Datasheet SC1565IS-1.8TR, SC1565IS-2.5TR, SC1565IST-1.8, SC1565IST-1.8TR, SC1565IST-2.5 Datasheet (Semtech Corporation)

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

VERY LOW DROPOUT 1.5 AMP
REGULATOR WITH ENABLE

SC1565

October 3, 2000

1

Volts

R2

R2)(R11.200VO+

=

FEATURES

•= 350mV dropout @ 1.5A

•= Adjustable output from 1.2V to 4.8V

(1)

•= 2.5V and 1.8V options (adjustable externally using

resistors)

(1)

•= Over current and over temperature protection

•= Enable pin

(1)

•= 10µA quiescent current in shutdown

(1)

•= Low reverse leakage (output to input)

•= Surface mount and through-hole packages

•= Full industrial temperature range

Note:
(1) SO-8 and TO-220-5L packages only.

DESCRIPTION

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 motherboar ds
or 2.8V on peripheral cards fr om the 3.3V supply thus
allowing the elimination of costly heatsinks.
Additionally, the 5-lead TO-220 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 the popular SO-8 surface
mount package with two internally preset output voltage
options, which are also adjustable using external
resistors. Also available are 5-lead and 3- lead TO-220

2.5V options (fixed output only for the 3-lead option)
and fixed output SOT-223 options.

APPLICATIONS

•= Battery powered systems

•= Motherboards

•= Peripheral cards

•= PCMCIA cards

TEL:[phone] FAX:[phone] WEB:http://www.semtech.com

ORDERING INFORMATION

Notes:
(1) Where -X.X denotes voltage options. Available
voltages are: 2.5V and 1.8V. Output voltage can be ad­justed (except SOT-223 and TO-220-3) using external
resistors, see Pin Description.
(2) Only available in tape and reel packaging. A reel
contains 2500 devices.
(3) Only available in tube packaging (no suffix re­quired).

DEVICE

(1)

PACKAGE

SC1565IS-X.X.TR

(2)

SO-8

SC1565IST-X.X.TR

(2)

SOT-223

SC1565IT-X.X

(3)

TO-220-3

SC1565I5T-X.X

(3)

TO-220-5

TYPICAL APPLICATIONS

VIN

VO

ENABLE

U1

SC1565IS-X.X

1
2
3
4 5

6

7

8

EN
VIN
VO
ADJ GND

GND

GND

GND

C1

C2

R1

R2

VIN

VO

ENABLE

U1

SC1565IS-X.X

1
2
3
4 5

6

7

8

EN
VIN
VO
ADJ GND

GND

GND

GND

C1

C2

VIN VO

C2

C1

U1

SC1565IT-2.5V and SC1565IST-X.X

1

2

3

VIN

GND

VO

VIN

ENABLE

VO

C1

C2

R1

R2

U1

SC1565I5T-2.5

2

1

3

5

4

VIN

EN

GND

ADJ

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.

Volts

R2

R2)(R11.200VO+

=

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

VERY LOW DROPOUT 1.5 AMP
REGULATOR WITH ENABLE

SC1565

October 3, 2000

2

ABSOLUTE MAXIMUM RATINGS

Parameter Symbol Max Units

Input Voltage V

IN

5.5 V

Power Dissipation P

D

Internally Limited W

Thermal Resistance Junction to Ambient
SO-8

(1)

SOT-223
TO-220-X

θ

JA

65
63
50

°C/W

Thermal Resistance Junction to Case
SO-8
SOT-223
TO-220-X

θ

JC

39
27

3

°C/W

Operating Ambient Temperature Range T

A

-40 to 85 °C

Operating Junction Temperature Range T

J

-40 to 150 °C

Storage Temperature Range T

STG

-65 to 150 °C

Lead Temperature (Soldering) 10 Sec. T

LEAD

300 °C

ESD Rating (Human body model) ESD 4 kV

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

ELECTRICAL CHARACTERISTICS

Unless specified: VEN = V

IN

Adjustable Option (V

ADJ

> V

TH(ADJ)

): VIN = 2.2 to 5.5V and IO = 10µA to 1.5A

Fixed Options (V

ADJ

= GND): VIN = (VO + 0.7V) to 5.5V and IO = 0A to 1.5A

Values in bold apply over the full operating temperature range.

