RT8059GJ5中文资料_数据手册_规格书

®

RT8059

1.5MHz, 1A, High Efficiency PWM Step-Down DC/DC Converter

General Description

Features

^zWide Input Voltage from 2.8V to 5.5V

^zAdjustable Output from 0.6V to V_IN

^z1A Output Current

The RT8059 is a high efficiency Pulse Width Modulated

(PWM) step-downDC/DC converter, capable of delivering

1A output current over a wide input voltage range from

2.8V to 5.5V. The RT8059 is ideally suited for portable

electronic devices that are powered by 1-cell Li-ion battery

or by other power sources within the range, such as cellular

phones, PDAs and handy-terminals.

^z95% Efficiency

^zNo Schottky Diode Required

^z1.5MHz Fixed Frequency PWM Operation

^zSmall TSOT-23-5 Package

^zRoHS Compliant and Halogen Free

Internal synchronous rectifier with low R_DS(ON)dramatically

reduces conduction loss at PWM mode. No external

Schottky diode is required in practical applications. The

RT8059 automatically turns off the synchronous rectifier

when the inductor current is low and enters discontinuous

PWM mode. This can increase efficiency in light load

condition.

Applications

z NIC Card

z CellularTelephones

z Personal InformationAppliances

z Wireless and DSL Modems

z MP3 Players

The RT8059 enters low dropout mode when normal PWM

cannot provide regulated output voltage by continuously

turning on the upper P-MOSFET. The RT8059 enters

shutdown mode and consumes less than 0.1μAwhen the

EN pin is pulled low.

z Portable Instruments

Pin Configurations

(TOP VIEW)

FB

VIN

The switching ripple can be easily smoothed out by small

package filtering elements due to a fixed operation

frequency of 1.5MHz. This along with small TSOT-23-5

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.

5

4

2

3

GND LX

EN

TSOT-23-5

Marking Information

BQ= : Product Code

Ordering Information

BQ=DNN

RT8059

DNN : Date Code

Package Type

J5 : TSOT-23-5

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.

©

is a registered trademark of Richtek Technology Corporation.

DS8059-04 December 2011

www.richtek.com

1

RT8059

Typical Application Circuit

L

2.2µH

4

1

V

3

5

IN

V

VIN

RT8059

OUT

LX

2.8V to 5.5V

C

4.7µF

IN

C1

R1

R2

C

OUT

10µF

EN

FB

GND

2

I

R2

R1

R2

⎛

⎞

⎟

V^OUT= V^REFx 1+

⎜

⎝

⎠

with R2 = 60kΩ to 300kΩ , I_R2= 2μA to 10μA,

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

Functional Pin Description

Pin No.

Pin Name

Pin Function

1

2

3

4

5

EN

GND

LX

Chip Enable (Active High). Do not leave the EN pin floating.

Ground.

Switch Node.

Power Input.

Feedback Input Pin.

VIN

FB

Function Block Diagram

VIN

EN

R

S1

OSC &

Shutdown

Control

Current

Limit

Detector

Slope

Compensation

Current

Sense

Control

Logic

Driver

LX

PWM

Comparator

Error

FB

Amplifier

RC

Zero

Detector

R

S2

COMP

UVLO

V

REF

GND

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2

DS8059-04 December 2011

RT8059

Absolute Maximum Ratings (Note 1)

z VINtoGND -------------------------------------------------------------------------------------------------------- 6.5V

z LX Pin Switch Voltage ------------------------------------------------------------------------------------------ −0.3V to (PVDD+ 0.3V)

< 30ns -------------------------------------------------------------------------------------------------------------- −5V to 7.5V

z EN, FB toGND --------------------------------------------------------------------------------------------------- V_IN+ 0.6V

z PowerDissipation, P_D@ T_A= 25°C

TSOT-23-5 --------------------------------------------------------------------------------------------------------- 0.392W

z Package Thermal Resistance (Note 2)

TSOT-23-5, θ_JA--------------------------------------------------------------------------------------------------- 255°C/W

z Junction Temperature Range ---------------------------------------------------------------------------------- 150°C

z Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------- 260°C

z StorageTemperature Range ----------------------------------------------------------------------------------- −65°C to 150°C

z ESD Susceptibility (Note 3)

