE RIPPLE

VIN =24V, VOUT = 5V, IOUT = 1.7A, MODE = SGND

20mV/div

(AC-

COUPLED)

toc20

2µs/div

VOUT

LOAD CURRENT TRANSIENT RESPONSE

VIN =24V, VOUT = 3.3V, IOUT = 0.05A - 0.85A,

MODE = OPEN

1A/div

toc23

200µs/div

VOUT

IOUT

100mV/div

(AC

COUPLED)

11.000

11.200

11.400

11.600

11.800

12.000

12.200

12.400

12.600

12.800

13.000

0 500 1000 1500

OUT

(V)

OUTPUT CURRENT (mA)

LOAD REGULATION

VOUT =12V, PFM MODE

toc17

MODE = OPEN

VIN =24V,

fSW = 1.2MHz

VIN =36V,

fSW = 1.2MHz

VIN =48V,

fSW = 1.2MHz

11.2

11.4

11.6

11.8

12.2

12.4

12.6

12.8

0 500 1000 1500

VOUT (V)

OUTPUT CURRENT (mA)

LOAD REGULATION

VOUT =12V, PWM MODE

toc18

MODE = SGND

VIN =24V,

fSW = 1.2MHz

VIN =36V,

fSW = 1.2MHz

VIN =48V,

fSW = 1.2MHz

OUTPUT VOLTAGE RIPPLE

VIN =24V, VOUT = 3.3V, IOUT = 1.7A, MODE = SGND

20mV/div

(AC-

COUPLED)

toc19

2us/div

VOUT

INPUT VOLTAGE RIPPLE

VIN =24V, VOUT = 3.3V, IOUT = 1.7A, MODE = SGND

200mV/div

(AC-

COUPLED)

toc21

2µs/div

VIN

INPUT VOLTAGE RIPPLE

VIN = 24V, VOUT = 5V, IOUT = 1.7A, MODE = SGND

200mV/div

(AC-

COUPLED)

toc22

2µs/div

VIN

LOAD CURRENT TRANSIENT RESPONSE

VIN =24V, VOUT = 3.3V, IOUT = 0.05A - 0.85A,

MODE = SGND

1A/div

toc24

200µs/div

VOUT

IOUT

100mV/div

(AC

COUPLED)

Maxim Integrated

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MAXM17505 4.5V to 60V, 1.7A High-Efciency, DC-DC Step-

Down Power Module with Integrated Inductor

Typical Operating Characteristics (continued)

(VIN = 4.5V to 60V, VOUT = 0.9V to 12V, IOUT = 0A to 1.7A, TA = +25°C, unless otherwise noted.)

LOAD CURRENT TRANSIENT RESPONSE

VIN =24V, VOUT = 3.3V, IOUT = 0.05A - 0.85A,

MODE = VCC

1A/div

toc25

200µs/div

IOUT

VOUT

100mV/div

(AC

COUPLED)

LOAD CURRENT TRANSIENT RESPONSE

VIN =24V, VOUT = 5V, IOUT = 0.05A - 0.85A,

MODE = OPEN

1A/div

toc26

200µs/div

IOUT

VOUT

100mV/div

(AC

COUPLED)

LOAD CURRENT TRANSIENT RESPONSE

VIN =24V, VOUT = 5V, IOUT = 0.05A - 0.85A,

MODE = SGND

1A/div

toc27

100µs/div

IOUT

VOUT

100mV/div

(AC

COUPLED)

LOAD CURRENT TRANSIENT RESPONSE

VIN =24V, VOUT = 5V, IOUT = 0.05A - 0.85A,

MODE = VCC

1A/div

toc28

100µs/div

IOUT

VOUT

100mV/div

(AC

COUPLED)

