ACT4088
Rev 2, 15-Nov-12
28V, 1.5A, 1.4MHz Step-Down DC/DC Converter in SOT23-6
FEATURES
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Wide 4.5V to 28V Input Voltage Range
1.5A Output Current (12V
IN
to 5V
OUT
)
Output Adjustable Down to 0.81V
0.3Ω Internal Power MOSFET
Up to 92% Efficiency
Stable with Low ESR Ceramic Output Capacitors
Fixed 1.4MHz Operating Frequency
Internal Soft-Start Function
Over Current Protection with Hiccup-Mode
Thermal Shutdown
Available in a SOT23-6 Package
GENERAL DESCRIPTION
The ACT4088 is a current-mode step-down DC/DC
converter that supplies up to 1.5A into 5V from a
12V input. 1.4MHz switching frequency allows the
use of tiny external components, and internal loop
compensation provides simple, stable power sup-
plies with a minimum of external components. Opti-
mized for use with ceramic input and output capaci-
tors, the ACT4088 provides a very compact 1.5A
power supply for space constrained mobile and
consumer applications.
The ACT4088 operates over a wide input voltage
range and utilizes current-mode operation to pro-
vide excellent line and load transient response
while requiring no external compensation compo-
nents. Fault protection includes cycle-by-cycle cur-
rent limiting, frequency fold-back, hiccup mode, and
thermal shutdown. Internal soft-start provides a
controlled startup with no overshoot, even at light
loads.
The ACT4088 is available in a tiny SOT23-6 pack-
age and requires very few external components.
APPLICATIONS
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TFT LCD Monitors
Portable DVDs, Headphones, MP3 Players, etc.
Car-Powered or Battery-Powered Equipment
Set-Top Boxes
Telecom Power Supplies
DSL and Cable Modems and Routers
TYPICAL APPLICATION CIRCUIT
V
IN
4.5V to 28V
IN
BST
ACT4088
ON
OFF
EN
SW
V
OUT
FB
G
Innovative Power
TM
-1-
www.active-semi.com
Copyright © 2012 Active-Semi, Inc.
ACTIVE-SEMI [ ACTIVE-SEMI, INC ]
