Rainbow Electronics MAX5066 User Manual

General Description

The MAX5066 is a two-phase, configurable single- or
dual-output buck controller with an input voltage range of

4.75V to 5.5V or from 5V to 28V. Each phase of the
MAX5066 is designed for 180° operation. A mode pin
allows for a dual-output supply or connecting two phases
together for a single-output, high-current supply. Each
output channel of the MAX5066 drives n-channel
MOSFETs and is capable of providing more than 25A of
load current. The MAX5066 uses average current-mode
control with a switching frequency up to 1MHz per phase
where each phase is 180° out of phase with respect to
the other. Out-of-phase operation results in significantly
reduced input capacitor ripple current and output volt­age ripple in dual-phase, single-output voltage applica­tions. Each buck regulator output has its own high­performance current and voltage-error amplifier that can
be compensated for optimum output filter L-C values and
transient response.

The device’s switching frequency can be programmed
from 100kHz to 1MHz with an external resistor. The
MAX5066 can be synchronized to an external clock. Each
output voltage is adjustable from 0.61V to 5.5V. Additional
features include thermal shutdown, “hiccup mode” short­circuit protection. Use the MAX5066 with adaptive voltage
positioning for applications that require a fast transient
response, or accurate output voltage regulation.

The MAX5066 is available in a thermally enhanced 28-pin
TSSOP package capable of dissipating 1.9W. The device
is rated for operation over the -40°C to +85°C extended,
or -40°C to +125°C automotive temperature range.

Applications

High-End Desktop Computers

Graphics Cards

Networking Systems

Point-of-Load High-Current/High-Density
Telecom DC-DC Regulators

RAID Systems

Features

♦ 4.75V to 5.5V or 5V to 28V Input

♦ Dual-Output Synchronous Buck Controller

♦ Configurable for Two Separate Outputs or One

Single Output

♦ Each Output is Capable of Up to 25A Output

Current

♦ Average Current-Mode Control Provides Accurate

Current Limit

♦ 180° Interleaved Operation Reduces Size of Input

Filter Capacitors

♦ Limits Reverse Current Sinking When Operated in

Parallel Mode

♦ Each Output is Adjustable from 0.61V to 5.5V

♦ Independently Programmable Adaptive Voltage

Positioning

♦ 100kHz to 1MHz per Phase Programmable

Switching Frequency

♦ Oscillator Frequency Synchronization from

200kHz to 2MHz

♦ Hiccup Mode Overcurrent Protection

♦ Overtemperature Shutdown

♦ Thermally Enhanced 28-Pin TSSOP Package

Capable of Dissipating 1.9W

♦ Operates Over -40°C to +85°C or -40°C to +125°C

Temperature Range

MAX5066

Configurable, Single-/Dual-Output, Synchronous

Buck Controller for High-Current Applications

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-3661; Rev 0; 5/05

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.

PART TEMP RANGE PIN-PACKAGE

MAX5066EUI -40

ο

C to +85οC 28 TSSOP

MAX5066AUI -40°C to +125°C 28 TSSOP

MAX5066

Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

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 to AGND.............................................................-0.3V to +30V

BST_ to AGND........................................................-0.3V to +35V

DH_ to LX_ ....................................-0.3V to (V

BST_

- V

LX_

) + 0.3V

DL_ to PGND..............................................-0.3V to (V

DD

+ 0.3V)

BST_ to LX_ ..............................................................-0.3V to +6V

V

DD

to PGND............................................................-0.3V to +6V

AGND to PGND .....................................................-0.3V to +0.3V

REG, RT/CLKIN, CSP_, CSN_ to AGND ..................-0.3V to +6V

All Other Pins to AGND ............................-0.3V to (V

REG

+ 0.3V)

REG Continuous Output Current

(Limited by Power Dissipation, No Thermal or Short-Circuit

Protection).........................................................................67mA

REF Continuous Output Current ........................................200µA

Continuous Power Dissipation (T

A

= +70°C)

28-Pin TSSOP (derate 23.8mW/°C above +70°C) .....1904mW

Package Thermal Resistance (

θJC) ...................................2°C/W

Operating Temperature Ranges

MAX5066EUI ...................................................-40°C to +85°C

MAX5066AUI .................................................-40°C to +125°C

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

Storage Temperature Range .............................-60°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

ELECTRICAL CHARACTERISTICS

(VIN= V

REG

= VDD= VEN= +5V, TA= TJ= T

MIN

to T

MAX

, unless otherwise noted, circuit of Figure 6. Typical values are at TA= +25°C.)