STARTUP THROUGH ENABLE

VIN = 24V, VOUT = 3.3V, IOUT = 0A, MODE = SGND

2V/div

toc29

1ms/div

VOUT

5V/div

RESET

20V/div

5V/div

STARTUP WITH 2.5V PREBIAS

VIN = 24V, VOUT = 3.3V, IOUT = 0A, MODE = SGND

2V/div

toc30

1ms/div

VOUT

5V/div

RESET

20V/div

5V/div

STARTUP WITH 2.5V PREBIAS

VIN = 24V, VOUT = 3.3V, IOUT = 0A, MODE = OPEN

2V/div

toc31

1ms/div

VOUT

5V/div

RESET

20V/div

5V/div

SHUTDOWN THROUGH ENABLE

VIN = 24V, VOUT = 3.3V, IOUT = 0A, MODE = SGND

2V/div

toc32

1ms/div

VOUT

5V/div

RESET

20V/div

5V/div

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MAXM17505 4.5V to 60V, 1.7A High-Efciency, DC-DC Step-

Down Power Module with Integrated Inductor

Typical Operating Characteristics (continued)

(VIN = 4.5V to 60V, VOUT = 0.9V to 12V, IOUT = 0A to 1.7A, TA = +25°C, unless otherwise noted.)

STARTUP THROUGH INPUT SUPPLY

VIN =24V, VOUT = 3.3V, IOUT = 1.7A, MODE = SGND

2V/div

toc33

1ms/div

VOUT 5V/div

VIN

RESET

20V/div

10V/div

STARTUP THROUGH ENABLE

VIN = 24V, VOUT = 5V, IOUT = 0A, MODE = SGND

2V/div

toc35

1ms/div

VOUT

5V/div

RESET

20V/div

5V/div

STARTUP THROUGH INPUT SUPPLY

VIN =24V, VOUT = 5V, IOUT = 1.7A, MODE = SGND

2V/div

toc37

1ms/div

VOUT

5V/div

VIN

RESET

20V/div

10V/div

SHUTDOWN THROUGH INPUT SUPPLY

VIN =24V, VOUT = 3.3V, IOUT = 1.7A, MODE = SGND

2V/div

toc34

100µs/div

VOUT

5V/div

VIN

RESET

20V/div

SHUTDOWN THROUGH ENABLE

VIN = 24V, VOUT = 5V, IOUT = 0A, MODE = SGND

2V/div

toc36

1ms/div

VOUT

5V/div

RESET

20V/div

5V/div

SHUTDOWN THROUGH INPUT SUPPLY

VIN =24V, VOUT = 5V, IOUT = 1.7A, MODE = SGND

2V/div

toc38

100µs/div

VOUT

5V/div

VIN

RESET

20V/div

Maxim Integrated

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MAXM17505 4.5V to 60V, 1.7A High-Efciency, DC-DC Step-

Down Power Module with Integrated Inductor

Typical Operating Characteristics (continued)

(VIN = 4.5V to 60V, VOUT = 0.9V to 12V, IOUT = 0A to 1.7A, TA = +25°C, unless otherwise noted.)

OUTPUT SHORT IN STEADY STATE

VIN = 24V, VOUT = 3.3V, IOUT = 0A to SHORT

MODE = SGND

2V/div

toc39

40ms/div

VOUT

10A/div

VIN

IOUT

20V/div

SYNC FREQUENCY AT 740 KHZ

VIN = 24V, VOUT = 5V, IOUT = 0A, MODE = GND

2V/div

toc41

2µs/div

VOUT

SYNC

20V/div

5V/div

OUTPUT SHORT DURING STARTUP

VIN = 24V, VOUT = 3.3V, IOUT = SHORT, MODE = SGND

2V/div

toc40

40ms/div

VOUT

10A/div

VIN

IOUT

20V/div

-150

-120

-90

-60

-30

120

150

1k 10k 100k 1Meg

-50

-40

-30

-20

-10

PHASE MARGIN (°)

GAIN (dB)

FREQUENCY (Hz)

CLOSED-LOOP BODE PLOT

VIN = 24V, VOUT = 3.3V, IOUT = 1.7A, MODE = SGND

GAIN

toc42

PHASE

0.5

1.5

2.5

0 10 20 30 40 50 60 70 80 90 100 110 120

OUTOPUT CURRENT (A)

AMBIENT TEMPERATURE (°C)

OUTPUT CURRENT

VS. AMBIENT TEMPERATURE

VIN =24V NO AIR FLOW toc43

VOUT = 3.3V

VOUT = 5V

VOUT =12V

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MAXM17505 4.5V to 60V, 1.7A High-Efciency, DC-DC Step-

Down Power Module with Integrated Inductor

Typical Operating Characteristics (continued)

OUTV

MODE

SYNC

PGND

EP2

RESET EN BSTPGNDIN LXLX

OUT OUT OUT

OUT

2829 21

23 222425

10987 14 15

1312

EP3

SGND

N.C.

