LT3014HVES5#TRM_技术文档

LT3014

20mA, 3V to 80V

Low Dropout Micropower

Linear Regulator

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FEATURES

DESCRIPTIO

The LT^®3014 is a high voltage, micropower low dropout

linear regulator. The device is capable of supplying 20mA

of output current with a dropout voltage of 350mV. De-

signed for use in battery-powered or high voltage sys-

tems, the low quiescent current (7µA operating and 1µA in

shutdown) makes the LT3014 an ideal choice. Quiescent

current is also well controlled in dropout.

■

Wide Input Voltage Range: 3V to 80V

■

Low Quiescent Current: 7µA

■

Low Dropout Voltage: 350mV

Output Current: 20mA

■

LT3014HV Survives 100V Transients (2ms)

■

No Protection Diodes Needed

■

Adjustable Output from 1.22V to 60V

■

1µA Quiescent Current in Shutdown

Other features of the LT3014 include the ability to operate

with very small output capacitors. The regulators are

stable with only 0.47µF on the output while most older

devices require between 10µF and 100µF for stability.

Small ceramic capacitors can be used without the neces-

sary addition of ESR as is common with other regulators.

Internal protection circuitry includes reverse-battery pro-

tection, current limiting, thermal limiting and reverse

current protection.

■

Stable with 0.47µF Output Capacitor

■

Stable with Aluminum, Tantalum or Ceramic

Capacitors

Reverse-Battery Protection

■

No Reverse Current Flow from Output

■

Thermal Limiting

Available in 5-Lead ThinSOT^TMand

■

8-Lead DFN Packages

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APPLICATIO S

Thedeviceisavailableasanadjustabledevicewitha1.22V

reference voltage. The LT3014 regulator is available in the

5-lead ThinSOT and 8-lead DFN packages.

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

ThinSOT is a trademark of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Protected by U.S. Patents including 6118263, 6144250.

■

Low Current High Voltage Regulators

■

Regulator for Battery-Powered Systems

■

Telecom Applications

Automotive Applications

■

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TYPICAL APPLICATIO

Dropout Voltage

400

350

300

250

200

150

100

50

5V Supply with Shutdown

V

OUT

IN

OUT

5V

20mA

V

IN

LT3014

3.92M

1.27M

5.4V TO

80V

0.47µF

1µF

SHDN

GND

ADJ

3014 TA01

V

OUTPUT

OFF

ON

SHDN

<0.3V

>2.0V

0

2

4

6

8

10 12 14 16 18 20

OUTPUT CURRENT (mA)

3014 TA02

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1

LT3014

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ABSOLUTE AXI U RATI GS ^{(Note 1)}

IN Pin Voltage, Operating ................................. ±80V

Transient (2ms Survival, LT3014HV).............. +100V

OUT Pin Voltage ............................................... ±60V

IN to OUT Differential Voltage........................... ±80V

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

SHDN Pin Input Voltage ................................... ±80V

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

Storage Temperature Range

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

DFN Package ............................... –65°C to 125°C

Operating Junction Temperature Range

(Notes 3, 10, 11) ......................... –40°C to 125°C

Lead Temperature, SOT-23

(Soldering, 10 sec) ..................................... 300°C

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PACKAGE/ORDER I FOR ATIO

TOP VIEW

OUT

ADJ

NC

1

2

3

4

8

7

6

5

IN

IN 1

GND 2

5 OUT

4 ADJ

NC

9

NC

SHDN 3

GND

SHDN

S5 PACKAGE

5-LEAD PLASTIC SOT-23

DD PACKAGE

8-LEAD (3mm × 3mm) PLASTIC DFN

EXPOSED PAD IS GND (PIN 9)

MUST BE SOLDERED TO PCB

T_JMAX= 125°C, θ_JA= 40°C/ W

T_JMAX= 125°C, θ_JA= 150°C/ W

_JC= 25°C/ W MEASURED AT PIN 2.

SEE APPLICATIONS INFORMATION SECTION.

θ

_JC= 10°C/ W MEASURED AT PIN 9.

ORDER PART NUMBER

S5 PART MARKING

ORDER PART NUMBER

DD PART MARKING

LT3014ES5

LT3014HVES5

LTBMF

LTBRS

LT3014EDD

LT3014HVEDD

LBMG

LBRT

Order Options Tape and Reel: Add #TR

Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF

Lead Free Part Marking: http://www.linear.com/leadfree/

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

ELECTRICAL CHARACTERISTICS

The

●

denotes specifications which apply over the full operating temperature range, otherwise specifications are at T = 25°C.

