LT1963AET-3.3 - Linear Technology

LT1963A Series

1963af

TYPICAL APPLICATION

APPLICATIO S

FEATURES

DESCRIPTIO

1.5A, Low Noise,

Fast Transient Response

LDO Regulators

■

Optimized for Fast Transient Response

■

Output Current: 1.5A

■

Dropout Voltage: 340mV

■

Low Noise: 40

RMS

(10Hz to 100kHz)

■

1mA Quiescent Current

■

No Protection Diodes Needed

■

Controlled Quiescent Current in Dropout

■

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

■

Adjustable Output from 1.21V to 20V

■

<1mA Quiescent Current in Shutdown

■

Stable with 10mF Output Capacitor

■

Stable with Ceramic Capacitors

■

Reverse Battery Protection

■

No Reverse Current

■

Thermal Limiting

The LT

1963A series are low dropout regulators opti-

mized for fast transient response. The devices are capable

of supplying 1.5A of output current with a dropout voltage

of 340mV. Operating quiescent current is 1mA, dropping

to < 1mA in shutdown. Quiescent current is well controlled;

it does not rise in dropout as it does with many other

regulators. In addition to fast transient response, the

LT1963A regulators have very low output noise which

makes them ideal for sensitive RF supply applications.

Output voltage range is from 1.21V to 20V. The LT1963A

regulators are stable with output capacitors as low as

10mF. Small ceramic capacitors can be used without the

necessary addition of ESR as is common with other

regulators. Internal protection circuitry includes reverse

battery protection, current limiting, thermal limiting and

reverse current protection. The devices are available in

fixed output voltages of 1.5V, 1.8V, 2.5V, 3.3V and as an

adjustable device with a 1.21V reference voltage. The

LT1963A regulators are available in 5-lead TO-220, DD,

3-lead SOT-223 and 8-lead SO packages.

3.3V to 2.5V Regulator

■

3.3V to 2.5V Logic Power Supplies

■

Post Regulator for Switching Supplies

, LTC and LT are registered trademarks of Linear Technology Corporation.

SHDN

10µF*

*TANTALUM,

CERAMIC OR

ALUMINUM ELECTROLYTIC

1963 TA01

OUT

VIN > 3V

SENSE

GND

LT1963A-2.5

2.5V

1.5A

10µF* ++

OUTPUT CURRENT (A)

DROPOUT VOLTAGE (mV)

200

300

1.6

1963 TA02

100

00.4 0.8 1.2

0.2 0.6 1.0 1.4

400

150

250

350

Dropout Voltage

LT1963A Series

1963af

(Note 1)

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

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

Input to Output Differential Voltage (Note 2) ......... ±20V

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

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

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

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

Operating Junction Temperature Range –45∞C to 125∞C

Storage Temperature Range ................. –65∞C to 150∞C

Lead Temperature (Soldering, 10 sec)..................300∞C

ABSOLUTE AXI U RATI GS

WWWU

ORDER PART

NUMBER

LT1963AEQ

LT1963AEQ-1.5

LT1963AEQ-1.8

LT1963AEQ-2.5

LT1963AEQ-3.3

JMAX

= 150∞C, q

= 30∞C/W

*PIN 5 = SENSE FOR LT1963A-1.8/LT1963A-2.5/LT1963A-3.3

= ADJ FOR LT1963A

ORDER PART

NUMBER

LT1963AET

LT1963AET-1.5

LT1963AET-1.8

LT1963AET-2.5

LT1963AET-3.3

*PIN 5 = SENSE FOR LT1963A-1.8/LT1963A-2.5/LT1963A-3.3

= ADJ FOR LT1963A

JMAX

= 150∞C, q

= 50∞C/W

Q PACKAGE

5-LEAD PLASTIC DD

TAB IS

GND

FRONT VIEW

SENSE/ADJ*

OUT

GND

SHDN

T PACKAGE

5-LEAD PLASTIC TO-220

SENSE/ADJ*

OUT

GND

SHDN

FRONT VIEW

TAB IS

GND

FRONT VIEW

TAB IS

GND

OUT

GND

ST PACKAGE

3-LEAD PLASTIC SOT-223

JMAX

= 150∞C, q

= 50∞C/W

LT1963AEST-1.5

LT1963AEST-1.8

LT1963AEST-2.5

LT1963AEST-3.3

ORDER PART

NUMBER

LT1963AES8

LT1963AES8-1.5

LT1963AES8-1.8

LT1963AES8-2.5

LT1963AES8-3.3

ORDER PART

NUMBER

TOP VIEW

GND

SHDN

OUT

SENSE/ADJ*

GND

S8 PACKAGE

8-LEAD PLASTIC SO

*PIN 2 = SENSE FOR LT1963A-1.8/LT1963A-2.5/LT1963A-3.3

= ADJ FOR LT1963A

JMAX

= 150∞C, q

= 70∞C/W

PACKAGE/ORDER I FOR ATIO

ST PART

MARKING

1963A

963A15

963A18

963A25

963A33

S8 PART

MARKING

963A15

963A18

963A25

963A33

Consult LTC Marketing for parts specified with wider operating temperature ranges.

