19-4321; Rev 3; 12/10
KIT
ATION
EVALU
BLE
AVAILA
6A, 2MHz Step-Down Regulator
with Integrated Switches
General Description
Features
♦
Internal 26mΩ R
DS(ON)
High-Side and 20mΩ
R
DS(ON)
Low-Side MOSFETs
♦
Continuous 6A Output Current Over Temperature
♦
±1% Output Accuracy Over Load, Line, and
Temperature
♦
Operates from 2.9V to 5.5V V
IN
Supply
♦
Adjustable Output from 0.6V to (0.9 x V
IN
)
♦
Soft-Start Reduces Inrush Supply Current
♦
500kHz to 2MHz Adjustable Switching Frequency
♦
Compatible with Ceramic, Polymer, and
Electrolytic Output Capacitors
♦
Nine Preset and Adjustable Output Voltages
0.6V, 0.7V, 0.8V, 1.0V, 1.2V, 1.5V, 1.8V, 2.0V,
2.5V, and Adjustable
♦
Monotonic Startup for Safe-Start Into Prebiased
Outputs
♦
Selectable Forced PWM or Skip Mode for Light
Load Efficiency
♦
Overcurrent and Overtemperature Protection
♦
Output Current Sink/Source Capable with Cycle-
by-Cycle Protection
♦
Open-Drain, Power-Good Output
♦
Lead-Free, 4mm x 4mm, 24-Pin Thin QFN Package
MAX15039
The MAX15039 high-efficiency switching regulator
delivers up to 6A load current at output voltages from
0.6V to 90% of V
IN
. The IC operates from 2.9V to 5.5V,
making it ideal for on-board point-of-load and postregu-
lation applications. Total output error is less than ±1%
over load, line, and temperature ranges.
The MAX15039 features fixed-frequency PWM mode
operation with a switching frequency range of 500kHz
to 2MHz set by an external resistor. The MAX15039
provides the option of operating in a skip mode to
improve light-load efficiency. High-frequency operation
allows for an all-ceramic capacitor design. The high
operating frequency also allows for small-size external
components.
The low-resistance on-chip nMOS switches ensure high
efficiency at heavy loads while minimizing critical induc-
tances, making the layout a much simpler task with
respect to discrete solutions. Following a simple layout
and footprint ensures first-pass success in new designs.
The MAX15039 comes with a high bandwidth (28MHz)
voltage-error amplifier. The voltage-mode control archi-
tecture and the voltage-error amplifier permit a type III
compensation scheme to be utilized to achieve maxi-
mum loop bandwidth, up to 20% of the switching fre-
quency. High loop bandwidth provides fast transient
response, resulting in less required output capacitance
and allowing for all-ceramic-capacitor designs.
The MAX15039 provides two three-state logic inputs to
select one of nine preset output voltages. The preset
output voltages allow customers to achieve
±1%
out-
put-voltage accuracy without using expensive 0.1%
resistors. In addition, the output voltage can be set to
any customer value by either using two external resis-
tors at the feedback with a 0.6V internal reference or
applying an external reference voltage to the REFIN
input. The MAX15039 offers programmable soft-start
time using one capacitor to reduce input inrush current.
Ordering Information
PART
MAX15039ETG+
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
24 Thin QFN-EP*
+Denotes
a lead(Pb)-free/RoHS-compliant package.
*EP
= Exposed pad.
Typical Operating Circuit
INPUT
2.9V TO 5.5V
IN
BST
EN
V
DD
MAX15039
LX
OUT
OUTPUT
1.8V, 6A
Applications
Server Power Supplies
POLs
ASIC/CPU/DSP Core and I/O Voltages
DDR Power Supplies
Base-Station Power Supplies
Telecom and Networking Power Supplies
RAID Control Power Supplies
CTL2
CTL1
FREQ
REFIN
SS
PGND
FB
COMP
V
DD
MODE
GND
PWRGD
Pin Configuration appears at end of data sheet.
________________________________________________________________
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.