Parameter Symbol Test Conditions Min Typ Max Units
VIN

Supply Voltage Range VIN

2.2 5.5

V

Quiescent Current I

Q

VIN = 3.3V 0.75

1.75

mA

V

IN

= 5.5V, VEN = 0V 10

35

µA

VO

Output Voltage

(1)

V

O

VIN = VO + 0.7V, IO = 10mA 0.99V

O

V

O

1.01V

O

V

(Internal Fixed Voltage)

0.98V

O

V

O

1.02V

O

Line Regulation

(1)

REG

(LINE)VIN

= (VO + 0.25V) to 5.5V, I

OUT

= 10mA 0.035

0.3

%

Load Regulation

(1)

REG

(LOAD)

VIN = VO + 0.7V 0.2

0.4

%

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

VERY LOW DROPOUT 1.5 AMP
REGULATOR WITH ENABLE

SC1565

October 3, 2000

3

ELECTRICAL CHARACTERISTICS

Unless specified: VEN = V

IN

Adjustable Option (V

ADJ

> V

TH(ADJ)

): VIN = 2.2 to 5.5V and IO = 10µA to 1.5A

Fixed Options (V

ADJ

= GND): VIN = (VO + 0.7V) to 5.5V and IO = 0A to 1.5A

Values in bold apply over the full operating temperature range.

Parameter Symbol Test Conditions Min Typ Max Units

Dropout Voltage

(2)

V

D

I

LOAD

= 10mA 2.5 10 mV

20

I

LOAD

= 500mA 115 300 mV

400

I

LOAD

= 1A 225 400 mV

500

I

LOAD

= 1.5A 350 500 mV

600

Minimum Load Current

(3)

I

O

VIN = VO + 0.7V 1

10

µA

Current Limit I

CL

1.50

2.50

3.50

A

ADJ

Reference Voltage

(1)

V

REF

VIN = 2.2V, V

ADJ

= V

OUT

, IO = 10mA 1.188 1.200 1.212 V

1.176 1.224

Adjust Pin Current

(4)

I

ADJ

V

ADJ

= V

REF

10

50

nA

Adjust Pin Threshold

(5)

V

TH(ADJ)

0.10

0.20

0.40

V

EN

Enable Pin Current I

EN

VEN = 0V, VIN = 3.3V 1.5

10

µA

Enable Pin Threshold V

IH

V

IN

= 3.3V

1.8

V

V

IL

V

IN

= 3.3V

0.4

OVER TEMPERATURE PROTECTION

High Trip level T

HI

170 °C

Hysteresis T

HYST

20 °C

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 this requirement.
Adjustable versions only.
(4) Guaranteed by design.
(5) When V

ADJ

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

error amplifier and connects V

ADJ

instead.

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

VERY LOW DROPOUT 1.5 AMP
REGULATOR WITH ENABLE

SC1565

October 3, 2000

4

PIN DESCRIPTIONS

Pin Name Pin Functiom

ADJ This pin, when grounded, sets the output voltage to that set by the internal feedback resistors. If ex-

ternal feedback resistors are used, the output voltage will be (See Application Circuit):

EN Enable Input. Pulling this pin below 0.4V turns the regulator off, reducing the quiescent current to a

fraction of its operating value. The device will be enabled if this pin is left open. Connect to VIN if not
being used.

GND Reference ground. Use all four pins on the SO-8 device for heatsinking. Use the tab on the TO-220

devices for heatsinking.

VIN Input voltage. For regulation at full load, the input to this pin must be between (VO + 0.7V) and 5.5V.

Minimum VIN = 2.2V.

VO This pin is the power output of the device.

