LT1763MPDE-2.5#TRPBF

LT1763 Series

500mA, Low Noise, LDO

Micropower Regulators

FEATURES

DESCRIPTION

TheLT^®1763seriesaremicropower,lownoise,lowdropout

regulators.Thedevicesarecapableofsupplying500mAof

output current with a dropout voltage of 300mV. Designed

foruseinbattery-poweredsystems,thelow30μAquiescent

current makes them an ideal choice. Quiescent current is

well controlled; it does not rise in dropout as it does with

many other regulators.

n

Low Noise: 20μV

Output Current: 500mA

(10Hz to 100kHz)

RMS

n

Low Quiescent Current: 30μA

Wide Input Voltage Range: 1.8V to 20V

Low Dropout Voltage: 300mV

Very Low Shutdown Current: < 1μA

No Protection Diodes Needed

Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 3V, 3.3V, 5V

Adjustable Output from 1.22V to 20V

Stable with 3.3μF Output Capacitor

Stable with Aluminum, Tantalum or Ceramic

Capacitors

A key feature of the LT1763 regulators is low output noise.

With the addition of an external 0.01μF bypass capacitor,

output noise drops to 20μV

bandwidth. The LT1763 regulators are stable with output

capacitors as low as 3.3μF. Small ceramic capacitors can

be used without the series resistance required by other

regulators.

over a 10Hz to 100kHz

RMS

n

Reverse Battery Protection

No Reverse Current

Overcurrent and Overtemperature Protected

8-Lead SO and 12-Lead (4mm × 3mm) DFN

Packages

Internal protection circuitry includes reverse battery

protection, current limiting, thermal limiting and reverse

currentprotection.Thepartscomeinﬁxedoutputvoltages

of 1.5V, 1.8V, 2.5V, 3V, 3.3V and 5V, and as an adjustable

device with a 1.22V reference voltage. The LT1763

regulators are available in 8-lead SO and 12-lead, low

proﬁle (4mm × 3mm × 0.75mm) DFN packages.

APPLICATIONS

n

Cellular Phones

n

Battery-Powered Systems

n

Noise-Sensitive Instrumentation Systems

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and

ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property

of their respective owners. Protected by U.S. Patents including 6144250, 6118263.

TYPICAL APPLICATION

Dropout Voltage

400

350

300

250

200

150

100

50

3.3V Low Noise Regulator

3.3V AT 500mA

20μV NOISE

IN

OUT

V

IN

RMS

+

3.7V TO

20V

1μF

SENSE

10μF

LT1763-3.3

0.01μF

SHDN

GND

BYP

1763 TA01

0

100

200

300

400

500

OUTPUT CURRENT (mA)

1763 TA02

1763fg

1

LT1763 Series

ABSOLUTE MAXIMUM RATINGS ^{(Note 1)}

IN Pin Voltage ........................................................ 20V

OUT Pin Voltage..................................................... 20V

Input to Output Differential Voltage........................ 20V

SENSE Pin Voltage ............................................... 20V

ADJ Pin Voltage ...................................................... 7V

BYP Pin Voltage..................................................... 0.6V

SHDN Pin Voltage ................................................ 20V

Output Short-Circuit Duration ........................ Indeﬁnite

Operating Junction Temperature Range (Note 2)

C, I Grade...........................................–40°C to 125°C

MP Grade...........................................–55°C to 125°C

Storage Temperature Range

S8 Package........................................–65°C to 150°C

DFN Package......................................–65°C to 150°C

Lead Temperature (Soldering, 10 sec)

S8 Package....................................................... 300°C

PIN CONFIGURATION

TOP VIEW

NC

OUT

1

2

3

4

5

6

12 NC

11 IN

10 IN

TOP VIEW

OUT

SENSE/ADJ*

GND

1

2

3

4

8

7

6

5

IN

OUT

GND

SHDN

13

GND

NC

9

8

7

NC

SENSE/ADJ*

BYP

SHDN

GND

BYP

S8 PACKAGE

8-LEAD PLASTIC SO

DE PACKAGE

12-LEAD (4mm × 3mm) PLASTIC DFN

T

JMAX

= 150°C, θ = 70°C/W, θ = 35°C/W

JA JC

T

= 125°C, θ = 40°C/W, θ = 5°C/W

JA JC

JMAX

*PIN 2: SENSE FOR LT1763-1.5/LT1763-1.8/LT1763-2.5/LT1763-3/LT1763-3.3/LT1763-5

ADJ FOR LT1763

EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB

*PIN 5: SENSE FOR LT1763-1.5/LT1763-1.8/LT1763-2.5/LT1763-3/LT1763-3.3/LT1763-5

ADJ FOR LT1763

SEE THE APPLICATIONS INFORMATION SECTION.

