Rainbow Electronics MAX15040 User Manual

General Description

The MAX15040 high-efficiency switching regulator
delivers up to 4A load current at output voltages from

0.6V to (0.9 x V

IN

). The device operates from 2.4V to

3.6V, making it ideal for on-board point-of-load and
postregulation applications. Total output-voltage accu­racy is within ±1% over load, line, and temperature.

The MAX15040 features 1MHz fixed-frequency PWM
mode operation. The high operating frequency allows
for small-size external components.

The low-resistance on-chip nMOS switches ensure high
efficiency at heavy loads while minimizing critical parasitic
inductances, making the layout a much simpler task with
respect to discrete solutions. Following a simple layout
and footprint ensures first-pass success in new designs.

The MAX15040 incorporates a high-bandwidth
(> 15MHz) voltage-error amplifier. The voltage-mode
control architecture and the voltage-error amplifier per­mit a Type III compensation scheme to achieve maxi­mum loop bandwidth, up to 200kHz. High loop
bandwidth provides fast transient response, resulting in
less required output capacitance and allowing for all­ceramic capacitor designs.

The MAX15040 features an output overload hiccup pro­tection and peak current limit on both high-side (sourc­ing current) and low-side (sinking and sourcing current)
MOSFETs, for ultra-safe operations in case of high out­put prebias, short-circuit conditions, severe overloads,
or in converters with bulk electrolytic capacitors.

The MAX15040 features an adjustable output voltage.
The output voltage is adjustable by using two external
resistors at the feedback or by applying an external ref­erence voltage to the REFIN/SS input. The MAX15040
offers programmable soft-start time using one capacitor
to reduce input inrush current. A built-in thermal shut­down protection assures safe operation under all condi­tions. The MAX15040 is available in a 2mm x 2mm,
16-bump (4 x 4 array), 0.5mm pitch WLP package.

Applications

Server Power Supplies
Point-of-Load
ASIC/CPU/DSP Core and I/O Voltages
DDR Power Supplies
Base-Station Power Supplies
Telecom and Networking Power Supplies
RAID Control Power Supplies

Features

o Internal 15mΩ R

DS(ON)

MOSFETs

o Continuous 4A Output Current

o ±1% Output-Voltage Accuracy Over Load, Line,

and Temperature

o Operates from 2.4V to 3.6V Supply

o Adjustable Output from 0.6V to (0.9 x V

IN

)

o Adjustable Soft-Start Reduces Inrush Supply

Current

o Factory-Trimmed 1MHz Switching Frequency

o Compatible with Ceramic, Polymer, and

Electrolytic Output Capacitors

o Safe Startup into Prebias Output

o Enable Input/Power-Good Output

o Fully Protected Against Overcurrent and

Overtemperature

o Overload Hiccup Protection

o Sink/Source Current in DDR Applications

o 2mm x 2mm, 16-Bump (4 x 4 Array), 0.5mm Pitch

WLP Package

MAX15040

High-Efficiency, 4A, Step-Down Regulator with

Integrated Switches in 2mm x 2mm Package

________________________________________________________________

Maxim Integrated Products

1

Ordering Information

19-4426; Rev 2; 7/10

EVALUATION KIT

AVAILABLE

+

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

Pin Configuration appears at end of data sheet.

OUTPUT

INPUT

2.4V TO 3.6V
BST

LX

IN

EN

V

DD

GND

FB

V

DD

COMP

PWRGD

REFIN/SS

GND

MAX15040

Typical Operating Circuit

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.

PART TEMP RANGE PIN-PACKAGE

M AX 15040E WE + - 40°C to + 85°C 16 WLP

MAX15040

High-Efficiency, 4A, Step-Down Regulator with
Integrated Switches in 2mm x 2mm Package

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VIN= VDD= 3.3V, TA = -40°C to +85°C. Typical values are at TA= +25°C, circuit of Figure 1, unless otherwise noted.) (Note 3)

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.

IN, VDD, PWRGD to GND ......................................-0.3V to +4.5V

LX to GND....................-0.3V to the lower of 4.5V or (V

IN

+ 0.3V)

LX Transient ..............(V

GND

- 1.5V, <50ns), (VIN+ 1.5V, <50ns)

COMP, FB, REFIN/SS,

EN to GND..............-0.3V to the lower of 4.5V or (V

DD

+ 0.3V)

LX RMS Current (Note 1) .........................................................5A

BST to LX..................................................................-0.3V to +4V

BST to GND ..............................................................-0.3V to +8V

Continuous Power Dissipation (T

A

= +70°C)

16-Bump (4 x 4 Array), 0.5mm Pitch WLP

(derated 12.5mW/°C above +70°C)...........................1000mW

Operating Temperature Range ...........................-40°C to +85°C

Junction Temperature......................................................+150°C

Continuous Operating Temperature at

Full Load Current (Note 2) ...........................................+105°C

Storage Temperature Range .............................-65°C to +150°C

Soldering Temperature (reflow) .......................................+260°C

Note 1: LX has internal clamp diodes to GND and IN. Applications that forward bias these diodes should take care not to exceed

the package power dissipation limit of the device.

