Rainbow Electronics MAX15058 User Manual

19-5478; Rev 2; 7/11

EVALUATION KIT

AVAILABLE

High-Efficiency, 3A, Current-Mode

Synchronous, Step-Down Switching Regulator

General Description

The MAX15058 high-efficiency, current-mode, synchro­nous step-down switching regulator with integrated
power switches delivers up to 3A of output current.
The device operates from 2.7V to 5.5V and provides an
output voltage from 0.6V up to 94% of the input voltage,
making the device ideal for distributed power systems,
portable devices, and preregulation applications.

The MAX15058 utilizes a current-mode control archi­tecture with a high-gain transconductance error ampli­fier. The current-mode control architecture facilitates
easy compensation design and ensures cycle-by-cycle
current limit with fast response to line and load transients.

The MAX15058 offers selectable skip-mode functional­ity to reduce current consumption and achieve a higher
efficiency at light output load. The low R

DS(ON)

inte­grated switches ensure high efficiency at heavy loads
while minimizing critical inductances, making the layout
design a much simpler task with respect to discrete
solutions. Utilizing a simple layout and footprint assures
first-pass success in new designs.

The MAX15058 features a 1MHz, factory-trimmed, fixed­frequency PWM mode operation. The high switching fre­quency, along with the PWM current-mode architecture,
allows for a compact, all-ceramic capacitor design.

The MAX15058 offers a capacitor-programmable soft­start reducing inrush current, startup into PREBIAS
operations, and a PGOOD open-drain output that can be
used as an interrupt and for power sequencing.

The MAX15058 is available in a 9-bump (3 x 3 array),

1.5mm x 1.5mm WLP package and is specified over the

-40NC to +85NC temperature range.

Applications

Distributed Power Systems

Preregulators for Linear Regulators

Portable Devices

Notebook Power

Server Power

IP Phones

Features

S Internal 30mI (typ) R

DS(ON)

(typ) Low-Side MOSFETs at 5V

S Continuous 3A Output Current Over Temperature

S 95% Efficiency with 3.3V Output at 3A

S 1% Output Voltage Accuracy Over Load, Line, and

Temperature

S Operates from 2.7V to 5.5V Supply

S Cycle-by-Cycle Overcurrent Protection

S Adjustable Output from 0.6V to Up to 0.94 x V

S Programmable Soft-Start

S Factory-Trimmed, 1MHz Switching Frequency

S Stable with Low-ESR Ceramic Output Capacitors

S Safe-Startup Into Prebiased Output

S External Reference Input

S Skip-Mode Functionality

S Enable Input/Power-Good Output

S Fully Protected Against Overcurrent and

Overtemperature

S Input Undervoltage Lockout

High-Side and 18mI

Ordering Information

PART TEMP RANGE PIN-PACKAGE

MAX15058EWL+ -40°C to +85°C 9 WLP

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

Typical Operating Circuit

INPUT

2.8V TO 5.5V

ENABLE

OFF

ON

IN LX

MAX15058

PGOOD

EN

SKIP

SS/REFIN

GND

COMP

FB

IN

OUTPUT

1.8V/3A

MAX15058

_______________________________________________________________ Maxim Integrated Products 1

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.

High-Efficiency, 3A, Current-Mode
Synchronous, Step-Down Switching Regulator

ABSOLUTE MAXIMUM RATINGS

IN, PGOOD to GND ................................................-0.3V to +6V

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

LX to GND .......................................-1V to (VIN + 0.3V) for 50ns

EN, COMP, FB, SS/REFIN, SKIP to GND ...-0.3V to (VIN + 0.3V)

LX Current (Note 1) ................................................... -6A to +6A

Output Short-Circuit Duration ....................................Continuous

Note 1: LX has internal clamp diodes to GND and IN. Applications that forward bias these diodes should not exceed the IC’s pack-

MAX15058

age power dissipation limits.

PACKAGE THERMAL CHARACTERISTICS (Note 2)

WLP

Junction-to-Case Thermal Resistance (BJC) ...................26NC/W

Junction-to-Ambient Thermal Resistance (BJA) .............. 71NC/W

Note 2: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-

layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.

