LT1763CS8-1.8#TRPBF - ANALOG DEVICES

For more information www.linear.com/LT1763

LT1763 Series

1763fh

Typical applicaTion

DescripTion

500mA, Low Noise, LDO

Micropower Regulators

The LT

1763 series are micropower, low noise, low dropout

regulators. The devices are capable of supplying 500mA of

output current with a dropout voltage of 300mV. Designed

for use in battery-powered systems, the low 30µA quiescent

current makes them an ideal choice. Quiescent current is

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

many other regulators.

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 20µVRMS over a 10Hz to 100kHz

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.

Internal protection circuitry includes reverse battery

protection, current limiting, thermal limiting and reverse

current protection. The parts come in ﬁxed output voltages

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 regu-

lators are available in 8-lead SO and 12-lead, low proﬁle

(4mm × 3mm × 0.75mm) DFN packages.

3.3V Low Noise Regulator

FeaTures

applicaTions

n Low Noise: 20µVRMS (10Hz to 100kHz)

n Output Current: 500mA

n Low Quiescent Current: 30µA

n Wide Input Voltage Range: 1.8V to 20V

n Low Dropout Voltage: 300mV

n Very Low Shutdown Current: < 1µA

n No Protection Diodes Needed

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

n Adjustable Output from 1.22V to 20V

n Stable with 3.3µF Output Capacitor

n Stable with Aluminum, Tantalum or Ceramic

Capacitors

n Reverse Battery Protection

n No Reverse Current

n Overcurrent and Overtemperature Protected

n 8-Lead SO and 12-Lead (4mm × 3mm) DFN

Packages

n Cellular Phones

n Battery-Powered Systems

n Noise-Sensitive Instrumentation Systems

Dropout Voltage

SHDN

0.01µF

10µF

1763 TA01

OUT

SENSE

VIN

3.7V TO

20V

BYP

GND

LT1763-3.3

3.3V AT 500mA

20µVRMS NOISE

1µF +

OUTPUT CURRENT (mA)

DROPOUT VOLTAGE (mV)

400

350

300

250

200

150

100

0400

1763 TA02

100 200 300 500

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.

For more information www.linear.com/LT1763

LT1763 Series

1763fh

absoluTe MaxiMuM raTings

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

(Note 1)

GND

SHDN

GND

OUT

SENSE/ADJ*

BYP

TOP VIEW

DE PACKAGE

12-LEAD (4mm × 3mm) PLASTIC DFN

TJMAX = 125°C, θJA = 40°C/W, θJC = 5°C/W

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

*PIN 5: SENSE FOR LT1763-1.5/L

T1763-1.8/LT1763-2.5/LT1763-3/LT1763-3.3/LT1763-5

ADJ FOR LT1763

SEE THE APPLICATIONS INFORMATION SECTION.

TOP VIEW

GND

SHDN

OUT

SENSE/ADJ*

GND

BYP

S8 PACKAGE

8-LEAD PLASTIC SO

TJMAX = 150°C, θJA = 70°C/W, θJC = 35°C/W

*PIN 2: 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* PACKAGE DESCRIPTION TEMPERATURE RANGE

LT1763CDE#PBF LT1763CDE#TRPBF 1763 12-Lead (4mm × 3mm) Plastic DFN –40°C to 125°C

LT1763IDE#PBF LT1763IDE#TRPBF 1763 12-Lead (4mm × 3mm) Plastic DFN –40°C to 125°C

LT1763MPDE#PBF LT1763MPDE#TRPBF 1763 12-Lead (4mm × 3mm) Plastic DFN –55°C to 125°C

LT1763CDE-1.5#PBF LT1763CDE-1.5#TRPBF 76315 12-Lead (4mm × 3mm) Plastic DFN –40°C to 125°C

LT1763IDE-1.5#PBF LT1763IDE-1.5#TRPBF 76315 12-Lead (4mm × 3mm) Plastic DFN –40°C to 125°C

LT1763MPDE-1.5#PBF LT1763MPDE-1.5#TRPBF 76315 12-Lead (4mm × 3mm) Plastic DFN –55°C to 125°C

LT1763CDE-1.8#PBF LT1763CDE-1.8#TRPBF 76318 12-Lead (4mm × 3mm) Plastic DFN –40°C to 125°C

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

For more information www.linear.com/LT1763

LT1763 Series

1763fh

LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE

LT1763IDE-1.8#PBF LT1763IDE-1.8#TRPBF 76318 12-Lead (4mm × 3mm) Plastic DFN –40°C to 125°C

LT1763MPDE-1.8#PBF LT1763MPDE-1.8#TRPBF 76318 12-Lead (4mm × 3mm) Plastic DFN –55°C to 125°C

LT1763CDE-2.5#PBF LT1763CDE-2.5#TRPBF 76325 12-Lead (4mm × 3mm) Plastic DFN –40°C to 125°C

LT1763IDE-2.5#PBF LT1763IDE-2.5#TRPBF 76325 12-Lead (4mm × 3mm) Plastic DFN –40°C to 125°C

LT1763MPDE-2.5#PBF LT1763MPDE-2.5#TRPBF 76325 12-Lead (4mm × 3mm) Plastic DFN –55°C to 125°C

LT1763CDE-3#PBF LT1763CDE-3#TRPBF 17633 12-Lead (4mm × 3mm) Plastic DFN –40°C to 125°C

LT1763IDE-3#PBF LT1763IDE-3#TRPBF 17633 12-Lead (4mm × 3mm) Plastic DFN –40°C to 125°C

LT1763MPDE-3#PBF LT1763MPDE-3#TRPBF 17633 12-Lead (4mm × 3mm) Plastic DFN –55°C to 125°C

LT1763CDE-3.3#PBF LT1763CDE-3.3#TRPBF 76333 12-Lead (4mm × 3mm) Plastic DFN –40°C to 125°C

LT1763IDE-3.3#PBF LT1763IDE-3.3#TRPBF 76333 12-Lead (4mm × 3mm) Plastic DFN –40°C to 125°C