LT1963A Series

1963af

PARAMETER CONDITIONS MIN TYP MAX UNITS

Minimum Input Voltage (Notes 4,12) I

LOAD

= 0.5A 1.9 V

LOAD

= 1.5A ●2.1 2.5 V

Regulated Output Voltage (Note 5) LT1963A-1.5 V

= 2.21V, I

LOAD

= 1mA 1.477 1.500 1.523 V

2.5V < V

< 20V, 1mA < I

LOAD

< 1.5A ●1.447 1.500 1.545 V

LT1963A-1.8 V

= 2.3V, I

LOAD

= 1mA 1.773 1.800 1.827 V

2.8V < V

< 20V, 1mA < I

LOAD

< 1.5A ●1.737 1.800 1.854 V

LT1963A-2.5 V

= 3V, I

LOAD

= 1mA 2.462 2.500 2.538 V

3.5V < V

< 20V, 1mA < I

LOAD

< 1.5A ●2.412 2.500 2.575 V

LT1963A-3.3 V

= 3.8V, I

LOAD

= 1mA 3.250 3.300 3.350 V

4.3V < V

< 20V, 1mA < I

LOAD

< 1.5A ●3.200 3.300 3.400 V

ADJ Pin Voltage LT1963A V

= 2.21V, I

LOAD

= 1mA 1.192 1.210 1.228 V

(Notes 4, 5) 2.5V < V

< 20V, 1mA < I

LOAD

< 1.5A ●1.174 1.210 1.246 V

Line Regulation LT1963A-1.5 DV

= 2.21V to 20V, I

LOAD

= 1mA ●2.0 6 mV

LT1963A-1.8 DV

= 2.3V to 20V, I

LOAD

= 1mA ●2.5 7 mV

LT1963A-2.5 DV

= 3V to 20V, I

LOAD

= 1mA ●3.0 10 mV

LT1963A-3.3 DV

= 3.8V to 20V, I

LOAD

= 1mA ●3.5 10 mV

LT1963A (Note 4) DV

= 2.21V to 20V, I

LOAD

= 1mA ●1.5 5 mV

Load Regulation LT1963A-1.5 V

= 2.5V, DI

LOAD

= 1mA to 1.5A 2 9 mV

= 2.5V, DI

LOAD

= 1mA to 1.5A ●18 mV

LT1963A-1.8 V

= 2.8V, DI

LOAD

= 1mA to 1.5A 2 10 mV

= 2.8V, DI

LOAD

= 1mA to 1.5A ●20 mV

LT1963A-2.5 V

= 3.5V, DI

LOAD

= 1mA to 1.5A 2.5 15 mV

= 3.5V, DI

LOAD

= 1mA to 1.5A ●30 mV

LT1963A-3.3 V

= 4.3V, DI

LOAD

= 1mA to 1.5A 3 20 mV

= 4.3V, DI

LOAD

= 1mA to 1.5A ●35 mV

LT1963A (Note 4) V

= 2.5V, DI

LOAD

= 1mA to 1.5A 2 8 mV

= 2.5V, DI

LOAD

= 1mA to 1.5A ●15 mV

Dropout Voltage I

LOAD

= 1mA 0.02 0.06 V

= V

OUT(NOMINAL)

LOAD

= 1mA ●0.10 V

(Notes 6, 7, 12) I

LOAD

= 100mA 0.10 0.17 V

LOAD

= 100mA ●0.22 V

LOAD

= 500mA 0.19 0.27 V

LOAD

= 500mA ●0.35 V

LOAD

= 1.5A 0.34 0.45 V

LOAD

= 1.5A ●0.55 V

GND Pin Current I

LOAD

= 0mA ●1.0 1.5 mA

= V

OUT(NOMINAL)

+ 1V I

LOAD

= 1mA ●1.1 1.6 mA

(Notes 6, 8) I

LOAD

= 100mA ●3.8 5.5 mA

LOAD

= 500mA ●15 25 mA

LOAD

= 1.5A ●80 120 mA

Output Voltage Noise C

OUT

= 10mF, I

LOAD

= 1.5A, BW = 10Hz to 100kHz 40 mV

RMS

ADJ Pin Bias Current (Notes 4, 9) 3 10 mA

Shutdown Threshold V

OUT

= Off to On ●0.90 2 V

OUT

= On to Off ●0.25 0.75 V

SHDN Pin Current V

SHDN

= 0V 0.01 1 mA

(Note 10) V

SHDN

= 20V 3 30 mA

Quiescent Current in Shutdown V

= 6V, V

SHDN

= 0V 0.01 1 mA

Ripple Rejection V

– V

OUT

= 1.5V (Avg), V

RIPPLE

= 0.5V

P-P

,5563dB

RIPPLE

= 120Hz, I

LOAD

= 0.75A

Current Limit V

= 7V, V

OUT

= 0V 2 A

= V

OUT(NOMINAL)

+ 1V, DV

OUT

= –0.1V ●1.6 A

The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25∞C. (Note 2)

ELECTRICAL CHARACTERISTICS

LT1963A Series

1963af

TYPICAL PERFOR A CE CHARACTERISTICS

OUTPUT CURRENT (A)

DROPOUT VOLTAGE (mV)

500

450

400

350

300

250

200

150

100

00.4 0.8 1.0

1963 • G01

0.2 0.6 1.2 1.4 1.6

= 125°C

= 25°C

OUTPUT CURRENT (A)

GUARANTEED DROPOUT VOLTAGE (mV)

600

500

400

300

200

100

000.4 0.8 1.0

1963 • G02

0.2 0.6 1.2 1.4 1.6

TJ ≤ 125°C

TJ ≤ 25°C

TEST POINTS

TEMPERATURE (°C)

–50

DROPOUT VOLTAGE (mV)

500

450

400

350

300

250

200

150

100

0050 75

1963 G03

–25 25 100 125

= 100mA

= 1mA

= 0.5A

= 1.5A

Typical Dropout Voltage Guaranteed Dropout Voltage Dropout Voltage

Note 1: Absolute Maximum Ratings are those values beyond which the life

of a device may be impaired.

