RT9261B-50GX - Richtek - Datasheet.Directory

RT9261B

DS9261B-16 April 2011 www.richtek.com

Pin Configurations

VFM Step-Up DC/DC Converter

Ordering Information

General Description

The RT9261B Series are VFM Step-up DC/DC converter

ICs with ultra low supply current by CMOS process and

suitable for use with battery-powered instruments.

The RT9261B IC con sists of a n oscillator , a VFM control

circuit, a driver transistor (LX switch), a reference voltage

unit, an error a mplifier , resistors for voltage detection, and

a LX switch protection circuit. A low ripple and high efficiency

step-up DC/DC converter can be constructed with the

RT9261B IC a nd only three external components.

The EN pin enables the circuit to set the standby supply

current at a maximum of 0.5μA.

Features

zMinimal Number of External Components (Only an

Inductor, a Diode, and a Capacitor)

zUltra Low Input Current (6.5μμ

μμ

μA at Switch Off)

zCapable of Supplying 50mA Output Current with

Internal Switch

z±±

±±

± 2% Output Voltage Accurac y

zLow Ripple and Low Noise

zLow Start-up Voltage, 0.8V at 1mA

z80% Efficiency with Low Cost Inductor

z+50 ppm/°C Low Temperature-Drift

zSOT-89 and SOT-23-5 Small Packages

zRoHS Compliant and 100% Lead (Pb)-Free

Applications

zPower source for battery-powered equipment

zPower source for ca meras, ca mcorders, VCRs, PDAs,

pagers, electronic data ba nks, and hand-held

communication equipment

zPower source for appliances, which require higher

voltage tha n that of batteries used in the a ppliances

(TOP VIEW)

Marking Information

For marking information, contact our sales representative

directly or through a Richtek distributor located in your

area.

GND VOUT

(TAB) LX

123

SOT-89

SOT-23-5

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.

EN VOUT NC

LX GND

RT9261B- Package Type

B : SOT-23-5

X : SOT-89

Lead Plating System

P : Pb Free

G : Green (Halogen Free and Pb Free)

Output Voltage

15 : 1.5V

16 : 1.6V

49 : 4.9V

50 : 5.0V

RT9261B

2DS9261B-16 April 2011www.richtek.com

Typical Application Circuit

Functional Pin Description

Function Block Diagram

* L1 ranges from 27μH to 120μH

Pin No. Pin Name Pin Function

SOT-23-5 SOT-89

1 -- EN Chip Enable (Active High) .

2 2 VOUT Output Voltage.

3 -- NC No Internal Connection.

4 1 GND Ground.

5 3 LX Pin for Switch ing.

VLX Limiter

Buffer

Chip Enable

OS C 190k H z +

Error

Amplifier

VREF

VOUT

LXSW

GND

VOUTLX GND

RT9261B

1N5819

VOUT

VIN COUT

22µF

VOUT

GND

RT9261B

1N5819

VOUT

VIN COUT

22µF

RT9261B

DS9261B-16 April 2011 www.richtek.com

Electrical Characteristics (Refer to Figure 1)

Absolute Maximum Ratings

zOutput V oltage ------------------------------------------------------------------------------------------------------ 8V

zLX Pin V oltage ------------------------------------------------------------------------------------------------------- 8V

zEN Pin Voltage(1) ---------------------------------------------------------------------------------------------------- −0.3 to VOUT +0.3V

zLX Pin Output Current --------------------------------------------------------------------------------------------- 400mA

zPower Dissipation, PD @ TA = 25°C

SOT-89 ---------------------------------------------------------------------------------------------------------------- 0.5W

SOT-23-5-------------------------------------------------------------------------------------------------------------- 0.25W

zPackage Thermal Resistance

SOT-89, θJC ---------------------------------------------------------------------------------------------------------- 100°C/W

SOT-89, θJA ---------------------------------------------------------------------------------------------------------- 300°C/W

SOT-23-5, θJA -------------------------------------------------------------------------------------------------------- 250°C/W

zOperating T emperature Range ----------------------------------------------------------------------------------- −20 to +85°C

zStorage T emperature Range -------------------------------------------------------------------------------------- −65°C to 150°C

zLead T emperature (Soldering, 10 sec.) ------------------------------------------------------------------------ 260°C

Notes:

(1) VIN = 1.8V, VSS = 0V, IOUT = 1mA, Topt = 25°C, and use External Circuit of Typical Application

(2) VIN = 3V, VSS = 0V, IOUT = 1mA, Topt= 25°C, and External Circuit of Typical Application

