Richtek RT9293A-20GJ6, RT9293A-20GQWA, RT9293AGJ6, RT9293AGQW, RT9293AGQWA Schematic [ru]

RT9293

Small Package, High Performance, Asynchronies Boost
for 10 WLED Driver

General Description

The RT9293 is a high frequency, asynchronous boost
converter. The internal MOSFET can support up to 10
White LEDs for backlighting a nd OLED power application,
and the internal soft start function ca n reduce the inrush
current. The device operates with 1-MHz fixed switching
frequency to allow small external components and to
simplify possible EMI problems. For the protection, the
RT9293A provides 50V OVP a nd the RT9293B provides
50V/20V OVP to allow inexpensive and small-output
cap acitors with lower voltage ratings. The LED current is
initially set with the external sense resistor R

SET

. The
RT9293 is available in the tiny pa ckage type TSOT -23-6
and WDFN-8L 2x2 pa ckages to provide the best solution
for PCB space saving and total BOM cost.

Ordering Information

-

RT9293

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.

( )

Package Type
J6 : TSOT-23-6
QW : WDFN-8L 2x2 (W-Type)

Lead Plating System
G : Green (Halogen Free and Pb Free)

OVP Voltage
Default : 50V (RT9293A/B)
20 : 20V (RT9293B)

Feedback Voltage Reference
A : 104mV
B : 300mV

Features

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z VIN Operating Range : 2.5V to 5.5V

zz

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z Internal Power N-MOSFET Switch

zz

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z Wide Range for PWM Dimming (100Hz to200kHz)

zz

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z Minimize the External Component Counts

zz

zz

z Internal Soft Start

zz

zz

z Internal Compensation

zz

zz

z Under Voltage Protection

zz

zz

z Over Voltage Protection

zz

zz

z Over Temperature Protection

zz

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z Small TSOT-23-6 and 8-Lead WDFN Packages

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z RoHS Compliant and Halogen Free

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Applications

z Cellular Phones
z Digital Camera s
z PDAs and Smart Phones a nd MP3 and OLED.
z Portable Instruments

Pin Configurations

(TOP VIEW)

VINVOUT EN

4

56

23

LX GND FB

TSOT-23-6

1

GND

2

VIN

3

VOUT

4

EN

WDFN-8L 2x2

8

LX

7

NC

GND

6

FB

9

5

GND

Marking Information

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

DS9293-01 April 2011 www.richtek.com

1

RT9293

Typical Application Circuit

22µH to 47µH

L

D

V

OUT

V

IN

Chip Enable

C

2.2µF

Functional Pin Description

Pin No.

RT9293□GJ6 RT9293□GQW

1 8 LX Switching Pin.
2

1, 5,

9 (Exposed pad)

3 6 FB Feedback Pin, put a resistor to GND to setting the current.
4 4 EN Chip Enable (A ctive High).
5 3 VOUT Output Voltage Pin.
6 2 VIN Input Supply.

Pin Name Pin Function

GND

LX
VIN

IN

EN
GND

RT9293

VOUT

FB

C

OUT

1µF

10 WLEDs

R

SET

Ground Pin. The exposed pad must be soldered to a large

PCB and connected to GND for maximum power dis sipation.

-- 7 NC No Internal Connection.

Function Block Diagram

Internal

Compensation

Internal

Soft Start

EA

GM

-

VIN

UVLO

OTP

PWM

-

+

+

+

Compensation

LPF

V

REF

Slope

Enable

Logic

Logic Control,

Minimum On

Time

Shutdown

20ms

1µA

OVP

OCP

Current-

Sense

Driver

PWM

Oscillator

Reference

Voltage

Bias

Current

LX

VOUT

GND

FB

EN

DS9293-01 April 2011www.richtek.com

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Absolute Maximum Ratings (Note 1)

RT9293

z Supply Input Voltage, V
z Switching Pin, LX---------------------------------------------------------------------------------------------------------- −0.3V to 50V
z VOUT------------------------------------------------------------------------------------------------------------------------- −0.3V to 46V
z Other Pins------------------------------------------------------------------------------------------------------------------- −0.3V to 6V
z Power Dissipation, P

------------------------------------------------------------------------------------------------ −0.3V to 6V

IN

@ T

D

= 25°C

A

TSOT-23-6------------------------------------------------------------------------------------------------------------------- 0.392W
WDFN−8L 2x2-------------------------------------------------------------------------------------------------------------- 0.606W

z Package Thermal Resistance (Note 2)

