Rainbow Electronics MAX15034 User Manual
General Description
The MAX15034 two-phase, configurable single- or dualoutput 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 currentmode 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 controller 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 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 shutdown and hiccup-mode, short-circuit protection. Use the
MAX15034 with adaptive voltage positioning for applications that require a fast transient response or accurate
output voltage regulation.
The MAX15034 is available in a thermally enhanced 28pin TSSOP package capable of dissipating 2.1W. The
device is rated for operation over the -40°C to +125°C
automotive temperature range.
Applications
High-End Computers/Workstations/Servers
Graphics Cards
Networking Systems
Point-of-Load High-Current/High-Density
Telecom DC-DC Regulators
RAID Systems
Features
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
MAX15034
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
________________________________________________________________
Maxim Integrated Products
1
Ordering Information
19-4218; Rev 0; 7/08
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.
+
Denotes a lead-free/RoHS-compliant package.
*
EP = Exposed pad.
PART TEMP RANGE PIN-PACKAGE
MAX15034AAUI+ -40°C to +125°C 28 TSSOP
MAX15034BAUI+ -40°C to +125°C 28 TSSOP-EP*
MAX15034
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, 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
Package Thermal Resistance (θ
JA
) (Note 1)
MAX15034A ................................................................71.6°C/W
MAX15034B ...................................................................37°C/W
Package Thermal Resistance (θ
JC
) (Note 1)
MAX15034A ...................................................................13°C/W
MAX15034B .....................................................................2°C/W
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
ELECTRICAL CHARACTERISTICS
(VIN= V
REG
= VDD= V
EN_
= +5V, TA= TJ= T
MIN
to T
MAX
, unless otherwise noted, circuit of Figure 6. Typical values are at TA= +25°C.)
(Note 2)
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
.
SYSTEM SPECIFICATIONS
Input Voltage Range V
Quiescent Supply Current I
STARTUP/INTERNAL REGULATOR OUTPUT (REG)
REG Undervoltage Lockout UVLO V
Hysteresis V
REG Output Accuracy VIN = 5.8V to 28V, I
REG Dropout VIN < 5.8V, I
INTERNAL REFERENCE
Internal Reference Voltage V
Digital Ramp Period for Soft-Start 1024
Soft-Start Voltage Steps 64 Steps
MOSFET DRIVERS
p-Channel Output Driver
Impedance
n-Channel Output Driver
Impedance
Output Driver Source Current I
Output Driver Sink Current I
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
R
R
DH_
DH_
IN
IN
HYST
EAN_
ON_P
ON_N
, I
DL_
, I
DL_
IN and REG shorted together for +5V
operation
f
= 500kHz, DH_ or DL_ = open 7 17 mA
OSC
rising 4.0 4.15 4.5 V
REG
SOURCE
= 60mA 0.5 V
SOURCE
EAN_ connected to
EAOUT_
(Note 3)
T
= 0 to 65mA 4.75 5.10 5.30 V
= -40°C to +125°C 0.605 0.6125 0.620 V
A
528
4.75 5.50
200 mV
1.35 3 Ω
0.45 1.35 Ω
2.5 A
5A
V
Clock
cycles
MAX15034
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VIN= V
REG
= VDD= V
EN_
= +5V, TA= TJ= T
MIN
to T
MAX
, unless otherwise noted, circuit of Figure 6. Typical values are at TA= +25°C.)