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PARAMETER

CONDITIONS

= 20mA

MIN

TYP

MAX

UNITS

Minimum Input Voltage

I

●

3

3.3

V

LOAD

ADJ Pin Voltage

(Notes 2, 3)

V

= 3.3V, I

= 100µA

LOAD

1.200

1.180

1.220

1.240

1.260

V

IN

3.3V < V < 80V, 100µA < I

< 20mA

●

IN

LOAD

Line Regulation

Load Regulation

∆V = 3.3V to 80V, I

= 100µA (Note 2)

LOAD

1

10

mV

IN

V

= 3.3V, ∆I

= 100µA to 20mA (Note 2)

= 100µA to 20mA

13

25

40

mV

IN

LOAD

●

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2

LT3014

ELECTRICAL CHARACTERISTICS

The

●

denotes specifications which apply over the full operating temperature range, otherwise specifications are at T = 25°C.

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PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Dropout Voltage

I

= 100µA

120

180

250

mV

LOAD

V

= V

(Notes 4, 5)

●

IN

OUT(NOMINAL)

I

= 1mA

200

300

350

270

360

mV

LOAD

I

= 10mA

350

450

mV

LOAD

I

= 20mA

410

570

mV

LOAD

GND Pin Current

= V

(Notes 4, 6)

I

= 0mA

= 100µA

= 1mA

= 10mA

= 20mA

●

7

12

40

250

650

20

30

100

450

1000

µA

LOAD

V

IN

OUT(NOMINAL)

Output Voltage Noise

ADJ Pin Bias Current

Shutdown Threshold

C

= 0.47µF, I

= 20mA, BW = 10Hz to 100kHz

115

4

µV

RMS

OUT

LOAD

(Note 7)

10

2

nA

V

= Off to On

= On to Off

●

1.3

V

OUT

0.25

SHDN Pin Current

(Note 8)

V

= 0V

= 6V

●

1

0

4

1

µA

SHDN

Quiescent Current in Shutdown

Ripple Rejection

V

= 6V, V

= 0V

●

1

4

µA

IN

SHDN

= 7V(Avg), V

= 0.5V , f

= 120Hz, I = 20mA

LOAD

60

25

70

dB

RIPPLE

P-P RIPPLE

Current Limit

V

= 7V, V

= 0V

mA

IN

OUT

= 3.3V, ∆V

= –0.1V (Note 2)

●

OUT

Input Reverse

Leakage Current

V

= –80V, V

= 0V

OUT

6

4

mA

IN

Reverse Output Current

(Note 9)

V

= 1.22V, V < 1.22V (Note 2)

2

µA

OUT

IN

Note 6: GND pin current is tested with V = V

(nominal) and a current

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.

IN

OUT

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

decreases slightly at higher input voltages.

Note 7: ADJ pin bias current flows into the ADJ pin.

Note 8: SHDN pin current flows out of the SHDN pin.

Note 2: The LT3014 is tested and specified for these conditions with the

ADJ pin connected to the OUT pin.

Note 3: 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 4: To satisfy requirements for minimum input voltage, the LT3014 is

tested and specified for these conditions with an external resistor divider

(249k bottom, 392k top) for an output voltage of 3.3V. The external

resistor divider adds a 5µA DC load on the output.

Note 9: 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 of the GND pin.

Note 10: The LT3014E is guaranteed to meet performance specifications

from 0°C to 125°C operating junction temperature. Specifications over

the –40°C to 125°C operating junction temperature range are assured by

design, characterization and correlation with statistical process controls.

Note 11: This IC includes overtemperature protection that is intended to

protect the device during momentary overload conditions. Junction

temperature will exceed 125°C when overtemperature protection is

active. Continuous operation above the specified maximum operating

junction temperature may impair device reliability.

Note 5: Dropout voltage is the minimum input to output voltage differential

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

output voltage is equal to (V – V

).

IN

DROPOUT

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3

LT3014

TYPICAL PERFOR A CE CHARACTERISTICS

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Typical Dropout Voltage

Guaranteed Dropout Voltage

Dropout Voltage

600

500

450

400

350

300

250

200

150

100

50

500

450

400

350

300

250

200

150

100

50

= TEST POINTS

T

J

≤ 125°C

T = 125°C

J

I

L

= 20mA

400

300

T

≤ 25°C

I

L

= 10mA

J

T = 25°C

J

I

L

= 1mA

200

100

0

I

L

= 100µA

0

2

4

6

8

10 12 14 16 18 20

0

2

4

6

8

10 12 14 16 18 20

–50

0

25

50

75 100 125

–25

OUTPUT CURRENT (mA)

TEMPERATURE (°C)