(Note 1)

PARAMETER

CONDITIONS

UNITS

SYSTEM SPECIFICATIONS

528

Input Voltage Range V

IN

IN and REG shorted together for +5V
operation

5.5

V

Quiescent Supply Current I

IN

f

OSC

= 500kHz, DH_, DL_ = open 4 20 mA

STARTUP/INTERNAL REGULATOR OUTPUT (REG)

REG Undervoltage Lockout UVLO V

REG

rising 4.0

4.5 V

Hysteresis V

HYST

mV

REG Output Accuracy VIN = 5.8V to 28V, I

SOURCE

= 0 to 65mA

V

REG Dropout VIN < 5.8V, I

SOURCE

= 60mA 0.5 V

INTERNAL REFERENCE

Internal Reference Voltage V

EAN_

EAN_ connected to EAOUT_ (Note 2)

V

Internal Reference Voltage
Accuracy

V

EAN_

VIN = V

REG

= 4.75V to 5.5V or VIN = 5V to

28V, EAN_ connected to EAOUT_ (Note 2)

%

EXTERNAL REFERENCE VOLTAGE OUTPUT (REF)

Accuracy V

REF

I

REF

= 100µA

3.3

V

Load Regulation I

REF

= 0 to 200µA 3.2 3.4 V

MOSFET DRIVERS

p-Channel Output Driver
Impedance

R

ON_P

4 Ω

n-Channel Output Driver
Impedance

R

ON_N

Ω

Output Driver Source Current

2.5 A

Output Driver Sink Current

8A

Nonoverlap Time (Dead Time) t

NO

C

DH_

or C

DL_

= 5nF 30 ns

SYMBOL

MIN TYP MAX

I

, I

DH_

I

, I

DH_

DL_

DL_

4.75

4.15

200

4.75 5.10 5.30

0.6135

-0.9 +0.9

3.23

1.35

0.45 1.35

3.37

MAX5066

Configurable, Single-/Dual-Output, Synchronous

Buck Controller for High-Current Applications

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VIN= V

REG

= VDD= VEN= +5V, TA= TJ= T

MIN

to T

MAX

, unless otherwise noted, circuit of Figure 6. Typical values are at TA= +25°C.)

(Note 1)

PARAMETER

CONDITIONS

TYP

UNITS

OSCILLATOR

RRT = 12.4kΩ

Switching Frequency f

SW

1MHz (max)
switching
frequency per
phase

R

RT

= 127kΩ 100

kHz

fSW = 250kHz nominal, RRT = 50kΩ

Switching Frequency Accuracy

f

SW

= 1MHz nominal, RRT = 12.4kΩ

%

RT/CLKIN Output Voltage

V

RT/CLKIN Current Sourcing
Capability

0.5 mA

RT/CLKIN Logic-High Threshold

2.4 V

RT/CLKIN Logic-Low Threshold

0.8 V

RT/CLKIN High Pulse Width

30 ns

RT/CLKIN Synchronization
Frequency Range

kHz

CURRENT LIMIT

Average Current-Limit Threshold

V

CL_

V

CSP_

- V

CSN_

22.5

mV

Reverse Current-Limit Threshold

V

RCL_

V

CSP_

- V

CSN_

mV

Cycle-by-Cycle Current-Limit
Threshold

V

CLpk_VCSP_

- V

CSN_

52.5 mV

Cycle-by-Cycle Current-Limit
Response Time

t

R

260 ns

DIGITAL FAULT INTEGRATION (DF_)

Number of Switching Cycles to
Shutdown in Current-Limit

NS

DF_

Clock

cycles

Number of Switching Cycles to
Recover from Shutdown

NR

DF_

Clock

cycles

CURRENT-SENSE AMPLIFIER

CSP_ to CSN_ Input Resistance R

CS_

kΩ

VIN = V

REG

= 4.75V to 5.5V or

V

IN

= 5V to 10V

V

Common-Mode Range

)

VIN = 7V to 28V

V

Input Offset Voltage

)

100 µV

Amplifier Gain A

V(CS)

36 V/V

-3dB Bandwidth f

-3dB

4

MHz

V

CSP_

= 5.5V, sinking 120

CSP_ Input Bias Current I

CSA(IN)