LT1763MPDE-3.3#PBF LT1763MPDE-3.3#TRPBF 76333 12-Lead (4mm × 3mm) Plastic DFN –55°C to 125°C

LT1763CDE-5#PBF LT1763CDE-5#TRPBF 17635 12-Lead (4mm × 3mm) Plastic DFN –40°C to 125°C

LT1763IDE-5#PBF LT1763IDE-5#TRPBF 17635 12-Lead (4mm × 3mm) Plastic DFN –40°C to 125°C

LT1763MPDE-5#PBF LT1763MPDE-5#TRPBF 17635 12-Lead (4mm × 3mm) Plastic DFN –55°C to 125°C

LT1763CS8#PBF LT1763CS8#TRPBF 1763 8-Lead Plastic SO –40°C to 125°C

LT1763IS8#PBF LT1763IS8#TRPBF 1763 8-Lead Plastic SO –40°C to 125°C

LT1763MPS8#PBF LT1763MPS8#TRPBF 1763MP 8-Lead Plastic SO –55°C to 125°C

LT1763CS8-1.5#PBF LT1763CS8-1.5#TRPBF 176315 8-Lead Plastic SO –40°C to 125°C

LT1763IS8-1.5#PBF LT1763IS8-1.5#TRPBF 176315 8-Lead Plastic SO –40°C to 125°C

LT1763CS8-1.8#PBF LT1763CS8-1.8#TRPBF 176318 8-Lead Plastic SO –40°C to 125°C

LT1763IS8-1.8#PBF LT1763IS8-1.8#TRPBF 176318 8-Lead Plastic SO –40°C to 125°C

LT1763CS8-2.5#PBF LT1763CS8-2.5#TRPBF 176325 8-Lead Plastic SO –40°C to 125°C

LT1763IS8-2.5#PBF LT1763IS8-2.5#TRPBF 176325 8-Lead Plastic SO –40°C to 125°C

LT1763MPS8-2.5#PBF LT1763MPS8-2.5#TRPBF 176325 8-Lead Plastic SO –55°C to 125°C

LT1763CS8-3#PBF LT1763CS8-3#TRPBF 17633 8-Lead Plastic SO –40°C to 125°C

LT1763IS8-3#PBF LT1763IS8-3#TRPBF 17633 8-Lead Plastic SO –40°C to 125°C

LT1763CS8-3.3#PBF LT1763CS8-3.3#TRPBF 176333 8-Lead Plastic SO –40°C to 125°C

LT1763IS8-3.3#PBF LT1763IS8-3.3#TRPBF 176333 8-Lead Plastic SO –40°C to 125°C

LT1763CS8-5#PBF LT1763CS8-5#TRPBF 17635 8-Lead Plastic SO –40°C to 125°C

LT1763IS8-5#PBF LT1763IS8-5#TRPBF 17635 8-Lead Plastic SO –40°C to 125°C

LT1763MPS8-5#PBF LT1763MPS8-5#TRPBF 17635 8-Lead Plastic SO –55°C to 125°C

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

Consult LTC Marketing for information on nonstandard lead based ﬁnish parts.

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/

orDer inForMaTion

For more information www.linear.com/LT1763

LT1763 Series

1763fh

elecTrical characTerisTics

PARAMETER CONDITIONS MIN TYP MAX UNITS

Minimum Operating Voltage C, I Grade: ILOAD = 500mA (Notes 3, 11)

MP Grade: ILOAD = 500mA (Notes 3, 11)

1.8

2.3

2.35

Regulated Output Voltage

(Note 4)

LT1763-1.5 VIN = 2V, ILOAD = 1mA

2.5V < VIN < 20V, 1mA < ILOAD < 500mA

1.485

1.462

1.5

1.515

1.538

LT1763-1.8 VIN = 2.3V, ILOAD = 1mA

2.8V < VIN < 20V, 1mA < ILOAD < 500mA

1.782

1.755

1.8

1.818

1.845

LT1763-2.5 VIN = 3V, ILOAD = 1mA

3.5V < VIN < 20V, 1mA < ILOAD < 500mA

2.475

2.435

2.5

2.525

2.565

LT1763-3 VIN = 3.5V, ILOAD = 1mA

4V < VIN < 20V, 1mA < ILOAD < 500mA

2.970

2.925

3.030

3.075

LT1763-3.3 VIN = 3.8V, ILOAD = 1mA

4.3V < VIN < 20V, 1mA < ILOAD < 500mA

3.267

3.220

3.3

3.333

3.380

LT1763-5 VIN = 5.5V, ILOAD = 1mA

6V < VIN < 20V, 1mA < ILOAD < 500mA

4.950

4.875

5.050

5.125

ADJ Pin Voltage

(Notes 3, 4)