ELECTRICAL CHARACTERISTICS

(VIN = 5V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 3)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

IN Voltage Range V
IN Shutdown Supply Current VEN = 0V 0.2 2
IN Supply Current I

V

Undervoltage Lockout

IN

Threshold

V

Undervoltage Lockout

IN

Hysteresis

ERROR AMPLIFIER

Transconductance g
Voltage Gain A
FB Set-Point Accuracy V
FB Input Bias Current I

COMP to Current-Sense
Transconductance

COMP Clamp Low VFB = 0.65V, VSS = 0.6V 0.94 V

POWER SWITCHES

LX On-Resistance, High-Side
pMOS

LX On-Resistance, Low-Side
nMOS

High-Side Switch Current-Limit
Threshold

Low-Side Switch Sink Current­Limit Threshold

Low-Side Switch Source Current­Limit Threshold

IN

MV

VEA

FB

FB

g

MC

I

HSCL

IN

VEN = 5V, VFB = 0.65V, no switching 1.56 2.3 mA

LX starts switching, VIN rising 2.6 2.7 V

LX stops switching, VIN falling 200 mV

Over line, load, and temperature 594 600 606 mV
VFB = 0.6V -500 +500 nA

Continuous Power Dissipation (TA = +70NC)
9-Bump WLP Multilayer Board

(derate 14.1mW/NC above TA = +70NC) .................... 1127mW

Operating Temperature Range .......................... -40NC to +85NC

Storage Temperature Range ............................ -65NC to +150NC

Soldering Temperature (reflow) ......................................+260NC

2.7 5.5 V

1.5 mS
90 dB

18 A/V

30

18

5 A

4 A

5 A

FA

mI

mI

2 ______________________________________________________________________________________

High-Efficiency, 3A, Current-Mode

Synchronous, Step-Down Switching Regulator

ELECTRICAL CHARACTERISTICS (continued)

(VIN = 5V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 3)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

LX Leakage Current VEN = 0V 10
RMS LX Output current 3 A

OSCILLATOR

Switching Frequency f
Maximum Duty Cycle D
Minimum Controllable On-Time 70 ns

Slope Compensation Ramp
Valley

Slope Compensation Ramp
Amplitude

ENABLE

EN Input High Threshold Voltage VEN rising 1.45 V
EN Input Low Threshold Voltage VEN falling 0.4 V
EN Input Leakage Current VEN = 5V 0.025
SKIP Input Leakage Current V

SOFT-START, PREBIAS, REFIN

Soft-Start Current I
SS/REFIN Discharge Resistance R

SS/REFIN Prebias Mode Stop
Voltage

External Reference Input Range 0 IN - 1.8 V

HICCUP

Number of Consecutive Current­Limit Events to Hiccup

Timeout 1024

POWER-GOOD OUTPUT

PGOOD Threshold VFB rising 0.535 0.555 0.575 V
PGOOD Threshold Hysteresis VFB falling 28 mV
PGOOD V
PGOOD Leakage V

THERMAL SHUTDOWN

Thermal Shutdown Threshold 150
Thermal Shutdown Hysteresis Temperature falling 20

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

OL

design and characterization.

SW

MAX

V

SLOPE

SS

Extrapolated to 100% duty cycle 320 mV

= VEN = 5V 25

SKIP

SS

V

SS/REFIN

I

SS/REFIN

V

SS/REFIN

I

PGOOD

PGOOD

= 0.45V, sourcing 10

= 10mA, sinking 8.3

rising 0.58 V

= 5mA, VFB = 0.5V 20 60 mV

= 5V, VFB = 0.65V 0.013

850 1000 1150 kHz

94 %

1.15 V

8 Events

FA

FA
FA

FA

I

Clock

Cycles

FA

NC
NC

MAX15058

_______________________________________________________________________________________ 3

High-Efficiency, 3A, Current-Mode
Synchronous, Step-Down Switching Regulator

Typical Operating Characteristics

(VIN = 5V, V

OUT

= 1.8V, I

= 3A, Circuit of Figure 5, TA = +25NC, unless otherwise noted.)