Note 2: Absolute maximum input to output differential voltage can not be

achieved with all combinations of rated IN pin and OUT pin voltages. With

the IN pin at 20V, the OUT pin may not be pulled below 0V. The total

measured voltage from IN to OUT can not exceed ±20V.

Note 3: The LT1963A regulators are tested and specified under pulse load

conditions such that T

ª T

. The LT1963A is 100% tested at

= 25∞C. Performance at –40∞C and 125∞C is assured by design,

characterization and correlation with statistical process controls.

Note 4: The LT1963A (adjustable version) is tested and specified for these

conditions with the ADJ pin connected to the OUT pin.

Note 5: 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 6: To satisfy requirements for minimum input voltage, the LT1963A

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

external resistor divider (two 4.12k resistors) for an output voltage of

2.4V. The external resistor divider will add a 300mA DC load on the output.

Note 7: 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

DROPOUT

Note 8: GND pin current is tested with V

= V

OUT(NOMINAL)

+ 1V and a

current source load. The GND pin current will decrease at higher input

voltages.

Note 9: ADJ pin bias current flows into the ADJ pin.

Note 10: SHDN pin current flows into the SHDN pin.

Note 11: 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 12. For the LT1963A, LT1963A-1.5 and LT1963A-1.8 dropout voltage

will be limited by the minimum input voltage specification under some

output voltage/load conditions.

Note 13. For the ST package, the input reverse leakage current increases

due to the additional reverse leakage current for the SHDN pin, which is

tied internally to the IN pin.

The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25∞C. (Note 2)

ELECTRICAL CHARACTERISTICS

PARAMETER CONDITIONS MIN TYP MAX UNITS

Input Reverse Leakage Current (Note 13) Q, T, S8 Packages V

= –20V, V

OUT

= 0V ●1mA

ST Package V

= –20V, V

OUT

= 0V ●2mA

Reverse Output Current (Note 11) LT1963A-1.5 V

OUT

= 1.5V, V

< 1.5V 600 1200 mA

LT1963A-1.8 V

OUT

= 1.8V, V

< 1.8V 600 1200 mA

LT1963A-2.5 V

OUT

= 2.5V, V

< 2.5V 600 1200 mA

LT1963A-3.3 V

OUT

= 3.3V, V

< 3.3V 600 1200 mA

LT1963A (Note 4) V

OUT

= 1.21V, V

< 1.21V 300 600 mA

LT1963A Series

1963af

TEMPERATURE (°C)

–50

OUTPUT VOLTAGE (V)

100

1963 G07

050

3.38

3.36

3.34

3.32

3.30

3.28

3.26

3.24

3.22 –25 25 75 125

= 1mA

TEMPERATURE (°C)

–50

ADJ PIN VOLTAGE (V)

100

1963 G08

050

1.230

1.225

1.220

1.215

1.210

1.205

1.200

1.195

1.190 –25 25 75 125

= 1mA

INPUT VOLTAGE (V)

QUIESCENT CURRENT (mA)

1963 G09

25678910

134

TJ = 25°C

RL = ∞

VSHDN = VIN

TYPICAL PERFOR A CE CHARACTERISTICS

LT1963A-3.3 Output Voltage

INPUT VOLTAGE (V)

QUIESCENT CURRENT (mA)

1963 G10

21056789

134

TJ = 25°C

RL = ∞

VSHDN = VIN

LT1963A ADJ Pin Voltage

LT1963A-1.8 Quiescent Current LT1963A-2.5 Quiescent Current

TEMPERATURE (°C)

–50

1.4

1.2

1.0

0.8

0.6

0.4

0.2

025 75

1963 G04

–25 0 50 100 125

QUIESCENT CURRENT (mA)

LT1963A-1.5/1.8/-2.5/-3.3

LT1963A

= 6V

= ∞, I

= 0

SHDN

= V

TEMPERATURE (°C)

–50

OUTPUT VOLTAGE (V)

100

1963 G05

050

1.84

1.83

1.82

1.81

1.80

1.79

1.78

1.77

1.76 –25 25 75 125

= 1mA

Quiescent Current LT1963A-1.8 Output Voltage

LT1963A-1.5 Output Voltage

TEMPERATURE (°C)

–50

OUTPUT VOLTAGE (V)

1.53

1963 G40

1.50

1.48

–25 0 50

1.47

1.46

1.54

1.52

1.51

1.49

75 100 125

= 1mA

TEMPERATURE (°C)

–50

OUTPUT VOLTAGE (V)

100

1963 G06

050

2.58

2.56

2.54

2.52

2.50

2.48

2.46

2.44

2.42 –25 25 75 125

= 1mA

LT1963A-2.5 Output Voltage

LT1963A-1.5 Quiescent Current

INPUT VOLTAGE (V)

QUIESCENT CURRENT (mA)

157

1963 G41

4910

2368

TJ = 25°C

RL = ∞

VSHDN = VIN

LT1963A Series

1963af

TYPICAL PERFOR A CE CHARACTERISTICS

INPUT VOLTAGE (V)

QUIESCENT CURRENT (mA)

1963 G11

21056789

134

TJ = 25°C

RL = ∞

VSHDN = VIN

LT1963A-3.3 Quiescent Current

INPUT VOLTAGE (V)

QUIESCENT CURRENT (mA)

1963 G12

42010 12 14 16 18

268

TJ = 25°C

RL = 4.3k

VSHDN = VIN

INPUT VOLTAGE (V)

GND PIN CURRENT (mA)