OUTPUT CURRENT (mA)

3014 G01

3014 G02

3014 G03

Quiescent Current

ADJ Pin Voltage

Quiescent Current

1.240

16

14

12

10

8

I

= 100µA

T = 25°C

V

= 6V

L

J

L

OUT

IN

L

R

V

= ∞

R

I

= ∞

1.235

1.230

14

12

= 1.22V

= 0

L

1.225

1.220

1.215

1.210

1.205

10

8

V

= V

IN

SHDN

V

= V

IN

SHDN

6

4

2

V

= 0V

SHDN

V

= 0V

5

SHDN

4

0

1.200

0

–25

0

50

75 100 125

1

2

3

6

7

9

–50

25

0

8

10

–25

0

50

75 100 125

–50

25

TEMPERATURE (°C)

INPUT VOLTAGE (V)

TEMPERATURE (°C)

3014 G05

3014 G06

3014 G04

GND Pin Current

GND Pin Current vs I

SHDN Pin Threshold

LOAD

1000

900

800

700

600

500

400

300

200

100

0

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

1000

900

800

700

600

500

400

300

200

100

0

T

= 25°C

V

T

= 3.3V

J

IN

J

*FOR V

= 1.22V

= 25°C

OUT

V

= 1.22V

OUT

R

L

= 61Ω

L

I

= 20mA*

R

I

= 122Ω

L

= 10mA*

R

L

= 1.22k

= 1mA*

L

I

0

1

2

3

4

5

6

7

8

9

10

–50 –25

0

25

50

75 100 125

0

2

4

6

8

10 12 14 16 18 20

INPUT VOLTAGE (V)

TEMPERATURE (°C)

OUTPUT CURRENT (mA)

3014 G09

3014 G07

3014 G08

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4

LT3014

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TYPICAL PERFOR A CE CHARACTERISTICS

SHDN Pin Current

ADJ Pin Bias Current

14

12

10

8

1.2

1.0

1.6

T = 25°C

V

SHDN

= 0V

J

CURRENT FLOWS

OUT OF SHDN PIN

CURRENT FLOWS

OUT OF SHDN PIN

1.4

1.2

0.8

0.6

1.0

0.8

0.6

0.4

0.2

6

0.4

0.2

0

4

2

0

–50

0

–25

0

50

75 100 125

25

2.5

3

–25

0

50

75 100 125

0

0.5

1

1.5

2

3.5

4

–50

25

SHDN PIN VOLTAGE (V)

TEMPERATURE (°C)

3014 G12

3014 G10

3014 G11

Current Limit

Reverse Output Current

50

45

40

35

30

25

20

15

10

5

100

90

80

70

60

50

40

30

20

10

0

80

V

= 7V

V

T

= 0V

T

= 25°C

J

IN

OUT

J

= 0V

= 25°C

V

= 0V

IN

OUT

70

60

ADJ PIN

ESD CLAMP

V

= V

ADJ

50

40

30

20

10

CURRENT FLOWS

INTO OUTPUT PIN

0

1

2

3

4

5

6

7

8

9

10

0

2

4

6

8

10 12 14 16 18 20

–50

0

25

50

75 100 125

–25

TEMPERATURE (°C)

OUTPUT VOLTAGE (V)

INPUT VOLTAGE (V)

3014 G15

3014 G13

3014 G14

Reverse Output Current

Input Ripple Rejection

72

8

80

V

= 0V

= V

V

= 7V + 0.5V

P-P

V

I

= 7V + 50mV

RIPPLE

IN

OUT

IN

RMS

= 1.22V

ADJ

RIPPLE AT f = 120Hz

= 20mA

L

70

68

7

6

70

60

I

= 20mA

L

66

64

62

60

58

5

4

3

2

1

50

40

30

20

10

C

= 4.7µF

OUT

C

= 0.47µF

OUT

56

0

–25

0

50

75 100 125

–50

25

–25

0

50

75 100 125

10

100

1k

10k

100k

1M

–50

25

TEMPERATURE (°C)

FREQUENCY (Hz)

3014 G18

3014 G17

3014 G16

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5

LT3014

TYPICAL PERFOR A CE CHARACTERISTICS

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Minimum Input Voltage

Load Regulation

Output Noise Spectral Density

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

10

1

0

I

= 20mA

∆I = 100µA TO 20mA

C

L

V

= 0.47µF

LOAD

L

OUT

V

= 1.22V

I

= 20mA

–5

= 1.22V

–10

–15

–20

–25

–30

–35

0.1

0.01

–40

–50 –25

0

25

50

75

100 125

–50 –25

0

25

50

75 100 125

10

100

1k

10k

100k

TEMPERATURE (°C)