ORDER INFORMATION

LEAD FREE FINISH

TAPE AND REEL

PART MARKING*

1763

PACKAGE DESCRIPTION

TEMPERATURE RANGE

–40°C to 125°C

–55°C to 125°C

–40°C to 125°C

–55°C to 125°C

–40°C to 125°C

–55°C to 125°C

–40°C to 125°C

–55°C to 125°C

LT1763CDE#PBF

LT1763CDE#TRPBF

LT1763IDE#TRPBF

LT1763MPDE#TRPBF

LT1763CDE-1.5#TRPBF

LT1763IDE-1.5#TRPBF

12-Lead (4mm × 3mm) Plastic DFN

LT1763IDE#PBF

1763

LT1763MPDE#PBF

LT1763CDE-1.5#PBF

LT1763IDE-1.5#PBF

LT1763MPDE-1.5#PBF

LT1763CDE-1.8#PBF

LT1763IDE-1.8#PBF

LT1763MPDE-1.8#PBF

LT1763CDE-2.5#PBF

LT1763IDE-2.5#PBF

LT1763MPDE-2.5#PBF

1763

76315

LT1763MPDE-1.5#TRPBF 76315

LT1763CDE-1.8#TRPBF

LT1763IDE-1.8#TRPBF

76318

LT1763MPDE-1.8#TRPBF 76318

LT1763CDE-2.5#TRPBF

LT1763IDE-2.5#TRPBF

76325

LT1763MPDE-2.5#TRPBF 76325

1763fg

2

LT1763 Series

ORDER INFORMATION

LEAD FREE FINISH

LT1763CDE-3#PBF

LT1763IDE-3#PBF

LT1763MPDE-3#PBF

LT1763CDE-3.3#PBF

LT1763IDE-3.3#PBF

LT1763MPDE-3.3#PBF

LT1763CDE-5#PBF

LT1763IDE-5#PBF

LT1763MPDE-5#PBF

LT1763CS8#PBF

LT1763IS8#PBF

TAPE AND REEL

PART MARKING*

17633

PACKAGE DESCRIPTION

TEMPERATURE RANGE

–40°C to 125°C

–55°C to 125°C

–40°C to 125°C

–55°C to 125°C

–40°C to 125°C

–55°C to 125°C

–40°C to 125°C

–55°C to 125°C

–40°C to 125°C

TEMPERATURE RANGE

–40°C to 125°C

–55°C to 125°C

–40°C to 125°C

–55°C to 125°C

–40°C to 125°C

–55°C to 125°C

–40°C to 125°C

–55°C to 125°C

–40°C to 125°C

LT1763CDE-3#TRPBF

LT1763IDE-3#TRPBF

LT1763MPDE-3#TRPBF

LT1763CDE-3.3#TRPBF

LT1763IDE-3.3#TRPBF

12-Lead (4mm × 3mm) Plastic DFN

8-Lead Plastic SO

17633

76333

LT1763MPDE-3.3#TRPBF 76333

LT1763CDE-5#TRPBF

LT1763IDE-5#TRPBF

LT1763MPDE-5#TRPBF

LT1763CS8#TRPBF

LT1763IS8#TRPBF

LT1763MPS8#TRPBF

LT1763CS8-1.5#TRPBF

LT1763IS8-1.5#TRPBF

LT1763CS8-1.8#TRPBF

LT1763IS8-1.8#TRPBF

LT1763CS8-2.5#TRPBF

LT1763IS8-2.5#TRPBF

LT1763CS8-3#TRPBF

LT1763IS8-3#TRPBF

LT1763CS8-3.3#TRPBF

LT1763IS8-3.3#TRPBF

LT1763CS8-5#TRPBF

LT1763IS8-5#TRPBF

TAPE AND REEL

17635

1763

8-Lead Plastic SO

LT1763MPS8#PBF

LT1763CS8-1.5#PBF

LT1763IS8-1.5#PBF

LT1763CS8-1.8#PBF

LT1763IS8-1.8#PBF

LT1763CS8-2.5#PBF

LT1763IS8-2.5#PBF

LT1763CS8-3#PBF

LT1763IS8-3#PBF

LT1763CS8-3.3#PBF

LT1763IS8-3.3#PBF

LT1763CS8-5#PBF

LT1763IS8-5#PBF

LEAD BASED FINISH

LT1763CDE

1763MP

176315

176318

176325

17633

176333

17635

PART MARKING*

1763

8-Lead Plastic SO

PACKAGE DESCRIPTION

LT1763CDE#TR

12-Lead (4mm × 3mm) Plastic DFN

LT1763IDE

LT1763IDE#TR

1763

LT1763MPDE

LT1763MPDE#TR

1763

LT1763CDE-1.5

LT1763CDE-1.5#TR

LT1763IDE-1.5#TR

LT1763MPDE-1.5#TR

LT1763CDE-1.8#TR

LT1763IDE-1.8#TR

LT1763MPDE-1.8#TR

LT1763CDE-2.5#TR

LT1763IDE-2.5#TR

LT1763MPDE-2.5#TR

LT1763CDE-3#TR

76315

76318

76325

17633

LT1763IDE-1.5

LT1763MPDE-1.5

LT1763CDE-1.8

LT1763IDE-1.8

LT1763MPDE-1.8

LT1763CDE-2.5

LT1763IDE-2.5

LT1763MPDE-2.5

LT1763CDE-3

LT1763IDE-3

LT1763IDE-3#TR

LT1763MPDE-3

LT1763MPDE-3#TR

–55°C to 125°C

1763fg

3

LT1763 Series

ORDER INFORMATION

LEAD FREE FINISH

LT1763CDE-3.3

LT1763IDE-3.3

LT1763MPDE-3.3

LT1763CDE-5

LT1763IDE-5

TAPE AND REEL

PART MARKING*

76333

PACKAGE DESCRIPTION

12-Lead (4mm × 3mm) Plastic DFN

8-Lead Plastic SO

TEMPERATURE RANGE

–40°C to 125°C

–55°C to 125°C

–40°C to 125°C

–55°C to 125°C

–40°C to 125°C

–55°C to 125°C

–40°C to 125°C

LT1763CDE-3.3#TR

LT1763IDE-3.3#TR

LT1763MPDE-3.3#TR

LT1763CDE-5#TR

LT1763IDE-5#TR

LT1763MPDE-5#TR

LT1763CS8#TR

76333

17635

LT1763MPDE-5

LT1763CS8

17635

1763

LT1763IS8

LT1763IS8#TR

1763

8-Lead Plastic SO

LT1763MPS8

LT1763CS8-1.5

LT1763IS8-1.5

LT1763CS8-1.8

LT1763IS8-1.8

LT1763CS8-2.5

LT1763IS8-2.5

LT1763CS8-3

LT1763IS8-3

LT1763MPS8#TR

LT1763CS8-1.5#TR

LT1763IS8-1.5#TR

LT1763CS8-1.8#TR

LT1763IS8-1.8#TR

LT1763CS8-2.5#TR

LT1763IS8-2.5#TR

LT1763CS8-3#TR

LT1763IS8-3#TR

LT1763CS8-3.3#TR

LT1763IS8-3.3#TR

LT1763CS8-5#TR

1763MP

176315

176318

176325

17633

8-Lead Plastic SO

17633

8-Lead Plastic SO

LT1763CS8-3.3

LT1763IS8-3.3

LT1763CS8-5

LT1763IS8-5

176333

17635

8-Lead Plastic SO

17635

8-Lead Plastic SO

LT1763IS8-5#TR

Consult LTC Marketing for parts speciﬁed with wider operating temperature ranges. *The temperature grade is identiﬁed by a label on the shipping container.

For more information on lead free part marking, go to: http://www.linear.com/leadfree/

For more information on tape and reel speciﬁcations, go to: http://www.linear.com/tapeandreel/

ELECTRICAL CHARACTERISTICS ^Thel denotes the speciﬁcations which apply over the full operating

temperature range, otherwise speciﬁcations are at T_A= 25°C. (Note 2)

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

l

Minimum Operating Voltage

C, I Grade: I

MP Grade: I

= 500mA (Notes 3, 11)

1.8

2.3

2.35

V

LOAD

Regulated Output Voltage

(Note 4)

LT1763-1.5

LT1763-1.8

LT1763-2.5

LT1763-3

V

= 2V, I

= 1mA

1.485

1.462

1.5

1.515

1.538

V

IN

LOAD

l

2.5V < V < 20V, 1mA < I

< 500mA

IN

LOAD

V

= 2.3V, I

= 1mA

LOAD

1.782

1.755

1.8

1.818

1.845

V

IN

2.8V < V < 20V, 1mA < I

IN

LOAD

V

= 3V, I

= 1mA

2.475

2.435

2.5

2.525

2.565

V

IN

LOAD

3.5V < V < 20V, 1mA < I

IN

LOAD

V

= 3.5V, I

IN

= 1mA

LOAD

2.970

2.925

3

3.030

3.075

V

IN

4V < V < 20V, 1mA < I

< 500mA

LOAD

LT1763-3.3

LT1763-5

V

= 3.8V, I

= 1mA

LOAD

3.267

3.220

3.3

3.333

3.380

V

IN

4.3V < V < 20V, 1mA < I

< 500mA

IN

LOAD

V

= 5.5V, I

IN

= 1mA

LOAD

4.950

4.875

5

5.050

5.125

V

IN

6V < V < 20V, 1mA < I

< 500mA

LOAD

1763fg

4

LT1763 Series

ELECTRICAL CHARACTERISTICS ^Thel denotes the speciﬁcations which apply over the full operating

temperature range, otherwise speciﬁcations are at T_A= 25°C. (Note 2)

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

ADJ Pin Voltage

(Notes 3, 4)

LT1763

V

= 2.2V, I

= 1mA

LOAD

1.208

1.190

1.220

1.232

1.250

V

IN

l

C, I Grade: 2.3V < V < 20V, 1mA < I

< 500mA

LOAD

IN

LOAD

MP Grade: 2.35V < V < 20V, 1mA < I

< 500mA

l

Line Regulation

LT1763-1.5

LT1763-1.8

LT1763-2.5

LT1763-3

C, I Grade: ΔV = 2V to 20V, I

= 1mA

LOAD

1

5

mV

IN

LOAD

MP Grade: ΔV = 2.1V to 20V, I

= 1mA

IN

ΔV = 2.3V to 20V, I

= 1mA

IN

LOAD

ΔV = 3V to 20V, I

= 1mA

IN

LOAD

ΔV = 3.5V to 20V, I

= 1mA

IN

LOAD

LT1763-3.3

LT1763-5

ΔV = 3.8V to 20V, I

ΔV = 5.5V to 20V, I

LT1763 (Note 3) C, I Grade: ΔV = 2V to 20V, I

LT1763 (Note 3) MP Grade: ΔV = 2.1V to 20V, I

= 1mA

IN

LOAD

= 1mA

IN

LOAD

Load Regulation

LT1763-1.5

LT1763-1.8

LT1763-2.5

LT1763-3

V

= 2.5V, ΔI

= 1mA to 500mA

3

8

mV

IN

LOAD

l

= 1mA to 500mA

15

V

= 2.8V, ΔI

= 1mA to 500mA

4

9

18

mV

IN

LOAD

V

= 3.5V, ΔI

= 1mA to 500mA

5

12

25

mV

IN

LOAD

V

= 4V, ΔI

= 1mA to 500mA

7

15

30

mV

IN

LOAD

LT1763-3.3

LT1763-5

V

= 4.3V, ΔI

= 1mA to 500mA

7

17

33

mV

IN

LOAD

V

= 6V, ΔI

= 1mA to 500mA

12

2

25

50

mV

IN

LOAD

LT1763 (Note 3)