(Note 2)
Nonoverlap Time (Dead Time) t
RT/CLKIN Output Voltage V
RT/CLKIN Current Sourcing
Capability
RT/CLKIN Logic-High Threshold V
RT/CLKIN Logic-Low Threshold V
RT/CLKIN High Pulse Width t
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
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
NO
RT/CLKIN
I
RT/CLKIN
RT/CLKIN_H
RT/CLKIN_L
RT/CLKIN
f
RT/CLKIN
V
CL_
V
RCL_
V
CL_ADJ
V
AVGLIMIT_GND
C
or C
DH_
fSW = 1MHz nominal, RRT = 12.4kΩ -10 +10
V
CSP_
V
CSP_
Resistor-divider connected from REG
to AVGLIMIT to AGND
- V
- V
DL_
CSN_
CSN_
= 5nF
-7.5 +7.5
1.225 V
0.5 mA
2.4 V
0.8 V
30 ns
200 2000 kHz
20.4 22.5 24.75 mV
-3.0 -1.53 -0.1 mV
V
AVGLIMIT
-
0.6/36
550 mV
%
V
Leakage Current at AVGLIMIT I
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 R
Common-Mode Range V
Input Offset Voltage V
Amplifier Gain A
AVGLIMIT
NS
NR
CMR(CS)
DF_
DF_
CS_
OS(CS)
V(CS)
V
AVGLIMIT
VIN = V
V
IN
VIN = 7V to 28V -0.3 +5.5 V
= 3V 100 nA
32,768
524,288
3.8 kΩ
= 4.75V to 5.5V or
REG
= 5V to 10V
-0.3 +3.6 V
100 μV
36 V/V
Clock
cycles
Clock
cycles
MAX15034
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(VIN= V
REG
= VDD= V
EN_
= +5V, TA= TJ= T
MIN
to T
MAX
, unless otherwise noted, circuit of Figure 6. Typical values are at TA= +25°C.)
(Note 2)
)
Note 2: The device is 100% production tested at TA= TJ= +125°C. Limits at TA= -40°C and TA= +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.
-3dB Bandwidth f
CSP_ Input Bias Current I
CURRENT-ERROR AMPLIFIER (CEA_)
Transconductance g
Open-Loop Gain A
VOLTAGE-ERROR AMPLIFIER (EAOUT_)
Open-Loop Gain A
Unity-Gain Bandwidth f
EAN_ Input Bias Current I
Error-Amplifier Output Clamping
High Voltage
Error-Amplifier Output Clamping
Low Voltage
EN_ INPUTS
EN_ Input High Voltage V
EN_ Hysteresis 0.05
EN_ Input Leakage Current I
Startup Delay Time to OUT_ t
MODE INPUT
MODE Logic-High Threshold V
MODE Logic-Low Threshold V
MODE Input Pulldown I
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 T
Thermal Shutdown Hysteresis T
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
-3dB
CSA(IN)
m
VOL(CEA)
VOL(EA)
UGEA
BIAS(EA)
V
C LM P_ H I (E A)
V
C LM P_LO ( EA
ENH
EN
START_DELAY
MODE_H
MODE_L
PULLDWN
SHDN
HYST
4 MHz
V
= 5.5V, sinking 120
CSP_
V
= 0V, sourcing 30
CSP_
550 μS
No load 50 dB
70 dB
3 MHz
V
= 2.0V 100 nA
EAN_
With respect to V
With respect to V
EN rising 1.2 1.222 1.245
From EN_ rising to V
- V
V
CSP_
CSN_
CM
CM
-200 +200 nA
rising 1 ms
OUT_
2.4 V
1V
-0.234 V
0.8 V
5μA
-2.1 mV
448
160
10
μA
V
Clock
cycles
°C
MAX15034
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
OSCILLATOR FREQUENCY vs. R
T
MAX15034 toc01
RT (kΩ)
OSCILLATOR FREQUENCY (kHz)
900800700600500400300200100
100
1000
10,000
10
0 1000
C
DH_
= C
DL_
= 0
SUPPLY CURRENT
vs. TEMPERATURE AND FREQUENCY
(V
IN
= 5V)
MAX15034 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
C
DH_
= C
DL_
= 0
fSW = 1MHz
fSW = 250kHz
fSW = 500kHz
fSW = 125kHz
SUPPLY CURRENT
vs. TEMPERATURE AND FREQUENCY
(V
IN
= 12V)
MAX15034 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
C
DH_
= C
DL_
= 0
fSW = 1MHz
fSW = 250kHz
fSW = 500kHz
fSW = 125kHz
SUPPLY CURRENT
vs. TEMPERATURE AND FREQUENCY
(V
IN
= 24V)
MAX15034 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
C
DH_
= C
DL_
= 0
fSW = 1MHz
fSW = 250kHz
fSW = 500kHz
fSW = 125kHz
SUPPLY CURRENT
vs. OSCILLATOR FREQUENCY
MAX15034 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
MAX15034 toc04
C
LOAD
(nF)
SUPPLY CURRENT (mA)
252015105
10
20
30
40
50
60
70
80
90
100
0
030
C
LOAD
= C
DH_
= C
DL_
REG LOAD REGULATION
MAX15034 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
MAX15034 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
OUTPUT LOAD-TRANSIENT RESPONSE
MAX15034 toc07
2ms/div
10A/div
I
OUT
V
OUT
100mV/div
AC-COUPLED
20A
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.)
