Datasheet

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High-Efficiency, 4A, Step-Down DC-DC

Regulators with Internal Power Switches

MAX15066/MAX15166

EVALUATION KIT AVAILABLE

General Description

The MAX15066/MAX15166 current-mode, synchronous,

DC-DC buck converters deliver an output current up to

4A with high efficiency. The devices operate from an

input voltage of 4.5V to 16V and provides an adjustable

output voltage from 0.606V to 90% of the input voltage.

The devices are ideal for distributed power systems,

notebook computers, nonportable consumer applica-

tions, and preregulation applications.

The devices feature a PWM mode operation with

an internally fixed switching frequency of 500kHz

(MAX15066) and 350kHz (MAX15166) capable of 90%

maximum duty cycle. The devices automatically enter

skip mode at light loads. The current-mode control

architecture simplifies compensation design and ensures

a cycle-by-cycle current limit and fast response to line

and load transients. A high gain transconductance error

amplifier allows flexibility in setting the external com-

pensation, simplifying the design and allowing for an

all-ceramic design.

The synchronous buck regulators feature internal

MOSFETs that provide better efficiency than asynchro-

nous solutions, while simplifying the design relative to

discrete controller solutions. In addition to simplifying

the design, the integrated MOSFETs minimize EMI,

reduce board space, and provide higher reliability by

minimizing the number of external components.

Additional features include an externally adjustable soft-

start, independent enable input and power-good output

for power sequencing, and thermal shutdown protec-

tion. The devices offer overcurrent protection (high-side

sourcing) with hiccup mode during an output short-

circuit condition. The devices ensure safe startup when

powering into a prebiased output.

The MAX15066/MAX15166 are available in a 2mm x

2mm, 16-bump (4 x 4 array), 0.5mm pitch wafer-level

package (WLP) and are fully specified from -40NC to

+85NC.

Applications

Distributed Power Systems

Preregulators for Linear Regulators

Home Entertainment (TV and Set-Top Boxes)

Network and Datacom

Servers, Workstations, and Storage

Features

S Integrated 40mΩ (High-Side) and 18.5mΩ

(Low-Side) R

DS-ON

Power MOSFETs

S High Efficiency

Up to 96% (5V Input and 3.3V Output)

Up to 93% (12V Input and 3.3V Output)

S Continuous 4A Output Current

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

Temperature

S 4.5V to 16V Input Voltage Range

S Adjustable Output Voltage Range from 0.606V to

(0.9 x V

)

S Fixed 500kHz (MAX15066) and 350kHz (MAX15166)

Switching Frequencies

S Programmable Soft-Start

S Stable with Low-ESR Ceramic Output Capacitors

S Safe Startup Into Prebiased Output

S Enable Input and Power-Good Output

S Cycle-by-Cycle Overcurrent Protection

S Fully Protected Against Overcurrent (Hiccup

Protection) and Overtemperature

S Automatic Skip Mode During Light Loads

S V

LDO Undervoltage Lockout

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

WLP

19-5224; Rev 4; 5/13

Typical Application Circuit

Ordering Information appears at end of data sheet.

COMP

BST

GND

PGOOD

MAX15066

MAX15166

INPUT

4.5V TO 16V

1.8V/4A

OUTPUT

For pricing, delivery, and ordering information, please contact Maxim Direct

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

Summary of content (21 pages)

