Richtek RT9266GE, RT9266PE, RT9266PX5 Schematic

®

RT9266

Tiny Package, High Efficiency, Step-up DC/DC Converter

General Description

The RT9266 is a compact, high eff iciency, a nd low voltage step-up DC/DC converter with a n Ada ptive Current Mode PWM control loop, includes an error amplifier, ramp generator, comparator , switch pa ss element and driver in which providing a stable and high ef ficient operation over a wide range of load currents. It operates in stable waveforms without external compensation.

The low start-up input voltage below 1V makes RT9266 suitable for 1 to 4 battery cells applications of providing up to 300mA output current. The 450kHz high switching rate minimized the size of external components. Besides, the 17μA low quiescent current together with high efficiency maintains long battery lifetime.

The output voltage is set with two external resistors. Both internal 2A switch and driver for driving external power devices (NMOS or NPN) are provided.

Ordering Information

RT9266

Package Type E : SOT-23-6 X5 : SOT-89-5

Features

zz

1.0V Low Start-up Input Voltage

z

zz

z High Supply Capability to Deliver 3.3V 100mA with

zz

1 Alkaline Cell

μμ

zz

z 17

μA Quiescent (Switch-off) Supply Current

zz

μμ

zz

z Zero Shutdown Mode Supply Current

zz

z 90% Efficiency

zz

z 450kHz Fixed Switching Frequency

zz

z Providing Flexibility for Using Internal and External

zz

Power Switches

zz

z Small SOT-23-6 & SOT-89-5 Package

zz

z RoHS Compliant and 100% Lead (Pb)-Free

zz

Applications

z PDA z DSC z LCD Pa nel z RF-Tags z MP3 z Portable Instrument z Wireless Equipment

Pin Configurations

Lead Plating System

(TOP VIEW)

P : Pb Free 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.

FB

VDD LX

56

23

EN EXT

SOT-23-6

4

1

GND

EN VDD FB

SOT-89-5

LXGND

45

23

Marking Information

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

DS9266-16 June 2013 www.richtek.com

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1

RT9266

Typical Application Circuit

V

IN

Figure 1. RT9266 T ypical Application for Portable Instruments

3.1V to 5V for 12V

2.8V to 5V for 9V

V

IN

+

C4

100µF

+

C3

100µF

EN

RT9266

EXT GNDLXFB

RVDD 100

3.3 to 10 µH

VDD

L1

4.7µH

L1

C2 1µF

1N5819

D1

1N5819

D1

R1

1.6M/3M

R2

980k/1M

+

C1 100µF

V

OUT

3.3V/5V

EN

CVDD 1µF

RM

0.22

Q1 N MOS

C3

0.1µF

R1

860k/620k

R2 100k

VDD

RT9266

GNDLXFB

EXT

Figure 2. RT9266 High V oltage Applications

C2

1µF

+

C1

100uF

12V/9V

300mA

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2

RT9266

V

3.3V/5V

L1

EN

+

C3

100µF

3.3 to 10 µH

VDD

RT9266

GNDLXFB

EXT

C2 1µF

V

IN

D1

1N5819

Q1 N MOS

R1

1.6M/3M

R2 980k/1M

+

C1 100µF

V

OUT

3.3V/5V

Figure 3. RT9266 for Higher Current Applications

LX FB

L1

4.7µH

Q1

N MOS

C8

1µF

C7 1µF

C6

0.1µF

R1

620k

R2 100k

IN

C2

1µF

EXT

C1

1µF

EN

R3

100

VDD

RT9266

GND

C3

10µF

C4

10µF

C5

10µF

V

OUT2

+18V

10mA

V

OUT1

+9V 10mA

V

OUT3

-9V 10mA

Figure 4. RT9266 for Multi-Output Applications

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3

RT9266

Test Circuit

I (VIN)

V

IN

A

+

C3

100µF

A

I (VDD)

VDD

EN

RT9266

EXT GNDLXFB

Functional Pin Description

Pin No.

SOT-23-6 SOT-89-5

1 1 EN 2 -- EXT 3 5 GND

Pin Name

L1

10µH

C2

1µF

D1

1N5819

R1

1.6M/3M

R2 980k/1M

C4

102

+

C1

100µF

Pin Function

Chip Enable (Active High). Output Pin for Driving External N-MOSFET . Ground.

C5

106

V

OUT

3.3V/5V

4 4 LX Pin for Switching. 5 2 VDD

6 3 FB

Function Block Diagram

VDD

FB

EN

In put Posi tive Powe r Pin of RT9266 . Feedback Input Pin.

