Richtek RT8003PQV Schematic [ru]

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 and N-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, C
inductor.

The RT8003 integrates two low R

DS(ON)

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 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.

capacitor and

OUT

230mΩ and 180mΩ

Features

l 2.4V to 5.5V Input Voltage Range
l Adjustable Output from 0.5V to V
l Guaranteed 600mA Output Current
l Accurate Reference : 0.5V (± 1.5%)
l Up to 90% Conversion Efficiency
l Typical Quiescent Current : 200µA
l Integrated Low R

High- and Low-Side Power

DS(ON)

IN

MOSFET Switches : 230mΩ and 180mΩ

l Current Mode PWM Operation
l Fixed Frequency : 2MHz
l 100% Maximum Duty Cycle for Lowest Dropout
l Internal Soft-Start
l No Schottky Diode Required
l Over-Temperature and Over-Current Protection
l Small 10-Lead VDFN 3x3 Package
l 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 Commer­ cial Standard)

Note :
Richtek Pb-free and Green 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.
} 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.

l Battery-Powered Equipments
l Low Power CPU and DSP Supplies
l Digital Cameras and Hard Disks
l Protable Instruments and Notebook Computers
l Celluar Phones, PDAs, and Handheld PCs
l USB-Based DSL Modems and Other Network Interface

Cards

Pin Configurations

(TOP VIEW)

1

LX

2

VDD

3

NC

4

NC

5

EN

VDFN-10L 3x3

GND

10

GND

9

GND

8

GND

7

COMP

9

11

FB

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RT8003

Typical Application Circuit

V

IN

2.4V to 4.2V

Chip Enable

Recommended component selection for Typical Application Circuit.

V

(V) VIN (V) CIN (µF) C

OUT

0.5 2.4 to 3.3

1 1/2.2 2.2/1 10 Open 10

C

1uF

C

COMP

10nF

OUT

IN

5

EN

7

(µF) L

2

VDD

LX

RT8003

FBCOMP

GND

8, 9, 10,
Exposed Pad (11)

(µH) R1 (kΩ) R2 (k Ω) C

OUT

1

6

L

2.2uH

OUT

R1
10k

R2

7.15k

V

OUT

1.2V/600mA

C

OUT

1uF

COMP

(nF)

1 2.4 to 3.6

1.2 2.4 to 4.2

1.8 2.4 to 5.5

2.5 3.3 to 5.5

3.3 4.2 to 5.5

1 1/2.2 2.2/1 10 10 10
1 1/2.2 2.2/1 10 7.15 10
1 1/2.2 2.2/1 10 3.83 10
1 1/2.2 2.2/1 10 2.49 10
1 1/2.2 2.2/1 10 1.78 10

Suggested Inductors

Component

Supplier

ABC SR0302

Sumida CDRH2D14

TDK VLP4612

Series Inductance

(µH)

1

2.2

2.2 94 1000 3.2x3.2x1.55
1

2.5

Suggested Capacitors For CIN and C
Component Supplier

TDK

C1608X5R1A105M 1 0603

Part No. Capacitance (uF) Case Size

C1608X5R1A225M 2.2 0603

Panasonic

ECJ1VB0J105M 1 0603
ECJ1VB0J225M 2.2 0603

TAIYO YUDEN

JMK107BJ105M 1 0603
JMK107BJ225M 2.2 0603

OUT

ESR

(mΩ)

60
90

110
170

Current Rating

(mA)

2100
1650

1500
1100

Dimensions

(mm)

3x2.8x2.5

4.6x3.4x1.2

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Functional Pin Description

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

Floating this pin is

Switcher Feedback Voltage. This pin is the inverting input of the error amplifier. FB

resistor divider network. FB

Compensation Input. This pin is the output of the internal error amplifier. Connect

and ground plane with

The exposed pad must be

).

t

signal, compensation and

RT8003

Pin No. Pin Name

1 LX Internal Power MOSFET Switches Output. Connect this pin to the inductor.
2 VDD

this pin with a low-ESR capacitor to GND

3, 4 NC No Internal Connection

5 EN

6 FB

Chip Enable (Active High). Logic low shuts down the converter.
forbidden.

senses the switcher output through an external
regulation voltage is 0.5V.

7 COMP

an external capacitor to compensate the regulator controlled loop.
Ties the pin directly to the cathode terminal of CIN and C

the lowest impedance. Signal and Common Ground (

8, 9, 10, 11

(Exposed Pad)

GND

soldered to a large PCB and connected to GND for maximum power dissipation
The GND pad area should be as large as possible and using many vias to conduc
the heat into the buried GND plate of PCB layer. All small­feedback components should connect to this pin.

