MAX1830 Datasheet, PDF (1/13 Pages) Maxim Integrated Products – 3A, 1MHz, Low-Voltage, Step-Down Regulators with Synchronous Rectification and Internal Switches

19-2198; Rev 0; 10/01
EVALUATION ^KIT
AVAILABLE
3A, 1MHz, Low-Voltage, Step-Down Regulators with
Synchronous Rectification and Internal Switches
General Description
The MAX1830/MAX1831 constant-off-time, pulse-width-
modulated (PWM) step-down DC-DC converters are
ideal for use in 5V and 3.3V to low-voltage conversion
necessary in notebook and subnotebook computers.
These devices feature internal synchronous rectification
for high efficiency and reduced component count. They
require no external Schottky diode. The internal 45mΩ
PMOS power switch and 55mΩ NMOS synchronous-rec-
tifier switch easily deliver continuous load currents up to
3A. The MAX1830 produces preset +2.5V, +1.8V, or
+1.5V output voltage or an adjustable output from +1.1V
to V_IN. The MAX1831 produces preset +3.3V, +2.5V, and
+1.5V output voltages and an adjustable output from
+1.1V to V_IN. They achieve efficiencies as high as 94%.
The MAX1830/MAX1831 use a unique current-mode,
constant-off-time, PWM control scheme, which includes
Idle Mode™ to maintain high efficiency during light-
load operation. The programmable constant-off-time
architecture sets switching frequencies up to 1MHz,
allowing the user to optimize performance trade-
offs between efficiency, output switching noise, compo-
nent size, and cost. Both devices are designed for con-
tinuous output currents up to 3A, an internal digital
soft-start to limit surge currents during startup, a 100%
duty cycle mode for low-dropout operation, and a
low-power shutdown mode that disconnects the input
from the output and reduces supply current below
1µA.The MAX1830/MAX1831 are available in 16-pin
QSOP packages.
For similar devices that provide continuous output
currents of 1A to 3A, refer to the MAX1644, MAX1623,
and MAX1742/MAX1842/MAX1843 data sheets.
Applications
5V or 3.3V to Low-Voltage Conversion
CPU I/O Supplies
Chipset Supplies
Notebook and Subnotebook Computers
Pin Configuration appears at end of data sheet.
Features
o ±1.5% Output Accuracy
o 94% Efficiency
o Internal PMOS/NMOS Switches
45mΩ/55mΩ On-Resistance at V_IN = +4.5V
50mΩ/55mΩ On-Resistance at V_IN = +3V
o Output Voltages
+3.3V, +2.5V, or +1.5V Pin Selectable (MAX1831)
+2.5V, +1.8V, or +1.5V Pin Selectable (MAX1830)
+1.1V to V_IN Adjustable (Both Devices)
o +3V to +5.5V Input Voltage Range
o 750µA (max) Operating Supply Current
o <1µA Shutdown Supply Current
o Programmable Constant-Off-Time Operation
o Up to 1MHz Switching Frequency
o Idle Mode Operation at Light Loads
o Thermal Shutdown
o Internal Digital Soft-Start Inrush Current Limiting
o 100% Duty Cycle During Low-Dropout Operation
o Output Short-Circuit Protection
o 16-Pin QSOP Package
PART
MAX1830EEE
MAX1831EEE
Ordering Information
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
16 QSOP
16 QSOP
Typical Configuration
INPUT
+3V TO
+5.5V
IN
LX
MAX1830 FB
MAX1831
V_CC
PGND
SHDN
COMP
TOFF
GND
FBSEL
REF
OUTPUT
+1.1V TO
V_IN
Idle Mode is a trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.