V

= 2.3V, ΔI

= 1mA to 500mA

6

12

mV

IN

LOAD

l

C, I Grade: V = 2.3V, ΔI

= 1mA to 500mA

LOAD

IN

LOAD

MP Grade: V = 2.35V, ΔI

= 1mA to 500mA

Dropout Voltage

I

= 10mA

0.13

0.17

0.20

0.30

0.19

0.25

V

LOAD

l

V

= V

OUT(NOMINAL)

IN

(Notes 5, 6, 11)

I

= 50mA

0.22

0.32

V

LOAD

I

= 100mA

0.24

0.34

V

LOAD

I

= 500mA

0.35

0.45

V

LOAD

l

GND Pin Current

I

= 0mA

30

65

1.1

2

75

120

1.6

3

μA

mA

LOAD

V

= V

= 1mA

IN

OUT(NOMINAL)

(Notes 5, 7)

= 50mA

= 100mA

= 250mA

= 500mA

5

8

11

16

Output Voltage Noise

ADJ Pin Bias Current

Shutdown Threshold

C

= 10μF, C

= 0.01μF, I

= 500mA, BW = 10Hz to 100kHz

20

30

μV

RMS

OUT

BYP

LOAD

(Notes 3, 8)

100

2

nA

l

V

OUT

V

OUT

= Off to On

= On to Off

0.8

0.65

V

0.25

50

SHDN Pin Current

(Note 9)

V

SHDN

V

SHDN

= 0V

= 20V

0.1

1

μA

Quiescent Current in Shutdown

Ripple Rejection

V

IN

= 6V, V

= 0V

0.1

65

1

μA

dB

SHDN

V

LOAD

– V

= 1.5V (Avg), V

= 0.5V , f

= 120Hz,

IN

OUT

RIPPLE

P-P RIPPLE

I

= 500mA

1763fg

5

LT1763 Series

ELECTRICAL CHARACTERISTICS ^Thel denotes the speciﬁcations which apply over the full operating

temperature range, otherwise speciﬁcations are at T_A= 25°C. (Note 2)

PARAMETER

CONDITIONS

= 7V, V = 0V

OUT

MIN

TYP

MAX

UNITS

Current Limit

V

IN

l

C, I Grade: V = V

+ 1V or 2.3V (Note 12), ΔV = –0.1V

OUT

520

mA

IN

OUT(NOMINAL)

MP Grade: V = 2.35V (Note 12), ΔV

= –0.1V

IN

OUT

l

Input Reverse Leakage Current

V

IN

= –20V, V

= 0V

1

mA

OUT

Reverse Output Current

(Note 10)

LT1763-1.5

LT1763-1.8

LT1763-2.5

LT1763-3

V

= 1.5V, V < 1.5V

10

5

20

10

μA

OUT

IN

= 1.8V, V < 1.8V

IN

= 2.5V, V < 2.5V

IN

= 3V, V < 3V

IN

LT1763-3.3

LT1763-5

= 3.3V, V < 3.3V

IN

= 5V, V < 5V

IN

LT1763 (Note 3)

= 1.22V, V < 1.22V

IN

Note 1: Stresses beyond those listed under Absolute Maximum Ratings

may cause permanent damage to the device. Exposure to any Absolute

Maximum Rating condition for extended periods may affect device

reliability and lifetime.

Note 6: Dropout voltage is the minimum input to output voltage differential

needed to maintain regulation at a speciﬁed output current. In dropout, the

output voltage will be equal to: V – V

.

IN

DROPOUT

Note 7: GND pin current is tested with V = V

or V = 2.3V

IN

OUT(NOMINAL)

Note 2: The LT1763 regulators are tested and speciﬁed under pulse

(C, I grade) or 2.35V (MP grade), whichever is greater, and a current

source load. This means the device is tested while operating in its dropout

region. This is the worst-case GND pin current. The GND pin current will

decrease slightly at higher input voltages.

Note 8: ADJ pin bias current ﬂows into the ADJ pin.

Note 9: SHDN pin current ﬂows into the SHDN pin.

Note 10: Reverse output current is tested with the IN pin grounded and the

OUT pin forced to the rated output voltage. This current ﬂows into the OUT

pin and out the GND pin.

load conditions such that T ≅ T . The LT1763 (C grade) is 100% tested

J

A

at T = 25°C; performance at –40°C and 125°C is assured by design,

A

characterization and correlation with statistical process controls. The

LT1763 (I grade) is guaranteed over the full –40°C to 125°C operating

junction temperature range. The LT1763 (MP grade) is 100% tested and

guaranteed over the –55°C to 125°C operating junction temperature range.

Note 3: The LT1763 (adjustable version) is tested and speciﬁed for these

conditions with the ADJ pin connected to the OUT pin.

Note 4: Operating conditions are limited by maximum junction

temperature. The regulated output voltage speciﬁcation will not apply

for all possible combinations of input voltage and output current. When

operating at maximum input voltage, the output current range must be

limited. When operating at maximum output current, the input voltage

range must be limited.

Note 5: To satisfy requirements for minimum input voltage, the LT1763

(adjustable version) is tested and speciﬁed for these conditions with an

external resistor divider (two 250k resistors) for an output voltage of

2.44V. The external resistor divider will add a 5μA DC load on the output.

Note 11: For the LT1763, LT1763-1.5 and LT1763-1.8 dropout voltage will

be limited by the minimum input voltage speciﬁcation under some output

voltage/load conditions. See the curve of Minimum Input Voltage in the

Typical Performance Characteristics.

Note 12: To satisfy requirements for minimum input voltage, current limit

is tested at V = V

+ 1V or 2.3V (C, I grade) or 2.35V

IN

OUT(NOMINAL)

(MP grade), whichever is greater.

1763fg

6

LT1763 Series

TYPICAL PERFORMANCE CHARACTERISTICS

Typical Dropout Voltage

Guaranteed Dropout Voltage

Dropout Voltage

500

450

400

350

300

250

200

150

100

50

500

450

400

350

300

250

200

150

100

50

500

450

400

350

300

250

200

150

100

50

= TEST POINTS

I

= 500mA

L

I

L

= 250mA

T

= 125°C

J

T

b 125°C

b 25°C

J

I = 100mA

L

T

J

T

= 25°C

J

I

= 1mA

L

I

L

= 10mA

I

L

= 50mA

0

–50

0

25

50

75 100 125

200

250 300 350 400 450 500

–25

0

50 100 150

250 300 350 400 450 500

0

50 100 150

TEMPERATURE (°C)

OUTPUT CURRENT (mA)

1763 G03

1763 G01

1763 G02

LT1763-1.5

Output Voltage

LT1763-1.8

Output Voltage

Quiescent Current

1.528

1.521

1.514

1.507

1.500

1.493

1.486

1.479

1.472

1.84

1.83

1.82

1.81

1.80

1.79

1.78

1.77

1.76

50

45

40

35

30

25

20

15

10

5

I

= 1mA

I = 1mA

L

V

= V

IN

SHDN

V

R

= 6V

IN

L

= d, I = 0 (LT1763-1.5/-1.8/-2.5/-3/-3.3/-5)

L

= 250k, I = 5μA (LT1763)

L

0

–25

0

25

50

75

125

–50 –25

0

25

50

75 100 125

–50 –25

0

25

50

75 100 125

–50

100

TEMPERATURE (°C)

1763 G04

1763 G05

1763 G06

LT1763-2.5

Output Voltage

LT1763-3

Output Voltage

LT1763-3.3

Output Voltage

2.54

2.53

2.52

2.51

2.50

2.49

2.48

2.47

2.46

3.060

3.045

3.030

3.015

3.000

2.985

2.970

2.955

2.940

3.360

3.345

3.330

3.315

3.300

3.285

3.270

3.255

3.240

I

= 1mA

I

= 1mA

I = 1mA

L

–25

0

25

50

75

125

–25

0

25

50

75

125

–50 –25

0

25

50

75 100 125

–50

100

–50

100

TEMPERATURE (°C)