Function Block Diagram

Pin Function

OUT

COMP

FB

EN

Shutdown

Control

Oscillator

V

REF

Slope

Compensation

+

Error

Amplifier

-

Current Limit

Detector

-

PWM

Comparator

+

Over

Temperature

Detector

Control

Logic

Zero

Detector

Current

Sense

Driver

VDD

LX

GND

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RT8003

Absolute Maximum Ratings (Note 1)

l Supply Voltage ---------------------------------------------------------------------------------------------------−0.3V to 6V
l LX Voltage---------------------------------------------------------------------------------------------------------−0.3V to (V
l Power Dissipation, P

@ T

D

= 25°C

A

VDFN-10L 3x3----------------------------------------------------------------------------------------------------1.923W

l Package Thermal Resistance (Note 2)

VDFN-10L 3x3, θJA-----------------------------------------------------------------------------------------------52°C/W

l Junction Temperature-------------------------------------------------------------------------------------------150°C
l Lead Temperature (Soldering, 10 sec.)----------------------------------------------------------------------260°C
l Storage Temperature Range-----------------------------------------------------------------------------------−65°C to 150°C
l ESD Susceptibility (Note 3)

HBM (Human Body Mode)-------------------------------------------------------------------------------------2kV
MM (Machine Mode)--------------------------------------------------------------------------------------------200V

Recommended Operating Conditions (Note 4)

l Supply Voltage---------------------------------------------------------------------------------------------------2.4V to 5.5V
l Enable Input Voltage,
l Ambient Temperature Range----------------------------------------------------------------------------------−40°C to 85°C
l Junction Temperature Range----------------------------------------------------------------------------------0°C to 125°C

-------------------------------------------------------------------------------------0V to 5.5V

VEN

DD

+ 0.3V)

Electrical Characteristics

(V

= 3.3V, T

DD

Supply Current

Quiescent Current

Shutdown Current I

Reference

Reference Voltage V

Oscillator

Switching Frequency Range
Maximum Duty Cycle DC

Output Voltage

Line Regulation
Load Regulation 10mA < I

Power Switches

R

DS(ON)

R

DS(ON)

Current Limit

= 25°C, unless otherwise specified)

A

Parameter Symbol

IQ

SHDN

REF

f

OSC

of P-Channel MOSFET R
of N-Channel MOSFET R

P_FET
N_FET

I

LIMIT

V

= 3.3V, V

EN

I

OUT

V

= 0V -- 0.01

EN

0.4925 0.5 0.5075 V

1.7 2.0 2.3 MHz
V

= V

DD

V

= 2.4V to 5.5V, I

DD

V

V

= 3.3V, ILX = 300mA

DD

V

= 3.3V, ILX = −300mA

DD

= 3.3V, V

DD

Test Conditions Min Typ Max Unit

= 0mA

OUT

LOAD

= V

FB

< 600mA -- -- +1.5

+ 0.15V,

REF

LOAD

= 100mA

90 200 400 µA

100 -- -- %

-- -- +1.5

100 230 600 mΩ
100 180 600

FB

= V

REF

- 0.15V

1.6 2 2.4 A

To be continued

1 µA

%
%

mΩ

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RT8003

Parameter Symbol

Logic Input

EN Threshold

Protection

Thermal Shutdown Temperature TSD -- 180
Thermal Shutdown Hysteresis ∆TSD -- 20 -- °C

Note 1. Stresses listed as the above "Absolute Maximum Ratings" may cause permanent damage to the device. These are for

Note 2. θJA is measured in the natural convection at TA = 25°C on a high effective thermal conductivity test board of

Note 3. Devices are ESD sensitive. Handling precaution recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.

Logic-Low Voltage VIL VDD = 2.4V to 5.5V, Shutdown -- -- 0.4

Logic-High Voltage VIH VDD = 2.4V to 5.5V, Enable 1.5

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.

JEDEC 51-7 thermal measurement standard.

Test Conditions Min Typ Max Unit

V

-- --

-- °C

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RT8003

Output Voltage Deviation (%)

Typical Operating Characteristics

Output Voltage Deviation vs. Output Current

0.10%

0.1

0.00%

0

-0.10%

-0.1

-0.20%

-0.2

-0.30%

-0.3

-0.40%

-0.4

-0.50%

-0.5

-0.60%

-0.6

-0.70%

-0.7

0 100 200 300 400 500 600 700 800

Output Current (mA)

Efficiency vs. Output Current

100%

100

Efficiency (%)

VIN = 3.3V, V

90%

90

80%

80

70%

70

60%

60

50%

50

40%

40

30%

30

20%

20

10%

10

0%

0

1 10 100 1000

= 1.2V

OUT

Output Current (mA)

Output Voltage Deviation (%)

Efficiency (%)