LT1763 VIN = 2.2V, ILOAD = 1mA

C, I Grade: 2.3V < VIN < 20V, 1mA < ILOAD < 500mA

MP Grade: 2.35V < VIN < 20V, 1mA < ILOAD < 500mA

1.208

1.190

1.220

1.232

1.250

Line Regulation LT1763-1.5 C, I Grade: ∆VIN = 2V to 20V, ILOAD = 1mA

LT1763-1.5 MP Grade: ∆VIN = 2.1V to 20V, ILOAD = 1mA

LT1763-1.8 ∆VIN = 2.3V to 20V, ILOAD = 1mA

LT1763-2.5 ∆VIN = 3V to 20V, ILOAD = 1mA

LT1763-3 ∆VIN = 3.5V to 20V, ILOAD = 1mA

LT1763-3.3 ∆VIN = 3.8V to 20V, ILOAD = 1mA

LT1763-5 ∆VIN = 5.5V to 20V, ILOAD = 1mA

LT1763 (Note 3) C, I Grade: ∆VIN = 2V to 20V, ILOAD = 1mA

LT1763 (Note 3) MP Grade: ∆VIN = 2.1V to 20V, ILOAD = 1mA

Load Regulation L

T1763-1.5 VIN = 2.5V, ∆ILOAD = 1mA to 500mA

VIN = 2.5V, ∆ILOAD = 1mA to 500mA

3 8

LT1763-1.8 VIN = 2.8V, ∆ILOAD = 1mA to 500mA

VIN = 2.8V, ∆ILOAD = 1mA to 500mA

4 9

LT1763-2.5 VIN = 3.5V, ∆ILOAD = 1mA to 500mA

VIN = 3.5V, ∆ILOAD = 1mA to 500mA

5 12

LT1763-3 VIN = 4V, ∆ILOAD = 1mA to 500mA

VIN = 4V, ∆ILOAD = 1mA to 500mA

7 15

LT1763-3.3 VIN = 4.3V, ∆ILOAD = 1mA to 500mA

VIN = 4.3V, ∆ILOAD = 1mA to 500mA

7 17

LT1763-5 VIN = 6V, ∆ILOAD= 1mA to 500mA

VIN = 6V, ∆ILOAD = 1mA to 500mA

12 25

LT1763 (Note 3) VIN = 2.3V, ∆ILOAD = 1mA to 500mA

C, I Grade: VIN = 2.3V, ∆ILOAD = 1mA to 500mA

MP Grade: VIN = 2.35V, ∆ILOAD = 1mA to 500mA

2 6

Dropout Voltage

VIN = VOUT(NOMINAL)

(Notes 5, 6, 11)

ILOAD = 10mA

0.13 0.19

0.25

ILOAD = 50mA

0.17 0.22

0.32

ILOAD = 100mA

0.20 0.24

0.34

ILOAD = 500mA

0.30 0.35

0.45

The l denotes the speciﬁcations which apply over the full operating

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

For more information www.linear.com/LT1763

LT1763 Series

1763fh

elecTrical characTerisTics

The l denotes the speciﬁcations which apply over the full operating

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

PARAMETER CONDITIONS MIN TYP MAX UNITS

GND Pin Current

VIN = VOUT(NOMINAL)

(Notes 5, 7)

ILOAD = 0mA

ILOAD = 1mA

ILOAD = 50mA

ILOAD = 100mA

ILOAD = 250mA

ILOAD = 500mA

1.1

120

1.6

µA

Output Voltage Noise COUT = 10µF, CBYP = 0.01µF, ILOAD = 500mA, BW = 10Hz to 100kHz 20 µVRMS

ADJ Pin Bias Current (Notes 3, 8) 30 100 nA

Shutdown Threshold VOUT = Off to On

VOUT = On to Off

0.25

0.8

0.65

2 V

SHDN Pin Current

(Note 9)

VSHDN = 0V

VSHDN = 20V

0.1

µA

Quiescent Current in Shutdown VIN = 6V, VSHDN = 0V 0.1 1 µA

Ripple Rejection VIN – VOUT = 1.5V (Avg), VRIPPLE = 0.5VP-P, fRIPPLE = 120Hz,

ILOAD = 500mA

50 65 dB

Current Limit VIN = 7V, VOUT = 0V

C, I Grade: VIN = VOUT(NOMINAL) + 1V or 2.3V (Note 12), ∆VOUT = –0.1V

MP Grade: VIN = 2.35V (Note 12), ∆VOUT = –0.1V

520

Input Reverse Leakage Current VIN = –20V, VOUT = 0V l1 mA

Reverse Output Current

(Note 10)

LT1763-1.5 VOUT = 1.5V, VIN < 1.5V

LT1763-1.8 VOUT = 1.8V, VIN < 1.8V

LT1763-2.5 VOUT = 2.5V, VIN < 2.5V

LT1763-3 VOUT = 3V, VIN < 3V

LT1763-3.3 VOUT = 3.3V, VIN < 3.3V

LT1763-5 VOUT = 5V, VIN < 5V

LT1763 (Note 3) VOUT = 1.22V, VIN < 1.22V

µA

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 2: The LT1763 regulators are tested and speciﬁed under pulse

load conditions such that TJ @ TA. The LT1763 (C grade) is 100% tested

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

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 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: VIN – VDROPOUT.

Note 7: GND pin current is tested with VIN = VOUT(NOMINAL) or VIN = 2.3V

(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.

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 VIN = VOUT(NOMINAL) + 1V or 2.3V (C, I grade) or 2.35V

(MP grade), whichever is greater.

For more information www.linear.com/LT1763

LT1763 Series

1763fh

Typical perForMance characTerisTics

Typical Dropout Voltage Guaranteed Dropout Voltage Dropout Voltage

OUTPUT CURRENT (mA)

500

450

400

350

300

250

200

150

100

DROPOUT VOLTAGE (mV)

1763 G01

0 50 100 150 200 250 300 350 400 450 500

TJ = 125°C

TJ = 25°C

OUTPUT CURRENT (mA)

500

450

400

350

300

250

200

150

100

GUARANTEED DROPOUT VOLTAGE (mV)

1763 G02

0 50 100 150 200 250 300 350 400 450 500

TJ ≤ 125°C

TJ ≤ 25°C

= TEST POINTS

TEMPERATURE (°C)

–50

DROPOUT VOLTAGE (mV)

050 75

1763 G03

–25 25 100 125

500

450

400

350

300

250

200

150

100

IL = 500mA

IL = 1mA

IL = 10mA

IL = 50mA

IL = 250mA

IL = 100mA

Quiescent Current

LT1763-1.5

Output Voltage

LT1763-1.8

Output Voltage

LT1763-2.5

Output Voltage

LT1763-3

Output Voltage

LT1763-3.3

Output Voltage

TEMPERATURE (°C)

–50

QUIESCENT CURRENT (µA)

100

1763 G04

0 50–25 25 75 125

VIN = 6V

RL = ∞, IL = 0 (LT1763-1.5/-1.8/-2.5/-3/-3.3/-5)

RL = 250k, IL = 5µA (LT1763)