TSOT-23-6, θJA------------------------------------------------------------------------------------------------------------- 255°C/W
WDFN−8L 2x2, θJA-------------------------------------------------------------------------------------------------------- 165°C/W
WDFN−8L 2x2, θJC-------------------------------------------------------------------------------------------------------- 20°C/W

z Lead T e mperature (Soldering, 10 sec.)------------------------------------------------------------------------------- 26 0°C
z Junction T emperature----------------------------------------------------------------------------------------------------- 150°C
z Storage T emperature Range -------------------------------------------------------------------------------------------- −65°C to 150°C

Recommended Operating Conditions (Note 3)

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

−40°C to 85°C

Electrical Characteristics

(V

= 3.7V, C

IN

Input Voltage VIN 2.5 -- 5.5 V
Under V oltage Lock Ou t V
UVLO Hyst er esis -- 0.1 -- V
Quiescent Current IQ FB = 1.5V, No Switching -- 400 600 μA
Supply Current IIN FB = 0V, Sw itc hi ng -- 1 2 mA

Shut down Current I
Line Re gulation VIN = 3 to 4.3V -- 1 -- %
Load Regulation 1mA to 20mA -- 1 -- %
Operation Frequency f
Maxi mu m Duty Cycle 90 9 2 -- %
Clo ck Rat e 0.1 -- 200 kHz

Feedback Reference
Voltage

= 2.2μF, C

IN

= 0.47μF, I

OUT

= 20mA, L = 22μH, TA = 25°C, unless otherwise specified)

OUT

Parameter Symbol Test Conditions Min Typ Max Unit

2 2.2 2.45 V

UVLO

VEN < 0.4V -- 1 4 μA

SHDN

0.75 1 1.25 MHz

OSC

RT9293A 94 104 114
RT9293B

V

REF

285 300 315

mV

On Res ist ance R

-- 0.7 1.2 Ω

DS(ON)

To be continued

DS9293-01 April 2011 www.richtek.com

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RT9293

Parameter Symbol Test Conditions Min Typ Max Unit

EN Threshold
Voltage

E N S ink C u rre n t

Logic-High VIH 1.4 -- -­Logic-Low V

-- -- 0.5

IL

I

IH

-- 1 --

μA

V

EN Hyster esi s -- 0.1 -- V
Over-V oltage

Threshold
Over-Current Threshold

OTP

OVP = 50V 42 46 50

V

RT9293B-20

OVP

I

OCP

T

OTP

16 17.5 20
1 1.2 -- A

-- 160 --

V

°C
OTP Hysteresis -- 30 -- °C
Shutdown Dela y



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

is measured in the natural convection at TA = 25°C on a low effective single layer thermal conductivity test board of

JA

JEDEC 51-3 thermal measurement standard. The case point of θ

T

SHDN

-- 20 -- ms

is on the expose pad for the WDFN package.

JC

DS9293-01 April 2011www.richtek.com

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Typical Operating Characteristics

)

)

RT9293

Efficiency vs. Output Current

100

90
80
70
60
50
40

Efficiency (%)

30
20
10

0

0 0.05 0.1 0.15 0.2 0.25 0.3

Output Current (A)

Output Voltage vs. Output Current

40

35

30

V

V

IN

V

OUT

= 4.5V

= 4V

IN

= 10V

Efficiency vs. Input Voltage

100

I

= 30mA

90
80
70
60
50
40

Efficiency (%)

30
20
10

0

2.533.544.555.5

I

LOAD

= 20mA

LOAD

I

LOAD

V

= 10mA

OUT

= 34V

Input Voltage ( V )

Quiescent Current vs. Input Voltage

500

450

400

25

20

Output Voltage (V)

15

V

= 3.7V, V

10

5 1525354555657585

IN

OUT

= 34V

Output Current (mA)

Frequency vs. Input Voltage

1100

1050

1000

950

900

Frequency ( kH z)

850

I

= 20mA

800

2.5 3 3.5 4 4.5 5 5.5

Input Voltage (V)

LED

350

300

Quiescent Curre nt (µA

250

200

2.5 3 3.5 4 4.5 5 5.5

Input Voltage (V )

Frequency vs. Temperature

1100

1050

1000

950

900

Frequency ( kHz

850

V

= 3.7V, I

800

-40 -25 -10 5 20 35 50 65 80 95 110 125

Temperature ( °C)

IN

V

LED

= 1.5V

FB

= 20mA

DS9293-01 April 2011 www.richtek.com

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