Internal Reference Volt age for the Error Amplifier is 1.25V.

RT9266

Q1 N MOS

R1

1.25V VDD

R2

Q2 N MOS

-

Loop Control Circuit

+

Over Temp.

Detector

Shut Down

EXT

LX

GND

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RT9266

Absolute Maximum Ratings

z Supply V oltage------------------------------------------------------------------------------------------------------ −0.3V to 7V z LX Pin Switch Voltage --------------------------------------------------------------------------------------------- −0.3V to 7V z Other I/O Pin Voltages -------------------------------------------------------------------------------------------- −0.3V to (V z LX Pin Switch Current --------------------------------------------------------------------------------------------- 2.5A z EXT Pin Driver Current --------------------------------------------------------------------------------------------- 200mA z Package Thermal Resista nce

SOT-23-6, θJC------------------------------------------------------------------------------------------------------- 145°C/W

SOT-89-5, θJC------------------------------------------------------------------------------------------------------- 45°C/W

z Operating Junction T emperature -------------------------------------------------------------------------------- 125°C z Storage T emperature Range ------------------------------------------------------------------------------------- −65°C to +150°C

NOTE: Absolute Maximum ratings are threshold limit values that must not be exceeded even for a n instant under a ny conditions. Moreover, such values f or any two items must not be rea ched simulta neously . Operation above these absolute maximum ratings may cause degradation or permanent da mage to the device. These are stress ratings only a nd do not necessarily imply functional operation below these limits

+ 0.3V)

DD

Recommended Operating Conditions (1)

z Junction T emperature Range-------------------------------------------------------------------------------------- −40°C to 125°C z Ambient T emperature Range-------------------------------------------------------------------------------------- −40°C to 85°C

Electrical Characteristics

(VIN = 1.5V, VDD set to 3.3V, Load Current = 0, TA = 25° C, unless otherwise specified)

Parameter Symbol Test Conditions Min Typ Max Unit

Sta rt- UP Vo l t a g e Operating VDD Range Shutdown Current I (VIN) I

Switch-off Current I (VDD) Continuous Switching Current No Load Curre nt I (VIN) I Feedback Reference V oltage Switching Frequency Maximum Duty LX ON Resistance Current Limit Setting EXT ON Re sistance to VDD EXT ON Re sistance to GND

V

I

ST

V

DD

EN Pin = 0V, VIN = 4.5V

OFF

I

SWITCH OFF

I

SWITCH NO LOAD

V F D

I

LIMIT

VIN = EN = 3.3V, VFB = GND

VIN = 1.5V, V

REF

V

S

V

MAX

V

= 1mA

L

pin voltag e

DD

VIN = 6V

OUT

Clo se Loo p, V DD = 3.3V 1.22 5 1.2 5 1. 27 5 V

= 3.3 V

DD

= 3.3V

DD

V

= 3.3V

DD

= 3.3V

DD

V

= 3.3V

DD

V

= 3.3V

DD

= 3.3V

-- 0.98 1.05 V 2 -- 6 V

-- 0.01 1

-- 17 25

0.4 0.55 0.7 mA

--

75

(2)

--

425 500 575 kHz

85 95 -- %

-- 0.3 1.1

1.6 2

2.6

(3)

-- 5 8.5 Ω

-- 5 8.5

μA μA

μA

Ω

A

Ω

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RT9266

Parameter Symbol Test Conditions Min Typ Max Unit

Line Regulation Load Re gul ation

ΔV ΔV

EN Pin Trip Level Tempera ture Stabi lit y for V

Thermal Shutdown Hysteresis

Note : (1). The device is not guaranteed to function outside its operating conditions. (2). No Load Current is highly dependent on practical system design and component selection that cannot be covered by

production testing. Typical No Load Current is verified by typical application circuit with recommended components. No

Load Current performance is guaranteed by Switch Off Current and Continuous Switching Current. (3). Current Limit is guaranteed by design at T (4). Load Regulation is not tested at production due to practical instrument limitation. Load Regulation performance is

dominantly dependent on DC loop gain and LX ON Resistance that are guaranteed by

Resistance

” tests in production.

OUT

TS

ΔT

VIN = 3. 5 ~ 6V, IL = 1mA

LINE

VIN = 2.5V, IL = 1 ~ 100mA

LOAD

= 3. 3V

V

DD

-- 50 --

SD

-- 10 --

= 25°C.