FREQUENCY (Hz)

3014 G21

3014 G19

3014 G20

10Hz to 100kHz Output Noise

Transient Response

0.04

0.02

0

V

= 7V

= 5V

V_OUT

200µV/DIV

IN

–0.02

–0.04

V

OUT

C

= C

= 0.47µF CERAMIC

IN

OUT

∆I

= 1mA TO 5mA

LOAD

6

4

C_OUT= 0.47µF

1ms/DIV

3014 G22

2

0

I_L= 20mA

V

_OUT= 1.22V

0

200

400

600

800

1000

TIME (µs)

3014 G23

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PI FU CTIO S ^{(SOT-23 Package/DD Package)}

appear at the load. The device will protect both itself and

the load.

IN (Pin 1/Pin 8): Input. Power is supplied to the device

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

pinifthedeviceismorethansixinchesawayfromthemain

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 0.1µF to 10µF is sufficient. The

LT3014 is designed to withstand reverse voltages on the

IN pin with respect to ground and the OUT pin. In the case

of a reversed input, which can happen if a battery is

plugged in backwards, the LT3014 will act as if there is a

diode in series with its input. There will be no reverse

current flow into the LT3014 and no reverse voltage will

GND (Pin 2/Pins 4, 9): Ground.

SHDN (Pin 3/Pin 5): Shutdown. The SHDN pin is used to

put the LT3014 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 only required to supply the pull-up current of the open-

collector gate, normally several microamperes. If unused,

the SHDN pin must be tied to IN or to a logic high.

3014fb

6

LT3014

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PI FU CTIO S ^{(SOT-23 Package/DD Package)}

OUT (Pin 5/Pin 1): Output. The output supplies power to

the load. A minimum output capacitor of 0.47µF 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

Information section for more information on output ca-

pacitance and reverse output characteristics.

ADJ (Pin 4/Pin 2): Adjust. This is the input to the error

amplifier. This pin is internally clamped to ±7V. It has a

bias current of 4nA which flows into the pin (see curve of

ADJPinBiasCurrentvsTemperatureintheTypicalPerfor-

mance Characteristics). The ADJ pin voltage is 1.22V

referenced to ground, and the output voltage range is

1.22V to 60V.

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APPLICATIO S I FOR ATIO

than 1.22V will be proportional to the ratio of the desired

output voltage to 1.22V (V_OUT/1.22V). For example, load

regulation for an output current change of 1mA to 20mA

is –13mV typical at V_OUT= 1.22V. At V_OUT= 12V, load

regulation is:

The LT3014 is a 20mA high voltage low dropout regulator

with micropower quiescent current and shutdown. The

device is capable of supplying 20mA at a dropout voltage

of 350mV. The low operating quiescent current (7µA)

drops to 1µA in shutdown. In addition to the low quiescent

current, the LT3014 incorporates several protection fea-

tures which make it ideal for use in battery-powered

systems. The device is protected against both reverse

input and reverse output voltages. In battery backup

applications where the output can be held up by a backup

batterywhentheinputispulledtoground,theLT3014acts

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

reverse current flow.

(12V/1.22V) • (–13mV) = –128mV

V

IN

OUT

LT3014

ADJ

OUT

+

R2

R1

V

IN

GND

3014 F01

R2

R1

V

= 1.22V 1 +

•

+ (I )(R2)

ADJ

OUT

ADJ

(

)

= 1.22V

= 4nA AT 25°C

I

ADJ

Adjustable Operation

OUTPUT RANGE = 1.22V TO 60V

The LT3014 has an output voltage range of 1.22V to 60V.

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 adjust pin at 1.22V

referenced to ground. The current in R1 is then equal to

Figure 1. Adjustable Operation

Output Capacitance and Transient Response

The LT3014 is designed to be stable with a wide range of

1.22V/R1 and the current in R2 is the current in R1 plus output capacitors. The ESR of the output capacitor affects

stability, most notably with small capacitors. A minimum

output capacitor of 0.47µF with an ESR of 3Ω or less is

the ADJ pin bias current. The ADJ pin bias current, 4nA

at 25°C, flows through R2 into the ADJ pin. The output

voltage can be calculated using the formula in Figure 1. recommended to prevent oscillations. The LT3014 is a

micropower device and output transient response will be

a function of output capacitance. Larger values of output

The value of R1 should be less than 1.62M to minimize

errors in the output voltage caused by the ADJ pin bias

current. Note that in shutdown the output is turned off 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 LT3014, will increase the

effective output capacitor value.

and the divider current will be zero. The device is tested

and specified with the ADJ pin tied to the OUT pin and a

5µA DC load (unless otherwise specified) for an output

voltageof1.22V.Specificationsforoutputvoltagesgreater

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7

LT3014

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APPLICATIO S I FOR ATIO

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 di-

electrics 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 2 and 3. When

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

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

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.