1763 G07

1763 G08

1763 G09

1763fg

7

LT1763 Series

TYPICAL PERFORMANCE CHARACTERISTICS

LT1763-5

Output Voltage

LT1763

ADJ Pin Voltage

LT1763-1.5

Quiescent Current

5.100

5.075

5.050

5.025

5.000

4.975

4.950

4.925

4.900

1.240

1.235

1.230

1.225

1.220

1.215

1.210

1.205

1.200

250

225

200

175

150

125

100

75

I

= 1mA

L

I = 1mA

L

T

R

= 25°C

J

L

= d

50

V

= V

IN

SHDN

25

V

= 0V

6

SHDN

0

–25

0

25

50

75

125

–25

0

25

50

75

125

–50

100

–50

100

0

1

2

3

4

5

7

8

9

10

TEMPERATURE (°C)

INPUT VOLTAGE (V)

1763 G10

1763 G11

1763 G12

LT1763-1.8

Quiescent Current

LT1763-2.5

Quiescent Current

LT1763-3

Quiescent Current

250

225

200

175

150

125

100

75

250

225

200

175

150

125

100

75

250

225

200

175

150

125

100

75

T

= 25°C

= d

T

= 25°C

= d

T = 25°C

J

R = d

L

J

L

J

L

R

50

V

= V

V

= V

V

= V

SHDN IN

SHDN

IN

SHDN

IN

25

V

= 0V

6

V

= 0V

8

V

SHDN

= 0V

8

SHDN

0

1

2

3

4

5

7

8

9

10

0

1

2

3

4

5

6

7

9

10

0

1

2

3

4

5

6

7

9

10

INPUT VOLTAGE (V)

1763 G13

1763 G14

1763 G15

LT1763-3.3

Quiescent Current

LT1763-5

Quiescent Current

LT1763

Quiescent Current

250

225

200

175

150

125

100

75

250

225

200

175

150

125

100

75

40

35

30

25

20

15

10

5

T

= 25°C

T

= 25°C

T

= 25°C

R = 250k

L

J

L

J

L

J

R

= d

R

= d

V

= V

IN

SHDN

50

V

= V

V

= V

SHDN IN

SHDN

IN

25

V

= 0V

8

V

= 0V

8

V

= 0V

SHDN

0

1

2

3

4

5

6

7

9

10

0

1

2

3

4

5

6

7

9

10

0

2

4

6

8

10 12 14 16 18 20

INPUT VOLTAGE (V)

1763 G16

1763 G17

1763 G18

1763fg

8

LT1763 Series

TYPICAL PERFORMANCE CHARACTERISTICS

LT1763-1.5

GND Pin Current

LT1763-1.8

GND Pin Current

LT1763-2.5

GND Pin Current

1200

1000

800

600

400

200

0

1200

1000

800

600

400

200

0

1200

1000

800

600

400

200

0

R

= 50Ω

L

R

L

= 36Ω

R

L

= 30Ω

L

I

= 50mA*

L

I

= 50mA*

I

= 50mA*

T

= 25°C

T

= 25°C

T = 25°C

J

V

J

= V

V

= V

V = V

IN SHDN

IN

SHDN

IN

SHDN

*FOR V

= 1.5V

*FOR V

= 1.8V

*FOR V

= 2.5V

OUT

R

I

= 250Ω

R

I

= 150Ω

= 10mA*

L

R

L

= 180Ω

L

= 10mA*

I

= 10mA*

L

R

= 1.5k

= 1mA*

R

L

= 2.5k

R

I

= 1.8k

L

I

L

I

= 1mA*

L

4

0

1

2

3

5

6

7

8

9

10

0

1

2

3

5

6

7

8

9

10

0

1

2

3

5

6

7

8

9

10

INPUT VOLTAGE (V)

1763 G19

1763 G20

1763 G21

LT1763-3

GND Pin Current

LT1763-3.3

GND Pin Current

LT1763-5

GND Pin Current

1200

1000

800

600

400

200

0

1200

1000

800

600

400

200

0

1200

1000

800

600

400

200

0

R

L

= 60Ω

R

L

= 66Ω

L

R

I

= 100Ω

= 50mA*

L

I

= 50mA*

I

= 50mA*

T

= 25°C

T

V

= 25°C

T = 25°C

J

V

= V

SHDN

V = V

IN SHDN

IN

SHDN

IN

*FOR V

= 3V

*FOR V

= 3.3V

*FOR V

= 5V

OUT

R

= 500Ω

= 10mA*

R

I

= 300Ω

= 10mA*

R

I

= 330Ω

L

I

= 10mA*

L

R

= 3k

R

L

= 5k

L

= 1mA*

R

I

= 3.3k

L

= 1mA*

L

I

= 1mA*

I

L

4

0

1

2

3

5

6

7

8

9

10

0

1

2

3

5

6

7

8

9

0

1

2

3

5

6

7

8

9

10

INPUT VOLTAGE (V)

1763 G22

1763 G23

1763 G24

LT1763

GND Pin Current

LT1763-1.5

GND Pin Current

LT1763-1.8

GND Pin Current

1200

1000

800

600

400

200

0

12

10

8

12

10

8

T

= 25°C

T = 25°C

J

IN

V

= V

SHDN

V = V

IN SHDN

R

L

= 24.4Ω

L

*FOR V

= 1.5V

*FOR V

= 1.8V

OUT

I

= 50mA*

R

= 3Ω

L

R

= 3.6Ω

L

I

= 500mA*

L

I

= 500mA*

L

T

= 25°C

= V

J

IN

V

R

= 6Ω

R

L

= 5Ω

= 300mA*

SHDN

L

6

*FOR V

= 1.22V

I

= 300mA*

I

OUT

L

R

L

= 122Ω

L

4

I

= 10mA*

R

L

= 15Ω

R

= 18Ω

L

I

= 100mA*

I

= 100mA*

L

R

I

= 1.22k

= 1mA*

2

L

0

4

0

1

2

3

5

6

7

8

9

10

0

1

2

3

5

6

7

8

9

0

1

2

3

5

6

7

8

9

10

INPUT VOLTAGE (V)

1763 G25

1763 G26

1763 G27

1763fg

9

LT1763 Series

TYPICAL PERFORMANCE CHARACTERISTICS

LT1763-2.5

GND Pin Current

LT1763-3

GND Pin Current

LT1763-3.3

GND Pin Current

12

10

8

12

10

8

12

10

8

T

= 25°C

T

= 25°C

T = 25°C

J

V

= V

V

= V

V = V

IN SHDN

IN

SHDN

IN

SHDN

*FOR V

= 2.5V

*FOR V

= 3V

*FOR V

= 3.3V

OUT

R

= 5Ω

L

R

= 6Ω

R = 6.6Ω

L

I

L

= 500mA*

I

L

= 500mA*

I = 500mA*

L

6

R

L

= 10Ω

6

R

L

= 11Ω

L

R

L

= 8.33Ω

L

I

= 300mA*

I

= 300mA*

I

= 300mA*

4

R

L

= 25Ω

R

L

= 30Ω

R = 33Ω

L

I

= 100mA*

I

= 100mA*

I

= 100mA*

2

0

4

0

1

2

3

5

6

7

8

9

10

0

1

2

3

5

6

7

8

9

10

0

1

2

3

5

6

7

8

9

10

INPUT VOLTAGE (V)

1763 G28

1763 G29

1763 G30

LT1763-5

GND Pin Current

LT1763

GND Pin Current

GND Pin Current vs I_LOAD

12

10

8

12

10

8

12

10

8

T

= 25°C

= V

T

= 25°C

= V

J

IN

V

IN

= V

+ 1V

J

IN

OUT(NOMINAL)

V

SHDN

R = 10Ω

L

*FOR V

= 1.22V

*FOR V

= 5V

OUT

I

= 500mA*

R

= 2.44Ω

L

I

= 500mA*

L

R

L

= 16.7Ω

L

= 300mA*

R

L

= 4.07Ω

6

I

= 300mA*

4

R

L

= 12.2Ω

R = 50Ω

L

= 100mA*

L

I

= 100mA*

I

2

0

4

200

250 300 350 400 450 500

0

1

2

3

5

6

7

8

9

10

0

1

2

3

5

6

7

8

9

10

0

50 100 150

INPUT VOLTAGE (V)