HBM (Human Body Mode) ------------------------------------------------------------------------------------- 2kV

MM (Machine Mode) -------------------------------------------------------------------------------------------- 200V

Recommended Operating Conditions (Note 4)

z Supply Input Voltage, V_IN-------------------------------------------------------------------------------------- 2.8V to 5.5V

z Junction Temperature Range ---------------------------------------------------------------------------------- −40°C to 125°C

z Ambient Temperature Range ---------------------------------------------------------------------------------- −40°C to 85°C

Electrical Characteristics

(V_IN= 3.6V, V_OUT= 2.5V, L = 2.2μH, C_IN= 4.7μF, C_OUT= 10μF, T_A= 25°C, unless otherwise specified)

Parameter

Quiescent Current

Symbol

Test Conditions

I_OUT= 0mA, V_FB= V_REF+ 5%

EN = GND

Min

--

Typ

78

Max

--

Unit

μA

V

I_Q

Shutdown Current

I_SHDN

V_REF

V_OUT

--

0.1

0.6

--

1

Reference Voltage

0.588

V_REF

0.612

V_IN− 0.2

Adjustable Output Range

(Note 5)

V

Adjustable Output Voltage

Accuracy

V

_IN= V_OUT+ ΔV to 5.5V,

ΔV_OUT

−3

--

3

%

0A < I_OUT< 1A, (Note 6)

FB Input Current

I_FB

V_FB= V_IN

−50

--

50

--

nA

P-MOSFET R_ON

R_{DS(ON)_P}

R_{DS(ON)_N}

I_{LM_P}

I_OUT= 200mA

V_IN= 2.8V to 5.5V

0.28

0.25

1.5

--

Ω

A

V

N-MOSFET R_ON

--

P-Channel Current Limit

--

Logic-High V_IH

1.5

--

EN Input Threshold

Voltage

Logic-Low

V_IL

V_IN= 2.8V to 5.5V

--

0.4

--

Under Voltage Lockout Threshold

2.3

0.2

V

V_UVLO

Under Voltage Lockout Hysteresis ΔV_UVLO

--

Oscillator Frequency

f_OSC

T_SD

I_OUT= 100mA

1.2

--

1.5

150

--

1.8

--

MHz

°C

Thermal Shutdown Temperature

Max. Duty Cycle

D_MAX

100

--

%

©

is a registered trademark of Richtek Technology Corporation.

DS8059-04 December 2011

www.richtek.com

3

RT8059

Note 1. Stresses beyond those listed “Absolute Maximum Ratings” may cause permanent damage to the device. These are

stress ratings only, and 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 may

affect device reliability.

Note 2. θ_JAis measured at T_A= 25°C on a low effective thermal conductivity single-layer test board per JEDEC 51-3.

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

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

Note 5. Guaranteed by design.

Note 6. ΔV = I_OUTx R_DS(ON)

©

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

4

DS8059-04 December 2011

RT8059

Typical Operating Characteristics

Efficiency vs. Load Current

Reference Voltage vs. Input Voltage

100

0.620

0.615

0.610

0.605

0.600

0.595

0.590

0.585

0.580

I_OUT= 0.1A

90

80

V_IN= 3.3V, V_OUT= 2.5V

V_IN= 5.5V, V_OUT= 2.5V

V_IN= 3.3V, V_OUT= 1.2V

V_IN= 5.5V, V_OUT= 1.2V

70

60

50

40

30

20

10

0

0.01

0.1

1

2.5

3

3.5

4

4.5

5

5.5

Load Current (A)

Input Voltage (V)

Reference Voltage vs. Temperature

Output Voltage vs. Output Current

0.620

1.230

1.225

1.220

1.215

1.210

1.205

1.200

1.195

1.190

1.185

1.180

V_IN= 3.3V

V_IN= 3.3V, I_OUT= 0.1A

0.615

0.610

0.605

0.600

0.595

0.590

0.585

0.580

0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

Output Current (A)

1

-50

-25

0

25

50

75

100

125

Temperature (°C)

