Semtech 1565

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SC1565Very Low Dropout

1.5 Amp Regulator With EnablePOWER MANAGEMENT

Revision: August 12, 2003

The SC1565 is a high performance positive voltage

regulator designed for use in applications requiring very

low dropout voltage at up to 1.5 Amps. Since it has

superior dropout characteristics compared to regular

LDOs, it can be used to supply 2.5V on motherboards or

2.8V on peripheral cards from the 3.3V supply thus

allowing the elimination of costly heatsinks. Additionally,

the 5-lead TO-220/TO-263 and SO-8 versions have an

enable pin to further reduce power dissipation while shut

down. The SC1565 provides excellent regulation over

variations in line, load and temperature.

The SC1565 is available in SO-8, 3-lead SOT-223, 3 and

5 lead TO-220 and 3 and 5 lead TO-263 packages. Three

lead packages are available with 1.8V and 2.5V fixedoutput options only. The SO-8, TO-220-5 and TO-263-5

are available with 1.8V and 2.5V internally preset

outputs that are also adjustable using external resistors.

350mV dropout @ 1.5A

Adjustable output from 1.2V to 4.8V(1)

2.5V and 1.8V options (adjustable externallyusing resistors)(1)

Over current and over temperature protection

Enable pin(1)

10A quiescent current in shutdown(1)

Low reverse leakage (output to input)

Surface mount and through-hole packages

Full industrial temperature range

TO-220, TO-263, SOT-223 and SO-8 Packages

Note:

(1) SO-8, TO-220-5 and TO-263-5 packages only.

Battery powered systems

Motherboards

Peripheral cards

Network cards

Set Top Boxes

Medical Equipment

Notebook Computers

VIN

VO

ENABLE

U1

SC1565IS-X.X

1

2

3

4 5

6

7

8EN

VIN

VO

ADJ GND

GND

GND

GND

C1

C2

VIN VO

C2

C1

U1SC1565IT-X.X

1

2

3VIN

GND

VO

Notes:

(1) Maximum VO setpoint for 1.8V parts = 5.4V.

(2) This device is designed to operate with ceramic input and output capacitors.

VIN

VO

ENABLE

U1

SC1565IS-X.X

1

2

3

4 5

6

7

8EN

VIN

VO

ADJ GND

GND

GND

GND

C1

C2

R1

R2

VoltsR2

R2)(R11.200VO

+=

VIN

ENABLE

VO

C1

C2

R1

R2

U1SC1565I5T-X.X

2

1

3

5

4VIN

EN GND ADJ

VO

Description Features

Applications

Typical Application Circuits

VoltsR2

R2)(R11.200VO

+=
http://www.digchip.com/datasheets/parts/datasheet/420/SC1565.phphttp://www.digchip.com/

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2 2003 Semtech Corp. www.semtech.com

SC1565

POWER MANAGEMENT

retemaraP lobmyS xaM stinU

egatloVtupnI V NI 7 V

noitapissiDrewoP PD

detimiLyllanretnI W

tneibmAotnoitcnuJecnatsiseRlamrehT8-OS )1(

322-TOSX-022-OTX-362-OT

AJ

56360506

W/C

esaCotnoitcnuJecnatsiseRlamrehT8-OS

322-TOSX-362-OT,X-022-OT

CJ

9372

3

W/C

egnaRerutarepmeTtneibmAgnitarepO TA

58+ot04- C

egnaRerutarepmeTnoitcnuJgnitarepO TJ

051+ot04- C

egnaRerutarepmeTegarotS TGTS

051+ot56- C

.ceS01)gniredloS(erutarepmeTdaeL TDAEL

003 C

)ledoMydoBnamuH(gnitaRDSE VDSE

4 Vk

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

retemaraP lobmyS snoitidnoCtseT niM pyT xaM stinU

NIV

egnaRegatloVylppuS VNI

2.2 5.5 V

tnerruCtnecseiuQ IQ

VNI

V3.3= 57.0 57.1 Am

VNI

V,V5.5=NE

V0= 01 53 A

OV

egatloVtuptuO )1( VO

VNI

V=O

I,V7.0+O

Am01= %1- VO

%1+ V

)egatloVdexiFlanretnI( %2- %2+

noitalugeReniL )1( GER)ENIL(

VNI

V(=O

I,V5.5ot)V52.0+TUO

Am01= 530.0 3.0 %

noitalugeRdaoL )1( GER)DAOL(

VNI

V=O

V7.0+ 2.0 4.0 %

egatloVtuoporD )2()1( VD

IO

Am01= 5.2 01 Vm

02

IO

Am005= 09 003 Vm

004

Absolute Maximum Ratings

Electrical CharacteristicsUnless specified: V

EN= V

IN. Adjustable Option (V

ADJ> V

TH(ADJ)): V

IN= 2.2V to 5.5V and I

O= 10A to 1.5A.

Fixed Options (VADJ

= GND): VIN

= (VO

+ 0.7V) to 5.5V and IO

= 0A to 1.5A. Values in boldapply over the full operating temperature range.

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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SC1565

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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% below the value

measured at a differential of 0.7V.