OUTPUT CURRENT (mA)

1763 G31

1763 G32

1763 G33

SHDN Pin Threshold

(On-to-Off)

SHDN Pin Threshold

(Off-to-On)

SHDN Pin Input Current

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

I

= 1mA

L

I

= 500mA

L

I

= 1mA

L

–50

0

25

50

75 100 125

–50

0

25

50

75 100 125

4

–25

0

1

2

3

6

7

8

9

10

5

TEMPERATURE (°C)

SHDN PIN VOLTAGE (V)

1763 G34

1763 G35

1763 G36

1763fg

10

LT1763 Series

TYPICAL PERFORMANCE CHARACTERISTICS

SHDN Pin Input Current

ADJ Pin Bias Current

Current Limit

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

140

120

100

80

V

= 20V

V

= 0V

SHDN

OUT

60

40

20

0

–25

0

25

50

75

125

–50

0

25

50

75

125

–50

100

4

7

–25

0

2

3

5

6

1

TEMPERATURE (°C)

INPUT VOLTAGE (V)

TEMPERATURE (°C)

1763 G37

1763 G38

1763 G39

Current Limit

Reverse Output Current

20

18

16

14

12

10

8

1.2

1.0

0.8

0.6

0.4

0.2

0

100

90

80

70

60

50

40

30

20

10

0

V

= 0V, V

= 1.22V (LT1763)

OUT

IN

V

= 7

OUT

T

= 25°C, V = 0V

IN

J

LT1763-1.5

= 1.5V (LT1763-1.5)

= 1.8V (LT1763-1.8)

= 2.5V (LT1763-2.5)

= 3V (LT1763-3)

= 0V

OUT

CURRENT FLOWS

INTO OUTPUT PIN

V

= V

(LT1763)

OUT

ADJ

= 3.3V (LT1763-3.3)

= 5V (LT1763-5)

LT1763

LT1763-1.8

LT1763-2.5

LT1763-3

LT1763-1.5/-1.8/

-2.5/-3/-3.3/-5

LT1763-3.3

6

4

LT1763

LT1763-5

2

0

–50

0

25

50

75 100 125

4

–50

0

25

50

75

125

–25

0

1

2

3

6

7

8

9

10

–25

100

5

TEMPERATURE (°C)

OUTPUT VOLTAGE (V)

1763 G40

1763 G42

1763 G41

Input Ripple Rejection

Ripple Rejection

68

66

64

62

60

58

56

54

52

80

70

60

50

40

30

20

10

0

80

70

60

50

40

30

20

10

0

C

= 0.01μF

BYP

C

= 10μF

OUT

C

= 1000pF

BYP

C

= 100pF

BYP

I

= 500mA

= V

V

= V

+

OUT (NOMINAL)

L

IN

I

= 500mA

IN

L

V

+

1V + 0.5V RIPPLE

P-P

OUT(NOMINAL)

V

= V

+

C

= 4.7μF

IN

OUT(NOMINAL)

OUT

1V + 50mV

C

RIPPLE

AT f = 120Hz

RMS

1V + 50mV

C

RIPPLE

1k

RMS

= 0

I

= 500mA

BYP

= 10μF

L

OUT

–25

0

25

50

75

125

–50

100

10

100

1k

10k

100k

1M

10

100

10k

100k

1M

FREQUENCY (Hz)

TEMPERATURE (°C)

1763 G43

1763 G44

1763 G45

1763fg

11

LT1763 Series

TYPICAL PERFORMANCE CHARACTERISTICS

LT1763

Output Noise Spectral Density

C_BYP= 0

Minimum Input Voltage

Load Regulation

5

0

2.50

2.25

2.00

1.75

1.50

1.25

1.00

0.75

0.50

0.25

0

10

1

LT1763-1.5

LT1763-2.5

LT1763

LT1763-3

LT1763-1.8

I

= 500mA

L

LT1763-3.3

LT1763-5

–5

I

= 1mA

L

LT1763-3

–10

–15

–20

–25

LT1763

LT1763-3.3

LT1763-5

LT1763-2.5

LT1763-1.8

LT1763-1.5

0.1

V

= V

+ 1V

IN

L

OUT(NOMINAL)

C

= 10μF

OUT

$I = 1mA TO 500mA

V

= 1.22V

OUT

I = 500mA

L

0.01

–50

0

25

50

75 100 125

–25

0

25

50

75

125

–50

100

10

100

1k

FREQUENCY (Hz)

10k

100k

TEMPERATURE (°C)

1763 G48

1763 G46

1763 G47

RMS Output Noise

vs Load Current (10Hz to 100kHz)

RMS Output Noise

vs Bypass Capacitor

Output Noise Spectral Density

10

1

160

140

120

100

80

160

C

I

= 10μF

C = 10μF

OUT

L

C

I

= 10μF

OUT

= 500mA

C

BYP

= 0

= 0.01μF

BYP

= 500mA

140

L

C

f = 10Hz TO 100kHz

C

= 1000pF

BYP

LT1763-5

120 LT1763-5

LT1763-5

LT1763-3.3

C

BYP

= 100pF

100

80

LT1763-3

LT1763

LT1763-2.5

60

LT1763

0.1

C

BYP

= 0.01μF

100

40

LT1763

LT1763-5

LT1763

LT1763-1.8

20

0

LT1763-1.5

0.01

0

0.01

10

1k

FREQUENCY (Hz)

10k

100k

0.1

1

10

100

1000

10

100

1000

(pF)

10000

LOAD CURRENT (mA)

C

BYP

1763 G49

1763 G51

1763 G50

LT1763-5

10Hz to 100kHz Output Noise

C_BYP= 100pF

LT1763-5

10Hz to 100kHz Output Noise

C_BYP= 0

10Hz to 100kHz Output Noise

C_BYP= 1000pF

V

OUT

V

OUT

100μV/DIV

1763 G53

1763 G54

1763 G52

1ms/DIV

C

I

= 10μF

C

= 10μF

OUT

C

I

= 10μF

OUT

L

OUT

L

= 500mA

I

= 500mA

L

= 500mA

1763fg

12

LT1763 Series

TYPICAL PERFORMANCE CHARACTERISTICS

LT1763-5

Transient Response

C_BYP= 0.01μF

LT1763-5

Transient Response

C_BYP= 0

10Hz to 100kHz Output Noise

C_BYP= 0.01μF

V

C

= 6V

V

C

= 6V

IN

0.4

0.2

0.10

0.05

0

= 10μF

OUT

0

V

–0.2

–0.4

–0.05

–0.10

OUT

100μV/DIV

600

400

200

0

600

400

200

0

1763 G55

1ms/DIV

C

L

= 10μF

OUT

I

= 500mA

400

TIME (μs)

0

200

600

800

1000

40

10 20 30

0

50 60 70 80 90 100

TIME (μs)

1763 G56

1763 G57

1763fg

13

LT1763 Series

PIN FUNCTIONS ^(DE12/S8)

NC (Pins 1, 4, 9, 12) DE12 Only: No Connect. No connect

BYP (Pin 6/Pin 4): Bypass. The BYP pin is used to bypass

thereferenceoftheLT1763regulatorstoachievelownoise

performance from the regulator. The BYP pin is clamped

pins have no connection to any internal circuitry. These

pins may be tied to either GND or V , or left ﬂoating.

IN

internally to 0.6V (one V ). A small capacitor from the

BE

OUT (Pins 2, 3/Pin 1): Output. The output supplies power

to the load. A minimum output capacitor of 3.3μF is re-

quired to prevent oscillations. Larger output capacitors

will be required for applications with large transient loads

tolimitpeakvoltagetransients. SeetheApplicationsInfor-

mationsectionformoreinformationonoutputcapacitance

and reverse output characteristics.

output to this pin will bypass the reference to lower the

output voltage noise. A maximum value of 0.01μF can

be used for reducing output voltage noise to a typical

20μV

over a 10Hz to 100kHz bandwidth. If not used,

RMS

this pin must be left unconnected.