EP1

MAXM17505 4.5V to 60V, 1.7A High-Efciency, DC-DC Step-

Down Power Module with Integrated Inductor

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Pin Conguration

PIN NAME FUNCTION

1, 7 N.C. No Connection

2 SYNC Frequency Synchronization. The device can be synchronized to an external clock using this pin.

See the External Frequency Synchronization section for more details.

3 SS Soft-Start Input. Connect a capacitor from SS to SGND to set the soft-start.

4 CF Compensation Filter. Connect capacitor from CF to FB to correct frequency with switching

frequency below 500kHz. Leave CF open otherwise.

5 FB Feedback Input. Connect FB to the center tap of an external resistor-divider from the OUT to

SGND to set the output voltage. See the Adjusting Output Voltage section for more details.

6RT Frequency Set. Connect a resistor from RT to SGND to set the regulator’s switching frequency.

Leave RT open for the default 500kHz frequency.

8 MODE

Light-Load Mode Selection. The MODE pin congures the MAXM17505 to operate in PWM, PFM,

or DCM mode of operation. Leave MODE unconnected for PFM operation (pulse skipping at light

loads). Connect MODE to SGND for constant-frequency PWM operation at all loads. Connect

MODE to VCC for DCM operation. See the MODE Setting section for more details.

9 VCC 5V LDO Output. No external connection.

10 SGND Analog Ground. Internally-shorted to PGND. Connect it to PGND through a single point at output

capacitor.

11, 26 PGND Power Ground. Connect the PGND pins externally to the power ground plane.

12–18 OUT Regulator Output Pin. Connect a capacitor from OUT to PGND. See the PCB Layout Guidelines

section for more connection details.

19–24 LX Internally Connected to EP2. Do not connect these pins to external components for any reason.

25 BST Boost Flying Cap Node. No external connection.

27 IN Input Supply Connection. Bypass to PGND with a capacitor; place the capacitor close to the IN

and PGND pins. See Table 1 for more details.

28 EN

Enable/Undervoltage-Lockout Input. Default enable through the pullup 3.3MΩ resistor between

EN and IN. Connect a resistor from EN to SGND to set the UVLO threshold. If the EN/UVLO pin

is driven by an external signal, a 50Ω damping resistor in series with the signal line driving EN/

UVLO is required.

29 RESET Open-Drain RESET Output. The RESET output is driven low if FB drops below 92% of its set

value. RESET goes high 1024 clock cycles after FB rises above 95% of its set value.

EP1 SGND Analog Ground. Connect this pad to 1in x 1in copper island with a lot of vias for cooling.

EP2 LX Switching Node. Connect this pad to a small copper area of 1in x 1in under the device for thermal

relief.

EP3 OUT Connect this pad to the OUT pins and copper area of 1in x 1in.

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Pin Description

HICCUP

10µH

0.47µF

4.7µF

2.2µF

PEAK

CURRENT-MODE

CONTROLLER

OSCILLATOR

MAXM17505

MODE

SELECTION

LOGIC

RESET

LOGIC

LDO

SGND

SYNC

PGND

RESET

MODE

1.215V

0.1µF

BST

OUT

3.3MΩ

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Functional Diagram

Design Procedure

Setting the Output Voltage

The MAXM17505 supports an adjustable output

voltage range of 0.9V to 12V from an input voltage range

of 4.5V to 60V by using a resistive feedback divider from

OUT to FB. Table 1 provides the feedback dividers for

desired input and output voltages. Other adjustable output

voltages can be calculated by following the procedure to

choose the resistive voltage-divider values:

Calculate resistor RU from the output to FB as follows:

C OUT

216 1000

RfC

=×

where RU is in kΩ, crossover frequency (fC) is in kHz, and

output capacitor (COUT) is in μF. Choose fC to be 1/9th of

the switching frequency (fSW) if the switching frequency

is less than or equal to 500kHz. If the switching frequency

is more than 500kHz, select fC to be 55kHz.