PAGE 1
EVALUATION KIT AVAILABLE MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches General Description The MAX15066/MAX15166 current-mode, synchronous, DC-DC buck converters deliver an output current up to 4A with high efficiency. The devices operate from an input voltage of 4.5V to 16V and provides an adjustable output voltage from 0.606V to 90% of the input voltage.
PAGE 2
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches ABSOLUTE MAXIMUM RATINGS IN to GND...............................................................-0.3V to +18V EN to GND...................................................-0.3V to (VIN + 0.3V) LX to GND.............. -0.3V to the lower of +18V and (VIN + 0.3V) LX to GND (for 50ns).....-1V to the lower of +18V and (VIN + 0.3V) PGOOD to GND.......................................................-0.
PAGE 3
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches ELECTRICAL CHARACTERISTICS (continued) (VIN = 12V, CVDD = 1FF, CIN = 22FF, TA = TJ = -40NC to +85NC, typical values are at TA = TJ = +25NC, unless otherwise noted.) (Note 4) PARAMETER Error-Amplifier Voltage Gain SYMBOL CONDITIONS MIN TYP MAX UNITS 612 mV +100 nA 5.5 FA 90 AVEA 600 FB Set-Point Accuracy VFB FB Input Bias Current IFB VFB = 0.5V or 0.7V SS Current ISS VSS = 0.
PAGE 4
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches ELECTRICAL CHARACTERISTICS (continued) (VIN = 12V, CVDD = 1FF, CIN = 22FF, TA = TJ = -40NC to +85NC, typical values are at TA = TJ = +25NC, unless otherwise noted.
PAGE 5
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches Typical Operating Characteristics (continued) (VIN = 12V, VOUT = 1.8V, CVDD = 1FF, CIN = 22FF, COUT = 47FF, TA = +25NC (Figure 1, MAX15066), unless otherwise noted.) LOAD-TRANSIENT RESPONSE (MAX15066) LOAD-TRANSIENT RESPONSE (MAX15066) MAX15066 toc07 MAX15066 toc06 VOUT 100mV/div AC-COUPLED VOUT 100mV/div AC-COUPLED IOUT 2A/div IOUT 2A/div 0A 100µs/div 100µs/div EFFICIENCY (5V) vs.
PAGE 6
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches Typical Operating Characteristics (continued) (VIN = 12V, VOUT = 1.8V, CVDD = 1FF, CIN = 22FF, COUT = 47FF, TA = +25NC (Figure 1, MAX15066), unless otherwise noted.) 606.8 606.6 606.2 606.0 605.8 605.6 1A LOAD 515 FREQUENCY (kHz) 606.4 FB (mV) 525 MAX15066 toc12 607.0 MAX15066 toc13 SWITCHING FREQUENCY vs. INPUT VOLTAGE (MAX15066) FB SET POINT vs.
PAGE 7
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches Typical Operating Characteristics (continued) (VIN = 12V, VOUT = 1.8V, CVDD = 1FF, CIN = 22FF, COUT = 47FF, TA = +25NC (Figure 1, MAX15066), unless otherwise noted.) SWITCHING BEHAVIOR (MAX15066) OUTPUT SHORT-CIRCUIT WAVEFORM MAX15066 toc19 MAX15066 toc18 VOUT 2V/div VLX 10V/div 0V VSS 1V/div 0V VOUT AC-COUPLED 10mV/div 0V IIN 0.
PAGE 8
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches Typical Operating Characteristics (continued) (VIN = 12V, VOUT = 1.8V, CVDD = 1FF, CIN = 22FF, COUT = 47FF, TA = +25NC (Figure 1, MAX15066), unless otherwise noted.) STARTUP INTO PREBIAS (4A LOAD) MAX15066 toc24 10 L = 2.2µH 0V ILOAD 5A/div 0A IL 5A/div 0A VOUT = 1.8V 8 VOUT = 2.5V 7 6 VOUT = 5.0V 5 VEN 10V/div 0V VOUT = 1.
PAGE 9
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches Pin Configuration TOP VIEW (BUMPS ON BOTTOM) + GND GND IN IN A1 A2 A3 A4 LX LX LX VDD B1 B2 B3 B4 BST I.C. I.C. EN C1 C2 C3 C4 PGOOD FB COMP SS D1 D2 D3 D4 WLP Pin Description BUMP NAME A1, A2 GND A3, A4 IN Power-Supply Input. Input supply range is from 4.5V to 16V. Connect A3 and A4 together as close as possible to the device.
PAGE 10
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches Block Diagram EN ENABLE CONTROL AND THERMAL SHUTDOWN VDD 5V LDO UVLO COMPARATOR 3.9V/3.75V BST BIAS GENERATOR VDD CURRENT-SENSE AMPLIFIER AND CURRENT LIMIT VOLTAGE REFERENCE IN LX LX CONTROL LOGIC MAX15066 MAX15166 VDD 1.6V CLAMP GND 5µA ZERO-CROSSING CURRENT LIMIT PWM COMPARATOR 0.606 SS FB ERROR AMPLIFIER C COMP OSCILLATOR 0.560V RISING, 0.
PAGE 11
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches INPUT 4.5V TO 16V IN BST EN LX 22µF 10nF VDD 1µF MAX15066 MAX15166 10kI 2.2µH COUT OUTPUT 270pF R1 FB COMP PGOOD RCOMP SS GND 10nF CCOMP 10kI COMPONENT MAX15066 MAX15166 COUT 1 x 47µF 4 x 47µF RCOMP 7.5kI 7.5kI CCOMP 2700pF 2700pF R1 20kI 5.1kI VOUT 1.8V 0.9V Figure 1.