GND (Pins 7, Exposed Pad Pin 13/Pins 3, 6, 7): Ground.

The exposed pad of the DFN package is an electrical con-

nection to GND. To ensure proper electrical and thermal

performance, solder Pin 13 to the PCB ground and tie

directly to Pin 7. Connect the bottom of the output volt-

age setting resistor divider directly to the GND pins for

optimum load regulation performance.

ADJ (Pin 5/Pin 2): Adjust. For the adjustable LT1763, this

is the input to the error ampliﬁer. This pin is internally

clamped to 7V. It has a bias current of 30nA which ﬂows

into the pin (see the curve of ADJ Pin Bias Current vs

Temperature in the Typical Performance Characteristics

section).TheADJpinvoltageis1.22Vreferencedtoground

and the output voltage range is 1.22V to 20V.

SHDN (Pin 8/Pin 5): Shutdown. The SHDN pin is used

to put the LT1763 regulators into a low power shutdown

state. The output will be off when the SHDN pin is pulled

low. The SHDN pin can be driven either by 5V logic or

open-collector logic with a pull-up resistor. The pull-up

resistor is required to supply the pull-up current of the

open-collector gate, normally several microamperes, and

the SHDN pin current, typically 1μA. If unused, the SHDN

SENSE (Pin 5/Pin 2): Output Sense. For ﬁxed volt-

age versions of the LT1763 (LT1763-1.5/LT1763-1.8/

LT1763-2.5/LT1763-3/LT1763-3.3/LT1763-5), the SENSE

pin is the input to the error ampliﬁer. Optimum regula-

tion will be obtained at the point where the SENSE pin

is connected to the OUT pin of the regulator. In critical

applications, small voltage drops are caused by the re-

pin must be connected to V . The device will be in the low

IN

sistance (R ) of PC traces between the regulator and the

P

power shutdown state if the SHDN pin is not connected.

load. These may be eliminated by connecting the SENSE

pin to the output at the load as shown in Figure 1 (Kelvin

Sense Connection).

IN(Pin10,11/Pin8):Input.Powerissuppliedtothedevice

through the IN pin. A bypass capacitor is required on this

pin if the device is more than six inches away from the

main input ﬁlter capacitor. In general, the output imped-

ance of a battery rises with frequency, so it is advisable to

include a bypass capacitor in battery-powered circuits. A

bypass capacitor in the range of 1μF to 10μF is sufﬁcient.

The LT1763 regulators are designed to withstand reverse

voltages on the IN pin with respect to ground and the OUT

pin. In the case of a reverse input, which can happen if

a battery is plugged in backwards, the device will act as

if there is a diode in series with its input. There will be

no reverse current ﬂow into the regulator and no reverse

voltage will appear at the load. The device will protect both

itself and the load.

R

P

8

1

IN

OUT

LT1763

+

5

2

+

SHDN SENSE

LOAD

V

IN

GND

3

R

P

1763 F01

Figure 1. Kelvin Sense Connection

Note that the voltage drop across the external PC traces will

add to the dropout voltage of the regulator. The SENSE pin

biascurrentis10μAatthenominalratedoutputvoltage.The

SENSE pin can be pulled below ground (as in a dual supply

system where the regulator load is returned to a negative

supply) and still allow the device to start and operate.

1763fg

14

LT1763 Series

APPLICATIONS INFORMATION

The LT1763 series are 500mA low dropout regulators with

micropowerquiescentcurrentandshutdown.Thedevices

are capable of supplying 500mA at a dropout voltage of

to 1.22V: V /1.22V. For example, load regulation for an

OUT

output current change of 1mA to 500mA is –2mV typical

at V

= 1.22V. At V

= 12V, load regulation is:

OUT

300mV. Output voltage noise can be lowered to 20μV

RMS

(12V/1.22V)(–2mV) = –19.6mV

over a 10Hz to 100kHz bandwidth with the addition of

a 0.01μF reference bypass capacitor. Additionally, the

referencebypasscapacitorwillimprovetransientresponse

oftheregulator,loweringthesettlingtimefortransientload

conditions. The low operating quiescent current (30μA)

drops to less than 1μA in shutdown. In addition to the

low quiescent current, the LT1763 regulators incorporate

several protection features which make them ideal for use

in battery-powered systems. The devices are protected

against both reverse input and reverse output voltages.

In battery backup applications where the output can be

held up by a backup battery when the input is pulled to

ground, the LT1763-X acts like it has a diode in series with

its output and prevents reverse current ﬂow. Additionally,

in dual supply applications where the regulator load is

returned to a negative supply, the output can be pulled

below ground by as much as 20V and still allow the device

to start and operate.

IN

OUT

ADJ

V

OUT

+

V

IN

R2

LT1763

GND

R2

⎞

⎟

⎠

R1

⎛

⎝

V_OUT= 1.22V 1+

+ I R2

_ADJ)( )

(

⎜

V

_ADJ= 1.22V

_ADJ= 30nA AT 25°C

OUTPUT RANGE = 1.22V TO 20V

R1

I

1763 F02

Figure 2. Adjustable Operation

Bypass Capacitance and Low Noise Performance

The LT1763 regulators may be used with the addition of

a bypass capacitor from V

to the BYP pin to lower

OUT

output voltage noise. A good quality low leakage capacitor

is recommended. This capacitor will bypass the reference

of the regulator, providing a low frequency noise pole.

The noise pole provided by this bypass capacitor will

Adjustable Operation

lower the output voltage noise to as low as 20μV

TheadjustableversionoftheLT1763hasanoutputvoltage

range of 1.22V to 20V. The output voltage is set by the

ratio of two external resistors, as shown in Figure 2. The

device servos the output to maintain the ADJ pin voltage

at 1.22V referenced to ground. The current in R1 is then

equal to 1.22V/R1 and the current in R2 is the current

in R1 plus the ADJ pin bias current. The ADJ pin bias

current, 30nA at 25°C, ﬂows through R2 into the ADJ pin.

The output voltage can be calculated using the formula in

Figure 2. The value of R1 should be no greater than 250k

to minimize errors in the output voltage caused by the

ADJ pin bias current. Note that in shutdown the output

is turned off and the divider current will be zero. Curves

of ADJ Pin Voltage vs Temperature and ADJ Pin Bias

CurrentvsTemperatureappearintheTypicalPerformance

Characteristics section.

RMS

with the addition of a 0.01μF bypass capacitor. Using

a bypass capacitor has the added beneﬁt of improving

transient response. With no bypass capacitor and a 10μF

output capacitor, a 10mA to 500mA load step will settle

to within 1% of its ﬁnal value in less than 100μs. With

the addition of a 0.01μF bypass capacitor, the output will

settle to within 1% for a 10mA to 500mA load step in less

than 10μs, with total output voltage deviation of less than

2.5% (see the LT1763-5 Transient Response curve in the

Typical Performance Characteristics section). However,

regulator start-up time is proportional to the size of the

bypass capacitor, slowing to 15ms with a 0.01μF bypass

capacitor and 10μF output capacitor.

The adjustable device is tested and speciﬁed with the ADJ

pin tied to the OUT pin for an output voltage of 1.22V.

Speciﬁcations for output voltages greater than 1.22V will

be proportional to the ratio of the desired output voltage

1763fg

15

LT1763 Series

APPLICATIONS INFORMATION

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

Output Capacitance and Transient Response

The LT1763 regulators are designed to be stable with a

wide range of output capacitors. The ESR of the output

capacitor affects stability, most notably with small capaci-

tors. A minimum output capacitor of 3.3μF with an ESR

of 3Ω, or less, is recommended to prevent oscillations.

The LT1763-X is a micropower device and output transient

response will be a function of output capacitance. Larger

values of output capacitance decrease the peak deviations

and provide improved transient response for larger load

current changes. Bypass capacitors, used to decouple

individual components powered by the LT1763-X, will

increase the effective output capacitor value. With larger

capacitors used to bypass the reference (for low noise

operation), larger values of output capacitors are needed.

