Richtek RT8003PQV Schematic [ru]
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RT8003
600mA, 2MHz, High-Efficiency Synchronous Buck PWM
Converter
General Description
The RT8003 is a high-efficiency synchronous buck PWM converter with integrated P-Channel andN-Channel power MOSFET switches. Capable of delivering 600mA output current over a wide input voltage range of 2.4V to 5.5V, the RT8003 is ideally suited for portable applications powered by a single Li-Ion battery or by 3-cell NiMH/NiCd batteries. The device operates at 2MHz PWM switching fixed frequency, can use smaller CIN, COUT capacitor and inductor.
The RT8003 integrates two low RDS(ON) 230mΩ and 180mΩ of highand low-side switching MOSFETs to reduce board space, as only resistors and capacitors along with one inductor are required externally for operation. The RT8003 has adjustable output range down to 0.5V. The other features include internal soft-start, chip enable, overtemperature and over-current protections. It is available in a space-saving VDFN-10L 3x3 package.
Features
•2.4V to 5.5V Input Voltage Range
•Adjustable Output from 0.5V to VIN
•Guaranteed 600mA Output Current
•Accurate Reference : 0.5V (±1.5%)
•Up to 90% Conversion Efficiency
•Typical Quiescent Current : 200μA
•Integrated Low RDS(ON) Highand Low-Side Power MOSFET Switches : 230mΩ and 180mΩ
•Current Mode PWM Operation
•Fixed Frequency : 2MHz
•100% Maximum Duty Cycle for Lowest Dropout
•Internal Soft-Start
•No Schottky Diode Required
•Over-Temperature and Over-Current Protection
•Small 10-Lead VDFN 3x3 Package
•RoHS Compliant and 100% Lead (Pb)-Free
Applications
Ordering Information
RT8003 
Package Type
QV : VDFN-10L 3x3 (V-Type)
Operating Temperature Range
P : Pb Free with Commercial Standard
G: Green (Halogen Free with Commercial Standard)
Note :
Richtek Pb-free and Green products are :
}RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
}Suitable for use in SnPb or Pb-free soldering processes.
}100% matte tin (Sn) plating.
Marking Information
For marking information, contact our sales representative directly or through a Richtek distributor located in your area, otherwise visit our website for detail.
•Battery-Powered Equipments
•Low Power CPU and DSP Supplies
•Digital Cameras and Hard Disks
•Protable Instruments and Notebook Computers
•Celluar Phones, PDAs, and Handheld PCs
•USB-Based DSL Modems and Other Network Interface Cards
Pin Configurations
(TOP VIEW)
LX |
1 |
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10 |
GND |
VDD 2 |
GND |
9 |
GND |
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NC 3 |
8 |
GND |
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NC 4 |
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7 |
COMP |
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EN |
5 |
11 |
9 |
FB |
VDFN-10L 3x3
DS8003-06 August 2007 |
www.richtek.com |
1
RT8003
Typical Application Circuit
VIN |
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2.4V to 4.2V |
CIN |
2 |
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LOUT |
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1uF |
VDD |
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Chip Enable |
5 |
EN |
LX |
1 |
2.2uH |
VOUT |
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1.2V/600mA |
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RT8003 |
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R1 |
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10k |
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7 |
COMP |
FB |
6 |
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COUT |
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CCOMP |
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1uF |
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GND |
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10nF |
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R2 |
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8, 9, 10, |
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7.15k |
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Exposed Pad (11) |
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Recommended component selection for Typical Application Circuit.
VOUT (V) |
VIN (V) |
CIN (μF) |
COUT (μF) |
LOUT (μH) |
R1 (kΩ) |
R2 (kΩ) |
CCOMP (nF) |
0.5 |
2.4 to 3.3 |
1 |
1/2.2 |
2.2/1 |
10 |
Open |
10 |
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1 |
2.4 to 3.6 |
1 |
1/2.2 |
2.2/1 |
10 |
10 |
10 |
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1.2 |
2.4 to 4.2 |
1 |
1/2.2 |
2.2/1 |
10 |
7.15 |
10 |
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1.8 |
2.4 to 5.5 |
1 |
1/2.2 |
2.2/1 |
10 |
3.83 |
10 |
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2.5 |
3.3 to 5.5 |
1 |
1/2.2 |
2.2/1 |
10 |
2.49 |
10 |
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3.3 |
4.2 to 5.5 |
1 |
1/2.2 |
2.2/1 |
10 |
1.78 |
10 |
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Suggested Inductors
Component |
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Series |
Inductance |
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ESR |
Current Rating |
Dimensions |
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Supplier |
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(µH) |
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(mΩ) |
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(mA) |
(mm) |
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ABC |
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SR0302 |
1 |
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60 |
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2100 |
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3x2.8x2.5 |
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2.2 |
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90 |
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1650 |
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Sumida |
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CDRH2D14 |
2.2 |
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94 |
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1000 |
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3.2x3.2x1.55 |
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TDK |
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VLP4612 |
1 |
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110 |
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1500 |
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4.6x3.4x1.2 |
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2.5 |
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170 |
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1100 |
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Suggested Capacitors For CIN and COUT |
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Component Supplier |
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Part No. |
Capacitance (uF) |
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Case Size |
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TDK |
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C1608X5R1A105M |
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1 |
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0603 |
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C1608X5R1A225M |
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2.2 |
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0603 |
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Panasonic |
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ECJ1VB0J105M |
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1 |
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0603 |
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ECJ1VB0J225M |
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2.2 |
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0603 |
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TAIYO YUDEN |
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JMK107BJ105M |
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1 |
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0603 |
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JMK107BJ225M |
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2.2 |
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0603 |
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www.richtek.com |
DS8003-06 August 2007 |
2
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RT8003 |
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Functional Pin Description |
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Pin No. |
Pin Name |
Pin Function |
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1 |
LX |
Internal Power MOSFET Switches Output. Connect this pin to the inductor. |
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2 |
VDD |
Power Input Supply. Input voltage which supplies current to the output pin. Connect |
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this pin with a low-ESR capacitor to GND |
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3, 4 |
NC |
No Internal Connection |
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5 |
EN |
Chip Enable (Active High). Logic low shuts down the converter. Floating this pin is |
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forbidden. |
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Switcher Feedback Voltage. This pin is the inverting input of the error amplifier. FB 6 FB senses the switcher output through an external resistor divider network. FB
regulation voltage is 0.5V.
