Rainbow Electronics MAX15038 - Manual

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
Features
♦ Internal 31mΩ R
DS(ON)
High-Side and 24m
Ω
R
DS(ON)
Low-Side MOSFETs
♦ Continuous 4A 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
MAX15038
4A, 2MHz Step-Down Regulator
with Integrated Switches
________________________________________________________________ Maxim Integrated Products 1
OUTPUT
1.8V, 4A
INPUT
2.9V TO 5.5V
BST
LX
OUT
IN
EN
V DD
CTL2
CTL1
PGND
FB
V DD COMP
PWRGD
FREQ
REFIN
SS
GND
MODE
MAX15038
Typical Operating Circuit
Ordering Information
19-4320; Rev 0; 10/08
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.
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.
Pin Configuration appears at end of data sheet.
EVALUATION KIT
AVAILABLE