For 100pF of bypass capacitance, 4.7μF of output capaci-

tor is recommended. With a 1000pF bypass capacitor or

larger, a 6.8μF output capacitor is recommended.

STABLE REGION

C

= 0

BYP

C

= 100pF

BYP

C

= 330pF

BYP

C

r 1000pF

BYP

1

3

6 9 10

7 8

2

4

5

OUTPUT CAPACITANCE (μF)

1763 F03

Figure 3. Stability

20

0

BOTH CAPACITORS ARE 16V,

1210 CASE SIZE, 10μF

X5R

Y5V

–20

–40

–60

–80

–100

The shaded region of Figure 3 deﬁnes the range over

whichtheLT1763regulatorsarestable. TheminimumESR

needed is deﬁned by the amount of bypass capacitance

used, while the maximum ESR is 3Ω.

Extra consideration must be given to the use of ceramic

capacitors. Ceramic capacitors are manufactured with a

variety of dielectrics, each with different behavior across

temperature and applied voltage. The most common

dielectrics used are speciﬁed with EIA temperature

characteristic codes of Z5U, Y5V, X5R and X7R. The Z5U

andY5Vdielectricsaregoodforprovidinghighcapacitances

in a small package, but they tend to have strong voltage

and temperature coefﬁcients, as shown in Figures 4

and 5. When used with a 5V regulator, a 16V 10μF Y5V

capacitor can exhibit an effective value as low as 1μF to

2μF for the DC bias voltage applied and over the operating

temperature range. The X5R and X7R dielectrics result in

more stable characteristics and are more suitable for use

as the output capacitor. The X7R type has better stability

across temperature, while the X5R is less expensive and is

availableinhighervalues.Carestillmustbeexercisedwhen

using X5R and X7R capacitors; the X5R and X7R codes

only specify operating temperature range and maximum

capacitancechangeovertemperature.Capacitancechange

due to DC bias with X5R and X7R capacitors is better than

0

8

12 14

2

4

6

10

16

DC BIAS VOLTAGE (V)

1763 F04

Figure 4. Ceramic Capacitor DC Bias Characteristics

40

20

X5R

0

–20

–40

Y5V

–60

–80

BOTH CAPACITORS ARE 16V,

1210 CASE SIZE, 10μF

–100

50

TEMPERATURE (°C)

100 125

–50 –25

0

25

75

1763 F05

Figure 5. Ceramic Capacitor Temperature Characteristics

1763fg

16

LT1763 Series

APPLICATIONS INFORMATION

Y5VandZ5Ucapacitors,butcanstillbesigniﬁcantenough

todropcapacitorvaluesbelowappropriatelevels.Capacitor

DC bias characteristics tend to improve as component

casesizeincreases, butexpectedcapacitanceatoperating

voltage should be veriﬁed.

Thermal Considerations

The power handling capability of the device will be limited

by the maximum rated junction temperature (125°C). The

power dissipated by the device will be made up of two

components:

Voltage and temperature coefﬁcients are not the only

sources of problems. Some ceramic capacitors have a

piezoelectric response. A piezoelectric device generates

voltage across its terminals due to mechanical stress,

similar to the way a piezoelectric accelerometer or

microphone works. For a ceramic capacitor, the stress

can be induced by vibrations in the system or thermal

transients. The resulting voltages produced can cause

appreciable amounts of noise, especially when a ceramic

capacitor isusedfor noisebypassing. A ceramic capacitor

producedFigure6’straceinresponsetolighttappingfroma

pencil.Similarvibrationinducedbehaviorcanmasquerade

as increased output voltage noise.

1. Output current multiplied by the input/output voltage

differential: (I )(V – V ), and

OUT

IN

OUT

2. GND pin current multiplied by the input voltage:

(I )(V ).

GND

IN

The GND pin current can be found by examining the GND

Pin Current curves in the Typical Performance Character-

istics section. Power dissipation will be equal to the sum

of the two components listed above.

TheLT1763seriesregulatorshaveinternalthermallimiting

designedtoprotectthedeviceduringoverloadconditions.

For continuous normal conditions, the maximum junction

temperature rating of 125°C must not be exceeded. It is

important to give careful consideration to all sources of

thermal resistance from junction-to-ambient. Additional

heat sources mounted nearby must also be considered.

LT1763-5

C

LOAD

= 10μF

= 0.01μF

= 100mA

OUT

BYP

I

V

For surface mount devices, heat sinking is accomplished

by using the heat spreading capabilities of the PC board

and its copper traces. Copper board stiffeners and plated

through-holes can also be used to spread the heat gener-

ated by power devices.

OUT

500μV/DIV

1763 F06

100ms/DIV

The following tables list thermal resistance for several

different board sizes and copper areas. All measurements

were taken in still air on 3/32" FR-4 board with one ounce

copper.

Figure 6. Noise Resulting from

Tapping on a Ceramic Capacitor

Table 1. DE Package, 12-Lead DFN

COPPER AREA

THERMAL RESISTANCE

BOARD AREA (JUNCTION-TO-AMBIENT)

TOPSIDE* BACKSIDE

2

2500mm

40°C/W

45°C/W

50°C/W

60°C/W

2

1000mm

2

225mm

100mm

2

* Device is mounted on topside

1763fg

17

LT1763 Series

APPLICATIONS INFORMATION

Table 2. SO-8 Package, 8-Lead SO

Protection Features

COPPER AREA

The LT1763 regulators incorporate several protection

featureswhichmakethemidealforuseinbattery-powered

circuits. In addition to the normal protection features

associated with monolithic regulators, such as current

limiting and thermal limiting, the devices are protected

against reverse input voltages, reverse output voltages

and reverse voltages from output to input.

THERMAL RESISTANCE

BOARD AREA (JUNCTION-TO-AMBIENT)

TOPSIDE* BACKSIDE

2500mm²

1000mm²

225mm²

100mm²

50mm²

2500mm²

60°C/W

68°C/W

74°C/W

86°C/W

Current limit protection and thermal overload protection

are intended to protect the device against current overload

conditionsattheoutputofthedevice.Fornormaloperation,

the junction temperature should not exceed 125°C.

* Device is mounted on topside

Calculating Junction Temperature

The input of the device will withstand reverse voltages of

20V. Current ﬂow into the device will be limited to less

than 1mA (typically less than 100μA) and no negative

voltage will appear at the output. The device will protect

both itself and the load. This provides protection against

batteries which can be plugged in backward.

Example: Given an output voltage of 3.3V, an input voltage

rangeof4Vto6V,anoutputcurrentrangeof0mAto250mA

and a maximum ambient temperature of 50°C, what will

the maximum junction temperature be?

The power dissipated by the device will be equal to:

I

(V

– V ) + I (V

)

OUT(MAX) IN(MAX)

OUT

GND IN(MAX)

The output of the LT1763-X can be pulled below ground

withoutdamagingthedevice.Iftheinputisleftopen-circuit

or grounded, the output can be pulled below ground by

20V. For ﬁxed voltage versions, the output will act like a

largeresistor,typically500korhigher,limitingcurrentﬂow

to less than 100μA. For adjustable versions, the output

will act like an open circuit; no current will ﬂow out of the

pin. If the input is powered by a voltage source, the output

will source the short-circuit current of the device and will

protect itself by thermal limiting. In this case, grounding

the SHDN pin will turn off the device and stop the output

from sourcing the short-circuit current.

where,

I

= 250mA

= 6V

OUT IN

OUT(MAX)

V

IN(MAX)

I

at (I

= 250mA, V = 6V) = 5mA

GND

So,

P = 250mA(6V – 3.3V) + 5mA(6V) = 0.71W

The thermal resistance will be in the range of 60°C/W to

86°C/W, depending on the copper area. So, the junction

temperature rise above ambient will be approximately

equal to:

The ADJ pin of the adjustable device can be pulled above

or below ground by as much as 7V without damaging the

device. If the input is left open-circuit or grounded, the

ADJ pin will act like an open circuit when pulled below

ground and like a large resistor (typically 100k) in series

with a diode when pulled above ground.