1963 G13

1231098765

= 25°C

SHDN

= V

*FOR V

OUT

= 1.8V

= 180, I

= 10mA*

= 18, I

= 100mA*

= 6, I

= 300mA*

INPUT VOLTAGE (V)

GND PIN CURRENT (mA)

1963 G14

1231098765

= 250, I

= 10mA*

= 25, I

= 100mA*

= 8.33, I

= 300mA*

= 25°C

SHDN

= V

*FOR V

OUT

= 2.5V

LT1963A Quiescent Current

LT1963A-1.8 GND Pin Current LT1963A-2.5 GND Pin Current

LT1963A-1.5 GND Pin Current

INPUT VOLTAGE (V)

GND PIN CURRENT (mA)

1963 G42

01234567 9

= 25°C

SHDN

= V

*FOR V

OUT

= 1.5V

= 5, I

= 300mA*

= 15, I

= 100mA*

= 150, I

= 10mA*

INPUT VOLTAGE (V)

GND PIN CURRENT (mA)

1963 G16

1231098765

= 121, I

= 10mA*

= 12.1, I

= 100mA*

= 4.33, I

= 300mA*

= 25°C

SHDN

= V

*FOR V

OUT

= 1.21V

LT1963A GND Pin Current

INPUT VOLTAGE (V)

GND PIN CURRENT (mA)

1963 G15

1231098765

= 330, I

= 100mA*

= 33, I

= 100mA*

= 11, I

= 300mA*

= 25°C

SHDN

= V

*FOR V

OUT

= 3.3V

LT1963A-3.3 GND Pin Current

INPUT VOLTAGE (V)

100

GND PIN CURRENT (mA)

1963 G17

012345678910

= 1.8, I

= 1A*

= 1.2, I

= 1.5A*

= 3.6, I

= 500mA*

= 25°C

SHDN

= V

*FOR V

OUT

= 1.8V

LT1963A-1.8 GND Pin CurrentLT1963A-1.5 GND Pin Current

INPUT VOLTAGE (V)

GND PIN CURRENT (mA)

100

1963 G43

021 43 67 9

510

= 25°C

SHDN

= V

*FOR V

OUT

= 1.5V

= 1, I

= 1.5A*

= 1.5, I

= 1A*

= 3, I

= 500mA*

LT1963A Series

1963af

SHDN Pin Input Current

TYPICAL PERFOR A CE CHARACTERISTICS

TEMPERATURE (°C)

–50

025 75

1963 G25

–25 0 50 100 125

SHDN PIN INPUT CURRENT (µA)

SHDN

= 20V

TEMPERATURE (°C)

–50

ADJ PIN BIAS CURRENT (µA)

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0050 75

1963 G26

–25 25 100 125

ADJ Pin Bias Current

INPUT VOLTAGE (V)

100

GND PIN CURRENT (mA)

1963 G18

012345678910

= 2.5, I

= 1A*

= 1.67, I

= 1.5A*

= 5, I

= 500mA*

= 25°C

SHDN

= V

*FOR V

OUT

= 2.5V

INPUT VOLTAGE (V)

100

GND PIN CURRENT (mA)

1963 G19

012345678910

= 3.3, I

= 1A*

= 2.2, I

= 1.5A*

= 6.6, I

= 500mA*

= 25°C

SHDN

= V

*FOR V

OUT

= 3.3V

INPUT VOLTAGE (V)

100

GND PIN CURRENT (mA)

1963 G20

012345678910

= 1.21, I

= 1A*

= 0.81, I

= 1.5A*

= 2.42, I

= 500mA*

= 25°C

SHDN

= V

*FOR V

OUT

= 1.21V

LT1963A-2.5 GND Pin Current LT1963A-3.3 GND Pin Current LT1963A GND Pin Current

OUTPUT CURRENT (A)

100

GND PIN CURRENT (mA)

1963 G21

0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

OUT (NOMINAL)

+1V

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

1963 G23

–25 25 100 125

= 1mA

= 1.5A

SHDN PIN VOLTAGE (V)

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

SHDN PIN INPUT CURRENT (µA)

1963 G24

0246810 12 14 16 18 20

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

1963 G22

–25 25 100 125

= 1mA

GND Pin Current vs ILOAD SHDN Pin Threshold (On-to-Off) SHDN Pin Threshold (Off-to-On)

SHDN Pin Input Current

LT1963A Series

1963af

TYPICAL PERFOR A CE CHARACTERISTICS

INPUT/OUTPUT DIFFERENTIAL (V)

02 6 10 14 18

CURRENT LIMIT (A)

3.0

2.5

2.0

1.5

1.0

0.5

0481216

1963 G27

= 125°C

= 25°C

= –50°C

∆V

OUT

= 100mV

Current Limit Current Limit

OUTPUT VOLTAGE (V)

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

REVERSE OUTPUT CURRENT (mA)

1963 G29

012345678910

LT1963A

LT1963A-1.5

LT1963A-3.3 T

= 25°C

= 0V

CURRENT FLOWS INTO

OUTPUT PIN

OUT

= V

ADJ

(LT1963A)

OUT

= V

(LT1963A-1.5/1.8/-2.5/-3.3)

LT1963A-2.5

LT1963A-1.8

TEMPERATURE (°C)

–50

REVERSE OUTPUT CURRENT (mA)

050 75

1963 G30

–25 25 100 125

LT1963A-1.8/-2.5/-3.3

LT1963A

VIN = 0V

VOUT = 1.21V (LT1963A)

VOUT = 1.5V (LT1963A-1.5)

VOUT = 1.8V (LT1963A-1.8)

VOUT = 2.5V (LT1963A-2.5)