V

CSP_

= 0V, sourcing 30

µA

SYMBOL

V

V

RT/CLKIN_H

V

RT/CLKIN_L

V

RT/CLKIN

I

RT/CLKIN

t

RT/CLKIN

f

RT/CLKIN

CMR(CS

V

OS(CS

MIN

MAX

1000

-7.5 +7.5

-10 +10

1.225

200 2000

20.4

24.75

-3.13 -1.63 -0.1

32,768

524,288

1.9835

-0.3 +3.6

-0.3 +5.5

MAX5066

Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VIN= V

REG

= VDD= VEN= +5V, TA= TJ= T

MIN

to T

MAX

, unless otherwise noted, circuit of Figure 6. Typical values are at TA= +25°C.)

(Note 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

CURRENT-ERROR AMPLIFIER (CEA_)

Transconductance g

M

550 µS

Open-Loop Gain

)

No load 50 dB

VOLTAGE ERROR AMPLIFIER (EAOUT_)

Open-Loop Gain

)

70 dB

Unity-Gain Bandwidth f

UGEA

3

MHz

EAN_ Input Bias Current

)

V

EAN_

= 2.0V 100 nA

Error Amplifier Output Clamping
High Voltage

V

CLMP_HI

(EA)

With respect to V

CM

1.14 V

Error Amplifier Output Clamping
Low Voltage

V

CLMP_LO

(EA)

With respect to V

CM

V

EN INPUT

EN Input High Voltage V

ENH

EN rising

EN Hysteresis 0.05

V

EN Input Leakage Current I

EN

-1 +1 µA

MODE INPUT

MODE Logic-High Threshold

2.4 V

MODE Logic-Low Threshold

0.8 V

MODE Input Pulldown

5µA

THERMAL SHUTDOWN

Thermal Shutdown T

SHDN

160

Thermal Shutdown Hysteresis T

HYST

10

°C

Note 1: The device is 100% production tested at TA= +85°C (MAX5066EUI). Limits at -40°C and +25°C and TA= TJ= +125°C

(MAX5066AUI) are guaranteed by design.

Note 2: The internal reference voltage accuracy is measured at the negative input of the error amplifiers (EAN_). Output voltage

accuracy must include external resistor-divider tolerances.

A

VOL(CEA

A

VOL(EA

I

BIAS(EA

V

MODE_H

V

MODE_L

I

PULLDWN

-0.234

1.204 1.222 1.240

OSCILLATOR FREQUENCY vs. R

T

MAX5066 toc01

RT (kΩ)

OSCILLATOR FREQUENCY (kHz)

900800700600500400300200100

100

1000

10,000

10

01000

CDH = CDL = 0

SUPPLY CURRENT

vs. TEMPERATURE AND FREQUENCY

(V

IN

= 5V)

MAX5066 toc02a

TEMPERATURE (°C)

SUPPLY CURRENT (mA)

11095-25 -10 5 35 50 6520 80

2

4

6

8

10

12

14

16

0

-40 125

CDH = CDL = 0

fSW = 1MHz

fSW = 250kHz

fSW = 500kHz

fSW = 125kHz

SUPPLY CURRENT

vs. TEMPERATURE AND FREQUENCY

(V

IN

= 12V)

MAX5066 toc02b

TEMPERATURE (°C)

SUPPLY CURRENT (mA)

11095-25 -10 5 35 50 6520 80

2

4

6

8

10

12

14

16

0

-40 125

CDH = CDL = 0

fSW = 1MHz

fSW = 250kHz

fSW = 500kHz

fSW = 125kHz

SUPPLY CURRENT

vs. TEMPERATURE AND FREQUENCY

(V

IN

= 24V)

MAX5066 toc02c

TEMPERATURE (°C)

SUPPLY CURRENT (mA)

11095-25 -10 5 35 50 6520 80

2

4

6

8

10

12

14

16

0

-40 125

CDH = CDL = 0

fSW = 1MHz

fSW = 250kHz

fSW = 500kHz

fSW = 125kHz

SUPPLY CURRENT

vs. OSCILLATOR FREQUENCY

MAX5066 toc03

FREQUENCY (kHz)

SUPPLY CURRENT (mA)

