MAX8576 Datasheet, PDF (1/18 Pages) Maxim Integrated Products – 3V to 28V Input, Low-Cost, Hysteretic Synchronous Step-Down Controllers

19-3289; Rev 1; 6/05
EVAALVUAAILTAIOBNLEKIT _{3V to 28V Input, Low-Cost, Hysteretic}
Synchronous Step-Down Controllers
General Description
The MAX8576–MAX8579 synchronous PWM buck con-
trollers use a hysteretic voltage-mode control algorithm
to achieve a fast transient response without requiring
loop compensation. The MAX8576/MAX8577 contain an
internal LDO regulator allowing the controllers to func-
tion from only one 3V to 28V input supply. The
MAX8578/MAX8579 do not contain the internal LDO
and require a separate supply to power the IC when the
input supply is higher than 5.5V. The MAX8576–
MAX8579 output voltages are adjustable from 0.6V to
0.9 x V_IN at loads up to 15A.
Nominal switching frequency is programmable over the
200kHz to 500kHz range. High-side MOSFET sensing is
used for adjustable hiccup current-limit and short-cir-
cuit protection. The MAX8576/MAX8578 can start up
into a precharged output without pulling the output volt-
age down. The MAX8577/MAX8579 have startup output
overvoltage protection (OVP), and will pull down a
precharged output.
Applications
Motherboard Power Supplies
AGP and PCI-Express Power Supplies
Graphic-Card Power Supplies
Set-Top Boxes
Point-of-Load Power Supplies
Features
♦ 3V to 28V Supply Voltage Range
♦ 1.2% Accurate Over Temperature
♦ Adjustable Output Voltage Down to 0.6V
♦ 200kHz to 500kHz Switching Frequency
♦ Adjustable Temperature-Compensated Hiccup
Current Limit
♦ Lossless Peak Current Sensing
♦ Monotonic Startup into Prebias Output
(MAX8576/MAX8578)
♦ Startup Overvoltage Protection
(MAX8577/MAX8579)
♦ Enable/Shutdown
♦ Adjustable Soft-Start
PART
MAX8576EUB
MAX8577EUB
MAX8578EUB
MAX8579EUB
Ordering Information
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
10 µMAX^®
10 µMAX
10 µMAX
10 µMAX
Typical Operating Circuit
INPUT
UP TO 28V
FB
OCSET
SS
IN
VL ^MAX8576 DH
MAX8577
GND
LX
DL
BST
OUTPUT
0.6V TO 0.9 x V_IN
µMAX is a registered trademark of Maxim Integrated Products, Inc.
Pin Configurations appear at end of data sheet.
________________________________________________________________ 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.