LOAD

EFFICIENCY vs. LOAD CURRENT

(PWM MODE)

100

V

= 3.3V

OUT

95

MAX15058

90

85

EFFICIENCY (%)

80

75

0 3.0

V

= 1.8V

OUT

V

OUTPUT CURRENT (A)

100

95

90

85

EFFICIENCY (%)

80

75

EFFICIENCY vs. OUTPUT CURRENT

MAX15058 toc01

100

95

90

85

EFFICIENCY (%)

80

75

0 3.0

OUT

V

= 1.5V

OUT

= 2.5V

V

OUT

VIN = 5V

2.52.01.51.00.5

= 1.2V

EFFICIENCY vs. OUTPUT CURRENT

(SKIP MODE)

V

= 2.5V

OUT

V

= 1.8V

OUT

0 3.0

V

= 1.5V

OUT

OUTPUT CURRENT (A)

V

= 1.2V

OUT

VIN = 3.3V

2.52.01.51.00.5

(FORCED PWM)

V

= 1.8V

OUT

OUTPUT CURRENT (A)

MAX15058 toc04

V

= 2.5V

OUT

V

= 1.5V

OUT

V

= 1.2V

OUT

VIN = 3.3V

2.52.01.51.00.5

1100

1080

1060

1040

1020

1000

980

960

SWITCHING FREQUENCY (kHz)

940

920

900

2.7 3.2 3.7 4.74.2 5.2

EFFICIENCY vs. LOAD CURRENT

100

95

MAX15058 toc02

90

85

EFFICIENCY (%)

80

V

OUT

75

70

0 3.0

SWITCHING FREQUENCY

vs. INPUT VOLTAGE

INPUT VOLTAGE (V)

(SKIP MODE)

V

= 1.8V

OUT

V

= 2.5V

OUT

= 3.3V

OUTPUT CURRENT (A)

MAX15058 toc05

MAX15058 toc03

V

= 1.5V

OUT

V

= 1.2V

OUT

VIN = 5V

2.52.01.51.00.5

OUTPUT VOLTAGE

vs. SUPPLY VOLTAGE

1.89

1.87

1.85

1.83

1.81

OUTPUT VOLTAGE (V)

1.79

1.77

I

= 0.5A

OUT

1.75

2.7 3.2 3.7 4.74.2 5.2
SUPPLY VOLTAGE (V)

MAX15058 toc06

1.89

1.87

1.85

1.83

1.81

OUTPUT VOLTAGE (V)

1.79

1.77

1.75
0 0.5 1.0 2.01.5 2.5 3.0

OUTPUT VOLTAGE

vs. OUTPUT CURRENT

V

= 3.3V

OUT

V

= 5V

OUT

OUTPUT CURRENT (A)

4 ______________________________________________________________________________________

MAX15058 toc07

High-Efficiency, 3A, Current-Mode

Synchronous, Step-Down Switching Regulator

Typical Operating Characteristics (continued)

(VIN = 5V, V

OUT

= 1.8V, I

= 3A, Circuit of Figure 5, TA = +25NC, unless otherwise noted.)

LOAD

MAX15058

50mV/div

AC-COUPLED

1A/div

LOAD-TRANSIENT RESPONSE

100µs/div

SWITCHING WAVEFORMS (I

0A

400ns/div

MAX15058 toc08

= 3A)

OUT

MAX15058 toc09b

VIN = 3.3V

V

OUT

20mV/div
AC-COUPLED

I

LX

1AV/div

V

LX

5V/div

SWITCHING WAVEFORMS (I

0A

400ns/div

OUT

MAX15058 toc09a

SWITCHING WAVEFORM IN SKIP MODE

= 10mA)

(I

OUT

10

µs/div

MAX15058 toc10

= 3A)

V

OUT

20mV/div
AC-COUPLED

I

LX

1AV/div

V

LX

5V/div

V

OUT

50mV/div
AC-COUPLED

I

LX

1A/div

V

LX

5V/div

INPUT AND OUTPUT

WAVEFORMS (I

400ns/div

OUT

= 3A)

MAX15058 toc11

INPUT
20mV/div
AC-COUPLED

OUTPUT
100mV/div
AC-COUPLED

SHUTDOWN WAVEFORM

10

µs/div

MAX15058 toc12

V

ENABLE

5V/div

V

OUT

1V/div

I

LX

1A/div

V

PGOOD

5V/div

_______________________________________________________________________________________ 5

High-Efficiency, 3A, Current-Mode
Synchronous, Step-Down Switching Regulator

Typical Operating Characteristics (continued)

(VIN = 5V, V

OUT

= 1.8V, I

= 3A, Circuit of Figure 5, TA = +25NC, unless otherwise noted.)