Frequency vs. Temperature

Current Limit vs. Temperature

2.1

1.9

1.7

1.5

1.3

1.1

0.9

0.7

0.5

1.70

1.65

1.60

1.55

1.50

1.45

1.40

1.35

1.30

1.25

1.20

V_IN= 3.3V, V_OUT= 1.2V,

I_OUT= 0.3A

V_IN= 3.3V, V_OUT= 1.2V

-50

-25

0

25

50

75

100

125

-50

-25

0

25

50

75

100

125

Temperature (°C)

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DS8059-04 December 2011

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5

RT8059

Load Transient Response

V_IN= 3.3V, V_OUT= 1.2V,

_OUT= 0.1A to 1A

V_IN= 3.3V, V_OUT= 1.2V,

I_OUT= 0.5A to 1A

I

V_OUT

(50mV/Div)

V_OUT

(50mV/Div)

I_OUT

(500mA/Div)

Time (100μs/Div)

Switching

V_IN= 3.3V, V_OUT= 1.2V,

I_OUT= 0.5A

V_IN= 3.3V, V_OUT= 1.2V,

I_OUT= 1A

V_OUT

(5mV/Div)

V_LX

(2V/Div)

I_OUT

(1A/Div)

Time (250ns/Div)

Power On from EN

Power Off from EN

V_IN= 3.3V,

V_OUT= 1.2V,

I_OUT= 1A

V_OUT= 1.2V,

I_OUT= 1A

V_EN

(2V/Div)

V_OUT

(500mV/Div)

I_OUT

(1A/Div)

Time (500μs/Div)

©

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

6

DS8059-04 December 2011

RT8059

Applications Information

The basic RT8059 application circuit is shown in Typical

Application Circuit. External component selection is

determined by the maximum load current and begins with

the selection of the inductor value and operating frequency

current is exceeded. This results in an abrupt increase in

inductor ripple current and consequent output voltage ripple.

Do not allow the core to saturate!

Different core materials and shapes will change the size/

current and price/current relationship of an inductor.

followed by C_INand C_OUT

.

Toroid or shielded pot cores in ferrite or permalloy materials

are small and don't radiate energy but generally cost more

than powdered iron core inductors with similar

characteristics. The choice of which style inductor to use

mainly depends on the price vs size requirements and

any radiated field/EMI requirements.

Inductor Selection

For a given input and output voltage, the inductor value

and operating frequency determine the ripple current. The

ripple current ΔI_Lincreases with higher V_INand decreases

with higher inductance.

V

f ×L

V_OUT

V

IN

⎡

_OUT⎤ ⎡

× 1−

⎥ ⎢

⎤

ΔI_L=

⎢

⎣

⎥

⎦

⎦ ⎣

C_INand C_OUTSelection

The input capacitance, C_IN, is needed to filter the

trapezoidal current at the source of the top MOSFET. To

prevent large ripple voltage, a low ESR input capacitor

sized for the maximum RMS current should be used. RMS

current is given by :

Having a lower ripple current reduces the ESR losses in

the output capacitors and the output voltage ripple. Highest

efficiency operation is achieved at low frequency with small

ripple current. This, however, requires a large inductor.

Areasonable starting point for selecting the ripple current

is ΔI_L= 0.4(I_MAX). The largest ripple current occurs at the

highest V_IN. To guarantee that the ripple current stays

below a specified maximum, the inductor value should be

chosen according to the following equation :

V_OUT

V

IN

I_RMS= I_OUT(MAX)

−1

V

V_OUT

IN

This formula has a maximum at V_IN= 2V_OUT, where

I_RMS= I_OUT/2. This simple worst-case condition is

commonly used for design because even significant

deviations do not result in much difference.Note that ripple

current ratings from capacitor manufacturers are often

based on only 2000 hours of life which makes it advisable

to further derate the capacitor, or choose a capacitor rated

at a higher temperature than required. Several capacitors

may also be paralleled to meet size or height requirements

in the design.

⎡

⎤

V

OUT

⎡

⎤

OUT

f × ΔIL(MAX)

L =

× 1−

⎢

⎥

⎦

⎢

⎣

⎥

⎦

V

IN(MAX)

⎣

Inductor Core Selection

Once the value for L is known, the type of inductor can be

selected. High efficiency converters generally cannot afford

the core loss found in low cost powdered iron cores, forcing

the use of more expensive ferrite or mollypermalloy cores.

