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

 

10

GND

VDD 2

GND

9

GND

NC 3

8

GND

NC 4

 

7

COMP

EN

5

11

9

FB

VDFN-10L 3x3

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1

RT8003

Typical Application Circuit

VIN

 

 

 

 

 

 

2.4V to 4.2V

CIN

2

 

 

 

 

 

 

 

LOUT

 

 

1uF

VDD

 

 

 

Chip Enable

5

EN

LX

1

2.2uH

VOUT

 

 

 

 

1.2V/600mA

 

 

RT8003

 

 

 

R1

 

 

 

 

 

 

10k

 

7

COMP

FB

6

 

COUT

 

CCOMP

 

1uF

 

GND

 

 

 

 

10nF

 

 

 

R2

 

8, 9, 10,

 

 

 

 

 

 

 

7.15k

 

 

Exposed Pad (11)

 

 

 

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

 

 

 

 

 

 

 

 

1

2.4 to 3.6

1

1/2.2

2.2/1

10

10

10

 

 

 

 

 

 

 

 

1.2

2.4 to 4.2

1

1/2.2

2.2/1

10

7.15

10

 

 

 

 

 

 

 

 

1.8

2.4 to 5.5

1

1/2.2

2.2/1

10

3.83

10

 

 

 

 

 

 

 

 

2.5

3.3 to 5.5

1

1/2.2

2.2/1

10

2.49

10

 

 

 

 

 

 

 

 

3.3

4.2 to 5.5

1

1/2.2

2.2/1

10

1.78

10

 

 

 

 

 

 

 

 

Suggested Inductors

Component

 

 

Series

Inductance

 

ESR

Current Rating

Dimensions

 

Supplier

 

 

 

 

(µH)

 

(mΩ)

 

(mA)

(mm)

 

ABC

 

SR0302

1

 

60

 

2100

 

3x2.8x2.5

 

 

2.2

 

90

 

1650

 

 

 

 

 

 

 

 

 

 

 

 

Sumida

 

CDRH2D14

2.2

 

94

 

1000

 

3.2x3.2x1.55

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TDK

 

VLP4612

1

 

110

 

1500

 

4.6x3.4x1.2

 

 

2.5

 

170

 

1100

 

 

 

 

 

 

 

 

 

 

 

 

Suggested Capacitors For CIN and COUT

 

 

 

 

 

 

Component Supplier

 

Part No.

Capacitance (uF)

 

Case Size

TDK

 

 

C1608X5R1A105M

 

1

 

 

0603

 

 

 

C1608X5R1A225M

 

2.2

 

 

0603

 

 

 

 

 

 

 

 

 

Panasonic

 

 

ECJ1VB0J105M

 

1

 

 

0603

 

 

 

ECJ1VB0J225M

 

2.2

 

 

0603

 

 

 

 

 

 

 

 

 

TAIYO YUDEN

 

JMK107BJ105M

 

1

 

 

0603

 

 

JMK107BJ225M

 

2.2

 

 

0603

 

 

 

 

 

 

 

 

 

www.richtek.com

DS8003-06 August 2007

2

Richtek RT8003PQV Schematic

 

 

RT8003

Functional Pin Description

Pin No.

Pin Name

Pin Function

1

LX

Internal Power MOSFET Switches Output. Connect this pin to the inductor.

 

 

 

2

VDD

Power Input Supply. Input voltage which supplies current to the output pin. Connect

this pin with a low-ESR capacitor to GND

 

 

3, 4

NC

No Internal Connection

 

 

 

5

EN

Chip Enable (Active High). Logic low shuts down the converter. Floating this pin is

forbidden.

 

 

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

an external capacitor to compensate the regulator controlled loop.

 

 

 

 

Ties the pin directly to the cathode terminal of CIN and COUT and ground plane with

 

 

the lowest impedance. Signal and Common Ground (The exposed pad must be

8, 9, 10, 11

GND

soldered to a large PCB and connected to GND for maximum power dissipation).

(Exposed Pad)

The GND pad area should be as large as possible and using many vias to conduct

 

 

 

the heat into the buried GND plate of PCB layer. All small-signal, compensation and

 

 

feedback components should connect to this pin.

Function Block Diagram

EN

 

 

 

 

VDD

Shutdown

Slope

Current Limit

Over

Current

 

Temperature

 

Control

Compensation

Detector

Detector

Sense

 

Oscillator

 

-

 

 

 

COMP

 

PWM

Control

Driver

LX

 

Comparator

Logic

 

 

VREF

+

+

 

 

 

 

 

 

 

 

Error

 

 

 

 

 

Amplifier

 

Zero

 

 

FB

-

 

 

 

 

Detector

 

 

 

 

 

 

 

GND

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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

 

VDFN-10L 3x3 ----------------------------------------------------------------------------------------------------

1.923W

Package Thermal Resistance (Note 2)

 

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)

 

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

 

Max

Unit

 

 

 

 

 

 

 

 

Supply Current

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Quiescent Current

IQ

VEN = 3.3V, VFB = VREF + 0.15V,

90

200

 

400

µA

IOUT = 0mA

 

 

 

 

 

 

 

 

Shutdown Current

ISHDN

VEN = 0V

--

0.01

 

1

µA

Reference

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reference Voltage

VREF

 

0.4925

0.5

 

0.5075

V

Oscillator

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Switching Frequency Range

fOSC

 

1.7

2.0

 

2.3

MHz

Maximum Duty Cycle

DC

VDD = VOUT

100

--

 

--

%

Output Voltage

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Line Regulation

 

VDD = 2.4V to 5.5V, ILOAD = 100mA

--

--

 

+1.5

%

Load Regulation

 

10mA < ILOAD < 600mA

--

--

 

+1.5

%

Power Switches

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RDS(ON) of P-Channel MOSFET

RP_FET

VDD = 3.3V, ILX = 300mA

100

230

 

600

mΩ

RDS(ON) of N-Channel MOSFET

RN_FET

VDD = 3.3V, ILX = 300mA

100

180

 

600

mΩ

Current Limit

ILIMIT

VDD = 3.3V, VFB = VREF - 0.15V

1.6

2

 

2.4

A

 

 

 

 

 

To be continued

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