LOAD

MAX15058

100

90

80

70

60

50

40

30

SHUTDOWN CURRENT (nA)

20

10

0

2.7

SOFT-START WAVEFORMS

(PWM MODE) (I

200µs/div

SHUTDOWN CURRENT

vs. INPUT VOLTAGE

VEN = 0V

INPUT VOLTAGE (V)

OUT

= 3A)

MAX15058 toc13a

5.24.74.23.73.2

V

ENABLE

5V/div
V

OUT

1V/div

I

LX

1A/div

V

PGOOD

5V/div

MAX15058 toc14

SOFT-START WAVEFORMS

(SKIP MODE) (I

200µs/div

SHORT-CIRCUIT HICCUP MODE

200µs/div

OUT

= 3A)

MAX15058 toc13b

MAX15058 toc15

V

ENABLE

5V/div
V

OUT

1V/div

I

LX

1A/div

V

PGOOD

5V/div

I

IN

500mA/div

V

OUT

200mV/div

I

OUT

5A/div

RMS INPUT CURRENT

200

vs. INPUT VOLTAGE

160

120

80

RMS INPUT CURRENT (mA)

40

0

2.8 5.5

SHORT CIRCUIT ON OUTPUT

INPUT VOLTAGE (V)

MAX15058 toc16

FEEDBACK VOLTAGE (V)

5.24.94.64.34.03.73.43.1

FB VOLTAGE vs. TEMPERATURE

606

604

602

600

598

596

594

-40

AMBIENT TEMPERATURE (°C)

MAX15058 toc17

NO LOAD

806040200-20

6 ______________________________________________________________________________________

High-Efficiency, 3A, Current-Mode

Synchronous, Step-Down Switching Regulator

Typical Operating Characteristics (continued)

(VIN = 5V, V

OUT

= 1.8V, I

= 3A, Circuit of Figure 5, TA = +25NC, unless otherwise noted.)

LOAD

MAX15058

SOFT-START WAVEFORMS

(EXTERNAL REFIN) (PWM MODE)

200

µs/div

MAX15058 toc18a

NO LOAD

STARTING INTO A PREBIASED OUTPUT

= 2A)

(I

OUT

MAX15058 toc19

V

SS/ REFIN

500mV/div
V

OUT

1V/div

I

LX

1A/div

V

PGOOD

5V/div

V

ENABLE

5V/div
V

OUT

1V/div

I

LX

1A/div

SOFT-START WAVEFORMS

(EXTERNAL REFIN) (SKIP MODE)

200

µs/div

MAX15058 toc18b

NO LOAD

STARTING INTO A PREBIASED OUTPUT

(NO LOAD)

MAX15058 toc20a

V

SS/ REFIN

500mV/div
V

OUT

1V/div

I

LX

1A/div

V

PGOOD

5V/div

V

ENABLE

5V/div
V

OUT

1V/div

I

LX

1A/div

V

1.8V

PGOOD

5V/div

V

OUT

500mV/div

I

L

1A/div

V

SS/REFIN

500mV/div

PWM MODE

200

µs/div

STARTING INTO A PREBIASED OUTPUT

SKIP MODE

(NO LOAD)

200

µs/div

MAX15058 toc20b

V

PGOOD

5V/div

V

ENABLE

5V/div
V

OUT

1V/div

I

LX

1A/div

V

PGOOD

5V/div

PWM MODE

200

µs/div

STARTING INTO A PREBIASED OUTPUT

HIGHER THAN SET OUTPUT

µs/div

400

MAX15058 toc21

10I LOAD AT OUT

_______________________________________________________________________________________ 7