SEMTECH SC4211 Technical data

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Very Low Input /Very Low Dropout

1 Amp Regulator With Enable

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Description Features

SC4211

The SC4211 is a high performance positive voltage
regulator designed for use in applications requiring very
low Input voltage and very low dropout voltage at up to 1
amp. It operates with a Vin as low as 1.4V, with output
voltage programmable as low as 0.5V. The SC4211 fea­tures ultra low dropout, ideal for applications where Vout
is very close to Vin. Additionally, the SC4211 has an en­able pin to further reduce power dissipation while shut­down. The SC4211 provides excellent regulation over varia­tions in line, load and temperature.

The SC4211 is available in the SOIC-8EDP (Exposed Die
Pad) package. The output voltage can be set via an exter­nal divider or to 0.5V depending on how the FB pin is con­figured.

Typical Application Circuits

 Input Voltage as low as 1.4V
 250mV dropout @ 1A
 Adjustable output from 0.5V to 3.3V
 Over current and over temperature protection
 Enable pin
 10µA quiescent current in shutdown
 Low reverse leakage (output to input)
 Full industrial temperature range
 Available in SOIC-8EDP package

Applications

 Telecom/Networking cards
 Motherboards/Peripheral cards
 Industrial Applications
 Wireless infrastructure
 Set top boxes
 Medical equipment
 Notebook computers
 Battery powered systems

VIN

ENABLE

ENABLE

SC4211

4

NC

3

VIN

2

EN

C1

C1

U1

SC4211

4

NC

3

VIN

2

EN

U1

5

NC

6

VO

7

FB

81

GNDNC

5

NC

6

VO

7

FB

81

GNDNC

R1

R2

VO

+

R2

R2)(R10.5

Volts

=

VO

C2

VO = 0.5VVIN

C2

Revision October 18, 2004

1 www.semtech.com

SC4211

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Absolute Maximum Ratings

Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified in
the Electrical Characteristics section is not implied.

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egatloVetulosbABF,oV,NE,niV 7V

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)1(

PDE8-CIOS

)1(

PDE8-CIOS

tneibmAotnoitcnuJecnatsiseRlamrehT

esaCotnoitcnuJecnatsiseRlamrehT

egnaRerutarepmeTtneibmAgnitarepO T

egnaRerutarepmeTnoitcnuJgnitarepO T

egnaRerutarepmeTegarotS T

.ceS01)gniredloS(erutarepmeTdaeL T

)ledoMydoBnamuH(gnitaRDSE V

Note: (1) 2 square inch of FR-4, double sided, 1 oz. minimum copper weight.

Electrical Characteristics

Unless specified: VEN = VIN, VFB = VO, VIN = 1.40V to 5.5V, VIN = (VO + 0.5V) to 5.5V and IO = 1mA to 1A.
Values in bold apply over the full operating temperature range.

retemaraPlobmySsnoitidnoCtseTniMpyTxaMstinU

NIV

egnaRegatloVylppuSV

tnerruCtnecseiuQI

OV

)1(

egatloVtuptuO

)egatloVdexiFlanretnI(

)1(

noitalugeReniL

)1(

noitalugeRdaoL

)2()1(

egatloVtuoporD

NI

VNIV=

V

NI

V

NI

O

Q

V

O

IlluF

GER

)ENIL(

GER

V

D

VNIV(=

V

)DAOL(

NI

VNIV(=

O

V(=

O

O

I,V3.3=

A0= 3 Am

TUO

V,V5.5=

V0=01 05 Aµ

NE

I,V5.0+

TUO

Vdna,

TUO

I

O

NI

V,)V5.0+

NI

V,)V5.0+

NI

I,)V5.0+

TUO

Am01=5.201Vm

Am01=%5.1-VO%5.1+V

egnaR %3-%3+

I,V3.3<

TUO

I,V3.3>

TUO

D

θ

AJ

θ

CJ

A

J

GTS

DAEL

DSE

63W/C°

2Vk

detimiLyllanretnIW

5.5W/C°

58+ot04-C°

051+ot04-C°

051+ot56-C°

003C°

04.15.5 V

Am01=52.0 0.1 %

Am01=5.0 5.1 %

A1otAm01=5.0 5.1 %

02

I

O

Am005=09002Vm

003

Notes:
(1) Low duty cycle pulse testing with Kelvin connections required.
(2) Defined as the input to output differential at which the output voltage drops to 1.5% below the value measured at a

differential of 0.5V.
(3) Required to maintain regulation. Voltage set resistors R1 and R2 are usually utilized to meet this requirement.
(4) Guaranteed by design.