PAGE 12
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches The devices enter discontinuous mode when load current (ILOAD) and inductor ripple current (DIL) are such that: ∆IL 1  V − VOUT  VOUT = 0.21A (typ) ILOAD − = ILOAD − ×  IN × 2 2  L × fSW  VIN During skip-mode operation, the devices skip switch cycles, switching only as needed to service the load.
PAGE 13
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches Thermal-Shutdown Protection The devices contain an internal thermal sensor that limits the total power dissipation in the device and protects it in the event of an extended thermal fault condition. When the die temperature exceeds +160NC (typ), the thermal sensor shuts down the device, turning off the DC-DC converter and the LDO regulator to allow the die to cool.
PAGE 14
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches Output-Capacitor Selection The key selection parameters for the output capacitor are capacitance, ESR, ESL, and voltage-rating requirements. These affect the overall stability, output ripple voltage, and transient response of the DC-DC converter.
PAGE 15
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches or approximately as: IL ISKIP-LIMIT ILOAD tON tOFF1 VOUT-RIPPLE tOFF2 = n x TCK VOUT  1 1  + t OFF2 = L × I SKIP −LIMIT ×    VIN − VOUT VOUT  I  ×  SKIP −LIMIT − ILOAD  2   ILOAD Finally, frequency in skip mode is: fSKIP = Figure 2.
PAGE 16
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches FEEDBACK DIVIDER POWER MODULATOR ERROR AMPLIFIER COMPENSATION RAMP VOUT R1 *CFF C FB OUTPUT FILTER AND LOAD VIN gMC COMP VFB QHS IL L CONTROL LOGIC VCOMP gMV R2 PWM COMPARATOR RC ROUT DCR QLS VOUT IOUT ESR RLOAD COUT CC VCOMP GMOD VOUT IL ROUT = REF 10 AVEA(dB)/20 gMV NOTE: THE GMOD STAGE SHOWN ABOVE MODELS THE AVERAGE CURRENT OF THE INDUCTOR, IL, INJECTED INTO THE OUTPUT LOAD, I
PAGE 17
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches As previously mentioned, the power modulator’s dominate pole is a function of the parallel effects of the load resistance and the current-loop gain’s equivalent impedance: fPMOD = 1 −1   1 K S × (1 − D) − 0.5     2π × C OUT × ESR +  +    RLOAD   fSW × L     Knowing that the ESR is typically much smaller than the parallel combination of the load and the current loop, e.g.
PAGE 18
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches 1ST ASYMPTOTE R2 x (R1 + R2)-1 x 10AVEA(dB)/20 x gMC x RLOAD x {1 + RLOAD x [KS x (1 – D) – 0.5] x (L x fSW)-1}-1 2ND ASYMPTOTE R2 x (R1 + R2)-1 x gMV x (2GCC)-1 x gMC x RLOAD x {1 + RLOAD x [KS x (1 – D) – 0.5] x (L x fSW)-1}-1 GAIN 3RD ASYMPTOTE R2 x (R1 + R2)-1 x gMV x (2GCC)-1 x gMC x RLOAD x {1 + RLOAD x [KS x (1 – D) – 0.5] x (L x fSW)-1}-1 x (2GCOUT x {RLOAD-1 + [KS(1 – D) – 0.
PAGE 19
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches Closing the Loop: Designing the Compensation Circuitry 1) Select the desired crossover frequency. Choose fCO between 1/5 to 1/10 of fSW. 2) Select RC by setting the system transfer’s fourth asymptote gain equal to unity (assuming fCO > fZ1, fP2, and fP1). RC becomes:  R LOADK S (1 − D) − 0.
PAGE 20
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches Layout Procedure Careful PCB layout is critical to achieve clean and stable operation. It is highly recommended to duplicate the MAX15066/MAX15166 evaluation kit layout for optimum performance. If deviation is necessary, follow these guidelines for good PCB layout: 1) Connect input and output capacitors to the power ground plane; connect all other capacitors to the signal ground plane.
PAGE 21
MAX15066/MAX15166 High-Efficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches Revision History REVISION NUMBER REVISION DATE 0 4/10 Initial release 4/10 Revised the General Description, Absolute Maximum Ratings, Typical Operating Characteristics, and the PWM Comparator, Output-Capacitor Selection, Compensation Design Guidelines, and the Closing the Loop: Designing the Compensation Circuitry sections. Updated Figures 3 and 4.