Parameter Symbol Test Conditions Min Typ Max Unit

Output Voltage A ccuracy ΔVOUT -2 -- +2 %

Input Voltage VIN -- -- 7 V

Start-up Voltage VST I

OUT = 1mA, VIN: 0 → 2V -- 0.8 1 V

Hold-on Voltage VHO I

OUT = 1mA, VIN: 2 → 0V 0.7 -- -- V

VOUT ≤ 3.5V (1) -- 24 36

Input Cur r e nt 1 VIN in continuou s

switching 3.5V < VOUT ≤ 5V (2) -- 36 45 μA

Input Cur r e nt 2 (1) (2) V

OUT in switch off condition -- 6.5 10 μA

VOUT ≤ 3.5V (1) -- 18 36 Input Current 3 (guaranteed by

I1 and I2) V

IN in no load 3.5V < VOUT ≤ 5V (2) -- 20 45 μA

VOUT ≤ 3.5V (1) 120 -- --

LX Switching Current ISWITCHING V

LX = 0.4V 3.5V < VOUT ≤ 5V (2) 160 -- -- mA

LX Leakage Current ILEAKAGE V

LX = 6V -- -- 0.5 μA

VOUT = 2.5V to 5V 140 190 240 kHz

Maximum Oscillat or Frequen cy F MAX VOUT = 1.5V to 2.4V 140 190 320 kHz

VOUT = 2 .5V to 5V 6 5 75 85 %

Oscillator Duty Cycle DOSC On (VLX “L”) side VOUT = 1 .5V to 2.4V 6 0 70 80 %

Efficiency -- 80 -- %

VLX Voltage Limit LX switch on 0.65 0.8 1.0 V

Notes: (1) Applicable to RT9261B-xxCB

RT9261B

4DS9261B-16 April 2011www.richtek.com

Electrical Characteristics (Refer to Figure 2)

Notes:

(1) VIN = 1.8V, VSS = 0V, I OUT = 1mA, Topt = 25°C, and use External Circuit of Typical Application

(2) VIN = 3V, VSS = 0V, IOUT = 1mA, Topt= 25°C, and External Circuit of Typical Application

Parameter Symbol Test Conditions Min Typ Max Unit

O ut put Voltag e Ac cur acy ΔVOUT −2 -- +2 %

Input Voltage VIN -- -- 7 V

Start-up Voltage VST I

OUT = 1 mA, VIN: 0 → 2V -- 0.8 1 V

Hold-on Voltage VHO I

OUT = 1 mA, VIN: 2 → 0V 0.7 -- - - V

Efficiency -- 80 -- %

VOUT ≤ 3.5V (1) -- 24 36

Input Current 1 VIN in continuous

switching 3.5V < VOUT ≤ 5V (2) -- 36 45 μA

Inp ut Curr ent 2 (1) (2) V

OUT in switch off condition -- 6.5 10 μA

VOUT ≤ 3.5V (1) -- 18 36 Input Current 3 (guaranteed by

I1 and I2) V

IN in no load 3.5V < VOUT ≤ 5V (2) -- 20 45 μA

VOUT ≤ 3.5V (1) 120 -- --

LX Switching Current ISWITCHING V

LX = 0.4V 3.5V < VOUT ≤ 5V (2) 160 -- -- mA

LX Leakage Current ILEAKAGE V

LX = 6V -- -- 0.5 μA

E N “H” Leve l VIN = VOUT * 0.9 0.4 x

VOUT -- -- V

E N “L” L evel VIN = VOUT * 0.9 -- -- 0.2 V

EN “H” Input Current EN = V OUT -- -- 0.5 μA

EN “ L” Input Curr ent EN = 0V −0.5 -- -- μA

VOUT = 2.5V to 5V 140 190 240 kHz

Maximum Oscillat or Frequen cy F MAX VOUT = 1.5V to 2.4V 140 190 320 kHz

VOUT = 2.5V to 5V 6 5 75 85 %

Oscillator Duty Cycle DOSC On (VLX “L”) side VOUT = 1.5V to 2.4V 6 0 70 80 %

VLX Volta ge Limit LX switch on 0.65 0.8 1.0 V

RT9261B

DS9261B-16 April 2011 www.richtek.com

Typical Operating Characteristics

Start-up/Hold-on Voltage vs. Output Current

0.5

1.5

2.5

0 30 60 90 120 150 180

Output Current (mA)

