MAX8654 Datasheet, PDF (1/17 Pages) Maxim Integrated Products – 12V, 8A 1.2MHz Step-Down Regulator

19-0588; Rev 0; 8/06
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12V, 8A 1.2MHz
Step-Down Regulator
General Description
The MAX8654 high-efficiency switching regulator delivers
up to 8A of load current at output voltages from 0.6V to
0.85 x V_IN. The IC operates from 4.5V to 14V, making it
ideal for on-board point-of-load and postregulation appli-
cations, with total output error less than ±1% over load,
line, and temperature ranges.
The MAX8654 is a fixed-frequency PWM mode regulator
with a switching frequency range of 250kHz to 1.2MHz
set by an external resistor or SYNC input. High-frequency
operation allows for an all-ceramic-capacitor solution. A
SYNCOUT output is provided to synchronize a second
regulator switching 180° out-of-phase with the first to
reduce the input ripple current and consequently reduce
the required input capacitance. The high operating fre-
quency minimizes the size of external components.
The on-board low R_DS(ON) dual-nMOS design keeps
the board cooler at heavy loads while minimizing the
critical inductances, making the layout a much simpler
task with respect to the discrete solutions.
The MAX8654 comes with a high-bandwidth (20MHz)
voltage-error amplifier. The voltage-mode control archi-
tecture and the op-amp voltage-error amplifier permit a
type 3 compensation scheme to be utilized to achieve
maximum loop bandwidth, up to 20% of the switching
frequency. High loop bandwidth achieves fast transient
response resulting in less output capacitance required.
The MAX8654 offers programmable soft-start to accom-
modate different types of output capacitors and reduce
input inrush current. The MAX8654 is available in a 36-
lead thin QFN package.
Applications
POL Power Supplies
Servers
DDR Memory
RAID Power Supplies
Network Power Supplies
Graphic Cards
Pin Configuration appears at end of data sheet.
Features
♦ Internal 26mΩ R_DS(ON) MOSFETs
♦ Guaranteed 8A Output Current
♦ Adjustable Overcurrent Protection
♦ 1% Output Accuracy Over Temperature
♦ Operates from 4.5V to 14V Supply
♦ Adjustable Output from 0.6V to 0.85 x V_IN
♦ Soft-Start Reduces Inrush Supply Current
♦ 250kHz to 1.2MHz Adjustable Switching or SYNC
Input
♦ Compatible with Ceramic, Polymer, and
Electrolytic Output Capacitors
♦ SYNCOUT Synchronizes 2nd Regulator 180°
Out-of-Phase
♦ 36-Pin, Lead-Free, 6mm x 6mm Thin QFN Package
Ordering Information
PART
TEMP RANGE ^PIN-
PACKAGE
PKG
CODE
MAX8654ETX+ -40°C to +85°C
+Denotes lead-free package.
*EP = Exposed pad.
36 Thin QFN-EP*
(6mm x 6mm)
T3666-3
Typical Operating Circuit
INPUT
4.5V TO 14V
IN
BST
VP
LX
VL
OUTPUT
UP TO 8A
VL
PGND
VDL
MAX8654 _FB
FREQ
ILIM
REFIN
COMP
SS
SYNC
VL
SYNCOUT
IN
EN
PWRGD
GND
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