VSHDN = VIN

TEMPERATURE (°C)

–50

OUTPUT VOLTAGE (V)

100

1763 G05

0 50

1.528

1.521

1.514

1.507

1.500

1.493

1.486

1.479

1.472

–25 25 75 125

IL = 1mA

TEMPERATURE (°C)

–50

OUTPUT VOLTAGE (V)

100

1763 G06

0 50

1.84

1.83

1.82

1.81

1.80

1.79

1.78

1.77

1.76

–25 25 75 125

IL = 1mA

TEMPERATURE (°C)

–50

OUTPUT VOLTAGE (V)

100

1763 G07

0 50

2.54

2.53

2.52

2.51

2.50

2.49

2.48

2.47

2.46

–25 25 75 125

IL = 1mA

TEMPERATURE (°C)

–50

OUTPUT VOLTAGE (V)

100

1763 G08

0 50

3.060

3.045

3.030

3.015

3.000

2.985

2.970

2.955

2.940

–25 25 75 125

IL = 1mA

TEMPERATURE (°C)

–50

OUTPUT VOLTAGE (V)

100

1763 G09

0 50

3.360

3.345

3.330

3.315

3.300

3.285

3.270

3.255

3.240

–25 25 75 125

IL = 1mA

For more information www.linear.com/LT1763

LT1763 Series

1763fh

Typical perForMance characTerisTics

LT1763-5

Output Voltage

LT1763

ADJ Pin Voltage

LT1763-1.5

Quiescent Current

TEMPERATURE (°C)

–50

OUTPUT VOLTAGE (V)

100

1763 G10

0 50

5.100

5.075

5.050

5.025

5.000

4.975

4.950

4.925

4.900

–25 25 75 125

IL = 1mA

TEMPERATURE (°C)

–50

ADJ PIN VOLTAGE (V)

100

1763 G11

0 50

1.240

1.235

1.230

1.225

1.220

1.215

1.210

1.205

1.200

–25 25 75

125

IL = 1mA

INPUT VOLTAGE (V)

QUIESCENT CURRENT (µA)

250

225

200

175

150

125

100

1763 G12

21 3 5 7 9

4610

VSHDN = VIN

TJ = 25°C

RL = ∞

VSHDN = 0V

LT1763-1.8

Quiescent Current

LT1763-2.5

Quiescent Current

LT1763-3

Quiescent Current

LT1763-3.3

Quiescent Current

LT1763-5

Quiescent Current

LT1763

Quiescent Current

INPUT VOLTAGE (V)

QUIESCENT CURRENT (µA)

250

225

200

175

150

125

100

1763 G13

21 3 5 7 9

4610

VSHDN = VIN

TJ = 25°C

RL = ∞

VSHDN = 0V

INPUT VOLTAGE (V)

QUIESCENT CURRENT (µA)

250

225

200

175

150

125

100

1763 G14

21 3 5 7 9

4610

VSHDN = VIN

TJ = 25°C

RL = ∞

VSHDN = 0V

INPUT VOLTAGE (V)

QUIESCENT CURRENT (µA)

250

225

200

175

150

125

100

1763 G15

21 3 5 7 9

4610

VSHDN = VIN

TJ = 25°C

RL = ∞

VSHDN = 0V

INPUT VOLTAGE (V)

QUIESCENT CURRENT (µA)

250

225

200

175

150

125

100

1763 G16

21 3 5 7 9

4610

VSHDN = VIN

TJ = 25°C

RL = ∞

SHDN

VSHDN = 0V

INPUT VOLTAGE (V)

QUIESCENT CURRENT (µA)

250

225

200

175

150

125

100

1763 G17

21 3 5 7 9

4610

VSHDN = VIN

TJ = 25°C

RL = ∞

SHDN

VSHDN = 0V

INPUT VOLTAGE (V)

QUIESCENT CURRENT (µA)

016

1763 G18

42 6 10 14 18

812 20

VSHDN = VIN

TJ = 25°C

RL = 250k

VSHDN = 0V

For more information www.linear.com/LT1763

LT1763 Series

1763fh

Typical perForMance characTerisTics

LT1763-1.5

GND Pin Current

LT1763-1.8

GND Pin Current

LT1763-2.5

GND Pin Current

INPUT VOLTAGE (V)

1200

1000

800

600

400

200

GND PIN CURRENT (µA)

1763 G19

0123456 7 8 9 10

RL = 30Ω

IL = 50mA*

RL = 150Ω

IL = 10mA*

RL = 1.5k

IL = 1mA*

TJ = 25°C

VIN = VSHDN

*FOR VOUT = 1.5V

INPUT VOLTAGE (V)

1200

1000

800

600

400

200

GND PIN CURRENT (µA)

1763 G20

0123456 7 8 9 10

RL = 36Ω

IL = 50mA*

RL = 180Ω

IL = 10mA*

RL = 1.8k

IL = 1mA*

TJ = 25°C

VIN = VSHDN

*FOR VOUT = 1.8V

INPUT VOLTAGE (V)

1200

1000

800

600

400

200

GND PIN CURRENT (µA)

1763 G21

0123456 7 8 9 10

RL = 50Ω

IL = 50mA*

RL = 250Ω

IL = 10mA*

RL = 2.5k

IL = 1mA*

TJ = 25°C

VIN = VSHDN

*FOR VOUT = 2.5V

LT1763-3

GND Pin Current

LT1763-3.3

GND Pin Current

LT1763-5

GND Pin Current

LT1763

GND Pin Current

LT1763-1.5

GND Pin Current

LT1763-1.8

GND Pin Current

INPUT VOLTAGE (V)

1200

1000

800

600

400

200

GND PIN CURRENT (µA)

1763 G22

0123456 7 8 9 10

RL = 60Ω

IL = 50mA*

RL = 300Ω

IL = 10mA*

RL = 3k

IL = 1mA*

TJ = 25°C

VIN = VSHDN

*FOR VOUT = 3V

INPUT VOLTAGE (V)