6A, 2MHz Step-Down Regulator
with Integrated Switches
MAX15039
ABSOLUTE MAXIMUM RATINGS
IN, PWRGD to GND..................................................-0.3V to +6V
V
DD
to GND..................-0.3V to the lower of +4V or (V
IN
+ 0.3V)
COMP, FB, MODE, REFIN, CTL1, CTL2, SS,
FREQ to GND ..........................................-0.3V to (V
DD
+ 0.3V)
OUT, EN to GND ......................................................-0.3V to +6V
BST to LX..................................................................-0.3V to +6V
BST to GND ............................................................-0.3V to +12V
PGND to GND .......................................................-0.3V to +0.3V
LX to PGND ..................-0.3V to the lower of +6V or (V
IN
+ 0.3V)
LX to PGND ..........-1V to the lower of +6V or (V
IN
+ 1V) for 50ns
I
LX(RMS)
(Note 1) ......................................................................6A
V
DD
Output Short-Circuit Duration .............................Continuous
Converter Output Short-Circuit Duration ....................Continuous
Continuous Power Dissipation (T
A
= +70°C)
24-Pin TQFN (derate 27.8mW/°C above +70°C) ........2222mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°C
Note 1:
LX has internal clamp diodes to PGND and IN. Applications that forward bias these diodes should take care not to exceed
the IC’s package power dissipation limits.
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 2)
TQFN
Junction-to-Ambient Thermal Resistance (
θ
JA
) ............36°C/W
Junction-to-Case Resistance (
θ
JC
).................................6°C/W
Note 2:
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
EN
= 5V, C
VDD
= 2.2µF, T
A
= T
J
= -40°C to +85°C, typical values are at T
A
= +25°C, circuit of Figure 1, unless otherwise
noted.) (Note 3)
PARAMETER
IN
IN Voltage Range
IN Supply Current
Total Shutdown Current from IN
3.3V LDO (V
DD
)
V
DD
rising
V
DD
Undervoltage Lockout
Threshold
V
DD
Output Voltage
V
DD
Dropout
V
DD
Current Limit
BST
BST Supply Current
PWM COMPARATOR
PWM Comparator Propagation
Delay
PWM Peak-to-Peak Ramp
Amplitude
PWM Valley Amplitude
10mV overdrive
20
1
0.8
ns
V
V
V
BST
= V
IN
= 5V, V
LX
= 0 or 5V, V
EN
= 0V
0.025
µA
LX starts/stops switching
V
DD
falling
Minimum glitch-width
rejection
V
IN
= 5V, I
VDD
= 0 to 10mA
V
IN
= 2.9V, I
VDD
= 10mA
V
IN
= 5V, V
DD
= 0V
25
40
3.1
2.35
2.6
2.55
10
3.3
3.5
0.08
2.8
V
µs
V
V
mA
f
S
= 1MHz, no load
V
IN
= 5V, V
EN
= 0V
V
IN
= V
DD
= 3.3V, V
EN
= 0V
V
IN
= 3.3V
V
IN
= 5V
2.9
4.9
5.2
10
45
5.5
8
8.5
20
V
mA
µA
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
6A, 2MHz Step-Down Regulator
with Integrated Switches
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
EN
= 5V, C
VDD
= 2.2μF, T
A
= T
J