A

-- 1.5 10 mV/V

0.25

(4)

-- mV/mA

--

0.4 0.8 1.2 V ppm/°C

°C

“Line Regulation” and “LX ON

6

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DS9266-16 June 2013www.richtek.com

Typical Operating Characteristics

(Refer to Test Circuit)

RT9266

95

V

= 5V, TA = 25°C

OUT

90

V

= 4.5V

IN

V

= 4.0V

IN

85

V

= 3.5V

IN

V

= 3.0V

IN

80

V

= 2.5V

IN

Efficiency (%)

70

V

= 2.0V

IN

75

= 1.5V

V

IN

000 001 010 100 1000

Output Current (mA)

Input Current I(VDD) vs. Output Current

250

V

Efficiency vs . Output Current

= 3V, V

IN

200

μ

150

100

Input Current ( A)

50

OUT

= 5V

Efficiency vs. Output Current

95

V

= 3.3V, TA = 25°C

OUT

90

V

= 3.0V

V

IN

= 2.5V

= 2.0V

85

80

Eff iciency (%)

V

= 1.5V

IN

75

70

V

= 1.0V

IN

0.1 1 10 100 1000

Output Current (mA)

Inpu t Curre nt I(VDD) vs. Input Voltage

21

V

= 5V @ no load

OUT

20

μ

19

18

17

Input Current ( A)

16

0

0.01 0.1 1 10 100 1000

Output Current (mA)

Supply Current I(VIN) vs. Input Voltage

180

V

= 5V @ no load

OUT

150

μ

120

90

60

Supply Current ( A) 1

30

0

1.5 2.0 2.5 3.0 3.5 4.0 4.5

Input Voltage (V)

©

15

2.5 3.0 3.5 4.0 4.5 5.0

Input V o lta ge (V)

Supply Current I(VIN) vs. Input Voltage

90

V

= 3.3V @ no load

OUT

80

μ

70

60

50

Supply Current ( A)

40

30

1.5 2 2.5 3 3.5

Input Voltage (V)

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RT9266

Start Up Voltage (V)

Switching Rate Frequency (KHz).

Swichting Frequency vs. VDD Pin Voltage

Switching Frequency vs. VDD Pin Voltage

600

V

IN

500

= 2.4V to 2.8V

V

= 3V to 5.6V

IN

Start Up Voltage vs. Output Current

1.6

V

= 3.3V

OUT

1.4

1.2

400

300

200

V

= 1.2V to 2.2V

IN

Switching Frequency (kHz)

100

0 1 2 3 4 5 6

VDD Pin Voltage (V)

LX & Output Ripple

V

= 1V, V

IN

= 3.3V @ 100mA

OUT

1.0

0.8

0.6

0.4

0.2

0.0 0 30 60 90 120 150 180 210

(In C.R. mode)

Output Current (mA)

LX & Output Ripple

V

= 1V, V

IN

= 3.3V @ 10mA

OUT

Output Ripple LX

Time (1µs/Div)

LX & Output Ripple

V

= 2V, V

IN

Output Ripple LX

©

= 3.3V @ 200mA

OUT

Time (1µs/Div)

Output Ripple LX

V

= 2V, V

IN

Time (1µs/Div)

LX & Output Ripple

= 3.3V @ 10mA

OUT

Time (1µs/Div)

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RT9266

Output Ripple LX

V

IN

= 3V, V

IN

= 2V, V

LX & Output Ripple

= 3.3V @ 200mA

OUT

Time (1µs/Div)

LX & Output Ripple

= 5V @ 200mA

OUT

Output Ripple LX

V

IN

LX & Output Ripple

= 3V, V

= 3.3V @ 10mA

OUT

Time (1µs/Div)

LX & Output Ripple

= 2V, V

= 5V @ 20mA

OUT

Output Ripple LX

Time (1µs/Div)

LX & Output Ripple

V

= 3V, V

IN

Output Ripple LX

©

= 5V @ 200mA

OUT

Time (1µs/Div)

Output Ripple LX

V

= 3V, V

IN

Time (1µs/Div)

LX & Output Ripple

= 5V @ 20mA

OUT

Time (1µs/Div)

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RT9266

Output Ripple LX

LX & Output Ripple

V

= 4.5V, V

IN

Transient Response

V

= 2V, V

IN

I

OUT

= 10mA 200mA

= 5V @ 200mA

OUT

Time (1µs/Div)

= 3.3V

Output Ripple LX

LX & Output Ripple

V

= 4.5V, V

IN

Transient Response

V

= 3V, V

IN

I

OUT

= 10mA 200mA

= 5V @ 20mA

OUT

Time (1µs/Div)

