rt8009

Manufacturer Part Numberrt8009
Description1.25mhz, 600ma, High Efficiency Step-down Dc/dc Converter
ManufacturerRichtek Technology Corporation
rt8009 datasheet
 


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1.25MHz, 600mA, High Efficiency PWM Step-Down DC/DC
Converter
General Description
The RT8009 is a high-efficiency pulse-width-modulated
(PWM) step-down DC-DC converter. Capable of delivering
600mA output current over a wide input voltage range from
2.5 to 5.5V, the RT8009 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
reduces conduction loss at PWM mode. No external
Schottky diode is required in practical application. The
RT8009 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 RT8009 enters Low-Dropout mode when normal PWM
cannot provide regulated output voltage by continuously
turning on the upper P-MOSFET. RT8009 enter shutdown
mode and consumes less than 0.1uA 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 1.25MHz. 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.
Pin Configurations
(TOP VIEW)
VIN
1
5
GND
2
EN
3
4
SOT-23-5/TSOT-23-5
DS8009-03 March 2007
Features
+2.5V to +5.5V Input Range
Adjustable Output From 0.5V to V
1.0V, 1.2V, 1.5V, 1.8V, 2.5V and 3.3V Fixed/
Adjustable Output Voltage
600mA Output Current
95% Efficiency
No Schottky Diode Required
1.25MHz Fixed-Frequency PWM Operation
dramatically
DS(ON)
Small SOT-23-5 and TSOT-23-5 Package
RoHS Compliant and 100% Lead (Pb)-Free
Applications
Cellular Telephones
Personal Information Appliances
Wireless and DSL Modems
MP3 Players
Portable Instruments
Ordering Information
RT8009(-
LX
Note :
RichTek Pb-free and Green products are :
FB/VOUT
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.
100% matte tin (Sn) plating.
RT8009
IN
)
Package Type
B : SOT-23-5
J5 : TSOT-23-5
Operating Temperature Range
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commer-
cial Standard)
Output Voltage
Default : Adjustable
10 : 1.0V
12 : 1.2V
15 : 1.5V
18 : 1.8V
25 : 2.5V
33 : 3.3V
www.richtek.com
1

rt8009 Summary of contents

  • Page 1

    ... The RT8009 is a high-efficiency pulse-width-modulated (PWM) step-down DC-DC converter. Capable of delivering 600mA output current over a wide input voltage range from 2.5 to 5.5V, the RT8009 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 ...

  • Page 2

    ... Typical Application Circuit 2.5V to 5.5V 2.5V to 5.5V Layout Guide V IN VIN GND Layout note: 1. The distance that C connects should be placed near RT8009. OUT www.richtek.com VIN RT8009 4.7uF 3 EN VOUT GND 2 Figure 1. Fixed Voltage Regulator ...

  • Page 3

    ... Chip Enable (Active High, do not leave EN pin floating, and V Feedback Input Pin. Pin for Switching. EN OSC & Shutdown Control Current Sense PWM Comparator RC UVLO & Power Good Detector V REF Pin Function EN VIN Current Limit Detector Control Driver Logic Zero Detector GND RT8009 < 0.6V). IN RS1 LX RS2 www.richtek.com 3 ...

  • Page 4

    ... RT8009 Absolute Maximum Ratings Supply Input Voltage ------------------------------------------------------------------------------------------------------ 6.5V Enable, FB Voltage ------------------------------------------------------------------------------------------------------- V Power Dissipation 25° SOT-23-5, TSOT-23-5 ----------------------------------------------------------------------------------------------------- 0.4W Package Thermal Resistance (Note 4) SOT-23-5, TSOT-23-5, θ ----------------------------------------------------------------------------------------------- 250°C/W JA SOT-23-5, TSOT-23-5, θ ----------------------------------------------------------------------------------------------- 130°C/W JC Junction Temperature Range -------------------------------------------------------------------------------------------- 150°C Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- 260°C ...

  • Page 5

    ... DS (ON)_N OUT 2.5V to 5.5 V LIM_P 2.5V to 5.5V EN_H 2.5V to 5.5V EN_L 3.6V 100mA OSC 3.6V 25° low effective thermal conductivity test board of A RT8009 Min Typ (Note 5) − − 3. 2. 1.5 -- ...

  • Page 6

    ... RT8009 Typical Operating Characteristics Efficiency vs. Load Current 100 1.8V OUT 0 0.01 0.11 0.21 Load Current (A) Load Regulation 1.810 1.805 1.800 V IN 1.795 1.790 V = 2.5V IN 1.785 1.780 1.775 V = 1.8V OUT 1.770 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 Load Current (A) Frequency vs. Input Voltage 1.26 1.24 1.22 1.20 1.18 1. 1.8V OUT 1.14 2.5 2.8 3.1 3.4 3.7 Input Voltage (V) www.richtek.com 6 0 ...

  • Page 7

    ... V = 1.8V IN OUT 0.508 0.505 0.503 0.500 0.498 0.495 0.493 0.490 -50 - Temperature (°C) Load Transient Response V = 3.3V 1.8V 300mA to 600mA IN OUT OUT Time (100μs/Div) Power 3.3V 1.8V 600mA IN OUT OUT EN OUT Time (100μs/Div) RT8009 75 100 125 www.richtek.com 7 ...

  • Page 8

    ... RT8009 Applications Information The basic RT8009 application circuit is shown in Typical Application Circuit. External component selection is determined by the maximum load current and begins with the selection of the inductor value and operating frequency followed by C and OUT Inductor Selection For a given input and output voltage, the inductor value and operating frequency determine the ripple current. The ripple current Δ ...

  • Page 9

    ... losses are calculated from the resistances of the and external inductor R SW and the duty cycle (DC) as follows : DS(ON DS(ON)TOP DS(ON)BOT for both the top and bottom MOSFETs can be DS(ON) RT8009 that is typically (1−DC) www.richtek.com 9 ...

  • Page 10

    ... D(MAX) TSOT-23-5 packages The maximum power dissipation depends on operating ambient temperature for fixed T resistance θ . For RT8009 packages, the Figure derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. The value of junction to case thermal resistance θ ...

  • Page 11

    ... Connect feedback network behind the output capacitors. Keep the loop area small. Place the feedback components near the RT8009. Connect all analog grounds to a command node and then connect the command node to the power ground behind the output capacitors. An example of 2-layer PCB layout is shown in Figure 7 and Figure 8 for reference ...

  • Page 12

    ... RT8009 Outline Dimension Symbol www.richtek.com Dimensions In Millimeters Min Max 0.889 1.295 0.000 0.152 1.397 1.803 0.356 0.559 2.591 2.997 2.692 3.099 0.838 1.041 0.080 0.254 0.300 0.610 SOT-23-5 Surface Mount Package H L Dimensions In Inches ...

  • Page 13

    ... TSOT-23-5 Surface Mount Package Richtek Technology Corporation Taipei Office (Marketing) 8F, No. 137, Lane 235, Paochiao Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek.com RT8009 H L Dimensions In Inches Min Max 0.028 0.039 0.000 0.004 0.055 ...