= -40°C to +85°C, typical values are at T
A
= +25°C, circuit of Figure 1, unless otherwise
noted.) (Note 3)
PARAMETER
ERROR AMPLIFIER
COMP Clamp Voltage, High
COMP Clamp Voltage, Low
COMP Slew Rate
COMP Shutdown Resistance
Internally Preset Output Voltage
Accuracy
FB Set-Point Value
FB to OUT Resistor
Open-Loop Voltage Gain
Error-Amplifier Unity-Gain
Bandwidth
Error-Amplifier and REFIN
Common-Mode Input Range
Error-Amplifier Maximum Output
Current
FB Input Bias Current
CTL_
CTL_ Input Bias Current
V
CTL_
= 0V
V
CTL_
= V
DD
Low, falling
CTL_ Input Threshold
Open
High, rising
Hysteresis
REFIN
REFIN Input Bias Current
REFIN Offset Voltage
LX (All Pins Combined)
LX On-Resistance, High Side
LX On-Resistance, Low Side
I
LX
= -2A
I
LX
= 2A
High-side sourcing
LX Current-Limit Threshold
Low-side sinking
Zero-crossing current threshold, MODE = V
DD
LX Leakage Current
V
IN
= 5V, V
EN
= 0V
V
LX
= 0V
V
LX
= 5V
V
IN
= V
BST
- V
LX
= 3.3V
V
IN
= V
BST
- V
LX
= 5V
V
IN
= 3.3V
V
IN
= 5V
9
35
26
25
20
11
11
0.2
-0.01
-0.01
μA
A
35
45
mΩ
mΩ
V
REFIN
= 0.6V
V
REFIN
= 0.9V, FB shorted to COMP
-4.5
-185
+4.5
nA
mV
All VID transitions
-7.2
7.2
0.8
V
DD
/2
V
DD
-
0.8
50
mV
V
μA
V
DD
= 2.9V to 3.5V
V
COMP
= 1V,
V
REFIN
= 0.6V
V
FB
= 0.7V, sinking
V
FB
= 0.5V, sourcing
0
1
-1
-125
V
IN
= 2.9V to 5V, V
FB
= 0.5V, V
REFIN
= 0.6V
V
IN
= 2.9V to 5V, V
FB
= 0.7V, V
REFIN
= 0.6V
V
FB
step from 0.5V to 0.7V in 10ns
From COMP to GND, V
IN
= 3.3V, V
COMP
= 100mV,
V
EN
= V
SS
= 0V
V
REFIN
= V
SS
, MODE = GND
CTL1 = CTL2 = GND, MODE = GND
All VID settings except CTL1 = CTL2 = GND
-1
0.594
5.5
0.6
8
115
28
V
DD
- 2
2
0.7
1.6
6
+1
0.606
10.5
V
V
V/μs
Ω
%
V
kΩ
dB
MHz
V
mA
nA
CONDITIONS
MIN
TYP
MAX
UNITS
MAX15039
CTL1 = CTL2 = GND
_______________________________________________________________________________________
3
6A, 2MHz Step-Down Regulator
with Integrated Switches
MAX15039
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
EN
= 5V, C
VDD
= 2.2μF, T
A
= T
J
= -40°C to +85°C, typical values are at T
A
= +25°C, circuit of Figure 1, unless otherwise
noted.) (Note 3)
PARAMETER
LX Switching Frequency
Switching Frequency Range
LX Minimum Off-Time
LX Maximum Duty Cycle
LX Minimum Duty Cycle
Average Short-Circuit IN Supply
Current
RMS LX Output Current
ENABLE
EN Input Logic-Low Threshold
EN Input Logic-High Threshold
EN Input Current
MODE
Logic-low, falling
MODE Input-Logic Threshold
MODE Input-Logic Hysteresis
MODE Input Bias Current
SS
SS Current
THERMAL SHUTDOWN
Thermal-Shutdown Threshold
Thermal-Shutdown Hysteresis
POWER GOOD (PWRGD)
Power-Good Threshold Voltage
Power-Good Edge Deglitch
PWRGD Output-Voltage Low
PWRGD Leakage Current
HICCUP OVERCURRENT LIMIT
Current-Limit Startup Blanking
Autoretry Restart Time
112
896
Clock
cycles
Clock