Actual core loss is independent of core size for a fixed

inductor value but it is very dependent on the inductance

selected. As the inductance increases, core losses

decrease. Unfortunately, increased inductance requires

more turns of wire and therefore, results in higher copper

losses.

The selection of C_OUTis determined by the effective series

resistance (ESR) that is required to minimize voltage ripple

and load step transients, as well as the amount of bulk

capacitance that is necessary to ensure that the control

loop is stable. Loop stability can be checked by viewing

the load transient response as described in a later section.

The output ripple, ΔV_OUT, is determined by :

Ferrite designs have very low core losses and are preferred

at high switching frequencies, so design goals can

concentrate on copper loss and preventing saturation.

Ferrite core material saturates “hard”, which means

that inductance collapses abruptly when the peak design

⎡

⎣

⎤

⎦

1

ΔV_OUT≤ ΔI_LESR +

⎢

⎥

8fC_OUT

where f is the switching frequency and ΔI_Lis the inductor

ripple current.

©

is a registered trademark of Richtek Technology Corporation.

DS8059-04 December 2011

www.richtek.com

7

RT8059

The output ripple is highest at maximum input voltage

since ΔI_Lincreases with input voltage. Multiple capacitors

placed in parallel may be needed to meet the ESR and

RMS current handling requirements.Dry tantalum, special

polymer, aluminum electrolytic and ceramic capacitors are

all available in surface mount packages. Special polymer

capacitors offer very low ESR but have lower capacitance

density than other types. Tantalum capacitors have the

highest capacitance density but it is important to only

use types that have been surge tested for use in switching

power supplies. Aluminum electrolytic capacitors have

significantly higher ESR but can be used in cost-sensitive

applications provided that consideration is given to ripple

current ratings and long term reliability. Ceramic capacitors

have excellent low ESR characteristics but can have a

high voltage coefficient and audible piezoelectric effects.

The high Q of ceramic capacitors with trace inductance

can also lead to significant ringing.

For adjustable voltage mode, the output voltage is set by

an external resistive voltage divider according to the

following equation :

R1

V_OUT= V_REF(1+

)

R2

where V_REFis the internal reference voltage (0.6V typ.)

Checking Transient Response

The regulator loop response can be checked by looking

at the load transient response. Switching regulators take

several cycles to respond to a step in load current. When

a load step occurs, V_OUTimmediately shifts by an amount

equal to ΔI_LOAD(ESR), where ESR is the effective series

resistance of C_OUT. ΔI_LOADalso begins to charge or

discharge C_OUTgenerating a feedback error signal used

by the regulator to return V_OUTto its steady-state value.

During this recovery time, V_OUTcan be monitored for

overshoot or ringing which would indicate a stability

problem.

Using Ceramic Input and Output Capacitors

Thermal Considerations

Higher values, lower cost ceramic capacitors are now

becoming available in smaller case sizes. Their high ripple

current, high voltage rating and low ESR make them ideal

for switching regulator applications. However, care must

be taken when these capacitors are used at the input and

output. When a ceramic capacitor is used at the input

and the power is supplied by a wall adapter through long

wires, a load step at the output can induce ringing at the

input, V_IN. At best, this ringing can couple to the output

and be mistaken as loop instability. At worst, a sudden

inrush of current through the long wires can potentially

cause a voltage spike at V_INlarge enough to damage the

part.

For continuous operation, do not exceed absolute

maximum junction temperature. The maximum power

dissipation depends on the thermal resistance of the IC

package, PCB layout, rate of surrounding airflow, and

difference between junction and ambient temperature. The

maximum power dissipation can be calculated by the

following formula :

P_D(MAX)= (T_J(MAX)− T_A) / θ_JA

where T_J(MAX)is the maximum junction temperature, T_Ais

the ambient temperature, and θ_JAis the junction to ambient

thermal resistance.