VOUT = 3.3V (LT1963A-3.3)

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

TEMPERATURE (°C)

–50

CURRENT LIMIT (A)

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0050 75

1963 G28

–25 25 100 125

VIN = 7V

VOUT = 0V

Reverse Output Current

FREQUENCY (Hz)

RIPPLE REJECTION (dB)

010 1k 10k 1M

1963 G31

100 100k

OUT

= 10µF TANTALUM

OUT

= 100µF TANTALUM

+10  1µF CERAMIC

= 0.75A

= V

OUT(NOMINAL)

+1V + 50mV

RMS

RIPPLE

TEMPERATURE (°C)

–50

62 25 75

1963 G32

–25 0 50 100 125

RIPPLE REJECTION (dB)

= 0.75A

= V

OUT(NOMINAL)

+1V + 0.5V

P-P

RIPPLE AT f = 120Hz

Reverse Output Current

Ripple Rejection Ripple Rejection

TEMPERATURE (°C)

–50

MINIMUM INPUT VOLTAGE (V)

3.0

2.5

2.0

1.5

1.0

0.5

025 75

1963 G33

–25 0 50 100 125

= 1.5A I

= 500mA

= 100mA

LT1963A Minimum Input Voltage

LT1963A Series

1963af

TYPICAL PERFOR A CE CHARACTERISTICS

TEMPERATURE (°C)

–50

LOAD REGULATION (mV)

–5

–10

–15

–20 25 75

1963 G34

–25 0 50 100 125

LT1963A

LT1963A-3.3

LT1963A-1.8

LT1963A-2.5

LT1963A-1.5

= V

OUT(NOMINAL)

+1V

(LT1963A-1.8/-2.5/-3.3)

= 2.7V (LT1963A/LT1963A-1.5)

∆I

= 1mA TO 1.5A

FREQUENCY (Hz)

0.01

OUTPUT NOISE SPECTRAL DENSITY (µV/√Hz)

0.1

1.0

1k 100k

1963 G35

100 10k

OUT

= 10µF

=1.5A

LT1963A-3.3 LT1963A-2.5

LT1963A-1.8 LT1963A

LT1963A-1.5

LOAD CURRENT (A)

OUTPUT NOISE VOLTAGE (µVRMS)

0.0001 0.01 0.1 10

1063 G36

0.001 1

COUT = 10µF

LT1963A-3.3

LT1963A-2.5

LT1963A-1.8

LT1963A-1.5

LT1963A

OUT

100µV/DIV

1ms/DIV

OUT

= 10µF

LOAD

= 1.5A

1963 G37

TIME (µs)

200

150

100

–50

–100

0.6

0.4

0.2

OUTPUT VOLTAGE

DEVIATION (mV)

1963 G38

0246810 12 14 16 18 20

= 4.3V

= 3.3µF TANTALUM

OUT

= 10µF TANTALUM

LOAD

CURRENT (A)

TIME (µs)

150

100

–50

–100

–150

1.5

1.0

0.5

OUTPUT VOLTAGE

DEVIATION (mV)

LOAD

CURRENT (A)

1963 G39

050100 150 250 300 350 400 450 500200

= 4.3V

= 33µF TANTALUM

OUT

= 100µF TANTALUM

+10  1µF CERAMIC

Load Regulation Output Noise Spectral Density

RMS Output Noise vs Load

Current (10Hz to 100kHz) LT1963A-3.3 10Hz to 100kHz Output Noise

LT1963A-3.3 Transient Response LT1963A-3.3 Transient Response

LT1963A Series

1963af

Figure 1. Kelvin Sense Connection

SHDN

1963 F01

OUT

VIN

SENSE

GND

LT1963A

LOAD

PI FU CTIO S

OUT: Output. The output supplies power to the load. A

minimum output capacitor of 10mF is required to prevent

oscillations. Larger output capacitors will be

required for applications with large transient loads to limit

peak voltage transients. See the Applications Information

section for more information on output capacitance and

reverse output characteristics.

SENSE: Sense. For fixed voltage versions of the LT1963A

(LT1963A-1.5/LT1963A-1.8/LT1963A-2.5/LT1963A-3.3),

the SENSE pin is the input to the error amplifier. Optimum

regulation 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 resis-

tance (R

) 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). Note that the voltage drop across the exter-

nal PC traces will add to the dropout voltage of the regu-

lator. The SENSE pin bias current is 600mA 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.

ADJ: Adjust. For the adjustable LT1963A, this is the input

to the error amplifier. This pin is internally clamped to ±7V.

It has a bias current of 3mA which flows into the pin. The

ADJ pin voltage is 1.21V referenced to ground and the

output voltage range is 1.21V to 20V.

SHDN: Shutdown. The SHDN pin is used to put the

LT1963A 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 3mA. If unused, the SHDN pin

must be connected to V

. The device will be in the low

power shutdown state if the SHDN pin is not connected.

IN: 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 impedance 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 1mF to 10mF is sufficient. The LT1963A

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.

LT1963A Series

1963af

Figure 2. Adjustable Operation

1963 F02

OUT

ADJ

GND

LT1963A

RIR

OUT ADJ

ADJ

Áˆ

˜+

()()

=∞

121 1 2

121

m AT 25 C

OUTPUT RANGE = 1.21V TO 20V

Figure 3. Ceramic Capacitor DC Bias Characteristics

APPLICATIO S I FOR ATIO

WUUU

DC BIAS VOLTAGE (V)

CHANGE IN VALUE (%)

1963 F03

–20

–40

–60

–80

–100 04810

26 12 14

X5R

Y5V

BOTH CAPACITORS ARE 16V,

1210 CASE SIZE, 10µF

The LT1963A series are 1.5A low dropout regulators op-

timized for fast transient response. The devices are ca-

pable of supplying 1.5A at a dropout voltage of 350mV.

