DataSheet39.com

What is ACT4072?

This electronic component, produced by the manufacturer "Active-Semi", performs the same function as "Wide Input 2A Step Down Converter".


ACT4072 Datasheet PDF - Active-Semi

Part Number ACT4072
Description Wide Input 2A Step Down Converter
Manufacturers Active-Semi 
Logo Active-Semi Logo 


There is a preview and ACT4072 download ( pdf file ) link at the bottom of this page.





Total 10 Pages



Preview 1 page

No Preview Available ! ACT4072 datasheet, circuit

www.DataSheet4U.com
ACT4072
Rev 1, 12/2006
Wide Input 2A Step Down Converter
FEATURES
 2A Output Current
 Up to 95% Efficiency
 Up to 30V Input Range
 6µA Shutdown Supply Current
 400kHz Switching Frequency
 Adjustable Output Voltage
 Cycle-by-Cycle Current Limit Protection
 Thermal Shutdown Protection
 Frequency FoldBack at Short Circuit
 Stability with Wide Range of Capacitors,
Including Low ESR Ceramic Capacitors
 SOP-8 Package
APPLICATIONS
GENERAL DESCRIPTION
The ACT4072 is a current-mode step-down
DC/DC converter that generates up to 2A output
current at 400kHz switching frequency. The
device utilizes Active-Semi’s proprietary
ISOBCD30 process for operation with input
voltage up to 30V.
Consuming only 6µA in shutdown mode, the
ACT4072 is highly efficient with peak efficiency at
95% when in operation. Protection features
include cycle-by-cycle current limit, thermal
shutdown, and frequency foldback at short circuit.
The ACT4072 is available in SOP-8 package and
requires very few external devices for operation.
 TFT LCD Monitors or Televisions and HDTV
 Portable DVD Players
 Car-Powered or Battery-Powered Equipment
 Set-Top Boxes
 Telecom Power Supplies
 DSL and Cable Modems and Routers
TYPICAL APPLICATION CIRCUIT
Innovative Products. Active Solutions.
-1-
www.active-semi.com
Copyright © 2006 Active-Semi, Inc.

line_dark_gray
ACT4072 equivalent
www.DataSheet4U.com
ACT4072
APPLICATIONS INFORMATION
Output Voltage Setting
Figure 1 shows the connections for setting the out-
put voltage. Select the proper ratio of the two feed-
back resistors RFB1 and RFB2 based on the output
voltage. Typically, use RFB2 ≈ 10kΩ and determine
RFB1 from the output voltage:
RFB1
RFB2

VOUT
1.222V
-1
Figure 1:
Output Voltage Setting
(1)
Inductor Selection
The inductor maintains a continuous current to the
output load. This inductor current has a ripple that is
dependent on the inductance value: higher induc-
tance reduces the peak-to-peak ripple current. The
trade off for high inductance value is the increase in
inductor core size and series resistance, and the
reduction in current handling capability. In general,
select an inductance value L based on ripple current
requirement:
 L VOUT VIN -VOUT
V f I KIN SW OUTMAX RIPPLE
(2)
where VIN is the input voltage, VOUT is the output
voltage, fSW is the switching frequency, IOUTMAX is the
maximum output current, and KRIPPLE is the ripple
factor. Typically, choose KRIPPLE = 20% to 30%
corresponding to the peak-to-peak ripple current
being 20% to 30% of the maximum output current.
With this inductor value (Table 1), the peak inductor
current is IOUT × (1 + KRIPPLE / 2). Make sure that this
peak inductor current is less that the 2.4A current
limit. Finally, select the inductor core size so that it
does not saturate at 2.4A.
Table 1:
Typical Inductor Values
VOUT
L
1.5V
6.8μH
1.8V
6.8μH
2.5V
10μH
3.3V
15μH
5V
22μH
Input Capacitor
The input capacitor needs to be carefully selected to
maintain sufficiently low ripple at the supply input of
the converter. A low ESR capacitor is highly recom-
mended. Since a large current flows in and out of
this capacitor during switching, its ESR also affects
efficiency.
The input capacitance needs to be higher than
10µF. The best choice is the ceramic type, however,
low ESR tantalum or electrolytic types may also be
used provided that the RMS ripple current rating is
higher than 50% of the output current. The input
capacitor should be placed close to the IN and G
pins of the IC, with shortest possible traces. In the
case of tantalum or electrolytic types, they can be
further away if a small parallel 0.1µF ceramic ca-
pacitor is placed right next to the IC.
Output Capacitor
The output capacitor also needs to have low ESR to
keep low output voltage ripple. The output ripple
voltage is:
R L K RRIPPLE
OUTMAX RIPPLE ESR
VIN
28fSW 2LCOUT
(3)
where IOUTMAX is the maximum output current,
KRIPPLE is the ripple factor, RESR is the ESR
resistance of the output capacitor, fSW is the
switching frequency, L is the inductor value, COUT is
the output capacitance.
In the case of ceramic output capacitors, RESR is
very small and does not contribute to the ripple.
Therefore, a lower capacitance value can be used
for ceramic type, typically choose a capacitance of
about 22µF.
In the case of tantalum or electrolytic type, the ripple
is dominated by RESR multiplied by the ripple current.
In that case, the output capacitor is chosen to have
sufficiently low due to ESR, typically choose a ca-
pacitor with less than 50mΩ ESR.
Rectifier Diode
Use a Schottky diode as the rectifier to conduct cur-
rent when the High-Side Power Switch is off. The
Schottky diode must have current rating higher than
the maximum output current and the reverse volt-
age rating higher than the maximum input voltage.
Innovative Products. Active Solutions.
-5-
www.active-semi.com
Copyright © 2006 Active-Semi, Inc.


line_dark_gray

Preview 5 Page


Part Details

On this page, you can learn information such as the schematic, equivalent, pinout, replacement, circuit, and manual for ACT4072 electronic component.


Information Total 10 Pages
Link URL [ Copy URL to Clipboard ]
Download [ ACT4072.PDF Datasheet ]

Share Link :

Electronic Components Distributor


An electronic components distributor is a company that sources, stocks, and sells electronic components to manufacturers, engineers, and hobbyists.


SparkFun Electronics Allied Electronics DigiKey Electronics Arrow Electronics
Mouser Electronics Adafruit Newark Chip One Stop


Featured Datasheets

Part NumberDescriptionMFRS
ACT4070The function is Wide Input 3A Step Down Converter. Active-SemiActive-Semi
ACT4070The function is Wide Input 3A Step Down Converter. Active-SemiActive-Semi
ACT4070BThe function is Wide Input 3A Step Down Converter. Active-SemiActive-Semi

Semiconductors commonly used in industry:

1N4148   |   BAW56   |   1N5400   |   NE555   |  

LM324   |   BC327   |   IRF840  |   2N3904   |  



Quick jump to:

ACT4     1N4     2N2     2SA     2SC     74H     BC     HCF     IRF     KA    

LA     LM     MC     NE     ST     STK     TDA     TL     UA    



Privacy Policy   |    Contact Us     |    New    |    Search