RT8008

Manufacturer Part NumberRT8008
Description1.5MHz, 600mA, High Efficiency PWM Step-Down DC/DC Converter
ManufacturerRICHTEK [Richtek Technology Corporation]
RT8008 datasheet
 


1
Page 1
2
Page 2
3
Page 3
4
Page 4
5
Page 5
6
Page 6
7
Page 7
8
Page 8
9
Page 9
10
Page 10
11
12
13
14
Page 1/14

Download datasheet (212Kb)Embed
Next
1.5MHz, 600mA, High Efficiency PWM Step-Down DC/DC
Converter
General Description
The RT8008 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
2.5V to 5.5V, the RT8008 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
RT8008 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 RT8008 enters Low-Dropout mode when normal PWM
cannot provide regulated output voltage by continuously
turning on the upper P-MOSFET. RT8008 enter shutdown
mode and consumes less than 0.1 A 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.
Pin Configurations
(TOP VIEW)
EN
1
5
GND
2
LX
3
4
SOT-23-5/TSOT-23-5
DS8008-04 March 2007
Features
+2.5V to +5.5V Input Range
l
Adjustable Output From 0.6V to V
l
1.0V, 1.2V, 1.5V, 1.8V, 2.5V and 3.3V Fixed/
l
Adjustable Output Voltage
600mA Output Current, 1A Peak Current
l
95% Efficiency
l
No Schottky Diode Required
l
1.5MHz Fixed-Frequency PWM Operation
l
dramatically
DS(ON)
Small SOT-23-5 and TSOT-23-5 Package
l
RoHS Compliant and 100% Lead (Pb)-Free
l
Applications
Cellular Telephones
l
Personal Information Appliances
l
Wireless and DSL Modems
l
MP3 Players
l
Portable Instruments
l
Ordering Information
RT8008(-
FB/VOUT
Note :
RichTek Pb-free and Green products are :
VIN
}
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.
RT8008
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

RT8008 Summary of contents

  • Page 1

    ... The RT8008 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 2.5V to 5.5V, the RT8008 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

    ... C1) should be in the range between 3x10 Layout Guide GND VIN VOUT GND Layout note: 1. The distance that C connects should be placed near RT8008. OUT www.richtek.com VIN RT8008 4.7uF 1 EN VOUT GND 2 Figure 1. Fixed Voltage Regulator 4 V ...

  • Page 3

    ... Chip Enable (Active High, do not leave EN pin floating, and V Ground. Pin for Switching. Power Input. Feedback Input Pin. 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 RT8008 < 0.6V). IN RS1 LX RS2 www.richtek.com 3 ...

  • Page 4

    ... RT8008 Absolute Maximum Ratings Supply Input Voltage ---------------------------------------------------------------------------------------------------- 6.5V l Enable, FB Voltage ------------------------------------------------------------------------------------------------------ V l Power Dissipation SOT-23-5, TSOT-23-5 --------------------------------------------------------------------------------------------------- 0.4W Package Thermal Resistance (Note 4) l SOT-23-5, TSOT-23-5, ---------------------------------------------------------------------------------------------- 250 C/W JA SOT-23-5, TSOT-23-5, --------------------------------------------------------------------------------------------- 130 C/W JC Junction Temperature Range ------------------------------------------------------------------------------------------ 150 C l Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------ 260 C l Storage Temperature Range ------------------------------------------------------------------------------------------- 150 C ...

  • Page 5

    ... RDS(ON) OUT 2.5V to 5.5 V P(LM 2.5V to 5.5V ENH 2.5V to 5.5V ENL 3.6V 100mA OSC IN OUT 3.6V low effective single layer thermal conductivity test board of A RT8008 Min Typ -- 1.8 -- ...

  • Page 6

    ... RT8008 Typical Operating Characteristics Efficiency vs. Load Current 100 0.01 0.11 0.21 Load Current (A) Output Voltage vs. Load Current 1.220 1.215 1.210 1.205 1.200 1.195 1.190 1.185 1.180 0 0.1 0.2 Load Current (A) Frequency vs. Input Voltage 1.50 1.48 1.45 1.43 1.40 1.38 1.35 2.5 3 3.5 Input Voltage (V) www.richtek.com 1.2V OUT 0.31 0.41 0. 2.5V ...

  • Page 7

    ... OUT (500mA/Div) = 600mA OUT V (2V/Div) V OUT (500mV/Div (200mA/Div) Output Voltage vs. Temperature 1.25 1.23 1.21 1.19 1.17 V 1.15 -50 - Temperature ( C) Load Transient Response V = 3.3V 1.2V 300mA to 600mA IN OUT OUT Time (50 s/Div) Power 3.3V 1.2V 600mA IN OUT OUT EN Time (100 s/Div) RT8008 = 3.3V OUT 75 100 125 www.richtek.com 7 ...

  • Page 8

    ... RT8008 Power Off V = 3.3V 1.2V OUT V EN (2V/Div) V OUT (500mV/Div (200mA/Div) Time (100 s/Div) www.richtek.com 8 = 600mA OUT DS8008-04 March 2007 ...

  • Page 9

    ... Applications Information The basic RT8008 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 ...

  • Page 10

    ... IN part. Output Voltage Programming The resistive divider allows the V of the output voltage as shown in Figure 4. FB RT8008 GND Figure 4. Setting the Output Voltage For adjustable about voltage mode, the output voltage is set by an external resistive divider according to the following equation : R1 ...

  • Page 11

    ... D(MAX) TSOT-23-5 packages The maximum power dissipation depends on operating ambient temperature for fixed T resistance . For RT8008 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 popular for users ...

  • Page 12

    ... RT8008 } Connect feedback network behind the output capacitors. Keep the loop area small. Place the feedback components near the RT8008. } Connect all analog grounds to a command node and then connect the command node to the power ground behind the output capacitors example of 2-layer PCB layout is shown in Figure 7 to Figure 8 for reference ...

  • Page 13

    ... SOT-23-5 Surface Mount Package RT8008 H L Dimensions In Inches Min Max 0.035 0.051 0.000 0.006 0.055 0.071 0.014 0.022 0.102 0.118 0.106 0.122 0.033 ...

  • Page 14

    ... RT8008 Symbol Richtek Technology Corporation Headquarter 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 www.richtek.com Dimensions In Millimeters Min Max 0.700 1.000 0.000 0.100 1.397 1.803 0.300 0.559 2.591 3.000 2.692 3 ...