Richtek RT8010BGQW Schematic [ru]

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RT8010B

1.5MHz, 800mA, High Efficiency PWM Step-Down DC/DC Converter

General Description

The RT8010B is a high-efficiency Pulse-Width-Modulated (PWM) step-down DC/DC converter. Capable of delivering 800mA output current over a wide input voltage range from 2.5V to 4V, the RT8010B is ideally suited for portable electronic devices that are powered from 1-cell Li-ion battery or from other power sources such as cellular phones, PDAs and hand-held devices.

Two operating modes are available including PWM/LowDropout autoswitch and shut-down modes. The internal synchronous rectifier with low RDS(ON) dramatically reduces conduction loss at PWM mode. No external Schottky diode is required in practical application.

The RT8010B enters Low-Dropout mode when normal PWM can not provide regulated output voltage by continuously turning on the upper PMOS. The RT8010B enters shut-down mode and consumes less than 0.1μA when EN pin is pulled low.

The switching ripple is easily smoothed-out by small package filtering elements due to a fixed operating frequency of 1.5MHz. This along with small WDFN-8L 2x2 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.

Ordering Information

RT8010B

Package Type

QW : WDFN-8L 2x2 (W-Type)

Lead Plating System

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.

Features

2.5V to 4V Input Range

Output Voltage (Adjustable Output From 0.6V to VIN) 800mA Output Current

95% Efficiency

No Schottky Diode Required

1.5MHz Fixed Frequency PWM Operation Small 8-Lead WDFN Package

RoHS Compliant and Halogen Free

Applications

Mobile Phones

Personal Information Appliances

Wireless and DSL Modems

MP3 Players

Portable Instruments

Pin Configurations

(TOP VIEW)

EN

1

 

8

PGND

FB

2

 

7

PGND

VIN

3

9

6

PGND

LX

4

5

AGND

 

WDFN-8L 2x2

Marking Information

For marking information, contact our sales representative directly or through a Richtek distributor located in your area.

DS8010B-04 March 2011

www.richtek.com

 

1

Richtek RT8010BGQW Schematic

RT8010B

Typical Application Circuit

VIN

2.5V to 4V

VOUT = VREF x 1+ R2R1

 

 

 

L

 

3

VIN

LX 4

2.2µH

 

CIN

RT8010B

C1

R1

4.7µF

 

1

EN

FB 2

 

 

 

IR2

R2

 

 

 

6, 7, 8 PGND

AGND 5

 

 

VOUT

COUT

10µF

with R2 = 75kΩ to 200kΩ,

and (R1 x C1) should be in the range between 3x10-6 and 6x10-6 for component selection.

Functional Pin Description

Pin No.

Pin Name

Pin Function

1

EN

Chip Enable (Active High).

2

FB

Feedback Pin.

3

VIN

Power Input.

4

LX

Pin for Switching.

5

AGND

Analog Ground.

6, 7, 8

PGND

Power Ground.

9 (Exposed Pad)

NC

No Internal Connection.

Function Block Diagram

 

 

EN

 

 

VIN

 

 

 

 

OSC &

 

 

RS1

 

 

 

 

Current

 

 

 

 

 

 

Shutdown

 

 

 

 

 

 

Limit

 

 

 

 

 

 

Control

 

 

 

 

 

 

Detector

 

 

 

 

 

Slope

 

 

 

 

 

 

 

 

 

 

 

 

 

Compensation

Current

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sense

 

 

 

 

 

 

 

 

Control

Driver

LX

 

 

 

 

PWM

Logic

 

 

 

 

 

 

 

 

 

 

 

FB

Error

Comparator

 

 

 

 

 

 

Amplifier

 

 

 

 

 

 

 

RC

 

 

 

RS2

 

 

 

COMP

UVLO &

 

 

PGND

 

 

 

Power Good

 

 

 

 

 

 

 

Detector

VREF

 

 

 

 

 

 

 

 

AGND

 

 

 

 

 

 

 

www.richtek.com

 

 

 

 

DS8010B-04

March

2011

2

 

 

 

 

 

 

 

 

RT8010B

Absolute Maximum Ratings (Note 1)

 

Supply Input Voltage ------------------------------------------------------------------------------------------------------

6.5V

EN, FB Pin Voltage -------------------------------------------------------------------------------------------------------

−0.3V to VIN

Power Dissipation, PD @ TA = 25°C

 

WDFN-8L 2x2 --------------------------------------------------------------------------------------------------------------

