MAX15038 Datasheet, PDF (1/18 Pages) Maxim Integrated Products – 4A, 2MHz Step-Down Regulator with Integrated Switches

19-4320; Rev 0; 10/08
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4A, 2MHz Step-Down Regulator
with Integrated Switches
General Description
The MAX15038 high-efficiency switching regulator
delivers up to 4A 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 MAX15038 features fixed-frequency PWM mode
operation with a switching frequency range of 500kHz
to 2MHz set by an external resistor. The MAX15038
provides the option of operating in a pulse-skip mode
to improve light-load efficiency. High-frequency opera-
tion 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 MAX15038 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 MAX15038 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 MAX15038 offers programmable soft-start
time using one capacitor to reduce input inrush current.
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
Pin Configuration appears at end of data sheet.
Features
o Internal 31mΩ R_DS(ON) High-Side and 24mΩ
R_DS(ON) Low-Side MOSFETs
o Continuous 4A Output Current Over Temperature
o ±1% Output Accuracy Over Load, Line, and
Temperature
o Operates from 2.9V to 5.5V V_IN Supply
o Adjustable Output from 0.6V to (0.9 x V_IN)
o Soft-Start Reduces Inrush Supply Current
o 500kHz to 2MHz Adjustable Switching Frequency
o Compatible with Ceramic, Polymer, and
Electrolytic Output Capacitors
o 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
o Monotonic Startup for Safe-Start into Prebiased
Outputs
o Selectable Forced PWM or Skip Mode for Light
Load Efficiency
o Overcurrent and Overtemperature Protection
o Output Current Sink/Source Capable with Cycle-
by-Cycle Protection
o Open-Drain Power-Good Output
o Lead-Free, 4mm x 4mm, 24-Pin Thin QFN Package
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX15038ETG+ -40°C to +85°C
24 Thin QFN-EP*
+Denotes a lead-free/RoHS-compliant package.
*EP = Exposed pad.
Typical Operating Circuit
INPUT
2.9V TO 5.5V
IN
BST
MAX15038
EN
LX
VDD
OUT
OUTPUT
1.8V, 4A
PGND
CTL2
CTL1
FB
FREQ
REFIN
SS
COMP
VDD
MODE
PWRGD
GND
________________________________________________________________ Maxim Integrated Products 1
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