1200

1000

800

600

400

200

GND PIN CURRENT (µA)

1763 G23

0123456 7 8 9 10

RL = 66Ω

IL = 50mA*

RL = 330Ω

IL = 10mA*

RL = 3.3k

IL = 1mA*

TJ = 25°C

VIN = VSHDN

*FOR VOUT = 3.3V

INPUT VOLTAGE (V)

1200

1000

800

600

400

200

GND PIN CURRENT (µA)

1763 G24

0123456 7 8 9 10

RL = 100Ω

IL = 50mA*

RL = 500Ω

IL = 10mA*

RL = 5k

IL = 1mA*

TJ = 25°C

VIN = VSHDN

*FOR VOUT = 5V

INPUT VOLTAGE (V)

1200

1000

800

600

400

200

GND PIN CURRENT (µA)

1763 G25

0123456 7 8 9 10

RL = 24.4Ω

IL = 50mA*

RL = 122Ω

IL = 10mA*

RL = 1.22k

IL = 1mA*

TJ = 25°C

VIN = VSHDN

*FOR VOUT = 1.22V

INPUT VOLTAGE (V)

GND PIN CURRENT (mA)

1763 G26

0123456 7 8 9 10

RL = 3Ω

IL = 500mA*

RL = 5Ω

IL = 300mA*

RL = 15Ω

IL = 100mA*

TJ = 25°C

VIN = VSHDN

*FOR VOUT = 1.5V

INPUT VOLTAGE (V)

GND PIN CURRENT (mA)

1763 G27

0123456 7 8 9 10

RL = 3.6Ω

IL = 500mA*

RL = 6Ω

IL = 300mA*

RL = 18Ω

IL = 100mA*

TJ = 25°C

VIN = VSHDN

*FOR VOUT = 1.8V

For more information www.linear.com/LT1763

LT1763 Series

1763fh

Typical perForMance characTerisTics

LT1763-2.5

GND Pin Current

LT1763-3

GND Pin Current

LT1763-3.3

GND Pin Current

INPUT VOLTAGE (V)

GND PIN CURRENT (mA)

1763 G28

0123456 7 8 9 10

RL = 5Ω

IL = 500mA*

RL = 8.33Ω

IL = 300mA*

RL = 25Ω

IL = 100mA*

TJ = 25°C

VIN = VSHDN

*FOR VOUT = 2.5V

INPUT VOLTAGE (V)

GND PIN CURRENT (mA)

1763 G29

0123456 7 8 9 10

RL = 6Ω

IL = 500mA*

RL = 10Ω

IL = 300mA*

RL = 30Ω

IL = 100mA*

TJ = 25°C

VIN = VSHDN

*FOR VOUT = 3V

INPUT VOLTAGE (V)

GND PIN CURRENT (mA)

1763 G30

0123456 7 8 9 10

RL = 6.6Ω

IL = 500mA*

RL = 11Ω

IL = 300mA*

RL = 33Ω

IL = 100mA*

TJ = 25°C

VIN = VSHDN

*FOR VOUT = 3.3V

SHDN Pin Threshold

(On-to-Off)

SHDN Pin Threshold

(Off-to-On) SHDN Pin Input Current

TEMPERATURE (°C)

–50

SHDN PIN THRESHOLD (V)

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0050 75

1763 G34

–25 25 100 125

IL = 1mA

TEMPERATURE (°C)

–50

SHDN PIN THRESHOLD (V)

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0050 75

1763 G35

–25 25 100 125

IL = 500mA

IL = 1mA

SHDN PIN VOLTAGE (V)

SHDN PIN INPUT CURRENT (µA)

1763 G36

0123456 7 8 9 10

1.4

1.2

1.0

0.8

0.6

0.4

0.2

LT1763-5

GND Pin Current

LT1763

GND Pin Current GND Pin Current vs ILOAD

INPUT VOLTAGE (V)

GND PIN CURRENT (mA)

1763 G31

0123456 7 8 9 10

RL = 10Ω

IL = 500mA*

RL = 16.7Ω

IL = 300mA*

RL = 50Ω

IL = 100mA*

TJ = 25°C

VIN = VSHDN

*FOR VOUT = 5V

INPUT VOLTAGE (V)

GND PIN CURRENT (mA)

1763 G32

0123456 7 8 9 10

RL = 2.44Ω

IL = 500mA*

RL = 4.07Ω

IL = 300mA*

RL = 12.2Ω

IL = 100mA*

TJ = 25°C

VIN = VSHDN

*FOR VOUT = 1.22V

OUTPUT CURRENT (mA)

GND PIN CURRENT (mA)

1763 G33

0 50 100 150 200 250 300 350 400 450 500

VIN = VOUT(NOMINAL) + 1V

For more information www.linear.com/LT1763

LT1763 Series

1763fh

Typical perForMance characTerisTics

SHDN Pin Input Current ADJ Pin Bias Current Current Limit

TEMPERATURE (°C)

–50

SHDN PIN INPUT CURRENT (µA)

100

1763 G37

0 50

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

–25 25 75 125

VSHDN = 20V

TEMPERATURE (°C)

–50

ADJ PIN BIAS CURRENT (nA)

050 75

1763 G38

–25 25 100 125

140

120

100

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

INPUT VOLTAGE (V)

CURRENT LIMIT (A)

245

1763 G39

1367

VOUT = 0V

Current Limit Reverse Output Current Reverse Output Current

Input Ripple Rejection Input Ripple Rejection Ripple Rejection

TEMPERATURE (°C)

–50

CURRENT LIMIT (A)

1.2

1.0

0.8

0.6

0.4

0.2

0050 75

1763 G40

–25 25 100 125

VIN = 7

VOUT = 0V

OUTPUT VOLTAGE (V)

100

REVERSE OUTPUT CURRENT (µA)

1763 G41

0123456 7 8 9 10

TJ = 25°C, VIN = 0V

CURRENT FLOWS

INTO OUTPUT PIN

VOUT = VADJ (LT1763)