Output Voltage Deviation vs. Temperature

0.40%

0.4

0.20%

0.2

0.00%

0

-0.20%

-0.2

-0.40%

-0.4

-0.60%

-0.6

-0.80%

-0.8

-1.00%

-1.0

-1.20%

-1.2

-1.40%

-1.4

-1.60%

-1.6

-1.80%

-1.8

-50 -25 0 25 50 75 100 125 150

Temperature

(°C)

Efficiency vs. Temperature

100%

100

90%

90

80%

80

70%

70

60%

60

50%

50

40%

40

30%

30

20%

20

10%

10

VIN = 3.3V, V

0%

0

-50 -25 0 25 50 75 100 125 150

= 1.2V, I

OUT

Temperature

= 200mA

OUT

(°C)

Frequency vs. Input Voltage

2.15

2.1

2.05

2

1.95

Frequency (MHz)

1.9

1.85

2.5 3 3.5 4 4.5 5 5.5

Input Voltage(V)

2.05

2

1.95

1.9

1.85

Frequency (MHz)

1.8

1.75

-50 -25 0 25 50 75 100 125

Frequency vs.Temperature

Temperature

(°C)

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RT8003

Quiescent Current vs. Input Voltage

300

VFB = 0.65V

250

200

150

100

Quiescent Current (uA)

50

0

2.5 3 3.5 4 4.5 5 5.5

Input Voltage(V)

V

vs. Temperature

0.52

0.515

0.51

0.505

(V)

0.5

REF

V

0.495

0.49

0.485

0.48

-50 -25 0 25 50 75 100 125

REF

Temperature

(°C)

Quiescent Current vs. Temperature

250

VIN = 3.3V, VFB = 0.65V

200

150

100

Quiescent Current (uA)

50

0

-50 -25 0 25 50 75 100 125

Temperature

V

vs. Input Voltage

0.52

0.515

0.51

0.505

(V)

0.5

REF

V

0.495

0.49

0.485

0.48

2.5 3 3.5 4 4.5 5 5.5

REF

Input Voltage (V)

(°C)

Current Limit vs. Input Voltage

3

2.5

Load Transient Response

VIN = 3.3V, V
I

= 50mA to 600mA

OUT

OUT

= 1.2V

Output

2

1.5

1

Current Limit (A)

0.5

0

2.5 3 3.5 4 4.5 5 5.5

Input Voltage (V)

Voltage

Load

Current

(50mV/Div)

(200mA/Div)

Time (250µs/Div)

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RT8003

Output

Voltage

V

Output

Voltage

LX

VIN = 3.3V, V

(10mV/Div)

(1V/Div)

(500mV/Div)

Steady State

= 1.2V, I

OUT

Time (25µs/Div)

= 0mA, C

OUT

Soft Start Function

OUT

= 1uF

Output

Voltage

V

LX

VIN = 3.3V, V

(10mV/Div)

(1V/Div)

Steady State

= 1.2V, I

OUT

Time (250ns/Div)

OUT

= 600mA, C

OUT

= 1uF

V

EN

Input

Current

(2V/Div)

(200mA/Div)
V

= 3.3V, V

IN

= 1.2V, I

OUT

OUT

Time (500µs/Div)

= 600mA

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Application Information

RT8003

RT8003 is a pulse-width-modulated (PWM) step-down DC­DC converter. Capable of delivering 600mA output current
over a wide input voltage range from 2.4V to 5.5V. The
RT8003 is ideally suited for portable electronic devices
that are powered from 1-cell Li-ion battery or from other
power sources within the range such as cellular phones,
PDAs and handy terminals.

Chip Enable/Disable and Soft Start

Four operational modes are available: PWM, PSM, Low­Drop-Out and shut-down modes. Pulling EN pin lower than

0.4V shuts down the RT8003 and reduces its quiescent
current to 1µA. Pulling EN pin higher than 1.5V enables
the RT8003 and initiates the softstart cycle. RT8003 has
internal soft-start that can reduce the Inrush Current during
the rising of Output Voltage.

PWM Operation

During normal operation, the RT8003 regulates output
voltage by switching at a constant frequency transferring
the power to the load in each cycle by PWM. The RT8003
uses a slope-compensated, current-mode PWM controller
capable of achieving 100% duty cycle. At each rising edge
of the internal oscillator, the Control Logic cell sends a
PWM ON signal to the Driver cell to turn on internal P­MOSFET. This allows current to ramp up through the
inductor to the load, and stores energy in a magnetic field.
The switch remains on until either the current-limit is
tripped or the PWM comparator signals for the output in
regulation. After the switch is turned off, the inductor
releases the magnetic energy and forces current through
the N-MOSFET synchronous rectifier to the output-filter
capacitor and load. The output-filter capacitor stores charge
when the inductor current is above the average output
current and releases charge when the inductor current is
below the average current to smooth the output voltage
across the load. A Zero Detector monitors inductor current
by sensing voltage drop across the N-MOSFET
synchronous rectifier when it turns on. The N-MOSFET
turns off and allows the converter entering discontinuous
conduction mode when the inductor current decreases to
zero. The zero current detection on threshold is about
80mA.This reduces conduction loss and increase power
conversion efficiency at light load condition.

