RT8024
1
DS8024-02 March 2011 www.richtek.com
Features
zz
zz
z
2.5V to 5.5V Input Range
zz
zz
z Adjustable Output From 0.6V to V
IN
zz
zz
z 1.0V, 1.2V, 1.5V, 1.8V, 2.5V and 3.3V Fixed/
Adjustable Output Voltage
zz
zz
z 400mA Output Current, 1A Peak Current
zz
zz
z 95% Efficiency
zz
zz
z No Schottky Diode Required
zz
zz
z 1.5MHz Fixed Frequency PWM Operation
zz
zz
z Small SOT-23-5 and TSOT-23-5 Package
zz
zz
z RoHS Compliant and Halogen Free
Applications
z Cellular Telephones
z Personal Information Appliances
z Wireless and DSL Modems
z MP3 Players
z Portable Instruments
1.5MHz, 400mA, High Efficiency PWM Step-Down
DC/DC Converter
General Description
The RT8024 is a high-efficiency pulse-width-modulated
(PWM) step-down DC/DC converter. Capable of delivering
400mA output current over a wide input voltage range from
2.5V to 5.5V, the RT8024 is ideally suited for portable
electronic devices that are powered from 1-cell Li-ion
battery or from other power sources within the range such
as cellular phones, PDAs and handy-terminals.
Internal synchronous rectifier with low R
DS(ON)
dramatically
reduces conduction loss at PWM mode. No external
Schottky diode is required in practical application. The
RT8024 automatically turns off the synchronous rectifier
while the inductor current is low and enters discontinuous
PWM mode. This can increase efficiency at light load
condition.
The RT8024 enters Low-Dropout mode when normal PWM
cannot provide regulated output voltage by continuously
turning on the upper P-MOSFET. RT8024 enter shutdown
mode and consumes less than 0.1μA when EN pin is pulled
low.
The switching ripple is easily smoothed-out by small
package filtering elements due to a fixed operation
frequency of 1.5MHz. This along with small SOT-23-5 and
TSOT-23-5 package provides small PCB area application.
Other features include soft start, lower internal reference
voltage with 2% accuracy, over temperature protection,
and over current protection.
Note :
Richtek products are :
` RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
` Suitable for use in SnPb or Pb-free soldering processes.
Ordering Information
Pin Configurations
(TOP VIEW)
SOT-23-5/TSOT-23-5
EN GND LX
FB/VOUT VIN
4
23
5
RT8024(- )
Package Type
B : SOT-23-5
J5 : TSOT-23-5
Output Voltage
Default : Adjustable
10 : 1.0V
12 : 1.2V
15 : 1.5V
18 : 1.8V
25 : 2.5V
33 : 3.3V
Lead Plating System
G : Green (Halogen Free and Pb Free)
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
RT8024
2
DS8024-02 March 2011www.richtek.com
Layout note:
1. The distance that C
IN
connects to V
IN
is as close as possible (Under 2mm).
2. C
OUT
should be placed near RT8024.
Typical Application Circuit
Figure 1. Fixed Voltage Regulator
Figure 2. Adjustable Voltage Regulator
+=
R2
R1
1 x VV
REFOUT
with R2 = 300kΩ to 60kΩ so the I
R2
= 2μA to 10μA,
and (R1 x C1) should be in the range between 3x10
-6
and 6x10
-6
for component selection.
Layout Guide
Figure 3
EN
GND
LX
VOUT
2
3
5
4
1
VIN
GND
V
IN
V
OUT
C
OUT
C
IN
GND
L
EN
GND
LX
FB
2
3
5
4
1
VIN
GND
V
IN
V
OUT
C
OUT
C
IN
GND
C1
R1
R2
L
V
OUT
4.7µF
10µF
VIN
LX
GND
RT8024
EN VOUT
2.2µH
2.2V to 5.5V
V
IN
V
OUT
C
IN
L
5
3
4
1
2
C
OUT
4.7µF
10µF
VIN
LX
GND
RT8024
EN FB
2.2µH
2.2V to 5.5V
V
IN
V
OUT
C
IN
L
5
3
4
1
2
C
OUT
R1
R2
C1
I
R2
RT8024
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DS8024-02 March 2011 www.richtek.com
Functional Pin Description
Pin No. Pin Name Pin Function
1 EN Chip Enable (Active High, do not leave EN pin floating, and V
EN
< V
IN
+ 0.6V).
2 GND Ground.
3 LX Pin for Switching.
4 VIN Power Input.
5 FB/VOUT Feedback Input Pin.
Function Block Diagram
COMP
RC
RS1
RS2
EN
VIN
LX
FB/VOUT
UVLO &
Power Good
Detector
V
REF
Slope
Compensation
Current
Sense
OSC &
Shutdown
Control
Zero
Detector
Current
Limit
Detector
Driver
Control
Logic
PWM
Comparator
Error
Amplifier
GND

RT8024-12GB

Mfr. #:
Manufacturer:
Description:
IC REG BUCK 1.2V 400MA SOT23-5
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
T/T Paypal Visa MoneyGram Western Union

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