Start-up/ Hold-on Volt age V s tart / V hold (V )1

VOUT = 3.3V

L = 47μH

Vstart

Vhold

Output Current vs. Ripple Voltage

0 50 100 150 200

Output Current (mA)

Ripple Voltage (mVp-p)1

VOUT = 3.3V

COUT = 68μF

L = 47μH

2.5V

2.0V

3.0V

1.5V

1.0V

Output Current vs . Ripple Voltage

100

150

200

250

300

0 50 100 150 200

Output Current (mA)

Ripple Voltage (mVp-p) 1

VOUT = 3.3V

COUT = 20μF

L = 47μH

2.5V

2.0V 3.0V

1.5V

1.0V

Output Current vs. Ripple Voltage

0 50 100 150 200

Output Current (mA)

Ripple Voltage (mVp-p)1

VOUT = 3.3V

COUT = 170μF

L = 47μH

2.5V

2.0V

3.0V

1.5V

1.0V

Output Voltage vs. Output Current

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 50 100 150 200

Output Current (mA)

Output Voltage (V ) 1

VOUT = 3.3V

L = 47μH

2.5V

2.0V

3.0V

1.5V

1.0V

Efficiency vs. output Current

0 50 100 150 200

Output Cu rrent (mA)

Effici ency (%)1

VOUT = 3.3V

L = 47μH

2.5V

2.0V

3.0V

1.5V

1.0V

RT9261B

6DS9261B-16 April 2011www.richtek.com

Output Current vs . Ripple Voltage

0 50 100 150 200

Output Current (mA)

Ripple Voltage (mVp-p) 1

VOUT = 3.3V

COUT = 68μF

L = 100μH

2.5V

2.0V

3.0V

1.5V

1.0V

Output Current vs. Ripple Voltage

0 50 100 150 200

Output Current (mA)

Ripple Voltage (mVp-p) 1

VOUT = 3.3V

COUT = 170μF

L = 100μH

2.5V

2.0V 3.0V

1.5V

1.0V

Output Curren t vs . Ripple Voltage

100

150

200

250

300

0 50 100 150 200

Output Current (mA)

Ripple Voltage (mVp-p) 1

VOUT = 3.3V

COUT = 20μF

L = 100μH

2.5V

2.0V 3.0V

1.5V

1.0V

Efficiency vs. output Current

100

0 50 100 150 200

Output Cu rren t (mA)

Efficiency (%) 1

VOUT = 3.3V

L = 100μH

2.5V

2.0V

3.0V

1.5V

1.0V

Output Voltage vs. Output Current

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 50 100 150 200

Output Current (mA)

Output Voltage (V ) 1

VOUT = 3.3V

L = 100μH

2.5V

2.0V

3.0V

1.5V

1.0V

Start-up/Hold-on Voltage vs. Output Current

0.5

1.5

2.5

0 20406080100120

Output Current (mA)

Start-up/ Hold-on Volt age V s tart / V hold (V )1

VOUT = 3.3V

L = 100μH

Vstart

Vhold

RT9261B

DS9261B-16 April 2011 www.richtek.com

Outline Dimension

AA1

SOT-23-5 Surface Mount Package

Dimensions In Mill imeters Dimensions In Inch es

Symbol Min Max Min Max

A 0.889 1.295 0.035 0.051

A1 0.000 0.152 0.000 0.006

B 1.397 1.803 0.055 0.071

b 0.356 0.559 0.014 0.022

C 2.591 2.997 0.102 0.118

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

RT9261B

8DS9261B-16 April 2011www.richtek.com

Information that is provided by Richtek Technology Corporation is believed to be accurate and reli able. Richtek reserve s the right to make any cha nge in circuit de sign,

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.

Richtek Technology Corporation

Headquarter

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

Hsinchu, Taiwan, R.O.C.

Tel: (8863)5526789 Fax: (8863)5526611

Richtek Technology Corporation

Taipei Office (Marketing)

5F, No. 95, Minchiuan Road, Hsintien City

Taipei County, Taiwan, R.O.C.

Tel: (8862)86672399 Fax: (8862)86672377

Email: marketing@richtek.com

3-Lead SOT -89 Surf ace Mount

Dim e nsion s In Millimet e rs Dimensio ns In I nche s

Symbol Min Max Min Max

A 1.397 1.600 0.055 0.063

b 0.356 0.483 0.014 0.019

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 1.753 0.055 0.069

e 1.448 1.549 0.057 0.061

H 0.356 0.432 0.014 0.017