0.71W(75°C/W) = 53.3°C

The maximum junction temperature will then be equal to

the maximum junction temperature rise above ambient

plus the maximum ambient temperature, or:

T

= 50°C + 53.3°C = 103.3°C

JMAX

In situations where the ADJ pin is connected to a resistor

divider that would pull the ADJ pin above its 7V clamp

voltageiftheoutputispulledhigh,theADJpininputcurrent

must be limited to less than 5mA. For example, a resistor

divider is used to provide a regulated 1.5V output from the

1.22V reference when the output is forced to 20V.

1763fg

18

LT1763 Series

APPLICATIONS INFORMATION

The top resistor of the resistor divider must be chosen to

limit the current into the ADJ pin to less than 5mA when

the ADJ pin is at 7V. The 13V difference between output

and ADJ pin divided by the 5mA maximum current into the

ADJ pin yields a minimum top resistor value of 2.6k.

When the IN pin of the LT1763-X is forced below the OUT

pin, or the OUT pin is pulled above the IN pin, input cur-

rent will typically drop to less than 2μA. This can happen

if the input of the device is connected to a discharged

(low voltage) battery and the output is held up by either

a backup battery or a second regulator circuit. The state

of the SHDN pin will have no effect on the reverse output

current when the output is pulled above the input.

In circuits where a backup battery is required, several

different input/output conditions can occur. The output

voltage may be held up while the input is either pulled

to ground, pulled to some intermediate voltage or is left

open-circuit. Current ﬂow back into the output will follow

the curve shown in Figure 7.

100

T

= 25°C

= 0V

J

IN

LT1763-1.5

V

90

80

70

60

50

40

30

20

10

0

CURRENT FLOWS

INTO OUTPUT PIN

V

= V

(LT1763)

OUT

ADJ

LT1763

LT1763-1.8

LT1763-2.5

LT1763-3

LT1763-5

LT1763-3.3

4

0

1

2

3

5

6

7

8

9

10

OUTPUT VOLTAGE (V)

1763 F07

Figure 7. Reverse Output Current

1763fg

19

LT1763 Series

PACKAGE DESCRIPTION

DE/UE Package

12-Lead Plastic DFN (4mm × 3mm)

(Reference LTC DWG # 05-08-1695 Rev D)

0.40 p 0.10

4.00 p0.10

(2 SIDES)

R = 0.115

TYP

7

12

0.70 p0.05

R = 0.05

TYP

3.30 p0.05

3.60 p0.05

3.30 p0.10

3.00 p0.10

(2 SIDES)

2.20 p0.05

PIN 1

TOP MARK

(NOTE 6)

1.70 p 0.05

1.70 p 0.10

PIN 1 NOTCH

R = 0.20 OR

PACKAGE

OUTLINE

0.35 s 45o

CHAMFER

(UE12/DE12) DFN 0806 REV D

6

1

0.25 p 0.05

0.75 p0.05

0.25 p 0.05

0.200 REF

0.50 BSC

2.50 REF

BOTTOM VIEW—EXPOSED PAD

0.00 – 0.05

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED

NOTE:

1. DRAWING PROPOSED TO BE A VARIATION OF VERSION

(WGED) IN JEDEC PACKAGE OUTLINE M0-229

2. DRAWING NOT TO SCALE

5. EXPOSED PAD SHALL BE SOLDER PLATED

6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION

ON THE TOP AND BOTTOM OF PACKAGE

3. ALL DIMENSIONS ARE IN MILLIMETERS

4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE

MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE

S8 Package

8-Lead Plastic Small Outline (Narrow .150 Inch)

(Reference LTC DWG # 05-08-1610)

.189 – .197

(4.801 – 5.004)

NOTE 3

.045 .005

.160 .005

.050 BSC

7

5

8

6

.053 – .069

(1.346 – 1.752)

.004 – .010

(0.101 – 0.254)

.245

MIN

.150 – .157

(3.810 – 3.988)

NOTE 3

.228 – .244

(5.791 – 6.197)

.050

(1.270)

BSC

.014 – .019

(0.355 – 0.483)

TYP

.010 – .020

(0.254 – 0.508)

.030 .005

TYP

s 45°

1

3

4

2

RECOMMENDED SOLDER PAD LAYOUT

.008 – .010

(0.203 – 0.254)

0°– 8° TYP

NOTE:

INCHES

(MILLIMETERS)

1. DIMENSIONS IN

3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.

MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)

.016 – .050

2. DRAWING NOT TO SCALE

(0.406 – 1.270)

SO8 0303

1763fg

20

LT1763 Series

REVISION HISTORY ^{(Revision history begins at Rev G)}

REV

DATE

DESCRIPTION

PAGE NUMBER

G

5/10

Updated Order Information to add MP-grade to all versions of DFN package

Revised Line Regulation section of Electrical Characteristics

Consolidated GND and exposed pad descriptions in Pin Descriptions section

Added LT3085 to Related Parts

2 to 4

5

14

22

1763fg

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-

tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

21

LT1763 Series

TYPICAL APPLICATION

Paralleling of Regulators for Higher Output Current

R1

0.1Ω

3.3V

1A

IN

OUT

SENSE

LT1763-3.3

+

C1

10μF

C2

10μF

V

> 3.8V

C4

0.01μF

IN

SHDN

BYP

GND

R2

0.1Ω

IN

OUT

C5

0.01μF

R6

LT1763

2k

BYP

ADJ

SHDN

GND

R3

2.2k

R4

2.2k

R7

1.21k

8

3

2

R5

10k

+

1

1/2 LT1490

C3

–

4

0.01μF

1763 TA03

RELATED PARTS

PART NUMBER

LT1120

DESCRIPTION

125mA Low Dropout Regulator with 20μA I

COMMENTS

Includes 2.5V Reference and Comparator

Q

LT1121

150mA Micropower Low Dropout Regulator

700mA Micropower Low Dropout Regulator

30μA I , SOT-223 Package

Q

LT1129

50μA Quiescent Current

LT1175

500mA Negative Low Dropout Micropower Regulator

300mA Low Dropout Micropower Regulator with Shutdown

3A Low Dropout Regulator with 50μA I

45μA I , 0.26V Dropout Voltage, SOT-223 Package

Q

LT1521

15μA I , Reverse Battery Protection

Q

LT1529

500mV Dropout Voltage

Q

LT1613

1.4MHz Single-Cell Micropower DC/DC Converter

SOT-23 Package, Internally Compensated

LT1761 Series

LT1762 Series

LT1764A

LT1962

100mA, Low Noise, Low Dropout Micropower Regulators in SOT-23

150mA, Low Noise, LDO Micropower Regulators

20μA Quiescent Current, 20μV

25μA Quiescent Current, 20μV

Noise, ThinSOT™

Noise, MS8

RMS

3A, Fast Transient Response Low Dropout Regulator

300mA, Fast Transient Response Low Dropout Regulator

1.5A, Fast Transient Response Low Dropout Regulator

50mA, 80V Low Noise, LDO Micropower Regulator

340mV Dropout Voltage, DD, TO220

270mV Dropout Voltage, 20μV

340mV Dropout Voltage, 40μV

, MS8

RML

LT1963A

LT3010

, DD, TO220, S8, SOT-223

300mV Dropout Voltage, MS8E

LT3021

500mA, Low Voltage, Very Low Dropout Linear Regulator

500mA Parallelable, Low Noise, Low Dropout Linear Regulator

160mV Dropout Voltage, DFN-8 and SOIC-8 Packages

LT3085

275mV Dropout Voltage (2 Supply Operation), MSOP-8 and

2mm × 3mm DFN-6 Packages

1763fg

LT 0510 REV G • PRINTED IN USA

LinearTechnology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

22

●

(408) 432-1900 FAX: (408) 434-0507 www.linear.com


型号：	LT1763MPDE-2.5#TRPBF
厂家：	Linear
描述：	LT1763 - 500mA, Low Noise, LDO Micropower Regulators; Package: DFN; Pins: 12; Temperature Range: -55°C to 125°C 线性稳压器IC 调节器电源电路光电二极管输出元件
文件：	总22页 (文件大小：1120K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

LT1763MPDE-2.5#TRPBF [Linear]

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