DataSheet39.com

What is ACT4075?

This electronic component, produced by the manufacturer "Active-Semi", performs the same function as "Wide Input 2.5A Step Down Converter".


ACT4075 Datasheet PDF - Active-Semi

Part Number ACT4075
Description Wide Input 2.5A Step Down Converter
Manufacturers Active-Semi 
Logo Active-Semi Logo 


There is a preview and ACT4075 download ( pdf file ) link at the bottom of this page.





Total 10 Pages



Preview 1 page

No Preview Available ! ACT4075 datasheet, circuit

ACT4075
Rev PrA, 13-Aug-07
Advanced Product Information – All Information Subject to Change
Wide Input 2.5A Step Down Converter
FEATURES
2.5A Output Current
Up to 95% Efficiency
4.5V to 32V Input Range
6µA Shutdown Supply Current
410kHz Switching Frequency
Adjustable Output Voltage
Cycle-by-Cycle Current Limit Protection
Thermal Shutdown Protection
Internal Soft Start Function
Frequency Fold Back at Short Circuit
Stability with Wide Range of Capacitors,
Including Low ESR Ceramic Capacitors
SOP-8/EP (Exposed Pad) Package
APPLICATIONS
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
GENERAL DESCRIPTION
The ACT4075 is a current-mode step-down DC/DC
converter that generates up to 2.5A output current
at 410kHz switching frequency. The device utilizes
Active-Semi’s proprietary ISOBCD30 process for
operation with input voltage up to 32V.
Consuming only 6μA in shutdown mode, the
ACT4075 is highly efficient with peak efficiency at
95% when in operation. Protection features include
cycle-by-cycle current limit, thermal shutdown, and
frequency fold back at short circuit. The device also
includes an internal soft start function to prevent
overshoot.
The ACT4075 is available in SOP-8/EP exposed
pad package and requires very few external de-
vices for operation.
TYPICAL APPLICATION CIRCUIT
Innovative Products. Active Solutions.
-1-
www.active-semi.com
Copyright © 2007 Active-Semi, Inc.

line_dark_gray
ACT4075 equivalent
ACT4075
Rev PrA, 13-Aug-07
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)
ACT4075
FB
VOUT
RFB1
RFB2
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
VINfSW IOUTMAXKRIPPLE
(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 = between 20% and
30% to correspond to the peak-to-peak ripple current
being a percentage 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 5A current
limit. Finally, select the inductor core size so that it
does not saturate at 5A.
Table 1:
Typical Inductor Values
VOUT
L
1.5V
6.8μH
1.8V
6.8μH
2.5V
6.8μH
3.3V
8.5μH
5V
15μH
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 large current flows in and out of this
capacitor during switching, its ESR also affects effi-
ciency.
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 traces possible. 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:
V I K RRIPPLE OUTMAX RIPPLE RIPPLE
28
VIN
fSW 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. There-
fore, a lower capacitance value can be used for ce-
ramic type. 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 ESR.
For ceramic output type, typically choose a capaci-
tance of about 22µF. For tantalum or electrolytic type,
choose a capacitor 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 © 2007 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 ACT4075 electronic component.


Information Total 10 Pages
Link URL [ Copy URL to Clipboard ]
Download [ ACT4075.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