cycles
V
FB
falling, V
REFIN
= 0.6V
V
FB
rising, V
REFIN
= 0.6V
V
FB
rising or falling
I
PWRGD
= 4mA
V
IN
= V
PWRGD
= 5V, V
FB
= 0.7V, V
REFIN
= 0.6V
88
90
92.5
48
0.03
0.01
0.1
92
%
V
REFIN
Clock
cycles
V
μA
Rising
165
25
°C
°C
V
SS
= 0.45V, V
REFIN
= 0.6V, sourcing
6.7
8
9.3
μA
Logic V
DD
/2 or open, rising
Logic-high, rising
MODE falling
MODE = GND
MODE = V
DD
26
50
74
5
-5
5
%V
DD
μA
%V
DD
EN falling
EN rising
V
EN
= 0 or 5V, V
IN
= 5V
1.5
0.01
0.9
V
V
μA
R
FREQ
= 49.9kΩ
R
FREQ
= 49.9kΩ
OUT connected to GND, V
IN
= 5V
6
92
95
5
0.35
15
V
IN
= 2.9V to 5.5V
CONDITIONS
R
FREQ
= 49.9kΩ
R
FREQ
= 23.6kΩ
MIN
0.9
1.8
500
TYP
1
2
MAX
1.1
2.2
2000
78
UNITS
MHz
kHz
ns
%
%
A
A
4
_______________________________________________________________________________________
6A, 2MHz Step-Down Regulator
with Integrated Switches
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
EN
= 5V, C
VDD
= 2.2μF, T
A
= T
J
= -40°C to +85°C, typical values are at T
A
= +25°C, circuit of Figure 1, unless otherwise
noted.) (Note 3)
PARAMETER
FB Hiccup Threshold
Hiccup Threshold Blanking Time
V
FB
falling
V
FB
falling
CONDITIONS
MIN
TYP
70
28
MAX
UNITS
%
V
REFIN
μs
MAX15039
Note 3:
Specifications are 100% production tested at T
A
= +25°C. Limits over the operating temperature range are guaranteed by design.
Typical Operating Characteristics
(Typical values are V
IN
= V
EN
= 5V, V
OUT
= 1.8V, R
FREQ
= 49.9kΩ, I
OUT
= 6A, T
A
= +25°C, circuit of Figure 1, unless otherwise noted.)
EFFICIENCY
vs. OUTPUT CURRENT
MAX15039 toc01
EFFICIENCY
vs. OUTPUT CURRENT
MAX15039 toc02
FREQUENCY
vs. INPUT VOLTAGE
2.15
2.10
FREQUENCY (MHz)
MAX15039 toc03
100
90
EFFICIENCY (%)
80
70
60
V
OUT
= 1.2V
50
40
0.1
1.0
OUTPUT CURRENT (A)
PWM
SKIP
100
90
EFFICIENCY (%)
80
70
60
50
V
IN
= 3.3V
40
V
OUT
= 2.5V
V
OUT
= 1.8V
V
OUT
= 1.2V
2.20
V
OUT
= 2.5V
V
OUT
= 1.8V
2.05
2.00
1.95
1.90
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
R
FREQ
= 23.2kΩ
1.80
2.5
3.0
3.5
4.0
4.5
5.0
5.5
INPUT VOLTAGE (V)
PWM
SKIP
1.0
OUTPUT CURRENT (A)
10.0
1.85
10.0
0.1
FREQUENCY
vs. INPUT VOLTAGE
MAX15039 toc04
LOAD REGULATION
-0.05
OUTPUT-VOLTAGE CHANGE (%)
-0.10
-0.15
-0.20
-0.25
-0.30
-0.35
-0.40
-0.45
-0.50
-0.12
0
1
2
3
4
5
6
7
2.5
5.5
V
OUT
= 1.8V
V
OUT
= 2.5V
V
OUT
= 1.2V
MAX15039 toc05a
LINE REGULATION (LOAD = 6A)
MAX15039 toc05b
1.20
1.15
1.10
FREQUENCY (MHz)
1.05
1.00
0.95
0.90
0.85
0.80
2.5
3.0
3.5
4.0
4.5
5.0
INPUT VOLTAGE (V)
T
A
= -40°C
R
FREQ
= 49.9kΩ
T
A
= +25°C
T
A
= +85°C
0
0
OUTPUT-VOLTAGE CHANGE (%)
-0.02
V
OUT
= 1.8V
-0.04
-0.06
-0.08
V
OUT
= 1.2V
-0.10
3.0
3.5
4.0
4.5
5.0
5.5
LOAD CURRENT (A)
INPUT VOLTAGE (V)
_______________________________________________________________________________________
5
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