(3) Required to maintain regulation. Voltage set resistors R1 and R2 are usually utilized to meet thisrequirement. Adjustable versions only.

(4) Guaranteed by design.

(5) When VADJ

exceeds this threshold, the Sense Select switch disconnects the internal feedback chain from

the error amplifier and connects VADJ

instead.

retemaraP lobmyS snoitidnoCtseT niM pyT xaM stinU

).tnoC(OV

egatloVtuoporD )2()1( IO

A1= 081 004 Vm

005

IO

A5.1= 072 005 Vm

006

tnerruCdaoLmuminiM )3( IO

VNI

V=O

V7.0+ 1 01 A

timiLtnerruC ILC

6.1 0.2 5.3 A

JDA

egatloVecnerefeR )1( VFER

VNI

V,V2.2=JDA

V=TUO I,

O Am01= 881.1 002.1 212.1 V

671.1 422.1

tnerruCniPtsujdA )4( IJDA

VJDA

V=FER

03 002 An

dlohserhTniPtsujdA )5( V)JDA(HT

50.0 02.0 04.0 V

NE

tnerruCniPelbanE INE

VNE

V,V0=NI

V3.3= 5.1 01 A

dlohserhTniPelbanE VHI

VNI

V3.3= 6.1 V

VLI

VNI

V3.3= 4.0

noitcetorPerutarepmeTrevO

levelpirThgiH TIH

071 C

siseretsyH TTSYH

02 C

Electrical Characteristics (Cont.)Unless specified: V

EN= V

IN. Adjustable Option (V

ADJ> V

TH(ADJ)): V

IN= 2.2V to 5.5V and I

O= 10A to 1.5A.

Fixed Options (VADJ

= GND): VIN

= (VO+ 0.7V) to 5.5V and I

O= 0A to 1.5A. Values in boldapply over the full operating temperature range.

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Notes:

(1) Where -X.X denotes voltage options. Available

voltages are: 2.5V and 1.8V. Output voltage can be

adjusted using external resistors, see Pin Descriptions

on page 5.

(2) Where -X.X denotes voltage options. Available

voltages are: 2.5V and 1.8V. Output not adjustable.

(3) Only available in tape and reel packaging. A ree

contains 2500 devices.

(4) Only available in tape and reel packaging. A ree

contains 800 devices.

(5) Only available in tube packaging. A tube contains 50

devices.

eciveD egakcaP

RTX.X-SI5651CS )3()1( 8-OS

RTX.X-TSI5651CS )3()2( 322-TOS

RTX.X-MI5651CS )4()2( 3-362-OT

RTX.X-M5I5651CS )4()1( 5-362-OT

X.X-TI5651CS )5()2( 3-022-OT

X.X-T5I5651CS )5()1( 5-022-OT

Pin Configurations Ordering Information

SO-8

SOT-223

TO-220-3 TO-220-5

3-022-OT,322-TOS

3-362-OTdna

NIP NOITCNUF

1 NIV

2 DNG

3 OV

DNGsiBAT

5-362-OTdna5-022-OT

NIP NOITCNUF

1 NE

2 NIV

3 DNG

4 OV

5 JDA

DNGsiBAT

TO-263-3 TO-263-5

Pin Configurations (Cont.)

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SC1565

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*

*

Block Diagram

* Not present on SOT-223, TO-220-3 or TO-263-3

Pin Descriptions

emaNniP noitpicseDniP

JDA lanretxefI.srotsiserkcabdeeflanretniehtybtestahtotegatlovtuptuoehtstes,dednuorgnehw,nipsihT:)1egapnostiucriCnoitacilppAeeS(eblliwegatlovtuptuoeht,desuerasrotsiserkcabdeef

NE fonoitcarfaottnerructnecseiuqehtgnicuder,fforotalugerehtsnrutV4.0wolebnipsihtgnilluP.tupnIelbanE.desugniebtonfiNIVottcennoC.nepotfelsinipsihtfidelbaneeblliwecivedehT.eulavgnitareposti

DNG 022-OT,322-TOSehtnobatehtesU.gniknistaehrofecived8-OSehtnosnipruofllaesU.dnuorgecnerefeR.gniknistaehrofsecived362-OTdna

NIV muminiM.V5.5dna)V7.0+OV(neewtebebtsumnipsihtottupnieht,daollluftanoitalugerroF.egatlovtupnI .V2.2=NIV

OV .ecivedehtfotuptuorewopehtsinipehT

VoltsR2

R2)(R11.200VO

+=

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SC1565

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2.450

2.460

2.470

2.480

2.490

2.500

2.510

2.520

2.530

2.540

2.550

-50 -25 0 25 50 75 100 125 150

TJ(C)

VO

(V)

VIN = 3.2V

IO= 10mA

IO= 1.5A

2.450

2.460

2.470

2.480

2.490

2.500

2.5102.520

2.530

2.540

2.550

-50 -25 0 25 50 75 100 125 150

TJ(C)

VO

(V)

VIN = 5.5V

IO= 10mA

IO= 1.5A

1.175

1.180

1.185

1.190

1.195

1.200

1.2051.210

1.215

1.220

1.225

-50 -25 0 25 50 75 100 125 150

TJ(C)