LT1763

LT1763-5

LT1763-1.5

LT1763-3.3

LT1763-3

LT1763-2.5

LT1763-1.8

REVERSE OUTPUT CURRENT (µA)

1763 G42

VIN = 0V, VOUT = 1.22V (LT1763)

VOUT = 1.5V (LT1763-1.5)

VOUT = 1.8V (LT1763-1.8)

VOUT = 2.5V (LT1763-2.5)

VOUT = 3V (LT1763-3)

VOUT = 3.3V (LT1763-3.3)

VOUT = 5V (LT1763-5)

LT1763-1.5/-1.8/

-2.5/-3/-3.3/-5

LT1763

TEMPERATURE (°C)

–50 0 50 75

–25 25 100 125

FREQUENCY (Hz)

RIPPLE REJECTION (dB)

10 1k 10k 1M

1763 G43

100 100k

IL = 500mA

VIN = VOUT(NOMINAL) +

1V + 50mVRMS RIPPLE

CBYP = 0

COUT = 4.7µF

COUT = 10µF

FREQUENCY (Hz)

RIPPLE REJECTION (dB)

10 1k 10k 1M

1763 G44

100 100k

IL = 500mA

VIN = VOUT(NOMINAL) +

1V + 50mVRMS RIPPLE

COUT = 10µF

CBYP = 0.01µF

CBYP = 100pF

CBYP = 1000pF

TEMPERATURE (°C)

–50

RIPPLE REJECTION (dB)

100

1763 G45

0 50

–25 25 75 125

VIN = VOUT (NOMINAL) +

1V + 0.5VP-P RIPPLE

AT f = 120Hz

IL = 500mA

For more information www.linear.com/LT1763

LT1763 Series

1763fh

Typical perForMance characTerisTics

Output Noise Spectral Density

CBYP = 0

LT1763

Minimum Input Voltage Load Regulation

TEMPERATURE (°C)

–50

MINIMUM INPUT VOLTAGE (V)

050 75

1763 G46

–25 25 100 125

2.50

2.25

2.00

1.75

1.50

1.25

1.00

0.75

0.50

0.25

IL = 1mA

VOUT = 1.22V

IL = 500mA

TEMPERATURE (°C)

–50

LOAD REGULATION (mV)

100

1763 G47

0 50–25 25 75 125

–5

–10

–15

–20

–25

VIN = VOUT(NOMINAL) + 1V

∆IL = 1mA TO 500mA

LT1763

LT1763-5

LT1763-3

LT1763-3.3

LT1763-1.5

LT1763-1.8

LT1763-2.5

FREQUENCY (Hz)

10 1k 10k 100k

1763 G48

100

0.1

0.01

OUTPUT NOISE SPECTRAL DENSITY (µV/

√

Hz)

COUT = 10µF

IL = 500mA

LT1763

LT1763-5

LT1763-1.5

LT1763-2.5

LT1763-1.8

LT1763-3.3

LT1763-3

LT1763-5

10Hz to 100kHz Output Noise

CBYP = 1000pF

LT1763-5

10Hz to 100kHz Output Noise

CBYP = 0

LT1763-5

10Hz to 100kHz Output Noise

CBYP = 100pF

1ms/DIV

VOUT

100µV/DIV

COUT = 10µF

IL = 500mA

1763 G52 1ms/DIV

VOUT

100µV/DIV

COUT = 10µF

IL = 500mA

1763 G53 1ms/DIV

VOUT

100µV/DIV

COUT = 10µF

IL = 500mA

1763 G54

Output Noise Spectral Density RMS Output Noise

vs Bypass Capacitor

RMS Output Noise

vs Load Current (10Hz to 100kHz)

FREQUENCY (Hz)

10 1k 10k 100k

1763 G49

100

0.1

0.01

OUTPUT NOISE SPECTRAL DENSITY (µV/√Hz)

LT1763

LT1763-5 CBYP = 1000pF

CBYP = 0.01µF

CBYP = 100pF

COUT = 10µF

IL = 500mA

CBYP (pF)

OUTPUT NOISE (µVRMS)

160

140

120

100

100 1000 10000

1763 G50

COUT = 10µF

IL = 500mA

f = 10Hz TO 100kHz

LT1763-5

LT1763-3.3

LT1763

LT1763-1.5

LT1763-3

LT1763-2.5

LT1763-1.8

LOAD CURRENT (mA)

0.01

OUTPUT NOISE (µVRMS)

160

140

120

100

0.1 1

1763 G51

10 100 1000

COUT = 10µF

LT1763-5

LT1763

CBYP = 0

CBYP = 0.01µF

For more information www.linear.com/LT1763

LT1763 Series

1763fh

Typical perForMance characTerisTics

LT1763-5

10Hz to 100kHz Output Noise

CBYP = 0.01µF

LT1763-5

Transient Response

CBYP = 0

LT1763-5

Transient Response

CBYP = 0.01µF

1ms/DIV

VOUT

100µV/DIV

COUT = 10µF

IL = 500mA

1763 G55

TIME (µs)

0.4

0.2

–0.2

–0.4

OUTPUT VOLTAGE

DEVIATION (V)

600

400

200

LOAD CURRENT

(mA)

1763 G56

0 200 400 600 800 1000

VIN = 6V

CIN = 10µF

COUT = 10µF

TIME (µs)

0.10

0.05

–0.05

–0.10

OUTPUT VOLTAGE

DEVIATION (V)

600

400

200

LOAD CURRENT

(mA)

1763 G57

0 20 30 50 70 9010 40 60 80 100

VIN = 6V

CIN = 10µF

COUT = 10µF

For more information www.linear.com/LT1763

LT1763 Series

1763fh

pin FuncTions

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

pins have no connection to any internal circuitry. These

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

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

to limit peak voltage transients. See the Applications Infor-

mation section for more information on output capacitance

and reverse output characteristics.

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). The ADJ pin voltage is 1.22V referenced to ground

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

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-

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

load. These may be eliminated by connecting the SENSE

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

Sense Connection).

