Richtek RT8005PQV Schematic [ru]
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RT8005
1A, 2MHz, High-Efficiency Synchronous Buck PWM Converter
General Description
The RT8005 is a high-efficiency synchronous buck PWM converter with integrated P-Channel andN-Channel power MOSFET switches. Capable of delivering 1Aoutput current over a wide input voltage range of 2.4V to 5.5V, the RT8005 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 RT8005 integratestwo low RDS(ON) 230mΩ and 180mΩ of high and low side switching MOSFETs to reduce board space, as only resistors and capacitors along with one inductor are required externally for operation. The RT8005 has adjustable output range down to 0.5V. The other features include internal soft-start, chip enable, over temperature 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 1A Output Current
•Accurate Reference : 0.5V (±1.5%)
•Up to 90% Conversion Efficiency
•Typical Quiescent Current : 200μA
•Integrated Low RDS(ON) High and 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
Ordering Information
RT8005 
Package Type
QV : VDFN-10L 3x3 (V-Type)
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Note :
Richtek 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.
Marking Information
For marking information, contact our sales representative directly or through a Richtek distributor located in your area.
Applications
•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 |
PGND |
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PVDD 2 |
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9 |
PGND |
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PVDD 3 |
GND |
8 |
GND |
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VDD |
4 |
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7 |
COMP |
EN |
5 |
11 |
9 |
FB |
VDFN-10L 3x3
DS8005-10 March 2011 |
www.richtek.com |
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RT8005
Typical Application Circuit
VIN |
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2.4V to 5.5V |
CIN |
4 |
2,3 |
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LOUT |
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2.2µF |
VDD |
PVDD |
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Chip Enable |
5 |
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LX |
1 |
2.2µH |
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VOUT |
EN |
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1.2V/1A |
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R1 |
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RT8005 |
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7 |
COMP |
FB |
6 |
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10k |
COUT |
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2.2µF |
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CCOMP |
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PGND |
9, 10 |
R2 |
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10nF |
GND |
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7.15k |
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8, |
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11 (Exposed Pad) |
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Recommended component selection for Typical Application Circuit.
VOUT (V) |
VIN (V) |
CIN (uF) |
COUT (uF) |
LOUT (uH) |
R1 (kΩ) |
R2 (kΩ) |
CCOMP (nF) |
0.5 |
2.4 to 5.5 |
2.2 |
2.2/4.7 |
2.2 |
10 |
Open |
10 |
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1 |
2.4 to 5.5 |
2.2 |
2.2/4.7 |
2.2 |
10 |
10 |
10 |
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1.2 |
2.4 to 5.5 |
2.2 |
2.2/4.7 |
2.2 |
10 |
7.15 |
10 |
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1.8 |
2.4 to 5.5 |
2.2 |
2.2/4.7 |
2.2 |
10 |
3.83 |
10 |
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2.5 |
3.3 to 5.5 |
2.2 |
2.2/4.7 |
2.2 |
10 |
2.49 |
10 |
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3.3 |
4.2 to 5.5 |
2.2 |
2.2/4.7 |
2.2 |
10 |
1.78 |
10 |
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Suggested Inductors
Component |
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Series |
Inductance |
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DCR |
Current Rating |
Dimensions |
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Supplier |
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(µH) |
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(mΩ) |
(mA) |
(mm) |
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ABC |
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SR0403 |
2.2 |
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47 |
2600 |
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4.5x4x3.2 |
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Sumida |
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CDRH3D16 |
2.2 |
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59 |
1750 |
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4x4x1.8 |
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GOTREND |
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GTSD53 |
2.2 |
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29 |
2410 |
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5x5x2.8 |
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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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C1608X5R1A225M |
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2.2 |
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0603 |
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Panasonic |
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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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JMK107BJ225M |
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2.2 |
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0603 |
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www.richtek.com |
DS8005-10 March 2011 |
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RT8005 |
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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, 3 |
PVDD |
Power Input Supply. Decouple this pin to PGND with a capacitor. |
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4 |
VDD |
Signal Input Supply. Decouple this pin to GND with a capacitor. Normally VDD is |
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equal to PVDD. |
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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. |
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6 |
FB |
FB senses the switcher output through an external resistor divider network. FB |
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regulation voltage is 0.5V. |
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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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8, |
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Signal Ground. All small-signal components, compensation components and the |
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GND |
exposed pad on the bottom side of the IC should connect to this ground, which in |
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Exposed Pad (11) |
turn connects to PGND at one point. The exposed pad must be soldered to a |
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large PCB and connected to GND for maximum power dissipation. |
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9, 10 |
PGND |
Power Ground. Connect this pin close to the terminal of CIN and COUT. |
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Function Block Diagram
EN |
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VDD |
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PVDD |
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 |
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PGND |
DS8005-10 March 2011 |
www.richtek.com |
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3 |
RT8005
Absolute Maximum Ratings (Note 1)
• Supply Voltage, PVDD and VDD ------------------------------------------------------------------------------ |
−0.3V to 6V |
• EN, FB Voltage --------------------------------------------------------------------------------------------------- |
−0.3V to VDD |
• PGNDtoGND ---------------------------------------------------------------------------------------------------- |
−0.3V to 0.3V |
• 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, PVDD and VDD ------------------------------------------------------------------------------ |
2.4V to 5.5V |
• Enable Input Voltage, VEN ------------------------------------------------------------------------------------- |
0V to VDD |
• Ambient Temperature Range ---------------------------------------------------------------------------------- |
−40°C to 85°C |
• Junction Temperature Range ---------------------------------------------------------------------------------- |
−40°C to 125°C |
Electrical Characteristics
(VDD = 3.3V, TA = 25°C, unless otherwise specified)
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Parameter |
Symbol |
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Test Conditions |
Min |
Typ |
Max |
Unit |
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Supply Current |
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Quiescent Current |
IQ |
VEN = 3.3V, VFB = VREF + 0.15V, |
-- |
200 |
400 |
µA |
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IOUT = 0mA |
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Shutdown Current |
ISHDN |
VEN = 0V |
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-- |
0.01 |
1 |
µA |
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Reference |
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Reference Voltage |
VREF |
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0.4925 |
0.5 |
0.5075 |
V |
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Oscillator |
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Switching Frequency Range |
fOSC |
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1.7 |
2.0 |
2.3 |
MHz |
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Maximum Duty Cycle |
DC |
VPVDD = VOUT |
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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 |
-- |
-- |
+1.5 |
% |
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Load Regulation |
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10mA < ILOAD < 600mA |
-- |
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+1.5 |
% |
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Power Switches |
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RDS(ON) of P-MOSFET |
RP_FET |
VPVDD = 3.3V, ILX = 300mA |
-- |
230 |
-- |
mΩ |
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R |
of N-MOSFET |
R |
VPVDD |
= 3.3V, ILX = |
− |
-- |
180 |
-- |
mΩ |
DS(ON) |
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N_FET |
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300mA |
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Current Limit |
ILIMIT |
VPVDD = 3.3V, VFB = VREF - 0.15V |
-- |
1.8 |
-- |
A |
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To be continued
www.richtek.com |
DS8005-10 March 2011 |
4 |
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