0.606W

Package Thermal Resistance (Note 2)

 

WDFN-8L 2x2, θJA ---------------------------------------------------------------------------------------------------------

165°C/W

WDFN-8L 2x2, θJC --------------------------------------------------------------------------------------------------------

20°C/W

Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------------

260°C

Storage Temperature Range --------------------------------------------------------------------------------------------

−65°C to 150°C

Junction Temperature -----------------------------------------------------------------------------------------------------

150°C

ESD Susceptibility (Note 3)

 

HBM (Human Body Mode) ----------------------------------------------------------------------------------------------

2kV

MM (Machine Mode) ------------------------------------------------------------------------------------------------------

200V

Recommended Operating Conditions

(Note 4)

Supply Input Voltage ------------------------------------------------------------------------------------------------------

2.5V to 4V

Junction Temperature Range --------------------------------------------------------------------------------------------

−40°C to 125°C

Ambient Temperature Range --------------------------------------------------------------------------------------------

−40°C to 85°C

Electrical Characteristics

(VIN = 3.6V, VOUT = 2.5V, VREF = 0.6V, L = 2.2μH, CIN = 4.7μF, COUT = 10μF, IMAX = 0.8A, TA = 25°C, unless otherwise specified)

Parameter

Symbol

Test Conditions

Min

Typ

Max

Unit

 

 

 

 

 

 

 

 

 

Input Voltage Range

VIN

 

 

2.5

--

4

V

 

 

 

 

 

 

 

 

 

Quiescent Current

IQ

IOUT = 0mA, VFB = VREF + 5%

--

50

70

μA

Shutdown Current

ISHDN

EN = GND

--

0.1

1

μ

 

 

 

 

 

 

 

A

Reference Voltage

VREF

For Adjustable Output Voltage

0.588

0.6

0.612

V

 

 

 

 

 

 

 

 

 

Adjustable Output Range

VOUT

(Note 6)

VREF

--

VIN − 0.2V

V

Output Voltage

Adjustable

VOUT

VIN = VOUT + V to 4V (Note 5)

3

--

+3

%

Accuracy

 

 

0A < IOUT < 0.8A

 

 

 

 

FB Input Current

IFB

VFB = VIN

−50

--

50

nA

P-MOSFET RON

RDS(ON)_P

IOUT = 200mA

VIN = 3.6V

--

0.28

--

Ω

VIN = 2.5V

--

0.38

--

 

 

 

 

 

 

N-MOSFET RON

RDS(ON)_N

IOUT = 200mA

VIN = 3.6V

--

0.25

--

Ω

VIN = 2.5V

--

0.35

--

 

 

 

 

 

 

P-Channel Current Limit

ILIM_P

VIN = 2.5V to 4V

1.2

1.5

--

A

EN High-Level Input Voltage

VEN_H

VIN = 2.5V to 4V

1.5

--

--

V

EN Low-Level Input Voltage

VEN_L

VIN = 2.5V to 4V

--

--

0.4

V

Under Voltage Lockout

UVLO

 

 

--

1.8

--

V

Threshold

 

 

 

 

 

 

 

 

 

Hysteresis

 

 

 

--

0.1

--

V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

To be continued

 

 

 

 

 

 

 

 

 

DS8010B-04 March 2011

 

 

 

 

 

www.richtek.com

 

 

 

 

 

 

 

 

3

RT8010B

Parameter

Symbol

Test Conditions

Min

Typ

Max

Unit

 

 

 

 

 

 

 

Oscillator Frequency

fOSC

VIN = 3.6V, IOUT = 100mA

1.2

1.5

1.8

MHz

Thermal Shutdown Temperature

TSD

 

--

160

--

°C

Max. Duty Cycle

 

 

100

--

--

%

 

 

 

 

 

 

 

 

LX Leakage Current

 

VIN = 3.6V, VLX = 0V or VLX = 3.6V

1

--

1

μ

 

 

 

 

 

A

Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability.

Note 2. θJA is measured in the natural convection at TA = 25°C on a high effective four layers thermal conductivity test board of JEDEC 51-7 thermal measurement standard. The case point of θJC is on the expose pad of the package.

Note 3 Devices are ESD sensitive. Handling precaution is recommended.

Note 4. The device is not guaranteed to function outside its operating conditions.

Note 5. V = IOUT x PRDS(ON)

Note 6. Guarantee by design.

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DS8010B-04 March 2011

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