OUT

R 0.9

R k , whereR is in k .

V 0.9

=ΩΩ

−

Input Voltage Range

Due to the limitation of minimum and maximum duty

cycle, the maximum value (VIN (MAX)) and minimum

value (VIN (MIN)) must accommodate the worst-case

conditions, accounting for the input voltage rises and

drops. To simplify, Table 1 provides operating input

voltage ranges of different desired output voltages.

Input Capacitor Selection

The input capacitor serves to reduce the current peaks

drawn from the input power supply and reduces switching

noise to the IC. The input capacitor values in Table 1 are

the minimum recommended values for desired input and

output voltages. Applying capacitor values larger than

those indicated in Table 1 are acceptable to improve the

dynamic response. For further operating conditions, the

total input capacitance must be greater than or equal to

the value given by the following equation in order to keep

the input-voltage ripple within specifications and minimize

the high-frequency ripple current being fed back to the

input source:

IN_AVG

I (1 D)

CV f

× −

=∆

where:

IIN_AVG is the average input current given by:

OUT

IN_AVG

=η×

D is the operating duty cycle, which is approximately

equal to VOUT/VIN.

∆VIN is the required input voltage ripple.

fSW is the operating switching frequency.

POUT is the out power, which is equal to VOUT x IOUT.

η is the efficiency.

The input capacitor must meet the ripple-current require-

ment imposed by the switching currents. The RMS input

ripple current is given by:

RMS OUT

I I D (1 D)= × ×−

The worst-case RMS current requirement occurs when

operating with D = 0.5. At this point, the above equation

simplifies to IRMS = 0.5 x IOUT.

For the MAXM17505 system (IN) supply, ceramic capaci-

tors are preferred due to their resilience to inrush

surge currents typical of systems, and due to their low

parasitic inductance that helps reduce the high-frequency

ringing on the IN supply when the internal MOSFETs are

turned off. Choose an input capacitor that exhibits less

than +10°C temperature rise at the RMS input current for

optimal circuit longevity.

Figure 1. Adjustable Output Voltage

OUT

MAXM17505

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Table 1. Selection Component Values

VIN (V) VOUT (V) CIN COUT RU (kΩ) RB (kΩ) fSW (kHz) RT (kΩ)

