Richtek RT8010BGQW Schematic [ru]

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

RT8010B

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/Low-

Dropout autoswitch and shut-down modes. The internal

synchronous rectifier with low R

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.

dramatically reduces

DS(ON)

Features



 2.5V to 4V Input Range





 Output Voltage (Adjustable Output From 0.6V to V





 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)

1

EN

2

FB

3

VIN

4

LX

WDFN-8L 2x2

8

PGND

7

PGND

6

PGND

9

5

AGND

Marking Information

)

IN

For marking information, contact our sales representative

Ordering Information

RT8010B

directly or through a Richtek distributor located in your

area.

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 require-

ments of IPC/JEDEC J-STD-020.

` Suitable for use in SnPb or Pb-free soldering processes.

DS8010B-04 March 2011 www.richtek.com

1

RT8010B

Typical Application Circuit

C

IN

4.7µF

6, 7, 8

3

VIN

RT8010B

1

EN

PGND

-6

and 6x10

4

LX

2

FB

5

AGND

-6

for component selection.

V

2.5V to 4V

R1

⎛

⎜

REFOUT

⎝

⎞

1 x VV

+=

⎟

R2

⎠

IN

with R2 = 75kΩ to 200kΩ,

and (R1 x C1) should be in the range between 3x10

Functional Pin Description

Pin No. Pin Name Pin Function

1 EN Ch ip Ena ble (Active H igh ).

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.

L

2.2µH

V

OUT

C1

R1

C

OUT

I

R2

R2

10µF

Function Block Diagram

Slope

Compensation

FB

Error

Amplifier

RC

COMP

EN VIN

OSC &

Shutdown

Control

Current

Sense

PWM

Comparator

UVLO &

Power Good

Detector

V

REF

Current

Limit

Detector

Control

Logic

Driver

RS1

LX

RS2

PGND

AGND

DS8010B-04 March 2011www.richtek.com

2

RT8010B

Absolute Maximum Ratings (Note 1)

 Supply Input Voltage------------------------------------------------------------------------------------------------------ 6.5V

 EN, FB Pin Voltage ------------------------------------------------------------------------------------------------------- −0.3V to V

 Power Dissipation, P

@ TA = 25°C

D

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--------------------------------------------------------------------------------------------

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

−40°C to 125°C

−40°C to 85°C

IN

Electrical Characteristics

(V

= 3.6V, V

IN

Input Voltage Range

Quiescent Current IQ I

Shutdown Current

Reference Voltage

Adjustable Output Range

Output Voltage

Accuracy

FB Input Current

P-MOSFET RON R

N-MOSFET RON R

P-Channel Current Limit I

EN High-Level Input Voltage

EN Low-Level Input Voltage

Under Voltage Lockout
Threshold

Hysteresis -- 0.1 -- V

OUT

= 2.5V, V

= 0.6V, L = 2.2μH, C

REF

= 4.7μF, C

IN

OUT

= 10μF, I

= 0.8A, T

MAX

= 25°C, unless otherwise specified)

A

Parameter Symbol Test Conditions Min Typ Max Unit

2.5 -- 4 V

= 0mA, VFB = V

OUT

EN = GND -- 0.1 1

+ 5% -- 50 70 μA

REF

μA

For Adjustable Output Voltage 0.588 0.6 0.612 V

(Note 6)

= V

V

IN

0A < I

= VIN

FB

I

OU T

I

OU T

= 2.5V to 4V 1.2 1.5 -- A

IN

+ ΔV to 4V (Note 5)

OUT

< 0.8A

OUT

= 200mA

= 200mA

VIN = 2.5V to 4V

VIN = 2.5V to 4V

V

REF

−3

−50 -- 50 nA

V

= 3.6V

IN

V

= 2.5V -- 0.38 --

IN

V

= 3.6V

IN

= 2.5V

V

IN

-- 0.28 --

-- 0.25 --

-- 0.35 --

1.5 -- -- V

-- -- 0.4 V

--

V

− 0.2V

IN

-- +3 %

V

Ω

Ω

Adjustable

V

IN

I

SH DN

V

REF

V

OUT

ΔV

OUT

V

I

FB

DS(ON)_P

DS(ON)_N

V

LIM_P

V

EN_H

V

EN_L

UVLO -- 1.8 -- V

To be continued

DS8010B-04 March 2011 www.richtek.com

3

RT8010B

Parameter Symbol Test Condit ions Min Typ Max Unit

Oscillator Frequency

Thermal Shutdown Temperature

V

f

OSC

T

SD

= 3.6V, I

IN

OU T

= 100mA

-- 160 --

1.2 1.5 1.8 MHz

°C

Max. Duty Cycle 100 -- -- %

LX Leakage Current

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. θ

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. ΔV = I

Note 6. Guarantee by design.

is measured in the natural convection at TA = 25°C on a high effective four layers thermal conductivity test board of

JA

JEDEC 51-7 thermal measurement standard. The case point of θ

x P

OUT

RDS(ON)

V

IN

= 3.6V, V

= 0V or V

LX

= 3.6V −1

LX

is on the expose pad of the package.

JC

-- 1

μA

DS8010B-04 March 2011www.richtek.com

4