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

the reference of the LT1763 regulators to achieve low noise

performance from the regulator. The BYP pin is clamped

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

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

20µVRMS over a 10Hz to 100kHz bandwidth. If not used,

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.

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

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

power shutdown state if the SHDN pin is not connected.

IN (Pin 10, 11/Pin 8): Input. Power is supplied to the device

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.

(DE12/S8)

Note that the voltage drop across the external PC traces will

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

bias current is 10µA at the nominal rated output voltage. 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.

SHDN

1763 F01

OUT

VIN SENSE

GND

LT1763

+LOAD

Figure 1. Kelvin Sense Connection

For more information www.linear.com/LT1763

LT1763 Series

1763fh

The LT1763 series are 500mA low dropout regulators with

micropower quiescent current and shutdown. The devices

are capable of supplying 500mA at a dropout voltage of

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

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

a 0.01µF reference bypass capacitor. Additionally, the

reference bypass capacitor will improve transient response

of the regulator, lowering the settling time for transient load

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.

Adjustable Operation

The adjustable version of the LT1763 has an output voltage

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

Current vs Temperature appear in the Typical Performance

Characteristics section.

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

applicaTions inForMaTion

Figure 2. Adjustable Operation

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

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

at VOUT = 1.22V. At VOUT = 12V, load regulation is:

(12V/1.22V)(–2mV) = –19.6mV

Bypass Capacitance and Low Noise Performance

The LT1763 regulators may be used with the addition of

a bypass capacitor from VOUT to the BYP pin to lower

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

lower the output voltage noise to as low as 20µVRMS

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.

1763 F02

OUT

VIN

VOUT

ADJ

GND

LT1763

InA

OUT ADJ

ADJ











+

()

=°

1221

122

AT 25 C

OUTPUT RANGE = 1.22V TO 20V

For more information www.linear.com/LT1763

LT1763 Series

1763fh

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.

The shaded region of Figure 3 deﬁnes the range over

which the LT1763 regulators are stable. The minimum ESR

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

and Y5V dielectrics are good for providing high capacitances

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

available in higher values. Care still must be exercised when

using X5R and X7R capacitors; the X5R and X7R codes

only specify operating temperature range and maximum

capacitance change over temperature. Capacitance change

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

applicaTions inForMaTion

OUTPUT CAPACITANCE (µF)

ESR (Ω)

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

3 10

1763 F03

2 4 5 67 8 9

STABLE REGION

CBYP = 330pF

CBYP ≥ 1000pF

CBYP = 100pF

CBYP = 0

Figure 3. Stability

DC BIAS VOLTAGE (V)

CHANGE IN VALUE (%)

1763 F04

–20

–40

–60

–80

–100 04810

2 6 12 14

X5R

Y5V

BOTH CAPACITORS ARE 16V,

1210 CASE SIZE, 10µF

TEMPERATURE (°C)

–50

–20

–40

–60

–80

–100

25 75

1763 F05

–25 0 50 100 125

Y5V

CHANGE IN VALUE (%)

X5R

BOTH CAPACITORS ARE 16V,

1210 CASE SIZE, 10µF

Figure 4. Ceramic Capacitor DC Bias Characteristics

Figure 5. Ceramic Capacitor Temperature Characteristics

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LT1763 Series

1763fh

Figure 6. Noise Resulting from

Tapping on a Ceramic Capacitor

Y5V and Z5U capacitors, but can still be signiﬁcant enough

to drop capacitor values below appropriate levels. Capacitor

DC bias characteristics tend to improve as component

case size increases, but expected capacitance at operating

voltage should be veriﬁed.

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 is used for noise bypassing. A ceramic capacitor

produced Figure 6’s trace in response to light tapping from a

pencil. Similar vibration induced behavior can masquerade

as increased output voltage noise.

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:

1. Output current multiplied by the input/output voltage

differential: (IOUT)(VIN – VOUT), and

2. GND pin current multiplied by the input voltage:

(IGND)(VIN).

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.

The LT1763 series regulators have internal thermal limiting

designed to protect the device during overload conditions.

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.

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.

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.

Table 1. DE Package, 12-Lead DFN

COPPER AREA

BOARD AREA

THERMAL RESISTANCE

(JUNCTION-TO-AMBIENT)TOPSIDE* BACKSIDE

2500mm22500mm22500mm240°C/W

1000mm22500mm22500mm245°C/W

225mm22500mm22500mm250°C/W

100mm22500mm22500mm260°C/W

* Device is mounted on topside

applicaTions inForMaTion

100ms/DIV

VOUT

500µV/DIV

1763 F06

LT1763-5

COUT = 10µF

CBYP = 0.01µF

ILOAD = 100mA

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LT1763 Series

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applicaTions inForMaTion

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

COPPER AREA

BOARD AREA

THERMAL RESISTANCE

(JUNCTION-TO-AMBIENT)TOPSIDE* BACKSIDE

2500mm

60°C/W

1000mm

2500mm

60°C/W

225mm

2500mm

68°C/W

100mm

2500mm

74°C/W

50mm

2500mm

86°C/W

* Device is mounted on topside

Calculating Junction Temperature

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

range of 4V to 6V, an output current range of 0mA to 250mA

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:

IOUT(MAX)(VIN(MAX) – VOUT) + IGND(VIN(MAX))

where,

IOUT(MAX) = 250mA

VIN(MAX) = 6V

IGND at (IOUT = 250mA, VIN = 6V) = 5mA

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:

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:

TJMAX = 50°C + 53.3°C = 103.3°C

Protection Features

The LT1763 regulators incorporate several protection

features which make them ideal for use in battery-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.

Current limit protection and thermal overload protection

are intended to protect the device against current overload

conditions at the output of the device. For normal operation,

the junction temperature should not exceed 125°C.

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.

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

without damaging the device. If the input is left open-circuit

or grounded, the output can be pulled below ground by

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

large resistor, typically 500k or higher, limiting current ﬂow

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.