= 3.3V

Output Transient Voltage

Transient Response

V

= 3V, V

IN

I

OUT

= 10mA 200mA

Time (50µs/Div)

= 5V

Time (50µs/Div)

Output Transient Voltage

Transient Response

V

= 4.5V, V

IN

I

= 10mA 200mA

OUT

Time (50µs/Div)

= 5V

OUT

Time (50µs/Div)

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RT9266

Output Voltage vs. Temperature

3.34

3.32

3.3

3.28

3.26

3.24

Output Voltage(V)

3.22

3.2

-40 -10 20 50 80 110 140

V

= 1.8V, V

IN

Temperature

= 3.3V, I

OUT

(°C)

= 100mA

Output Voltage vs. Temperature

5

4.98

4.96

4.94

4.92

4.9

Output Voltage(V)

4.88

4.86

4.84

-40 -10 20 50 80 110 140

V

= 3V, V

IN

Temperature

OUT

= 5V, I

(°C)

OUT

= 100mA

©

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RT9266

Application Information

Output Voltage Setting

Referring to T ypical Application Circuits, the output voltage of the switching regulator (V

) can be set with Equation

OUT

(1).

R1

V =( 1+ ) 1.25V

×OUT

(1)

R2

Feedback Loop Design

Referring to Typical Application Circuits. The selection of R1 and R2 based on the trade-off between quiescent current consumption and interference immunity is stated below:

z Follow Equation (1) z Higher R reduces the quiescent current (Path current =

1.25V/R2), however resistors beyond 5MΩ are not recommended.

z Lower R gives better noise immunity , and is less sensitive

to interference, layout parasitics, FB node le akage, a nd improper probing to FB pins.

Layout Guide

z A full GND plane without ga p brea k. z V

to GND noise bypa ss − Short a nd wide connection

DD

for the 1μF MLCC ca pa citor between Pin5 a nd Pin3.

z V

to GND noise bypass − Add a ca pa citor close to L1

IN

inductor, when VIN is not an idea voltage source.

z Minimized FB node copper area a nd keep far away from

noise sources.

z Minimized parasitic capacitance connecting to LX and

EXT nodes, which may cause additional switching loss.

Board Layout Example (2-Layer Board)

(Refer to T ypical Application Circuits Figure 2 for the board)

V

OUT

Prober Parasitics

_

Q +

z A proper value of feed f orward capa citor parallel with R1

R1

FB Pin

R2

can improve the noise i mmunity of the feedba ck loops, especially in a n improper layout. An empirical suggestion is around 0~33pF for feedback resistors of MΩ, and 10nF~0.1μF for feedback resistors of ten s to hundreds kΩ.

For application s without standby or suspend modes, lower values of R1 and R2 are preferred. For applications concerning the current consumption in standby or suspend modes, the higher values of R1 and R2 are needed. Such

“high impedance feedback loops” are sensitive to any

interference, which require careful layout and avoid a ny interference, e.g. probing to FB pin.

- Top Layer -

- Bottom Layer -

12

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DS9266-16 June 2013www.richtek.com

Outline Dimension

RT9266

H

D

L

C

b

A

e

Dimensions In Millimeters Dimensions In Inches

Symbol

Min Max Min Max

A 0.889 1.295 0.031 0.051

A1 0.000 0.152 0.000 0.006

B 1.397 1.803 0.055 0.071 b 0.250 0.560 0.010 0.022

C 2.591 2.997 0.102 0.118

B

A1

D 2.692 3.099 0.106 0.122

e 0.838 1.041 0.033 0.041

H 0.080 0.254 0.003 0.010

L 0.300 0.610 0.012 0.024

SOT-23-6 Surface Mount Package

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RT9266

D1

D b1

A

C

e e

A

b1

b

B

C1

H

Dimensions In Millimeters Dimensions In Inches

Symbol

Min Max Min Max

A 1.397 1.600 0.055 0.063 b 0.356 0.508 0.014 0.020 B 2.388 2.591 0.094 0.102

b1 0.406 0.533 0.016 0.021

C 3.937 4.242 0.155 0.167

C1 0.787 1.194 0.031 0.047

D 4.394 4.597 0.173 0.181

D1 1.397 1.702 0.055 0.067

e 1.397 1.600 0.055 0.063

H 0.356 0.432 0.014 0.017

5-Lead SOT-89 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.

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Richtek RT9266GE, RT9266PE, RT9266PX5 Schematic [ru]

Specifications and Main Features

Frequently Asked Questions

User Manual