2 2004 Semtech Corp. www.semtech.com

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Electrical Characteristics (Cont.)

Unless specified: VEN = VIN, VFB = VO, VIN = 1.40V to 5.5V, VIN = (VO + 0.5V) to 5.5V and IO = 1mA to 1A.
Values in bold apply over the full operating temperature range.

retemaraPlobmySsnoitidnoCtseTniMpyTxaMstinU

).tnoC(OV

SC4211

)2()1(

egatloVtuoporD

I

A1=002004Vm

O

005

)3(

tnerruCdaoLmuminiM

)4(

timiLtnerruC

I

O

I

LC

VNIV=

V5.0+ 1 Am

O

1.1 5.1A

kcabdeeF

)1(

egatloVecnerefeR

)4(

tnerruCniPkcabdeeF

V

FER

I

JDA

V

NI

IlluF

V,V3.3=

BF

TUO

VBFV=

V=

TUOI,O

Vdna,

NI

FER

Am01=594.05.0505.0V

egnaR 584.0515.0

08 002 An

NE

tnerruCniPelbanEI

dlohserhTniPelbanEV

NE

HI

V

LI

V

NE

V,V0=

V

NI

V

NI

V3.3=5.1 01 Aµ

NI

V3.3= 6.1 V

V3.3= 4.0

noitcetorPerutarepmeTrevO

levelpirThgiHT

siseretsyHT

IH

TSYH

061C°

01C°

Notes:
(1) Low duty cycle pulse testing with Kelvin connections required.
(2) Defined as the input to output differential at which the output voltage drops to 1.5% below the value measured at a

differential of 0.5V.
(3) Required to maintain regulation. Voltage set resistors R1 and R2 are usually utilized to meet this requirement.
(4) Guaranteed by design.

3 2004 Semtech Corp. www.semtech.com

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SC4211

Ordering Information

Pin Configuration

NC

EN

VIN

NC

Top View

GND

FB

VO

NC

rebmuNtraPegakcaPT(egnaR.pmeT

)3()2()1(

TRTS1124CS

BVE1124CSdraoBnoitaulavE

Note:
(1) Available voltage is : 0.5V or Output voltage can be adjusted using
external resistors, see Pin Descriptions.
(2) Only available in tape and reel packaging 2500 devices for the
SOIC-8EDP package.
(3) Lead free product.

PDE8-CIOS58+ot04-

O

C

Bottom View

GND

GND

FB

VO

NC

8

7

Exposed

Die Pad

6

5

1

2

3

4

NC

EN

VIN

NC

)

A

Pin Descriptions

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BF srotsiserkcabdeeflanretxefIV5.0tateseblliwegatlovtuptuoeht,nipoVehtotdetcennocsinipsihtnehW

VO

NE fonoitcarfaottnerructnecseiuqehtgnicuder,fforotalugerehtsnrutV4.0wolebnipsihtgnilluP.tupnIelbanE

DNG .nipCIehttarehtegotdetcennocebtsumdapeiddesopxeehtdnanipDNGehT:etoN.dnuorgecnerefeR

NIV muminiM.V5.5dna)V5.0+OV(neewtebebtsumnipsihtottupnieht,daollluftanoitalugerroF.egatlovtupnI

OV tayltceriddecalpebdluohsroticapaccimarecFu01fomuminimA.ecivedehtfotuptuorewopehtsinipehT

SOIC-8EDP

=

.nipsiht

R2

SOIC-8EDP

:)1egapnostiucriCnoitacilppAeeS(eblliwegatlovtuptuoeht,desuera

+

R2)(R10.5

Volts

.desugniebtonfiNIVottcennoC.nepotfelsinipsihtfidelbaneeblliwecivedehT.eulavgnitareposti

