19-3661; Rev 1; 8/05
KIT
ATION
EVALU
BLE
AVAILA
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
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 volt-
age ripple in dual-phase, single-output voltage applica-
tions. Each buck regulator output has its own high-
performance current and voltage-error amplifier that can
be compensated for optimum output filter L-C values and
transient response.
The MAX5066 offers two enable inputs with accurate
turn-on thresholds to allow for output voltage sequencing
of the two outputs. The device’s switching frequency can
be programmed from 100kHz to 1MHz with an external
resistor. The MAX5066 can be synchronized to an exter-
nal clock. Each output voltage is adjustable from 0.61V to
5.5V. Additional features include thermal shutdown, “hic-
cup mode” short-circuit protection. Use the MAX5066
with adaptive voltage positioning for applications that
require a fast transient response, or accurate output volt-
age 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.
♦
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
♦
Independent Shutdown for Each Output
♦
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
Features
MAX5066
Ordering Information
Applications
High-End Desktop Computers
Graphics Cards
Networking Systems
Point-of-Load High-Current/High-Density
Telecom DC-DC Regulators
RAID Systems
PART
MAX5066EUI
MAX5066AUI
TEMP RANGE
-40°C to +85°C
-40°C to +125°C
PIN-PACKAGE
28 TSSOP-EP*
28 TSSOP-EP*
*Exposed
Pad
________________________________________________________________
Maxim Integrated Products
1
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.
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
MAX5066
ABSOLUTE MAXIMUM RATINGS
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 (θ
JC
) ...................................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
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.
ELECTRICAL CHARACTERISTICS
(V
IN
= V
REG
= V
DD
= V
EN_
= +5V, T
A
= T
J
= T
MIN
to T
MAX
, unless otherwise noted, circuit of Figure 6. Typical values are at T
A
= +25°C.)
(Note 1)
PARAMETER
SYSTEM SPECIFICATIONS
5
Input Voltage Range
Quiescent Supply Current
REG Undervoltage Lockout
Hysteresis
REG Output Accuracy
REG Dropout
INTERNAL REFERENCE
Internal Reference Voltage
Internal Reference Voltage
Accuracy
Accuracy
Load Regulation
MOSFET DRIVERS
p-Channel Output Driver
Impedance
n-Channel Output Driver
Impedance
Output Driver Source Current
Output Driver Sink Current
Nonoverlap Time (Dead Time)
R
ON_P
R
ON_N
I
DH_
, I
DL_
I
DH_
, I
DL_
t
NO
C
DH_
or C
DL_
= 5nF
1.35
0.45
2.5
8
30
4
1.35
Ω
Ω
A
A
ns
V
EAN_
V
EAN_
EAN_ connected to EAOUT_ (Note 2)
V
IN
= V
REG
= 4.75V to 5.5V or V
IN
= 5V to
28V, EAN_ connected to EAOUT_ (Note 2)
I
REF
= 100µA
I
REF
= 0 to 200µA
-0.9
0.6135
+0.9
V
%
V
IN
I
IN
UVLO
V
HYST
V
IN
= 5.8V to 28V, I
SOURCE
= 0 to 65mA
V
IN
< 5.8V, I
SOURCE
= 60mA
4.75
IN and REG shorted together for +5V
operation
f
OSC
= 500kHz, DH_, DL_ = open
V
REG
rising
4.0
4.75
4
4.15
200
5.10
5.30
0.5
28
5.5
20
4.5
V
mA
V
mV
V
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
STARTUP/INTERNAL REGULATOR OUTPUT (REG)
EXTERNAL REFERENCE VOLTAGE OUTPUT (REF)
V
REF
3.23
3.2
3.3
3.37
3.4
V
V
2
_______________________________________________________________________________________
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
REG
= V
DD
= V
EN_
= +5V, T
A
= T
J
= T
MIN
to T
MAX
, unless otherwise noted, circuit of Figure 6. Typical values are at T
A
= +25°C.)