The low operating quiescent current (1mA) drops to less

than 1mA in shutdown. In addition to the low quiescent

current, the LT1963A regulators incorporate several pro-

tection 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 LT1963A-X

acts like it has a diode in series with its output and prevents

reverse current flow. Additionally, in dual supply applica-

tions 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 LT1963A has an output

voltage range of 1.21V 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 voltage at the ADJ

pin at 1.21V referenced to ground. The current in R1 is

then equal to 1.21V/R1 and the current in R2 is the current

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

current, 3mA 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 less than 4.17k 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.

The adjustable device is tested and specified with the ADJ

pin tied to the OUT pin for an output voltage of 1.21V.

Specifications for output voltages greater than 1.21V will

be proportional to the ratio of the desired output voltage to

1.21V: V

OUT

/1.21V. For example, load regulation for an

output current change of 1mA to 1.5A is –3mV typical at

OUT

= 1.21V. At V

OUT

= 5V, load regulation is:

(5V/1.21V)(–3mV) = –12.4mV

Output Capacitance and Transient Response

The LT1963A 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 10mF with an ESR of

3W or less is recommended to prevent oscillations. Larger

values of output capacitance can decrease the peak devia-

tions and provide improved transient response for larger

load current changes. Bypass capacitors, used to decouple

individual components powered by the LT1963A, will

increase the effective output capacitor value.

Extra consideration must be given to the use of ceramic

capacitors. Ceramic capacitors are manufactured with a

variety of dielectrics, each with different behavior over

temperature and applied voltage. The most common

dielectrics used are Z5U, Y5V, X5R and X7R. The Z5U and

Y5V dielectrics are good for providing high capacitances

in a small package, but exhibit strong voltage and tem-

perature coefficients as shown in Figures 3 and 4. When

used with a 5V regulator, a 10mF Y5V capacitor can exhibit

LT1963A Series

1963af

Figure 4. Ceramic Capacitor Temperature Characteristics

APPLICATIO S I FOR ATIO

WUUU

TEMPERATURE (°C)

–50

–20

–40

–60

–80

–100 25 75

1963 F04

–25 0 50 100 125

Y5V

CHANGE IN VALUE (%)

X5R

BOTH CAPACITORS ARE 16V,

1210 CASE SIZE, 10µF

an effective value as low as 1mF to 2mF 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.

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 micro-

phone works. For a ceramic capacitor the stress can be

induced by vibrations in the system or thermal transients.

Overload Recovery

Like many IC power regulators, the LT1963A-X has safe

operating area protection. The safe area protection de-

creases the current limit as input-to-output voltage in-

creases and keeps the power transistor inside a safe

operating region for all values of input-to-output voltage.

The protection is designed to provide some output current

at all values of input-to-output voltage up to the device

breakdown.

When power is first turned on, as the input voltage rises,

the output follows the input, allowing the regulator to start

up into very heavy loads. During the start-up, as the input

voltage is rising, the input-to-output voltage differential is

small, allowing the regulator to supply large output

currents. With a high input voltage, a problem can occur

wherein removal of an output short will not allow the

output voltage to recover. Other regulators, such as the

LT1085, also exhibit this phenomenon, so it is not unique

to the LT1963A-X.

The problem occurs with a heavy output load when the

input voltage is high and the output voltage is low. Com-

mon situations are immediately after the removal of a

short-circuit or when the shutdown pin is pulled high after

the input voltage has already been turned on. The load line

for such a load may intersect the output current curve at

two points. If this happens, there are two stable output

operating points for the regulator. With this double inter-

section, the input power supply may need to be cycled

down to zero and brought up again to make the output

recover.

Output Voltage Noise

The LT1963A regulators have been designed to provide

low output voltage noise over the 10Hz to 100kHz band-

width while operating at full load. Output voltage noise is

typically 40nV/÷Hz over this frequency bandwidth for the

LT1963A (adjustable version). For higher output voltages

(generated by using a resistor divider), the output voltage

noise will be gained up accordingly. This results in RMS

noise over the 10Hz to 100kHz bandwidth of 14mV

RMS

for

the LT1963A increasing to 38mV

RMS

for the LT1963A-3.3.

Higher values of output voltage noise may be measured

when care is not exercised with regards to circuit layout

and testing. Crosstalk from nearby traces can induce

unwanted noise onto the output of the LT1963A-X. Power

supply ripple rejection must also be considered; the

LT1963A regulators do not have unlimited power supply

rejection and will pass a small portion of the input noise

through to the output.

Thermal Considerations

The power handling capability of the device is limited by the

maximum rated junction temperature (125∞C). The power

dissipated by the device is made up of two components:

1. Output current multiplied by the input/output voltage

differential: (I

OUT

)(V

– V

OUT

), and

LT1963A Series

1963af

APPLICATIO S I FOR ATIO

WUUU

2. GND pin current multiplied by the input voltage:

GND

)(V

The GND pin current can be found using the GND Pin

Current curves in the Typical Performance Characteris-

tics. Power dissipation will be equal to the sum of the two

components listed above.

The LT1963A series regulators have internal thermal

limiting designed to protect the device during overload

conditions. For continuous normal conditions, the maxi-

mum 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 ambi-

ent. 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 1/16" FR-4 board with one ounce

copper.