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.

In situations where the ADJ pin is connected to a resistor

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

voltage if the output is pulled high, the ADJ pin input current

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.

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LT1763 Series

1763fh

Figure 7. Reverse Output Current

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.

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.

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.

OUTPUT VOLTAGE (V)

100

REVERSE OUTPUT CURRENT (µA)

1763 F07

0123456 7 8 9 10

TJ = 25°C

VIN = 0V

CURRENT FLOWS

INTO OUTPUT PIN

VOUT = VADJ (LT1763)

LT1763

LT1763-5

LT1763-3.3

LT1763-1.5

LT1763-1.8

LT1763-2.5

LT1763-3

applicaTions inForMaTion

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LT1763 Series

1763fh

package DescripTion

DE/UE Package

12-Lead Plastic DFN (4mm × 3mm)

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

4.00 ±0.10

(2 SIDES)

3.00 ±0.10

(2 SIDES)

NOTE:

1. DRAWING PROPOSED TO BE A VARIATION OF VERSION

(WGED) IN JEDEC PACKAGE OUTLINE M0-229

2. DRAWING NOT TO SCALE

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

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

0.40 ± 0.10

BOTTOM VIEW—EXPOSED PAD

1.70 ± 0.10

0.75 ±0.05

R = 0.115

TYP

R = 0.05

TYP

2.50 REF

127

PIN 1 NOTCH

R = 0.20 OR

0.35 × 45°

CHAMFER

PIN 1

TOP MARK

(NOTE 6)

0.200 REF

0.00 – 0.05

(UE12/DE12) DFN 0806 REV D

2.50 REF

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED

2.20 ±0.05

0.70 ±0.05

3.60 ±0.05

PACKAGE OUTLINE

3.30 ±0.10

0.25 ± 0.05

0.50 BSC

1.70 ± 0.05

3.30 ±0.05

0.50 BSC

0.25 ± 0.05

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LT1763 Series

1763fh

.016 – .050

(0.406 – 1.270)

.010 – .020

(0.254 – 0.508)× 45°

0°– 8° TYP

.008 – .010

(0.203 – 0.254)

SO8 REV G 0212

.053 – .069

(1.346 – 1.752)

.014 – .019

(0.355 – 0.483)

TYP

.004 – .010

(0.101 – 0.254)

.050

(1.270)

BSC

1234

.150 – .157

(3.810 – 3.988)

NOTE 3

8765

.189 – .197

(4.801 – 5.004)

NOTE 3

.228 – .244

(5.791 – 6.197)

.245

MIN .160 ±.005

RECOMMENDED SOLDER PAD LAYOUT

.045 ±.005

.050 BSC

.030 ±.005

TYP

INCHES

(MILLIMETERS)

NOTE:

1. DIMENSIONS IN

2. DRAWING NOT TO SCALE

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

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

4. PIN 1 CAN BE BEVEL EDGE OR A DIMPLE

S8 Package

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

(Reference LTC DWG # 05-08-1610 Rev G)

package DescripTion

Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.

For more information www.linear.com/LT1763

LT1763 Series

1763fh

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.

revision hisTory

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

H 11/14 Updated Order Information Table to add MP-grade to LT1763-2.5 and LT1763-5 in SO-8 package. 2-3

(Revision history begins at Rev G)

For more information www.linear.com/LT1763

LT1763 Series

1763fh

 LINEAR TECHNOLOGY CORPORATION 1999

LT 1114 REV H • PRINTED IN USA

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LT1763

relaTeD parTs

Typical applicaTion

PART NUMBER DESCRIPTION COMMENTS

LT1120 125mA Low Dropout Regulator with 20µA IQIncludes 2.5V Reference and Comparator

LT1121 150mA Micropower Low Dropout Regulator 30µA IQ, SOT-223 Package

LT1129 700mA Micropower Low Dropout Regulator 50µA Quiescent Current

LT1175 500mA Negative Low Dropout Micropower Regulator 45µA IQ, 0.26V Dropout Voltage, SOT-223 Package

LT1521 300mA Low Dropout Micropower Regulator with Shutdown 15µA IQ, Reverse Battery Protection

LT1529 3A Low Dropout Regulator with 50µA IQ500mV Dropout Voltage

LT1613 1.4MHz Single-Cell Micropower DC/DC Converter SOT-23 Package, Internally Compensated

LT1761 Series 100mA, Low Noise, Low Dropout Micropower Regulators in SOT-23 20µA Quiescent Current, 20µVRMS Noise, ThinSOT™

LT1762 Series 150mA, Low Noise, LDO Micropower Regulators 25µA Quiescent Current, 20µVRMS Noise, MS8

LT1764A 3A, Fast Transient Response Low Dropout Regulator 340mV Dropout Voltage, DD, TO220

LT1962 300mA, Fast Transient Response Low Dropout Regulator 270mV Dropout Voltage, 20µVRML, MS8

LT1963A 1.5A, Fast Transient Response Low Dropout Regulator 340mV Dropout Voltage, 40µVRML, DD, TO220, S8, SOT-223

LT3010 50mA, 80V Low Noise, LDO Micropower Regulator 300mV Dropout Voltage, MS8E

LT3021 500mA, Low Voltage, Very Low Dropout Linear Regulator 160mV Dropout Voltage, DFN-8 and SOIC-8 Packages

LT3085 500mA Parallelable, Low Noise, Low Dropout Linear Regulator 275mV Dropout Voltage (2 Supply Operation), MSOP-8 and

2mm × 3mm DFN-6 Packages

Paralleling of Regulators for Higher Output Current

0.01µF

0.1Ω

10k

2.2k

1.21k

10µF

1763 TA03

VIN > 3.8V

3.3V

0.01µF

4C3

0.01µF

SHDN

OUT

SENSE

BYP

GND

LT1763-3.3

SHDN

OUT

BYP

ADJ

GND

LT1763

SHDN

10µF

–

1/2 LT1490

2.2k