(Note 1)
PARAMETER
OSCILLATOR
1MHz (max)
switching
frequency per
phase
R
RT
= 12.4kΩ
R
RT
= 127kΩ
-7.5
-10
1.225
0.5
2.4
0.8
30
200
2000
1000
kHz
100
+7.5
+10
%
V
mA
V
V
ns
kHz
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX5066
Switching Frequency
f
SW
Switching Frequency Accuracy
RT/CLKIN Output Voltage
RT/CLKIN Current Sourcing
Capability
RT/CLKIN Logic-High Threshold
RT/CLKIN Logic-Low Threshold
RT/CLKIN High Pulse Width
RT/CLKIN Synchronization
Frequency Range
CURRENT LIMIT
Average Current-Limit Threshold
Reverse Current-Limit Threshold
Cycle-by-Cycle Current-Limit
Threshold
Cycle-by-Cycle Current-Limit
Response Time
DIGITAL FAULT INTEGRATION (DF_)
Number of Switching Cycles to
Shutdown in Current-Limit
Number of Switching Cycles to
Recover from Shutdown
CURRENT-SENSE AMPLIFIER
CSP_ to CSN_ Input Resistance
Common-Mode Range
Input Offset Voltage
Amplifier Gain
-3dB Bandwidth
CSP_ Input Bias Current
R
CS_
V
CMR(CS)
V
OS(CS)
A
V(CS)
f
-3dB
I
CSA(IN)
NS
DF_
NR
DF_
V
CL_
V
RCL_
V
CLpk_
t
R
V
RT/CLKIN
I
RT/CLKIN
V
RT/CLKIN_H
V
RT/CLKIN_L
t
RT/CLKIN
f
RT/CLKIN
f
SW
= 250kHz nominal, R
RT
= 50kΩ
f
SW
= 1MHz nominal, R
RT
= 12.4kΩ
V
CSP_
- V
CSN_
V
CSP_
- V
CSN_
V
CSP_
- V
CSN_
20.4
-3.13
22.5
-1.63
52.5
260
24.75
-0.1
mV
mV
mV
ns
32,768
524,288
Clock
cycles
Clock
cycles
kΩ
+3.6
+5.5
V
V
µV
V/V
MHz
120
30
µA
1.9835
V
IN
= V
REG
= 4.75V to 5.5V or
V
IN
= 5V to 10V
V
IN
= 7V to 28V
-0.3
-0.3
100
36
4
V
CSP_
= 5.5V, sinking
V
CSP_
= 0V, sourcing
_______________________________________________________________________________________
3
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
MAX5066
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
REG
= V
DD
= V
EN_
= +5V, T
A
= T
J
= T
MIN
to T
MAX
, unless otherwise noted, circuit of Figure 6. Typical values are at T
A
= +25°C.)
(Note 1)
PARAMETER
Transconductance
Open-Loop Gain
Open-Loop Gain
Unity-Gain Bandwidth
EAN_ Input Bias Current
Error Amplifier Output Clamping
High Voltage
Error Amplifier Output Clamping
Low Voltage
EN_ INPUTS
EN_ Input High Voltage
EN_ Hysteresis
EN_ Input Leakage Current
MODE INPUT
MODE Logic-High Threshold
MODE Logic-Low Threshold
MODE Input Pulldown
THERMAL SHUTDOWN
Thermal Shutdown
Thermal Shutdown Hysteresis
T
SHDN
T
HYST
160
10
°C
V
MODE_H
V
MODE_L
I
PULLDWN
5
2.4
0.8
V
V
µA
I
EN
-1
V
ENH
EN rising
1.204
1.222
0.05
+1
1.240
V
µA
SYMBOL
g
M
A
VOL(CEA)
A
VOL(EA)
f
UGEA
I
BIAS(EA)
V
CLMP_HI
(EA)
CONDITIONS
MIN
TYP
550
MAX
UNITS
µS
dB
dB
MHz
nA
V
V
CURRENT-ERROR AMPLIFIER (CEA_)
No load
50
70
3
V
EAN_
= 2.0V
With respect to V
CM
With respect to V
CM
100
1.14
-0.234
VOLTAGE ERROR AMPLIFIER (EAOUT_)
V
CLMP_LO
(EA)
Note 1:
The device is 100% production tested at T
A
= +85°C (MAX5066EUI) and T
A
= T
J
= +125°C (MAX5066AUI). Limits at -40°C
and +25°C 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.