Note 2: Continuous operation at full current beyond +105°C may degrade product life.

IN/V

IN and V

IN Supply Current No load, no switching

VDD Supply Current No load, no switching

Total Supply Current (IN + VDD) No load

Total Shutdown Current from IN
and V

VDD Undervoltage Lockout
Threshold

VDD UVLO Deglitching 2µs

BST

BST Leakage Current

PWM COMPARATOR

PWM Comparator Propagation
Delay

COMP

COMP Clamp Voltage High V

COMP Clamp Voltage Low V

COMP Slew Rate 1.6 V/µs

PWM Ramp Valley VDD = 2.4V to 3.6V 830 mV

PWM Ramp Amplitude 1V

COMP Shutdown Resistance From COMP to GND, VEN = 0V 8 Ω

PARAMETER CONDITIONS MIN TYP MAX UNITS

DD

Voltage Range 2.40 3.60 V

DD

VIN = 2.5V 0.52 1

= 3.3V 0.8 1.5

V

IN

VIN = 2.5V 3.7 5.5

= 3.3V 4 6

V

IN

VIN = VDD = 2.5V 12

= VDD = 3.3V 23

V

IN

DD

VIN = VDD = V

LX starts/stops switching

V

= V

BST

DD

= 3.6V or 0V, VEN = 0V

V

LX

10mV overdrive 10 ns

= 2.4V to 3.6V 2.03 V

DD

= 2.4V to 3.6V 0.73 V

DD

- VLX = 3.6V, VEN = 0V 0.1 2 µA

BST

VDD rising 2 2.2

falling 1.75 1.9

V

DD

= V

IN

= 3.6V,

TA = +25°C 2

T

= +85°C 0.025

A

mA

mA

mA

V

µA

MAX15040

High-Efficiency, 4A, Step-Down Regulator with

Integrated Switches in 2mm x 2mm Package

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VIN= VDD= 3.3V, TA = -40°C to +85°C. Typical values are at TA= +25°C, circuit of Figure 1, unless otherwise noted.) (Note 3)

PARAMETER CONDITIONS MIN TYP MAX UNITS

ERROR AMPLIFIER

FB Regulation Accuracy Using internal reference 0.594 0.600 0.606 V

Open-Loop Voltage Gain 1kΩ from COMP to GND (Note 4) 115 dB

Error-Amplifier Unity-Gain
Bandwidth

Error-Amplifier Common-Mode
Input Range

Error-Amplifier Minimum Output
Current

FB Input Bias Current VFB = 0.7V, using internal reference, TA = +25°C -200 -100 nA

REFIN/SS

REFIN/SS Charging Current V

REFIN/SS Discharge Resistance 520 Ω

REFIN/SS Common-Mode Range

REFIN/SS Offset Voltage Error amplifier offset

LX (ALL BUMPS COMBINED)

LX On-Resistance, High Side ILX = -0.4A

LX On-Resistance, Low Side ILX = 0.4A

LX Peak Current-Limit Threshold VIN = 2.5V

LX Switching Frequency VIN = 2.5V to 3.3V, TA = +25°C 0.92 1 1.03 MHz

LX Maximum Duty Cycle VIN = 2.5V to 3.3V, TA = +25°C 92 96 %

LX Minimum On-Time 80 ns

RMS LX Output Current 4A

ENABLE

EN Input Logic-Low Threshold 0.7 V

EN Input Logic-High Threshold 1.7 V

EN Input Current

Series 5kΩ, 100nF from COMP to GND (Note 4) 26 MHz

V

= 2.4V to 2.6V 0 VDD - 1.80

DD

V

= 2.6V to 3.6V 0 VDD - 1.85

DD

V

= 1.2V, sinking 500

COMP

V

= 1.0V, sourcing 1000

COMP

REFIN/SS

VDD = 2.4V to 2.6V 0 V

V

DD

V

EN

V

IN

= 0.45V 7 8 9 µA

= 2.6V to 3.6V 0 V

TA = +25°C 30 µV

-4.5 +4.5 mV

= 0 or 3.6V,

= VDD = 3.6V

VIN = V

= V

V

IN

VIN = 2.5V 16

V

= 3.3V 15

IN

High-side sourcing 5.5 7

Low-side sinking 5.5 7

TA = +25°C

= +85°C 0.2

T

A

TA = +25°C 1

T

= +85°C 0.3

A

- V

BST

LX

- V

BST

LX

VLX = 0V -2

V

LX

= 2.5V 21

= 3.3V 19

= 3.6V +2LX Leakage Current VIN = 3.6V, VEN = 0V

DD

DD

- 1.80

- 1.85

V

µA

V

mΩ

mΩ

A

µA

µA

EFFICIENCY

vs. OUTPUT CURRENT

MAX15040 toc01

OUTPUT CURRENT (A)