For recommended operating condition specifications of

the RT8059, the maximum junction temperature is 125°C

and T_Ais the ambient temperature. The junction to ambient

thermal resistance, θ_JA, is layout dependent. For TSOT-

23-5 packages, the thermal resistance, θ_JA, is 255°C/W

on a standard JEDEC 51-3 single-layer thermal test board.

The maximum power dissipation at T_A= 25°C can be

calculated by the following formula :

Output Voltage Setting

The resistive voltage divider allows the FB pin to sense a

fraction of the output voltage as shown in Figure 1.

V

OUT

R1

FB

RT8059

GND

P_D(MAX)= (125°C − 25°C) / (255°C/W) = 0.392W for

TSOT-23-5 package

R2

Figure 1. Setting Output Voltage

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8

DS8059-04 December 2011

RT8059

The maximum power dissipation depends on the operating

ambient temperature for fixed T_J(MAX)and thermal

resistance, θ_JA. For the RT8059 package, the derating

curves in Figure 2 allow the designer to see the effect of

rising ambient temperature on the maximum power

dissipation.

Layout Considerations

Follow the PCB layout guidelines for optimal performance

of the RT8059.

` Keep the trace of the main current paths as short and

wide as possible.

` Place the input capacitor as close as possible to the

0.42

Single-Layer PCB

0.39

device pins (VINandGND).

0.36

0.33

0.30

0.27

0.24

0.21

0.18

0.15

0.12

0.09

0.06

0.03

0.00

` LX node experiences high frequency voltage swings

and should be kept in a small area. Keep analog

components away from the LX node to prevent stray

capacitive noise pick-up.

` Place the feedback components as close as possible to

the FB pin.

` GND and Exposed Pad must be connected to a strong

ground plane for heat sinking and noise protection.

0

25

50

75

100

125

GND

V

IN

V

OUT

C

OUT

C

IN

Ambient Temperature (°C)

Figure 2.Derating Curves for RT8059 Package

L

4

3

2

1

LX

VIN

FB

GND

EN

C1

5

R1

R2

V

OUT

GND

Figure 3. PCB Layout Guide

©

is a registered trademark of Richtek Technology Corporation.

DS8059-04 December 2011

www.richtek.com

9

RT8059

Outline Dimension

H

D

L

B

C

A

b

A1

e

Dimensions In Millimeters

Dimensions In Inches

Symbol

Min

Max

1.000

0.100

1.803

0.559

3.000

3.099

1.041

0.254

0.610

Min

Max

A

A1

B

0.700

0.000

1.397

0.300

2.591

2.692

0.838

0.080

0.300

0.028

0.000

0.055

0.012

0.102

0.106

0.033

0.003

0.012

0.039

0.004

0.071

0.022

0.118

0.122

0.041

0.010

0.024

b

C

D

e

H

L

TSOT-23-5 Surface Mount Package

Richtek Technology Corporation

5F, No. 20, Taiyuen Street, Chupei City

Hsinchu, Taiwan, R.O.C.

Tel: (8863)5526789

Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should

obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot

assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be

accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third

parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries.

www.richtek.com

10

DS8059-04 December 2011

型号	制造商	描述	价格	文档
RT8060	RICHTEK	1.5MHz, 1A High Efficiency Step-Down Converter	获取价格
RT8060A	RICHTEK	1.5MHz, 1A High Efficiency Step-Down Converter	获取价格
RT8061A	RICHTEK	3A, 1MHz, Synchronous Step-Down Converter	获取价格
RT8062	RICHTEK	2A, 2MHz, Synchronous Step-Down Converter	获取价格
RT8063	RICHTEK	3A, 2MHz, Synchronous Step-Down Converter	获取价格
RT8064	RICHTEK	2A, 2MHz, Synchronous Step-Down Converter	获取价格
RT8064ZQW	RICHTEK	High Efficiency : Up to 95%, Adjustable Frequency : 200kHz to 2MHz	获取价格
RT8064ZSP	RICHTEK	2A, 2MHz, Synchronous Step-Down Converter	获取价格
RT8065	RICHTEK		获取价格
RT8068A	RICHTEK		获取价格

RT8059GJ5

RT8059GJ5 概述

RT8059GJ5 数据手册

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