19-4218; Rev 1; 10/11
KIT
ATION
EVALU
BLE
AVAILA
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
General Description
The MAX15034 two-phase, configurable single- or dual-
output buck controller has an input voltage range of
4.75V to 5.5V or 5V to 28V. A mode select input allows
for a dual-output supply or connecting two phases
together for a single-output, high-current supply. Each
output channel of the MAX15034 drives n-channel
MOSFETs and is capable of providing more than 25A of
load current. The MAX15034 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 volt-
age applications. Each controller has its own high-per-
formance current and voltage-error amplifier that can
be compensated for optimum output filter L-C values
and transient response.
The MAX15034 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 MAX15034 can be synchronized to an
external clock. Each output voltage is adjustable from
0.61V to 5.5V. Additional features include thermal shut-
down and hiccup-mode, short-circuit protection. Use the
MAX15034 with adaptive voltage positioning for applica-
tions that require a fast transient response or accurate
output voltage regulation.
The MAX15034 is available in a thermally enhanced 28-
pin TSSOP package capable of dissipating 2.1W. The
device is rated for operation over the -40°C to +125°C
automotive temperature range.
o
4.75V to 5.5V or 5V to 28V Input
o
Dual-Output Synchronous Buck Controller
o
Configurable for Two Separate Outputs (25A) or
One Single Output (50A)
o
Average Current-Mode Control with Accurate
Adjustable Current Limit
o
180° Interleaved Operation Reduces Size of Input
Filter Capacitors
o
Limits Reverse Current Sinking When Operated in
Parallel Mode
o
Each Output is Adjustable from 0.61V to 5.5V
o
Independently Programmable Adaptive Voltage
Positioning
o
Monotonic Startup into Prebiased Outputs
o
Independent Shutdown for Each Output
o
100kHz to 1MHz per Phase Programmable
Switching Frequency
o
Oscillator Frequency Synchronization from
200kHz to 2MHz
o
Digital Soft-Start on Outputs
o
Hiccup-Mode Overcurrent Protection
o
Overtemperature Shutdown
o
Thermally Enhanced 28-Pin TSSOP Package
Capable of Dissipating 2.1W
Features
MAX15034
Applications
High-End Computers/Workstations/Servers
Graphics Cards
Networking Systems
Point-of-Load High-Current/High-Density
Telecom DC-DC Regulators
RAID Systems
PART
MAX15034AAUI+
MAX15034BAUI+
MAX15034BAUI/V+
Ordering Information
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
28 TSSOP
28 TSSOP-EP*
28 TSSOP-EP*
+Denotes
a lead(Pb)-free/RoHS-compliant package.
*EP
= Exposed pad.
/V Denotes an automotive qualified part.
________________________________________________________________
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.
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
MAX15034
ABSOLUTE MAXIMUM RATINGS
IN, LX_ 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
AVGLIMIT, 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
Continuous Power Dissipation (T
A
= +70°C) (Note 1)
28-Pin TSSOP (derate 14mW/°C above +70°C) ..........1117mW
28-Pin TSSOP-EP (derate 27mW/°C above +70°C)........2162mW
Operating Temperature Range .........................-40°C to +125°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°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.
PACKAGE THERMAL CHARACTERISTICS (Note 1)
TSSOP
Junction-to-Ambient Thermal Resistance (θ
JA
)..................71.6°C/W
Junction-to-Case Thermal Resistance (θ
JC
)......................13°C/W
TSSOP-EP
Junction-to-Ambient Thermal Resistance (θ
JA
)..................37°C/W
Junction-to-Case Thermal Resistance (θ
JC
)......................2°C/W
Note 1:
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
(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 2)
PARAMETER
SYSTEM SPECIFICATIONS
5
Input Voltage Range
Quiescent Supply Current
REG Undervoltage Lockout
Hysteresis
REG Output Accuracy
REG Dropout
INTERNAL REFERENCE
Internal Reference Voltage
V
EAN_
EAN_ connected to
EAOUT_
(Note 3)
T
A
= -40°C to +125°C