Table 1. Q Package, 5-Lead DD

COPPER AREA THERMAL RESISTANCE

TOPSIDE* BACKSIDE BOARD AREA (JUNCTION-TO-AMBIENT)

2500mm

23∞C/W

1000mm

2500mm

25∞C/W

125mm

2500mm

33∞C/W

*Device is mounted on topside

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

COPPER AREA THERMAL RESISTANCE

TOPSIDE* BACKSIDE BOARD AREA (JUNCTION-TO-AMBIENT)

2500mm

55∞C/W

1000mm

2500mm

55∞C/W

225mm

2500mm

63∞C/W

100mm

2500mm

69∞C/W

*Device is mounted on topside.

Table 3. SOT-223 Package, 3-Lead SOT-223

COPPER AREA THERMAL RESISTANCE

TOPSIDE* BACKSIDE BOARD AREA (JUNCTION-TO-AMBIENT)

2500mm

42∞C/W

1000mm

2500mm

42∞C/W

225mm

2500mm

50∞C/W

100mm

2500mm

56∞C/W

1000mm

49∞C/W

1000mm

0mm

1000mm

52∞C/W

*Device is mounted on topside.

T Package, 5-Lead TO-220

Thermal Resistance (Junction-to-Case) = 4∞C/W

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

500mA 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:

OUT(MAX)

IN(MAX)

– V

OUT

) + I

GND

IN(MAX)

)

where,

OUT(MAX)

= 500mA

IN(MAX)

= 6V

GND

at (I

OUT

= 500mA, V

= 6V) = 10mA

So,

P = 500mA(6V – 3.3V) + 10mA(6V) = 1.41W

Using a DD package, the thermal resistance will be in the

range of 23∞C/W to 33∞C/W depending on the copper

area. So the junction temperature rise above ambient will

be approximately equal to:

1.41W(28∞C/W) = 39.5∞C

The maximum junction temperature will then be equal to

the maximum junction temperature rise above ambient

plus the maximum ambient temperature or:

JMAX

= 50∞C + 39.5∞C = 89.5∞C

LT1963A Series

1963af

APPLICATIO S I FOR ATIO

WUUU

Figure 5. Reverse Output Current

OUTPUT VOLTAGE (V)

REVERSE OUTPUT CURRENT (mA)

3.0

4.0

5.0

1963 F05

2.0

1.0

2.5

3.5

4.5

1.5

0.5

13469

510

LT1963A

OUT

= V

ADJ

= 25°C

= 0V

CURRENT FLOWS

INTO OUTPUT PIN

LT1963A-2.5

OUT

= V

LT1963A-3.3

OUT

= V

LT1963A-1.8

OUT

= V

LT1963A-1.5

OUT

= V

Protection Features

The LT1963A 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 opera-

tion, 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 100mA) and no negative voltage

will appear at the output. The device will protect both itself

and the load. This provides protection against batteries

that can be plugged in backward.

The output of the LT1963A 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 5k or higher, limiting current flow

to typically less than 600mA. 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 5k) 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 1.21V reference when the output is forced to 20V.

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 OUT and ADJ

pins 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 5.

When the IN pin of the LT1963A is forced below the OUT

pin or the OUT pin is pulled above the IN pin, input current

will typically drop to less than 2mA. 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.

LT1963A Series

1963af

10VAC AT

115VIN

10VAC AT

115VIN

–

750Ω

1/2

LT1018

1/2

LT1018

LT1006

10k

10k 10k

200k

0.1µF

22µF

1µF

0.033µF

1N4148

LT1004

1.2V

750Ω

C1A

C1B

34k*

12.1k*

3.3VOUT

1.5A

500µH

10000µF

TO ALL “+V”

POINTS

22µF

1N4002

1N4002 1N4002

1N4148

“SYNC”

90-140

VAC

1963 TA03

LT1963A-3.3

SHDN

OUT

GND

2.4k

L1 = COILTRONICS CTX500-2-52

L2 = STANCOR P-8559

* = 1% FILM RESISTOR

= NTE5437

TYPICAL APPLICATIO S

SCR Pre-Regulator Provides Efficiency Over Line Variations

LT1963A Series

1963af

PACKAGE DESCRIPTIO

Q(DD5) 1098

0.028 – 0.038

(0.711 – 0.965)

0.143+0.012

–0.020

()

3.632+0.305

–0.508

0.067

(1.70)

BSC

0.013 – 0.023

(0.330 – 0.584)

0.095 – 0.115

(2.413 – 2.921)

0.004+0.008

–0.004

()

0.102+0.203

–0.102

0.050 ± 0.012

(1.270 ± 0.305)

0.059

(1.499)

TYP

0.045 – 0.055

(1.143 – 1.397)

0.165 – 0.180

(4.191 – 4.572)

0.330 – 0.370

(8.382 – 9.398)

0.060

(1.524)

TYP

0.390 – 0.415

(9.906 – 10.541)

15° TYP

0.300

(7.620)

0.075

(1.905)

0.183

(4.648)

0.060

(1.524)

0.060

(1.524)

0.256

(6.502)

BOTTOM VIEW OF DD PAK

HATCHED AREA IS SOLDER PLATED

COPPER HEAT SINK

Q Package

5-Lead Plastic DD Pak

(Reference LTC DWG # 05-08-1461)

LT1963A Series

1963af

S8 Package

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

(Reference LTC DWG # 05-08-1610)

PACKAGE DESCRIPTIO

0.016 – 0.050

(0.406 – 1.270)

0.010 – 0.020

(0.254 – 0.508)¥ 45∞

0°– 8° TYP

0.008 – 0.010

(0.203 – 0.254)

SO8 1298

0.053 – 0.069

(1.346 – 1.752)