18001600400 600 800 12001000 1400

7

8

9

10

11

12

13

14

6

200 2000

C

DH_

= C

DL_

= 0

VIN = 24V

VIN = 5V

VIN = 12V

SUPPLY CURRENT

vs. DRIVER LOAD CAPACITANCE

MAX5066 toc04

C

LOAD

(nF)

SUPPLY CURRENT (mA)

252015105

10

20

30

40

50

60

70

80

90

100

0

030

C

LOAD

= CDH = C

DL

REG LOAD REGULATION

MAX5066 toc05

I

REG

(mA)

V

REG

(V)

908070605040302010

4.95

5.00

5.05

5.10

4.90
0100

VIN = 12V

VIN = 24V

VIN = 5.5V

REG LINE REGULATION

MAX5066 toc06

VIN (V)

V

REG

(V)

2321191715131197

4.98

5.00

5.02

5.04

5.06

5.08

5.10

4.96
5

I

REG

= 0

I

REG

= 60mA

REF LOAD REGULATION

MAX5066 toc07

I

REF

(µA)

V

REF

(V)

700600500400300200100

3.290

3.295

3.300

3.305

3.285
0800

VIN = 24V

VIN = 5V

VIN = 12V

Typical Operating Characteristics

(Circuit of Figure 6, TA= +25°C, unless otherwise noted. VIN= 12V, V

OUT1

= 0.8V, V

OUT2

= 1.3V, fSW= 500kHz per phase.)

MAX5066

Configurable, Single-/Dual-Output, Synchronous

Buck Controller for High-Current Applications

_______________________________________________________________________________________ 5

MAX5066

Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications

6 _______________________________________________________________________________________

REF LINE REGULATION

MAX5066 toc08

VIN (V)

V

REF

(V)

232119171513119

7

3.297

3.298

3.299

3.300

3.301

3.302

3.303

3.296
5

I

REF

= 200µA

I

REF

= 0

DRIVER RISE TIME

vs. LOAD CAPACITANCE

MAX5066 toc09

C

LOAD

(nF)

t

RISE

(ns)

201814 164 6 8 10 122

10

20

30

40

50

60

70

80

90

100

0

022

DH

DL

DRIVER FALL TIME

vs. LOAD CAPACITANCE

MAX5066 toc10

C

LOAD

(nF)

t

FALL

(ns)

201814 164 6 8 10 122

5

10

15

20

25

30

35

40

0

022

DH

DL

HIGH-SIDE DRIVER RISE TIME

(V

IN

= 12V, C

LOAD

= 10nF)

MAX5066 toc11

DH_
2V/div

20ns/div

HIGH-SIDE DRIVER FALL TIME

(V

IN

= 12V, C

LOAD

= 10nF)

MAX5066 toc12

DH_
2V/div

20ns/div

LOW-SIDE DRIVER RISE TIME

(V

IN

= 12V, C

LOAD

= 10nF)

MAX5066 toc13

DL_
2V/div

20ns/div

Typical Operating Characteristics (continued)

(Circuit of Figure 6, TA= +25°C, unless otherwise noted. VIN= 12V, V

OUT1

= 0.8V, V

OUT2

= 1.3V, fSW= 500kHz per phase.)

MAX5066

Configurable, Single-/Dual-Output, Synchronous

Buck Controller for High-Current Applications

_______________________________________________________________________________________ 7

LOW-SIDE DRIVER FALL TIME

(V

IN

= 12V, C

LOAD

= 10nF)

MAX5066 toc14

DL_
2V/div

20ns/div

OUT1/OUT2 OUT-OF-PHASE WAVEFORMS

(V

OUT1

= 0.8V, V

OUT2

= 1.3V)

MAX5066 toc15

OUT1
100mV/div

10µs/div

OUT2
100mV/div

LX2
10V/div

LX1
10V/div

TURN-ON/-OFF WAVEFORMS

(I

OUT1

= I

OUT2

= 10A)

MAX5066 toc16

2ms/div

EN
5V/div

V

OUT2

1V/div

V

OUT1

1V/div

SHORT-CIRCUIT CURRENT WAVEFORMS

(V

IN

= 5V)

MAX5066 toc17

200ms/div

I

OUT2

10A/div

I

OUT1

10A/div

Typical Operating Characteristics (continued)

(Circuit of Figure 6, TA= +25°C, unless otherwise noted. VIN= 12V, V

OUT1

= 0.8V, V

OUT2

= 1.3V, fSW= 500kHz per phase.)