PSM Operation

Consequently, the converter will enter pulse-skipping mode
(PSM) during extreme light load condition or when
modulation index (V

OUT/VIN

) is extreme low. This could
reduce switching loss and further increase power
conversion efficiency.

Over Current Protection

The RT8003 continuously monitors the inductor current
by sensing the voltage across the P-MOSFET when it
turns on. When the inductor current is higher than current
limit threshold (1.8A typical), OCP activates and forces
the P-MOSFET turning off to limit inductor current cycle
by cycle.But it will shut down when the V

trip the UV

OUT

protection.

Output Voltage Setting and Feedback Network

The output voltage can be set from V
divider as: the internal V

is 0.5V with 1.5% accuracy.

REF

to VIN by a voltage

REF

In practical application, keep R1 = 10kΩ respectively and
choose appropriate R2 according to the required output
voltage.

Inductor Selection

The output inductor is suggested as the table of suggested
inductors for optimal performance. Make sure that the
inductor will not saturate over the operation conditions
including temperature range, input voltage range, and
maximum output current. If possible, choose an inductor
with rated current higher than 2A so that it will not saturate
even under short circuit condition.

Input Capacitor Selection

The input capacitor can filter the input peak current and
noise at input voltage source. The capacitor with low ESR
(effective series resistance) provides the small drop voltage
to stabilize the input voltage during the transient loading.
For input capacitor selection, the ceramic capacitors larger
than 1µF is recommend. The capacitor must conform to
the RMS current requirement. The maximum RMS ripple
current is calculated as :

OUTINOUT

OUT(MAX)RMS

I I =

IN

V

) V- (V V

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RT8003

Output Capacitor Selection

The capacitor’ s ESR determines the output ripple voltage
and the initial voltage drop following a high slew-rate
transient’ s edge. Typically, if the ESR requirement is
satisfied, the capacitance is adequate to filtering. The
output ripple voltage can be calculated as:

Where f

COUT +∆=∆

= operating frequency, C

OSC

(ESR I V

1

)

f x C x 8

OSCOUT

= output

OUT

capacitance and ∆IC = ∆IL = ripple current in the inductor.
The ceramic capacitor with low ESR value provides the

low output ripple and low size profile. Connect a 1µF/2.2µF
ceramic capacitor at output terminal for good performance
and place the input and output capacitors as close as
possible to the device.

Layout Considerations

Follow the PCB layout guidelines for optimal performance
of RT8003.

L1

LX

V

IN

C1

R4

VDD

EN

RT8003

COMP

GND

FB

C2

R1

R2

C3

V

OUT

Figure 1

1. For the main current paths as indicated in bold lines in
Figure 1, keep their traces short and wide.

2. Put the input capacitor as close as possible to the device
pins (VDD and GND).

3. LX node is with high frequency voltage swing and should
be kept small area. Keep analog components away from
LX node to prevent stray capacitive noise pick-up.

4. Connect feedback network behind the output capacitors.
Keep the loop area small. Place the feedback components
near the RT8003.

5.Connect all analog grounds to a command node and
then connect the command node to the power ground
behind the output capacitors.

6. An example of 2-layer PCB layout is shown in Figure 2
to Figure 3 for reference.

Figure 2. Top Layer

Figure 3. Bottom Layer

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DS8003-06 August 2007www.richtek.com

Outline Dimension

RT8003

D

E

A

A3

A1

D2

L

E2

SEE DETAIL A

1

e

b

2

1 1

2

DETAIL A

Pin #1 ID and Tie Bar Mark Options

Note : The configuration of the Pin #1 identifier is optional,
but must be located within the zone indicated.

Dimensions In Millimeters

Dimensions In Inches

Symbol

Min Max Min Max

A 0.800 1.000 0.031 0.039
A1 0.000 0.050 0.000 0.002
A3 0.175 0.250 0.007 0.010

b 0.180 0.300 0.007 0.012

D 2.950 3.050 0.116 0.120
D2 2.300 2.650 0.091 0.104

E 2.950 3.050 0.116 0.120
E2 1.500 1.750 0.059 0.069

e 0.500 0.020
L 0.350 0.450

Richtek Technology Corporation

Headquarter
5F, No. 20, Taiyuen Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: [phone] Fax: [phone]

0.014 0.018

V-Type 10L DFN 3x3 Package

Richtek Technology Corporation

Taipei Office (Marketing)
8F, No. 137, Lane 235, Paochiao Road, Hsintien City
Taipei County, Taiwan, R.O.C.
Tel: [phone] Fax: [phone]
Email: [e-mail]

Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit
design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be
guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek.

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