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

 

10

PGND

PVDD 2

 

9

PGND

PVDD 3

GND

8

GND

VDD

4

 

7

COMP

EN

5

11

9

FB

VDFN-10L 3x3

DS8005-10 March 2011

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1

RT8005

Typical Application Circuit

VIN

 

 

 

 

 

 

 

2.4V to 5.5V

CIN

4

2,3

 

 

 

 

 

 

LOUT

 

 

 

2.2µF

VDD

PVDD

 

 

 

Chip Enable

5

 

LX

1

2.2µH

 

VOUT

EN

 

 

 

1.2V/1A

 

 

 

 

R1

 

 

RT8005

 

 

 

 

7

COMP

FB

6

 

10k

COUT

 

 

 

2.2µF

 

CCOMP

 

PGND

9, 10

R2

 

 

 

 

 

 

 

 

 

 

 

10nF

GND

 

 

 

7.15k

 

 

 

8,

 

 

 

 

 

 

 

11 (Exposed Pad)

 

 

 

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

 

 

 

 

 

 

 

 

1

2.4 to 5.5

2.2

2.2/4.7

2.2

10

10

10

 

 

 

 

 

 

 

 

1.2

2.4 to 5.5

2.2

2.2/4.7

2.2

10

7.15

10

 

 

 

 

 

 

 

 

1.8

2.4 to 5.5

2.2

2.2/4.7

2.2

10

3.83

10

 

 

 

 

 

 

 

 

2.5

3.3 to 5.5

2.2

2.2/4.7

2.2

10

2.49

10

 

 

 

 

 

 

 

 

3.3

4.2 to 5.5

2.2

2.2/4.7

2.2

10

1.78

10

 

 

 

 

 

 

 

 

Suggested Inductors

Component

 

 

Series

Inductance

 

DCR

Current Rating

Dimensions

 

Supplier

 

 

 

 

(µH)

 

(mΩ)

(mA)

(mm)

 

ABC

 

SR0403

2.2

 

47

2600

 

4.5x4x3.2

 

 

 

 

 

 

 

 

 

 

 

Sumida

 

CDRH3D16

2.2

 

59

1750

 

4x4x1.8

 

 

 

 

 

 

 

 

 

 

 

GOTREND

 

GTSD53

2.2

 

29

2410

 

5x5x2.8

 

 

 

 

 

 

 

 

 

 

Suggested Capacitors For CIN and COUT

 

 

 

 

 

Component Supplier

 

Part No.

Capacitance (uF)

 

Case Size

TDK

 

 

C1608X5R1A225M

 

2.2

 

0603

 

Panasonic

 

 

ECJ1VB0J225M

 

2.2

 

0603

 

TAIYO YUDEN

 

JMK107BJ225M

 

2.2

 

0603

 

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DS8005-10 March 2011

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RT8005

Functional Pin Description

Pin No.

Pin Name

Pin Function

 

 

 

 

 

1

LX

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

 

 

 

 

 

2, 3

PVDD

Power Input Supply. Decouple this pin to PGND with a capacitor.

 

 

 

 

 

4

VDD

Signal Input Supply. Decouple this pin to GND with a capacitor. Normally VDD is

 

equal to PVDD.

 

 

 

 

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.

 

6

FB

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.

 

 

 

 

8,

 

Signal Ground. All small-signal components, compensation components and the

 

GND

exposed pad on the bottom side of the IC should connect to this ground, which in

 

Exposed Pad (11)

turn connects to PGND at one point. The exposed pad must be soldered to a

 

 

 

 

 

large PCB and connected to GND for maximum power dissipation.

 

9, 10

PGND

Power Ground. Connect this pin close to the terminal of CIN and COUT.

 

Function Block Diagram

EN

 

VDD

 

 

PVDD

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

 

 

PGND

DS8005-10 March 2011

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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

 

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, 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)

 

Parameter

Symbol

 

Test Conditions

Min

Typ

Max

Unit

 

 

 

 

 

 

 

 

 

Supply Current

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Quiescent Current

IQ

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

--

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

VPVDD = 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-MOSFET

RP_FET

VPVDD = 3.3V, ILX = 300mA

--

230

--

mΩ

R

of N-MOSFET

R

VPVDD

= 3.3V, ILX =

--

180

--

mΩ

DS(ON)

 

N_FET

 

300mA

 

 

 

 

Current Limit

ILIMIT

VPVDD = 3.3V, VFB = VREF - 0.15V

--

1.8

--

A

To be continued

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