7 |
COMP |
Compensation Input. This pin is the output of the internal error amplifier. Connect |
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an external capacitor to compensate the regulator controlled loop. |
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Ties the pin directly to the cathode terminal of CIN and COUT and ground plane with |
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the lowest impedance. Signal and Common Ground (The exposed pad must be |
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8, 9, 10, 11 |
GND |
soldered to a large PCB and connected to GND for maximum power dissipation). |
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(Exposed Pad) |
The GND pad area should be as large as possible and using many vias to conduct |
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the heat into the buried GND plate of PCB layer. All small-signal, compensation and |
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feedback components should connect to this pin. |
Function Block Diagram
EN |
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VDD |
Shutdown |
Slope |
Current Limit |
Over |
Current |
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Temperature |
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Control |
Compensation |
Detector |
Detector |
Sense |
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Oscillator |
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- |
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COMP |
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PWM |
Control |
Driver |
LX |
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Comparator |
Logic |
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VREF |
+ |
+ |
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Error |
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Amplifier |
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Zero |
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FB |
- |
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Detector |
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GND |
DS8003-06 August 2007 |
www.richtek.com |
3
RT8003
Absolute Maximum Ratings (Note 1)
• Supply Voltage --------------------------------------------------------------------------------------------------- |
−0.3V to 6V |
• LX Voltage --------------------------------------------------------------------------------------------------------- |
−0.3V to (VDD + 0.3V) |
• Power Dissipation, PD @ TA = 25°C |
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VDFN-10L 3x3 ---------------------------------------------------------------------------------------------------- |
1.923W |
• Package Thermal Resistance (Note 2) |
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VDFN-10L 3x3, θJA ----------------------------------------------------------------------------------------------- |
52°C/W |
• Junction Temperature ------------------------------------------------------------------------------------------- |
150°C |
• Lead Temperature (Soldering, 10 sec.) ---------------------------------------------------------------------- |
260°C |
• Storage Temperature Range ----------------------------------------------------------------------------------- |
−65°C to 150°C |
• ESD Susceptibility (Note 3) |
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HBM (Human Body Mode) ------------------------------------------------------------------------------------- |
2kV |
MM (Machine Mode) -------------------------------------------------------------------------------------------- |
200V |
Recommended Operating Conditions |
(Note 4) |
• Supply Voltage --------------------------------------------------------------------------------------------------- |
2.4V to 5.5V |
• Enable Input Voltage, VEN ------------------------------------------------------------------------------------- |
0V to 5.5V |
• Ambient Temperature Range ---------------------------------------------------------------------------------- |
−40°C to 85°C |
• Junction Temperature Range ---------------------------------------------------------------------------------- |
0°C to 125°C |
Electrical Characteristics
(VDD = 3.3V, TA = 25°C, unless otherwise specified)
Parameter |
Symbol |
Test Conditions |
Min |
Typ |
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Max |
Unit |
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Supply Current |
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Quiescent Current |
IQ |
VEN = 3.3V, VFB = VREF + 0.15V, |
90 |
200 |
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400 |
µA |
IOUT = 0mA |
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Shutdown Current |
ISHDN |
VEN = 0V |
-- |
0.01 |
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1 |
µA |
Reference |
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Reference Voltage |
VREF |
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0.4925 |
0.5 |
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0.5075 |
V |
Oscillator |
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Switching Frequency Range |
fOSC |
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1.7 |
2.0 |
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2.3 |
MHz |
Maximum Duty Cycle |
DC |
VDD = VOUT |
100 |
-- |
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-- |
% |
Output Voltage |
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Line Regulation |
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VDD = 2.4V to 5.5V, ILOAD = 100mA |
-- |
-- |
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+1.5 |
% |
Load Regulation |
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10mA < ILOAD < 600mA |
-- |
-- |
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+1.5 |
% |
Power Switches |
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RDS(ON) of P-Channel MOSFET |
RP_FET |
VDD = 3.3V, ILX = 300mA |
100 |
230 |
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600 |
mΩ |
RDS(ON) of N-Channel MOSFET |
RN_FET |
VDD = 3.3V, ILX = −300mA |
100 |
180 |
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600 |
mΩ |
Current Limit |
ILIMIT |
VDD = 3.3V, VFB = VREF - 0.15V |
1.6 |
2 |
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2.4 |
A |
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To be continued |
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www.richtek.com |
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DS8003-06 August 2007 |
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