EFFICIENCY (%)

1

50

60

70

80

90

100

40

0.1 10

VDD = VIN = 3.3V

V

OUT

= 1.2V

V

OUT

= 1.8V

V

OUT

= 1.5V

V

OUT

= 2.5V

EFFICIENCY

vs. OUTPUT CURRENT

MAX15040 toc02

OUTPUT CURRENT (A)

EFFICIENCY (%)

1

50

60

70

80

90

100

40

0.1 10

VIN = VDD = 2.5V

V

OUT

= 1.8V

V

OUT

= 1.2V

V

OUT

= 1.5V

MAX15040

High-Efficiency, 4A, Step-Down Regulator with
Integrated Switches in 2mm x 2mm Package

4 _______________________________________________________________________________________

Note 3: Specifications are 100% production tested at TA = +25°C. Limits over the operating temperature range are guaranteed by

design and characterization.

Note 4: Guaranteed by design.

ELECTRICAL CHARACTERISTICS (continued)

(VIN= VDD= 3.3V, TA = -40°C to +85°C. Typical values are at TA= +25°C, circuit of Figure 1, unless otherwise noted.) (Note 3)

Typical Operating Characteristics

(VIN= VDD= 3.3V, output voltage = 1.8V, I

LOAD

= 4A, and TA = +25°C, circuit of Figure 1, unless otherwise noted.)

THERMAL SHUTDOWN

Thermal-Shutdown Threshold Rising +165 °C
Thermal-Shutdown Hysteresis 20 °C

POWER-GOOD (PWRGD)

Power-Good Threshold Voltage

Power-Good Edge Deglitch VFB falling or rising 48

PWRGD Output-Voltage Low I

PWRGD Leakage Current V

OVERCURRENT LIMIT (HICCUP MODE)

Current-Limit Startup Blanking 112

Restart Time 896

FB Hiccup Threshold VFB falling 70

Hiccup Threshold Blanking Time VFB falling 36 µs

PARAMETER CONDITIONS MIN TYP MAX UNITS

VFB falling, V

rising, V

V

FB

= 4mA (sinking) 0.03 0.15 V

PWRGD

= V

DD

PWRGD

REFIN/SS

REFIN/SS

= 0.6V 87 90 93

= 0.6V 92.5

= 3.6V, V

= 0.9V 0.01 µA

FB

% of

V

RE F IN /S S

Clock

cycles

Clock

cycles

Clock

cycles

% of

V

RE F IN /S S

MAX15040

High-Efficiency, 4A, Step-Down Regulator with

Integrated Switches in 2mm x 2mm Package

_______________________________________________________________________________________

5

Typical Operating Characteristics (continued)

(VIN= VDD= 3.3V, output voltage = 1.8V, I

LOAD

= 4A, and TA = +25°C, circuit of Figure 1, unless otherwise noted.)

EFFICIENCY

vs. OUTPUT CURRENT

100

90

80

70

EFFICIENCY (%)

V

OUT

60

50

VDD = 3.3V

= 2.5V

V

IN

40

0.1 10

V

= 1.8V

OUT

V

= 1.5V

OUT

= 1.2V

1

OUTPUT CURRENT (A)

MAX15040 toc03

LOAD REGULATION

0.10

0

-0.10

V

= 2.5V

-0.20

-0.30

OUTPUT VOLTAGE ERROR (%)

-0.40

-0.50

OUT

V

= 1.8V

OUT

V

= 1.5V

OUT

V

INTERNAL REFERENCE

04

LOAD CURRENT (A)

OUT

321

MAX15040 toc06

= 1.2V

vs. INPUT VOLTAGE

1.20

1.15

1.10

1.05

1.00

0.95

FREQUENCY (MHz)

0.90

TA = -40°C

0.85

0.80

2.4 3.6

LOAD-TRANSIENT RESPONSE

V

OUT

I

OUT

FREQUENCY

TA = +85°C

TA = +25°C

INPUT VOLTAGE (V)

40µs/div

3.43.22.6 2.8 3.0

MAX15040 toc07

0.5

0.4

MAX15040 toc04

AC-COUPLED
100mV/div

1A/div

0

0.3

0.2

0.1

-0.1

-0.2

OUTPUT VOLTAGE ERROR (%)

-0.3

-0.4

-0.5

V

LINE REGULATION

V

= 1.2V

OUT

0

V

= 1.8V

OUT

2.4 3.6
INPUT VOLTAGE (V)

SWITCHING WAVEFORMS

OUT

I

LX

V

LX

400ns/div

3.43.23.02.82.6

MAX15040 toc08

MAX15040 toc05

AC-COUPLED
50mV/div

2A/div

0

2V/div

0

SHUTDOWN WAVEFORM

V

EN

V

OUT

10µs/div

MAX15040 toc09

I

OUT

= 1.8A

2V/div

0

1V/div

0

V

EN

V

OUT

SOFT-START WAVEFORM

400µs/div

MAX15040 toc10

2V/div

0

1V/div

0