.gniknistaehrofecivedehtnodapeiddesopxeehtesU

seodylppustupniehttahterusneotnipsihtotylesolcdecalpebdluohsecnaticapacklubegralA.V4.1=NIV

.nipsihttayltceriddecalpebdluohsroticapaccimarecFu7.4fomuminimaoslA.V4.1wolebgaston

4 2004 Semtech Corp. www.semtech.com

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Block Diagram

SC4211

VIN

EN

Vdd

Vout

Vin

Rsense

+

UVLO

Thermal

Shutdown

+

-

Reverse Voltage
Shutdown

VOUT

Vpump

-

+

FB

-

0.5V Ref

GND

5 2004 Semtech Corp. www.semtech.com

POWER MANAGEMENT

()

()

Applications Information

SC4211

Introduction

The SC4211 is intended for applications where high cur­rent capability and very low dropout voltage are required.
It provides a very simple, low cost solution that uses very
little PCB real estate. Additional features include an en­able pin to allow for a very low power consumption standby
mode, and a fully adjustable output.

Component Selection

Input capacitor: A large bulk capacitance of about 100uF

should be closely placed to the input supply pin of the
SC4211 to ensure that Vin does not sag below 1.4V. Also a
minimum of 4.7µF ceramic capacitor is
recommended to be placed directly next to the Vin pin.
This allows for the device being some
distance from any bulk capacitance on the rail.
Additionally, input droop due to load transients is reduced,
improving load transient response. Additional capacitance
may be added if required by the application.

Output capacitor: a minimum bulk capacitance of 10µF,
along with a 0.1µF ceramic decoupling capacitor is
recommended. Increasing the bulk capacitance will
improve the overall transient response. The use of
multiple lower value ceramic capacitors in parallel to
achieve the desired bulk capacitance will not cause
stability issues. Although designed for use with ceramic
output capacitors, the SC4211 is extremely tolerant of out­put capacitor ESR values and thus will also work
comfortably with tantalum output capacitors.

Noise immunity: in very electrically noisy environments, it
is recommended that 0.1µF ceramic capacitors be placed
from IN to GND and OUT to GND as close to the device pins
as possible.

Thermal Considerations

The power dissipation in the SC4211 is approximately equal
to the product of the output current and the input to out­put voltage differential:

()

IVOUTVINP •−≈

OD

The absolute worst-case dissipation is given by:

IVINIVOUTVINP •+•−=

Q(MAX)(MAX)O(MAX)(MIN)(MAX)D(MAX)

For a typical scenario, VIN = 3.3V ± 5%, V

= 2.8V and

OUT

IO = 1A, therefore:

V

= 3.465V, V

IN(MAX)

Thus P

D(MAX)

= .722W.

Using this figure, and assuming T

= 2.744V and I

OUT(MIN)

= 1.75mA,

Q(MAX)

= 70°C, we can cal-

A(MAX)

culate the maximum thermal impedance allowable to main­tain T

≤ 150°C:

J

−

TT

P

D(MAX)

A(MAX)J(MAX)

R

−

=

A)(MAX)TH(J

()

−

=

70150

.722

°=

C/W110

This should be achievable for the SOIC-8EDP package
using PCB copper area to aid in conducting the heat away,
such as one square inch of copper connected to the ground
pins of the device. Internal ground/power planes and air
flow will also assist in removing heat. For higher ambient
temperatures it may be necessary to use additional cop­per area.

External voltage selection resistors: the use of 1%

resistors, and designing for a current flow ≥ 10µA is

recommended to ensure a well regulated output (thus R2

≤ 120kΩ).

6 2004 Semtech Corp. www.semtech.com

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Outline Drawing - SOIC-8EDP

SC4211

Land Pattern - SOIC-8EDP

7 2004 Semtech Corp. www.semtech.com

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Contact Information

SC4211

Semtech Corporation
Power Management Products Division
200 Flynn Road, Camarillo, CA 93012

Phone: [phone] FAX [phone]

8 2004 Semtech Corp. www.semtech.com