Active-Semi
FEATURES
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Wide 4.5V to 16V Input Voltage Range
1.2A 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
ACT4082A
Rev0, 16-May-08
16V, 1.2A, 1.4MHz Step-Down DC/DC Converter in SOT23-6
GENERAL DESCRIPTION
The ACT4082A is a current-mode step-down
DC/DC converter that supplies up to 1.2A into 5V
from a 12V input. 1.4MHz switching frequency al-
lows the use of tiny external components, and inter-
nal loop compensation provides simple, stable
power supplies with a minimum of external compo-
nents. Optimized for use with ceramic input and
output capacitors, the ACT4082A provides a very
compact 1.2A power supply for space constrained
mobile and consumer applications.
The ACT4082A 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 ACT4082A 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 16V
IN
BST
Active-Semi
ACT4082A
SW
ON
OFF
EN
FB
G
V
OUT
Innovative Power
TM
-1-
www.active-semi.com
Copyright © 2008 Active-Semi, Inc.
ACTIVE-SEMI [ ACTIVE-SEMI, INC ]