0.605
0.6125
0.620
V
Clock
cycles
Steps
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_ or DL_ = open
V
REG
rising
4.0
4.75
7
4.15
200
5.10
5.30
0.5
28
5.50
17
4.5
V
mA
V
mV
V
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
STARTUP/INTERNAL REGULATOR OUTPUT (REG)
Digital Ramp Period for Soft-Start
Soft-Start Voltage Steps
MOSFET DRIVERS
p-Channel Output Driver
Impedance
R
ON_P
1024
64
1.35
3
Ω
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 2)
PARAMETER
n-Channel Output Driver
Impedance
Output Driver Source Current
Output Driver Sink Current
Nonoverlap Time (Dead Time)
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
Internal Average Current-Limit
Threshold
Reverse Average Current-Limit
Threshold
External Average Current-Limit
Threshold Adjustment
AVGLIMIT Ground Threshold
Voltage
Leakage Current at AVGLIMIT
V
CL_
V
RCL_
V
CL_ADJ
V
AVGLIMIT_GND
I
AVGLIMIT
V
AVGLIMIT
= 3V
V
CSP_
- V
CSN_
V
CSP_
- V
CSN_
Resistor-divider connected from REG
to AVGLIMIT to AGND
20.4
-3.0
22.5
-1.53
V
AVGLIMIT
-
0.6/36
550
100
24.75
-0.1
mV
mV
V
mV
nA
SYMBOL
R
ON_N
I
DH_
, I
DL_
I
DH_
, I
DL_
t
NO
V
RT/CLKIN
I
RT/CLKIN
V
RT/CLKIN_H
V
RT/CLKIN_L
t
RT/CLKIN
f
RT/CLKIN
200
30
2000
2.4
0.8
C
DH_
or C
DL_
= 5nF
f
SW
= 1MHz nominal, R
RT
= 12.4kΩ
-7.5
-10
1.225
0.5
CONDITIONS
MIN
TYP
0.45
2.5
5
+7.5
+10
MAX
1.35
UNITS
Ω
A
A
%
V
mA
V
V
ns
kHz
MAX15034
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
R
CS_
V
CMR(CS)
V
OS(CS)
A
V(CS)
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
3.8
+3.6
+5.5
kΩ
V
V
µV
V/V
NS
DF_
NR
DF_
32,768
524,288
Clock
cycles
Clock
cycles
_______________________________________________________________________________________
3
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
MAX15034
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 2)
PARAMETER
-3dB Bandwidth
CSP_ Input Bias Current
SYMBOL
f
-3dB
I
CSA(IN)
V
CSP_
= 5.5V, sinking
V
CSP_
= 0V, sourcing
550
No load
50
70
3
V
EAN_
= 2.0V
With respect to V
CM
With respect to V
CM
100
1
-0.234
CONDITIONS
MIN
TYP
4
120
30
MAX
UNITS
MHz
µA
CURRENT-ERROR AMPLIFIER (CEA_)
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
Startup Delay Time to OUT_
MODE INPUT
MODE Logic-High Threshold
MODE Logic-Low Threshold
MODE Input Pulldown
PREBIASED OUTPUT
Peak Sink Current-Limit
Threshold during Reference
Soft-Start
Digital Ramp Period for
Stepping Peak Sink Current
Limit after Reference Soft-Start
THERMAL SHUTDOWN
Thermal Shutdown
Thermal Shutdown Hysteresis
T
SHDN
T
HYST
160
10
°C
V
CSP_
- V
CSN_
-2.1
mV
V
MODE_H
V
MODE_L
I
PULLDWN
5
2.4
0.8
V
V
µA
I
EN
t
START_DELAY
From EN_ rising to V
OUT_
rising
-200
1
V
ENH
EN rising
1.2
1.222
0.05
+200
1.245
V
nA
ms
g
m
A
VOL(CEA)
A
VOL(EA)
f
UGEA
I
BIAS(EA)
V
CLMP_HI (EA)
V
CLMP_LO (EA
)
µS
dB
dB
MHz
nA
V
V
VOLTAGE-ERROR AMPLIFIER (EAOUT_)
448
Clock
cycles
Note 2:
The device is 100% production tested at T
A
= T
J
= +125°C. Limits at T
A
= -40°C and T
A
= +25°C are guaranteed by design.
Note 3:
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
MAX15034
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)
MAX15034 toc01
MAX15034 toc02a
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
MAX15034 toc02b
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)
MAX15034 toc02c
SUPPLY CURRENT
vs. OSCILLATOR FREQUENCY
MAX15034 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_
MAX15034 toc04
16
14
SUPPLY CURRENT (mA)
12
10
8
6
4
2
0
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
C
DH_
= C
DL_
= 0
f
SW
= 1MHz
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
MAX15034 toc05
REG LINE REGULATION
MAX15034 toc06
OUTPUT LOAD-TRANSIENT RESPONSE
MAX15034 toc07
5.10
V
IN
= 24V
5.10
5.08
5.06
V
REG
(V)
5.04
5.02
5.00
I
REG
= 60mA
4.98
I
REG
= 0
20A
I
OUT
10A/div
5.05
V
REG
(V)
5.00
V
IN
= 5.5V
4.95
V
IN
= 12V
V
OUT
100mV/div
AC-COUPLED
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
2ms/div
V
IN
(V)
_______________________________________________________________________________________
5
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