MAX8664 Datasheet, PDF (1/26 Pages) Maxim Integrated Products – Low-Cost, Dual-Output, Step-Down Controller with Fast Transient Response

19-0796; Rev 0; 4/07
Low-Cost, Dual-Output, Step-Down
Controller with Fast Transient Response
General Description
The MAX8664 dual-output PWM controller is a low-cost,
high-performance solution for systems requiring dual
power supplies. It provides two individual outputs that
operate 180° out-of-phase to minimize input current
ripple, and therefore, capacitance requirements. Built-in
drivers are capable of driving external MOSFETs to
deliver up to 25A output current from each channel.
The MAX8664 operates from a 4.5V to 28V input volt-
age source and generates output voltages from 0.6V
up to 90% of the input voltage on each channel. Total
output regulation error is less than ±0.8% over load,
line, and temperature.
The MAX8664 operates with a constant switching fre-
quency adjustable from 100kHz to 1MHz. Built-in boost
diodes reduce external component count. Digital soft-
start eliminates input inrush current during startup. The
second output has an optional external REFIN2, facili-
tating tracking supply applications. Each output is
capable of sourcing and sinking current, making the
device a great solution for DDR applications.
The MAX8664 employs Maxim’s proprietary peak volt-
age-mode control architecture that provides superior
transient response during either load or line transients.
This architecture is easily stabilized using two resistors
and one capacitor for any type of output capacitors. Fast
transient response requires less output capacitance,
consequently reducing total system cost. The MAX8664B
latches off both controllers during a fault condition, while
the MAX8664A allows one controller to continue to func-
tion when there is a fault in the other controller.
Applications
Desktop and Notebook PCs
Graphic Cards
ASIC/CPU/DSP Power Supplies
Set-Top Box Power Supply
Printer Power Supply
Network Power Supply
POL Power Supply
Pin Configuration appears at end of data sheet.
Features
o ±0.8% Output Accuracy Over Load and Line
o Operates from a Single 4.5V to 28V Supply
o Simple Compensation for Any Type of Output
Capacitor
o Internal 6.5V Regulator for Gate Drive
o Integrated Boost Diodes
o Adjustable Output from 0.6V to 0.9 x V_IN
o Digital Soft-Start Reduces Inrush Current
o 100kHz to 1MHz Adjustable Switching
o 180° Out-of-Phase Operation Reduces Input
Ripple Current
o Overcurrent and Overvoltage Protection
o External Reference Input for Second Controller
o Prebiased Startup Operation
Ordering Information
PART
PIN-
PACKAGE
PKG
CODE
FAULT
ACTION
MAX8664AEEP+ 20 QSOP
E20-1 Independent
MAX8664BEEP+ 20 QSOP
E20-1
Joint
Note: This device operates over the -40°C to +85°C operating
temperature range.
+Denotes lead-free package.
Typical Operating Circuit
IN2
OUT2
IN
ILIM2
DH2
BST2
LX2
VL
ILIM1
DH1
BST1
LX1
DL2
DL1
MAX8664
GND
PGND
FB2
REFIN2
V_CC
FB1
PWRGD
OSC/EN12
IN1
OUT1
________________________________________________________________ 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.