0.014 – 0.019

(0.355 – 0.483)

TYP

0.004 – 0.010

(0.101 – 0.254)

0.050

(1.270)

BSC

1234

0.150 – 0.157**

(3.810 – 3.988)

8765

0.189 – 0.197*

(4.801 – 5.004)

0.228 – 0.244

(5.791 – 6.197)

DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH

SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE

DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD

FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE

LT1963A Series

1963af

ST Package

3-Lead Plastic SOT-223

(Reference LTC DWG # 05-08-1630)

PACKAGE DESCRIPTIO

0.114 – 0.124

(2.90 – 3.15)

0.248 – 0.264

(6.30 – 6.71)

0.130 – 0.146

(3.30 – 3.71)

0.264 – 0.287

(6.70 – 7.30)

0.0905

(2.30)

NOM

0.033 – 0.041

(0.84 – 1.04)

0.181

(4.60)

NOM

0.024 – 0.033

(0.60 – 0.84)

0.071

(1.80)

MAX

10°

MAX

0.012

(0.31)

MIN

0.0008 – 0.0040

(0.0203 – 0.1016)

10° – 16°

0.010 – 0.014

(0.25 – 0.36)

10° – 16°

ST3 (SOT-233) 1298

LT1963A Series

1963af

PACKAGE DESCRIPTIO

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 represen-

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

T Package

5-Lead Plastic TO-220 (Standard)

(Reference LTC DWG # 05-08-1421)

T5 (TO-220) 0399

0.028 – 0.038

(0.711 – 0.965)

0.067

(1.70) 0.135 – 0.165

(3.429 – 4.191)

0.700 – 0.728

(17.78 – 18.491)

0.045 – 0.055

(1.143 – 1.397)

0.095 – 0.115

(2.413 – 2.921)

0.013 – 0.023

(0.330 – 0.584)

0.620

(15.75)

TYP

0.155 – 0.195*

(3.937 – 4.953)

0.152 – 0.202

(3.861 – 5.131)

0.260 – 0.320

(6.60 – 8.13)

0.165 – 0.180

(4.191 – 4.572)

0.147 – 0.155

(3.734 – 3.937)

DIA

0.390 – 0.415

(9.906 – 10.541)

0.330 – 0.370

(8.382 – 9.398)

0.460 – 0.500

(11.684 – 12.700)

0.570 – 0.620

(14.478 – 15.748)

0.230 – 0.270

(5.842 – 6.858)

BSC

SEATING PLANE

* MEASURED AT THE SEATING PLANE

LT1963A Series

1963af

PART NUMBER DESCRIPTION COMMENTS

LT1120 125mA Low Dropout Regulator with 20mA I

Includes 2.5V Reference and Comparator

LT1121 150mA Micropower Low Dropout Regulator 30mA I

, SOT-223 Package

LT1129 700mA Micropower Low Dropout Regulator 50mA Quiescent Current

LT1175 500mA Negative Low Dropout Micropower Regulator 45mA I

, 0.26V Dropout Voltage, SOT-223 Package

LT1521 300mA Low Dropout Micropower Regulator with Shutdown 15mA I

, Reverse Battery Protection

LT1529 3A Low Dropout Regulator with 50mA I

500mV Dropout Voltage

LT1772 Constant Frequency, Current Mode Step-Down DC/DC Controller Up to 94% Efficiency, SOT-23 Package, 100% Duty Cycle

LTC1627 High Efficiency Synchronous Step-Down Switching Regulator Burst ModeTM Operation, Monolithic, 100% Duty Cycle

LT1761 Series 100mA, Low Noise, Low Dropout Micropower Regulators in SOT-23 20mA Quiescent Current, 20mV

RMS

Noise, ThinSOTTM Package

LT1762 Series 150mA, Low Noise, LDO Micropower Regulators 25mA Quiescent Current, 20mV

RMS

Noise, MSOP Package

LT1763 Series 500mA, Low Noise, LDO Micropower Regulators 30mA Quiescent Current, 20mV

RMS

Noise, SO-8 Package

LT1764A Series 3A, Fast Transient Response Low Dropout Regulator 340mV Dropout Voltage, 40mV

RMS

Noise

LT1962 Series 300mA, Low Noise, LDO Micropower Regulator 30mA Quiescent Current, 20mV

RMS

Noise, MSOP Package

LT1964 200mA, Low Noise, Negative LDO Micropower Regulator 30mA Quiescent Current, 30mV

RMS

Noise, ThinSOT Package

Burst Mode is a registered trademark of Linear Technology Corporation.

ThinSOT is a trademark of Linear Technology Corporation.

LT/TP 0602 2K • PRINTED IN USA

„ LINEAR TECHNOLOGY CORPORATION 2002

RELATED PARTS

LT1963A-3.3

SHDN

OUT

GND

LT1963A

SHDN

OUT

GND

0.01Ω

2.2k R4

2.2k R5

6.65k

4.12k

100µF

0.01µF

22µF

VIN > 3.7V

SHDN

3.3V

–

1/2

LT1366

1963 TA05

TYPICAL APPLICATIO S

Paralleling of Regulators for Higher Output Current

LT1004-1.2

> 2.7V C1

10µF

80.6k

2.2k

0.01Ω

2.2k

LT1963A-1.8

SHDN

OUT

GND

–

1/2

LT1366

100k

LOAD

470Ω

1µF

3.3µF

1963 TA04

NOTE: ADJUST R1 FOR

0A TO 1.5A CONSTANT CURRENT

Adjustable Current Source

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900

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FAX: (408) 434-0507

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