4
_______________________________________________________________________________________
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
MAX5066
Typical Operating Characteristics
(Circuit of Figure 6, T
A
= +25°C, unless otherwise noted. V
IN
= 12V, V
OUT1
= 0.8V, V
OUT2
= 1.3V, f
SW
= 500kHz per phase.)
SUPPLY CURRENT
vs. TEMPERATURE AND FREQUENCY
(V
IN
= 5V)
MAX5066 toc01
OSCILLATOR FREQUENCY vs. R
T
10,000
OSCILLATOR FREQUENCY (kHz)
C
DH
= C
DL
= 0
16
14
SUPPLY CURRENT (mA)
12
10
8
6
4
2
10
0 100 200 300 400 500 600 700 800 900 1000
R
T
(kΩ)
0
SUPPLY CURRENT
vs. TEMPERATURE AND FREQUENCY
(V
IN
= 12V)
C
DH
= C
DL
= 0
f
SW
= 1MHz
14
SUPPLY CURRENT (mA)
12
10
8
6
4
2
0
f
SW
= 125kHz
f
SW
= 250kHz
f
SW
= 500kHz
MAX5066 toc02b
MAX5066 toc02a
C
DH
= C
DL
= 0
f
SW
= 1MHz
f
SW
= 500kHz
16
1000
f
SW
= 250kHz
f
SW
= 125kHz
100
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
SUPPLY CURRENT
vs. TEMPERATURE AND FREQUENCY
(V
IN
= 24V)
MAX5066 toc02c
SUPPLY CURRENT
vs. OSCILLATOR FREQUENCY
MAX5066 toc03
SUPPLY CURRENT
vs. DRIVER LOAD CAPACITANCE
90
80
SUPPLY CURRENT (mA)
70
60
50
40
30
20
10
0
C
LOAD
= C
DH
= C
DL
MAX5066 toc04
16
14
SUPPLY CURRENT (mA)
12
10
8
6
4
2
0
C
DH
= C
DL
= 0
f
SW
= 1MHz
14
C
DH_
= C
DL_
= 0
13
SUPPLY CURRENT (mA)
12
11
10
9
8
7
6
V
IN
= 5V
V
IN
= 24V
V
IN
= 12V
100
f
SW
= 500kHz
f
SW
= 250kHz
f
SW
= 125kHz
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
200 400 600 800 1000 1200 1400 1600 1800 2000
FREQUENCY (kHz)
0
5
10
15
C
LOAD
(nF)
20
25
30
REG LOAD REGULATION
MAX5066 toc05
REG LINE REGULATION
MAX5066 toc06
REF LOAD REGULATION
MAX5066 toc07
5.10
V
IN
= 24V
5.10
5.08
5.06
V
REG
(V)
I
REG
= 0
3.305
5.05
V
REG
(V)
3.300
V
IN
= 24V
V
REF
(V)
5.00
V
IN
= 5.5V
4.95
V
IN
= 12V
5.04
5.02
5.00
I
REG
= 60mA
4.98
3.295
V
IN
= 5V
3.290
V
IN
= 12V
4.90
0
10 20 30 40 50 60 70 80 90 100
I
REG
(mA)
4.96
5
7
9
11
13
15
17
19
21
23
V
IN
(V)
3.285
0
100 200 300 400 500 600 700 800
I
REF
(µA)
_______________________________________________________________________________________
5