VREF(V)

VIN = 2.2V

IO= 10mA

IO= 1.5A

Typical Characteristics

Output Voltage (2.5V) vs. Junction

Temperature vs. Output Current

Output Voltage (2.5V) vs. Junction


Reference Voltage vs. Junction


Dropout Voltage (IOUT

= 0.5A) vs. Output

Voltage vs. Junction Temperature


= 1.5A) vs. Output



= 1A) vs. Output


0

50

100

150

200

250

300

350

400

450

500

550

600

2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6

VOUT(V)

VD

(mV)

TJ= 25C

TJ= 150C

TJ= -40C

0

50

100

150

200

250

300

350

400

450

500

2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6

VOUT(V)

VD

(mV)

Top to bottom:TJ= 150C

TJ= 25C

TJ= -40C

0

50

100

150

200

250

300

350

400

2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6

VOUT(V)

VD

(mV)

Top to bottom:

TJ= 150C

TJ= 25C

TJ= -40C

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SC1565

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500

510

520

530

540

550

560

570

580

590

600

-50 -25 0 25 50 75 100 125 150

TJ(C)

IQ(A)

VIN = 3.3V

0

1

2

3

4

5

6

7

8

9

10

-50 -25 0 25 50 75 100 125 150

TJ(C)

IQ(OFF)(A)

VIN = 5.5V

1.175

1.180

1.185

1.190

1.195

1.200

1.205

1.210

1.215

1.220

1.225

-50 -25 0 25 50 75 100 125 150

TJ(C)

VREF(V)

VIN = 5.5V

IO= 1.5A

IO= 10mA

Reference Voltage vs. Junction


Typical Characteristics (Cont.)

Quiescent Current vs.

Junction Temperature

Off-State Quiescent Current vs.

Junction Temperature

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Introduction

The SC1565 is intended for applications such as

graphics cards 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 4.7F ceramic capacitor is

recommended. 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 2.2F,

along with a 0.1F 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 SC1565 is extremely tolerant of

output capacitor ESR values and thus will also work

comfortably with tantalum output capacitors. For refer-

ence, the phase-margin contour of Figure 1 can be used

to choose an appropriate output capacitor for a given

stability requirement.

Noise immunity: in very electrically noisy environments,

it is recommended that 0.1F ceramic capacitors be

placed from IN to GND and OUT to GND as close to the

device pins as possible.

External voltage selection resistors: the use of 1%resistors, and designing for a current flow 10A is

recommended to ensure a well regulated output (thus

R2 120k).

Applications Information

Thermal Considerations

The power dissipation in the SC1565 is approximately

equal to the product of the output current and the input

to output voltage differential:

( ) OD IVOUTVINP

The absolute worst-case dissipation is given by:

)MAX(Q)MAX()MAX(O)MIN()MAX()MAX(D IVINIVOUTVINP +=

For a typical scenario, VIN

= 3.3V 5%, VOUT

= 2.8V and

IO = 1.5A, therefore:

VIN(MAX)

= 3.465V, VOUT(MIN)

= 2.744V and IQ(MAX)

= 1.75mA

Thus PD(MAX)

= 1.09W.

Using this figure, and assuming TA(MAX)

= 70C, we can

calculate the maximum thermal impedance allowable to

maintain TJ150C:

( ) ( )R

T T

PC WTH J A MAX

J MAX A MAX

D M AX( )( )

( ) ( )

( ) .. /

=

=

= 150 70

10973 4

This should be achievable for the SO-8 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. The SOT-223, TO-220 and TO-263

packages would not require heatsinking. Internal ground/

power planes and air flow will also assist in removing

heat. For higher ambient temperatures it may be neces

sary to use additional copper area.

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Applications Information (Cont.)

0.001 0.01 0.1 1 10

1.5A

150mA

15mA

1.5mA

ESR(Ohms)

Load

Co=2.2uF, Phase Margin: -15-35 35-85 85-135

0.001 0.01 0.1 1 10

1.5A

150mA

15mA

1.5mA

ESR(Ohms)

Load

Co=22uF, Phase Margin: -15-35 35-85 85-135

0.001 0.01 0.1 1 101.5A

150mA

15mA

1.5mA

ESR(Ohms)

Load

Co=220uF, Phase Margin: -15-35 35-85 85-135

Figure 1: Phase-margin Contour Plot

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SC1565

POWER MANAGEMENT

JEDEC REF: MS-012AA

Outline Drawing - SO-8

Land Pattern - SO-8

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SC1565

POWER MANAGEMENT

Land Pattern - SOT-223

Outline Drawing - SOT-223

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SC1565

POWER MANAGEMENT

Outline Drawing - T0-263-3

Minimum Land Pattern - TO-263-3

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SC1565

POWER MANAGEMENT

Outline Drawing - TO-263-5

Minimum Land Pattern - TO-263-5

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SC1565

POWER MANAGEMENT

Semtech Corporation

Power Management Products Division

200 Flynn Road, Camarillo, CA 93012

Phone: (805)498-2111 FAX (805)498-3804

Contact Information



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Semtech 1565