_______________________________________________________________________________________ 5
MAX15034
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
6 _______________________________________________________________________________________
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.)
DRIVER RISE TIME
vs. LOAD CAPACITANCE
100
90
80
70
60
(ns)
50
RISE
t
40
30
20
10
0
022
HIGH-SIDE DRIVER RISE TIME
= 12V, C
(V
IN
DRIVER FALL TIME
vs. LOAD CAPACITANCE
40
DH_
C
(nF)
LOAD
MAX15034 toc08
DL_
201814 164 6 8 10 122
35
30
25
(ns)
20
FALL
t
15
10
5
0
022
C
(nF)
LOAD
DL_
DH_
MAX15034 toc09
201814 164 6 8 10 122
HIGH-SIDE DRIVER FALL TIME
LOAD
= 10nF)
MAX15034 toc10
DH_
2V/div
(V
IN
= 12V, C
LOAD
= 10nF)
MAX15034 toc11
DH_
2V/div
= 12V, C
IN
20ns/div
LOAD
20ns/div
= 10nF)
20ns/div
LOW-SIDE DRIVER RISE TIME
(V
IN
= 12V, C
LOAD
20ns/div
= 10nF)
MAX15034 toc12
DL_
2V/div
LOW-SIDE DRIVER FALL TIME
(V
MAX15034 toc13
DL_
2V/div
MAX15034
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
TURN-ON/TURN-OFF WAVEFORM
MAX15034 toc15
1ms/div
V
OUT1
1V/div
EN1
5V/div
EN2
5V/div
V
OUT2
1V/div
_______________________________________________________________________________________ 7
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.)
SHORT-CIRCUIT CURRENT WAVEFORMS
(V
IN
= 5V)
MAX15034 toc16
200ms/div
I
OUT2
10A/div
I
OUT1
10A/div
AVERAGE CURRENT LIMIT
vs. V
AVGLIMIT
MAX15034 toc17
V
AVGLIMIT
(V)
AVERAGE CURRENT LIMIT (mV)
15
30
45
60
75
0
2.52.01.51.00.503.0
INTERNAL REFERENCE VOLTAGE
vs. TEMPERATURE
MAX15034 toc18
TEMPERATURE (°C)
INTERNAL REFERENCE VOLTAGE (V)
1109580655035205-10-25
0.610
0.615
0.620
0.605
-40 125
SWITCHING FREQUENCY
vs. TEMPERATURE
MAX15034 toc19
TEMPERATURE (°C)
SWITCHING FREQUENCY (kHz)
475
500
525
550
450
1109580655035205-10-25-40 125
OUT1/OUT2 OUT-OF-PHASE WAVEFORMS
(V
OUT1
= 0.8V, V
10μs/div
OUT2
= 1.3V)
MAX15034 toc14
LX1
10V/div
OUT1
100mV/div
LX2
10V/div
OUT2
100mV/div
MAX15034
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
8 _______________________________________________________________________________________
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.)
SOFT-START WAVEFORM
MAX15034 toc22
400μs/div
EN2
5V/div
V
OUT2
500mV/div
V
EAN2
200mV/div
PREBIASED OUTPUT CONDITION
MAX15034 toc23
400μs/div
EN2
5V/div
0V
V
OUT2
500mV/div
DH2
5V/div
DL2
5V/div
EAOUT2
1V/div
INTERNAL AVERAGE CURRENT LIMIT
vs. TEMPERATURE
MAX15034 toc20
TEMPERATURE (°C)
INTERNAL AVERAGE CURRENT LIMIT (mV)
21
22
23
24
25
20
1109580655035205-10-25-40 125
INTERNAL AVERAGE REVERSE
CURRENT LIMIT vs. TEMPERATURE
MAX15034 toc21
INTERNAL AVERAGE CURRENT LIMIT (mV)
-2.5
-2.0
-1.5
-1.0
-0.5
0
-3.0
TEMPERATURE (°C)
1109580655035205-10-25-40 125
PEAK PULLUP AND PULLDOWN CURRENT
OR DRIVER AT DH_ AND DL_
MAX15034 toc24
200ns/div
C
LOAD
= 10nF
DH_
500mV/div
DL_
500mV/div
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