4.5 to 15 0.9 3 x 2.2µF 1206 100V 2 x 100µF 1210 4V 35.7 Open 300 68.1

4.5 to 15 1 3 x 2.2µF 1206 100V 2 x 100µF 1210 4V 39.2 357 300 68.1

4.5 to 15 1.2 3 x 2.2µF 1206 100V 1 x 100µF 1 x 47µF 1210 4V 47.5 143 350 57.6

4.5 to 15 1.5 3 x 2.2µF 1206 100V 1 x 100µF 1210 4V 59 88.7 350 57.6

4.5 to 15 1.8 3 x 2.2µF 1206 100V 1 x 100µF 1210 4V 69.8 69.8 350 57.6

4.5 to 15 2.5 3 x 2.2µF 1206 100V 1 x 100µF 1210 4V 97.6 54.9 350 57.6

4.5 to 15 3.3 2 x 2.2µF 1206 100V 1 x 47µF 1210 10V 127 47.5 400 49.9

6.5 to 15 5 2 x 2.2µF 1206 100V 1 x 47µF 1210 10V 196 43.2 500 Open

11 to 15 8 2 x 2.2µF 1206 100V 1 x 10µF 1210 16V 309 39.2 800 23.7

4.5 to 28 0.9 3 x 2.2µF 1206 100V 3 x 100µF 1210 4V 35.7 Open 200 100

4.5 to 28 1 3 x 2.2µF 1206 100V 2 x 100µF 1 x 47µF 1210 4V 39.2 357 238 86.6

4.5 to 28 1.2 3 x 2.2µF 1206 100V 1 x 100µF 1 x 47µF 1210 4V 47.5 143 285 71.5

4.5 to 28 1.5 3 x 2.2µF 1206 100V 1 x 100µF 1210 4V 59 88.7 350 57.6

4.5 to 28 1.8 3 x 2.2µF 1206 100V 1 x 100µF 1210 4V 69.8 69.8 350 57.6

4.5 to 28 2.5 3 x 2.2µF 1206 100V 1 x 100µF 1210 4V 97.6 54.9 350 57.6

4.5 to 283.3 2 x 2.2µF 1206 100V 1 x 47µF 1210 10V 127 47.5 400 49.9

6.5 to 28 5 2 x 2.2µF 1206 100V 1 x 47µF 1210 10V 196 43.2 500 Open

11 to 28 8 2 x 2.2µF 1206 100V 1 x 10µF 1210 16V 309 39.2 800 23.7

18.5 to 28 12 2 x 2.2µF 1206 100V 1 x 10µF 1210 16V 475 38.3 1200 15.8

4.5 to 40 1.2 3 x 2.2µF 1206 100V 2 x 100µF 1210 4V 47.5 143 200 100

4.5 to 40 1.5 3 x 2.2µF 1206 100V 1 x 100µF 1 x 47µF 1210 4V 59 88.7 250 82.5

4.5 to 40 1.8 3 x 2.2µF 1206 100V 1 x 100µF 1210 4V 69.8 69.8 300 68.1

4.5 to 40 2.5 3 x 2.2µF 1206 100V 1 x 100µF 1210 4V 97.6 54.9 350 57.6

4.5 to 40 3.3 2 x 2.2µF 1206 100V 1 x 47µF 1210 10V 127 47.5 400 49.9

6.5 to 40 5 2 x 2.2µF 1206 100V 1 x 47µF 1210 10V 196 43.2 500 Open

11 to 40 8 2 x 2.2µF 1206 100V 1 x 10µF 1210 16V 309 39.2 800 23.7

18.5 to 40 12 2 x 2.2µF 1206 100V 1 x 10µF 1210 16V 475 38.3 1200 15.8

4.5 to 60 1.8 3 x 2.2µF 1206 100V 2 x 100µF 1210 4V 69.8 69.8 200 100.0

6 to 60 2.5 3 x 2.2µF 1206 100V 1 x 100µF 1210 4V 97.6 54.9 277 73.2

8 to 60 3.3 3 x 2.2µF 1206 100V 2 x 47µF 1210 10V 127 47.5 366 54.9

11 to 60 5 2 x 2.2µF 1206 100V 1 x 47µF 1210 10V 196 43.2 500 Open

17 to 60 8 2 x 2.2µF 1206 100V 1 x 10µF 1210 16V 309 39.2 888 21.5

25 to 60 12 2 x 2.2µF 1206 100V 1 x 10µF 1210 16V 475 38.3 1200 15.8

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Output Capacitor Selection

The X7R ceramic output capacitors are preferred due to

their stability over temperature in industrial applications.

The minimum recommended output capacitor values

in Table 1 are for desired output voltages to support

a dynamic step load of 50% of the maximum output

current in the application. For additional adjustable output

voltages, the output capacitance value is derived from the

following equation:

STEP RESPONSE

OUT

C2V

=×∆

0.33

RESPONSE f

≈+

where ISTEP is the step load transient, tRESPONSE is the

response time of the controller, ∆VOUT is the allowable

output ripple voltage during load transient, fC is the target

closed-loop crossover frequency, and fSW is the switching

frequency. Select fC to be 1/9th of fSW or 55kHz if the fSW

is greater than 500kHz.

Loop Compensation

The MAXM17505 integrates the internal compensation

to stabilize the control loop. Only the device requires

a combination of output capacitors and feedback

resistors to program the closed-loop crossover frequency

(fC) at 1/9th of switching frequency. Use Table 1 to select

component values to compensate with appropriate

operating switching frequency. Connect a 0402 ceramic

capacitor from CF to FB to correct frequency response

with switching frequency below 500kHz. Place a 2.2pF

capacitor for switching frequency below 300kHz, 1.2pF for

switching frequency range of 300kHz to 400kHz.

Setting the Switching Frequency (RT)

The switching frequency range of 100kHz to 1.8MHz are

recommended from Table 1 for desired input and output

voltages. The switching frequency of MAXM17505 can be

programmed by using a single resistor (RRT) connected

from the RT pin to SGND. The calculation of RRT resistor

is given by the following equation:

21000

R 1.7

≈−

where RRT is in kΩ and fSW is in kHz. Leaving the RT

pin open to operate at the default switching frequency of

500kHz.