Volts

R2

R2)(R11.200VO+

=

*

*

BLOCK DIAGRAM

* Not on 3-lead TO-220

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

VERY LOW DROPOUT 1.5 AMP
REGULATOR WITH ENABLE

SC1565

October 3, 2000

5

PIN CONFIGURATIONS

SO-8

Top View

SC1565 3-PIN VERSIONS

PIN FUNCTION

1VIN
2GND
3VO

TAB IS GROUND

TO-220-3

SC1565 5-PIN VERSIONS

PIN FUNCTION

1EN
2VIN
3GND
4VO
5ADJ

TAB IS GROUND

TO-220-5

PIN FUNCTION

1VIN
2GND
3VO

TAB IS GROUND

SOT-223

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

VERY LOW DROPOUT 1.5 AMP
REGULATOR WITH ENABLE

SC1565

October 3, 2000

6

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

T

J

(°C)

V

O

(V)

VIN = 5.5V

I

O

= 10mA

I

O

= 1.5A

TYPICAL CHARACTERISTICS

Output Voltage (2.5V) vs. Junction

Temperature vs. Output Current

0

100

200

300

400

500

600

0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75

I

O

(A)

V

D

(mV)

-40°C

0°C

25°C

150°C

Dropout Voltage vs. Output Current

vs. Junction Temperature

0

100

200

300

400

500

600

-50 -25 0 25 50 75 100 125 150

T

J

(°C)

V

D

(mV)

IO = 1.0A

IO = 0.5A

I

O

= 1.5A

Dropout Voltage vs. Junction

Temperature vs. Output Current

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

T

J

(°C)

V

O

(V)

VIN = 3.2V

I

O

= 10mA

I

O

= 1.5A

Output Voltage (2.5V) vs. Junction

Temperature vs. Output Current

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

T

J

(°C)

V

REF

(V)

VIN = 2.2V

I

O

= 10mA

I

O

= 1.5A

Reference Voltage vs. Junction

Temperature vs. Output Current

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

T

J

(°C)

V

REF

(V)

VIN = 5.5V

I

O

= 1.5A

I

O

= 10mA

Reference Voltage vs. Junction

Temperature vs. Output Current

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

VERY LOW DROPOUT 1.5 AMP
REGULATOR WITH ENABLE

SC1565

October 3, 2000

7

TYPICAL CHARACTERISTICS (Cont.)

0

1

2

3

4

5

6

7

8

9

10

-50 -25 0 25 50 75 100 125 150

T

J

(°C)

I

Q(OFF)

(µA)

VIN = 5.5V

Off-State Quiescent Current vs.

Junction Temperature

500

510

520

530

540

550

560

570

580

590

600

-50 -25 0 25 50 75 100 125 150

T

J

(°C)

I

Q

(µA)

VIN = 3.3V

Quiescent Current vs.

Junction Temperature

APPLICATIONS INFORMATION

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 4.7µF 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
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 SC1565 is extremely toler­ant of output capacitor ESR values and thus will also
work comfortably with tantalum output capacitors.

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).

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:

The absolute worst-case dissipation is given by:

For a typical scenario, VIN = 3.3V ± 5%, VOUT = 2.8V
and I

O

= 1.5A, therefore:

VIN

(MAX)

= 3.465V, VOUT

(MIN)

= 2.744V and

I

Q(MAX)

= 1.75mA,

Thus P

D(MAX)

= 1.09W.

Using this figure, and assuming T

A(MAX)

= 70°C, we can
calculate the maximum thermal impedance allowable
to maintain T

J

≤ 150°C:

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 and TO-220
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 necessary to use additional copper area.

()

OD

IVOUTVINP •−≈

(

)

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

IVINIVOUTVINP •+•−=

()

()

R

TT

P

CW

TH J A M AX

JMAX AMAX

DMAX

()( )

() ()

()

.

./

−

=

−
=

−
=°

150 70

109

734

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

VERY LOW DROPOUT 1.5 AMP
REGULATOR WITH ENABLE

SC1565

October 3, 2000

8

OUTLINE DRAWING - SO-8

JEDEC

REF: MS-012AA

LAND PATTERN - SO-8

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

VERY LOW DROPOUT 1.5 AMP
REGULATOR WITH ENABLE

SC1565

October 3, 2000

9

LAND PATTERN SOT-223

DEVICE OUTLINE SOT-223

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

VERY LOW DROPOUT 1.5 AMP
REGULATOR WITH ENABLE

SC1565

October 3, 2000

10

DEVICE OUTLINE - TO-220-3L

DEVICE OUTLINE - TO-220-5L

ECN00-1357