Soft-Start Capacitor Selection

The device implements an adjustable soft-start operation

to reduce inrush current during startup. A capacitor (CSS)

connected from the SS pin to SGND to program the

soft-start time.

The selected output capacitance (CSEL) and the output

voltage (VOUT) determine the minimum value of CSS, as

shown by the following equation:

SS SEL OUT

C 28 10 C V

−

≥× × ×

where CSS is in nF and CSEL is in µF.

The value of the soft-start capacitor is calculated from the

desired soft-start time as follows:

≈SS

5.55

where tSS is in ms and CSS is in nF.

Detailed Description

The MAXM17505 is a complete step-down DC-DC power

supply that delivers up to 1.7A output current. The device

provides a programmable output voltage to regulate up

to 12V through external resistor dividers from an input

voltage range of 4.5V to 60V. The recommended input

voltage in Table 1 is selected highly enough to support

the desired output voltage and load current. The device

includes an adjustable frequency feature range from

100kHz to 1.8MHz to reduce sizes of input and output

capacitors. The Functional Diagram shows a complete

internal block diagram of the MAXM17505 power module.

Input Undervoltage-Lockout Level

The MAXM17505 contains an internal pullup resistor

(3.3MΩ) from EN to IN to have a default startup voltage.

The device offers an adjustable input undervoltage-

lockout level to set the voltage at which the device is

turned on by a single resistor connecting from EN/UVLO

to SGND as equation:

ENU

INU

3.3 1215

R(V 1.215)

≈−

where RENU is in kΩ and VINU is the voltage at which

the device is required to turn on the device. Ensure that

VINU is high enough to support the VOUT. See Table 1

to set the proper VINU voltage greater than or equal the

minimum input voltage for each desired output voltage.

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Mode Selection (MODE)

The MAXM17505 features a MODE pin to configure the

device operating in PWM, PFM, or DCM control schemes.

The device operates in PFM mode at light loads if the

MODE pin is open. If the MODE pin connects to ground,

the device operates in constant-frequency PWM mode at

all loads. The device operates in constant-frequency DCM

mode at light loads when the MODE pin connects to VCC.

State changes of the MODE operation are only at power-

up and ignore during normal operation.

PWM Mode Operation

In PWM mode, the step-down controller is switching

a constant-frequency at all loads with a minimum sink

current limit threshold (-1.8A, typ) at light load. The

PWM mode of operation gives lower efficiency at light

loads compared to PFM and DCM modes of operation.

However, the PWM mode of operation is useful in applica-

tions sensitive to switching frequency.

PFM Mode Operation

In PFM mode, the controller forces the peak inductor

current in order to feed the light loads and maintain high

efficiency. If the load is lighter than the average PFM

value, the output voltage will exceed 102.3% of the feed-

back threshold and the controller enters into a hibernation

mode, turning off most of the internal blocks. The device

exits hibernation mode, and starts switching again, once

the output voltage is discharged to 101.1% of the feed-

back threshold. The device then begins the process of

delivering pulses of energy to the output repeatedly until it

reaches 102.3% of the feedback threshold. In this mode,

the behavior resembles PWM operation (with occasional

pulse-skipping), where the inductor current does not need

to reach the light-load level.

PFM mode offers the advantage of increased efficiency

at light loads due to a lower quiescent current drawn from

the supply. However, the output-voltage ripple is also

increased as compared to the PWM or DCM modes of

operation, and the switching frequency is not constant at

light loads.

DCM Mode Operation

DCM mode features constant frequency operation down

to lighter loads than PFM mode, accomplished by not

skipping pulses. DCM efficiency performance lies between

the PWM and PFM modes.

External Frequency Synchronization (SYNC)

The device can be synchronized by an external clock

signal on the SYNC pin. The external synchroniza-

tion clock frequency must be between 1.1 x fSW and

1.4 x fSW, where fSW is the frequency programmed

by the RT resistor. 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 greater than 160ns, and the

maximum external clock low pulse amplitude should be less

than 0.8V. Table 1 provides recommended synchronous

frequency ranges for desired output voltages. Connect

the SYNC pin to SGND if it is not used.

RESET Output

The device includes a RESET comparator to monitor the

output for undervoltage and overvoltage conditions. The

open-drain RESET output requires an external pullup

resistor from 10kΩ to 100kΩ to V

pin or maximum 6V

voltage source. RESET goes high impedance after the

regulator output increases above 95% of the designed

nominal regulated voltage. RESET goes low when the

regulator output voltage drops below 92% of the nominal

regulated voltage. RESET also goes low during thermal

shutdown.

Thermal Fault Protection

The MAXM17505 features a thermal-fault protection

circuit. When the junction temperature rises above +165°C

(typ), a thermal sensor activates the fault latch, pulls down

the RESET output, and shuts down the regulator. The

thermal sensor restarts the controllers after the junction

temperature cools by 10°C (typ). The soft-start resets

during thermal shutdown.

Power Dissipation and Output-Current Derating

The MAXM17505 output current needs to be derated

if the device needs to be operated in a high ambient-

temperature environment. The amount of current-derating

depends upon the input voltage, output voltage, and

ambient temperature. The derating curves in TOC43

from the Typical Operating Characteristics section can be

used as guidelines. The curves are based on simulating

thermal resistance model (ψJT), measuring thermal

resistance (ψTA), and measuring power dissipation

(PDMAX) on the bench.

The maximum allowable power losses can be calculated

using the following equation:

JMAX A

DMAX

−

=θ

where:

PDMAX is the maximum allowed power losses with

maximum allowed junction temperature.

TJMAX is the maximum allowed junction temperature.

TA is operating ambient temperature.

θJA is the junction to ambient thermal resistance.

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PCB Layout Guidelines

Careful PCB layout is critical to achieving low switching

losses and clean, stable operation.

Use the following guidelines for good PCB layout:

●Keep the input capacitors as close as possible to the

IN and PGND pins.

●Keep the output capacitors as close as possible to the

OUT and PGND pins.

●Keep the resistive feedback dividers as close as

possible to the FB pin.

●Connect all of the PGND connections to as large as

copper plane area as possible on the top layer.

●Connect EP1 to PGND and GND planes on bottom

layer.

●Use multiple vias to connect internal PGND planes to

the top layer PGND plane.

●Do not keep any solder mask on EP1, EP2, and EP3

on bottom layer. Keeping solder mask on exposed

pads decreases the heat dissipating capability.

●Keep the power traces and load connections

short. This practice is essential for high efciency.

Using thick copper PCBs (2oz vs. 1oz) can enhance

full-load efciency. Correctly routing PCB traces

is a difcult task that must be approached in terms

of fractions of centimeters, where a single milliohm

of excess trace resistance causes a measurable

efciency penalty.

Layout Recommendation

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PGND

OUT

SGND

OUT

1298

29 28 252627 2324

13 14 15

OUT

EP1

EP2

EP3

IN GND

PGND

PACKAGE

TYPE

PACKAGE

CODE

OUTLINE

NO.

LAND

PATTERN NO.

29 SiP L32915+1 21-0879 90-0459

PART TEMP RANGE MSL PIN-PACKAGE

MAXM17505ALJ+T -40°C to +125°C 3 29 SiP

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Package Information

For the latest package outline information and land patterns

(footprints), go to www.maximintegrated.com/packages. Note

that a “+”, “#”, or “-” in the package code indicates RoHS status

only. Package drawings may show a different suffix character, but

the drawing pertains to the package regardless of RoHS status.

Ordering Information

+Denotes a lead(Pb)-free/RoHS-compliant package.

T = Tape and reel.

Chip Information

PROCESS: BiCMOS

Revision History

REVISION

NUMBER

REVISION

DATE DESCRIPTION PAGES

CHANGED

0 11/14 Initial release —

1 4/15 Added application recommendation to avoid potential latch-up issue on EN pin and

added MSL 3 rating 11, 18

2 11/16 Updated Package Thermal Characteristics and notes sections, updated Pin 4 in the

Pin Description section, and updated the Loop Compensation section 2, 11, 15

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. The parametric values (min and max limits)

shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.

│

MAXM17505 4.5V to 60V, 1.7A High-Efciency, DC-DC Step-

Down Power Module with Integrated Inductor

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