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: I_OUT• (V_IN– V_OUT) and,

2. GND pin current multiplied by the input voltage:

I_GND• V_IN.

The GND pin current can be found by examining the GND

Pin Current curves in the Typical Performance Character-

istics.Powerdissipationwillbeequaltothesumofthetwo

components listed above.

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,

40

20

BOTH CAPACITORS ARE 16V,

1210 CASE SIZE, 10µF

0

X5R

0

–20

X5R

–20

–40

Y5V

–60

Y5V

–80

BOTH CAPACITORS ARE 16V,

1210 CASE SIZE, 10µF

–100

50

TEMPERATURE (°C)

100 125

–50 –25

0

25

75

0

8

12 14

2

4

6

10

16

DC BIAS VOLTAGE (V)

3014 F03

3014 F02

Figure 2. Ceramic Capacitor DC Bias Characteristics

Figure 3. Ceramic Capacitor Temperature Characteristics

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8

LT3014

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APPLICATIO S I FOR ATIO

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Continuous operation at large input/output voltage differ-

entials and maximum load current is not practical due to

thermal limitations. Transient operation at high input/

output differentials is possible. The approximate thermal

time constant for a 2500sq mm 3/32" FR-4 board with

maximumtopsideandbacksideareaforoneouncecopper

is 3 seconds. This time constant will increase as more

thermal mass is added (i.e. vias, larger board, and other

components).

The LT3014 regulator has internal thermal limiting de-

signed 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.

For an application with transient high power peaks, aver-

age power dissipation can be used for junction tempera-

turecalculationsaslongasthepulseperiodissignificantly

less than the thermal time constant of the device and

board.

The following table lists 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.

Calculating Junction Temperature

Example 1: Given an output voltage of 5V, an input voltage

range of 24V to 30V, an output current range of 0mA to

20mA, and a maximum ambient temperature of 50°C,

what will the maximum junction temperature be?

Table 1. SOT-23 Measured Thermal Resistance

COPPER AREA

THERMAL RESISTANCE

TOPSIDE

2500 sq mm

1000 sq mm

225 sq mm

100 sq mm

50 sq mm

BACKSIDE

2500 sq mm

BOARD AREA

2500 sq mm

(JUNCTION-TO-AMBIENT)

125°C/W

The power dissipated by the device will be equal to:

125°C/W

130°C/W

I

_OUT(MAX)• (V_IN(MAX)– V_OUT) + (I_GND• V_IN(MAX)

where:

I_OUT(MAX)= 20mA

)

135°C/W

150°C/W

Table 2. DFN Measured Thermal Resistance

V_IN(MAX)= 30V

COPPER AREA

THERMAL RESISTANCE

I_GNDat (I_OUT= 20mA, V_IN= 30V) = 0.55mA

TOPSIDE

2500 sq mm

1000 sq mm

225 sq mm

100 sq mm

BACKSIDE

2500 sq mm

BOARD AREA

2500 sq mm

(JUNCTION-TO-AMBIENT)

40°C/W

So:

45°C/W

P = 20mA • (30V – 5V) + (0.55mA • 30V) = 0.52W

50°C/W

The thermal resistance for the DFN package will be in the

rangeof40°C/Wto62°C/Wdependingonthecopperarea.

So the junction temperature rise above ambient will be

approximately equal to:

62°C/W

For the DFN package, the thermal resistance junction-to-

case(θ_JC),measuredattheexposedpadonthebackofthe

die, is 16°C/W.

0.52W • 50°C/W = 26°C

3014fb

9

LT3014

W U U

U

APPLICATIO S I FOR ATIO

The maximum junction temperature will then be equal to

the maximum junction temperature rise above ambient

plus the maximum ambient temperature or:

Protection Features

TheLT3014incorporatesseveralprotectionfeatureswhich

make it ideal for use in battery-powered circuits. In addi-

tion to the normal protection features associated with

monolithic regulators, such as current limiting and ther-

mal limiting, the device is protected against reverse-input

voltages, and reverse voltages from output to input.

T

_JMAX= 50°C + 26°C = 76°C

Example 2: Given an output voltage of 5V, an input voltage

of 48V that rises to 72V for 5ms(max) out of every 100ms,

and a 5mA load that steps to 20mA for 50ms out of every

250ms, what is the junction temperature rise above ambi-

ent? Using a 500ms period (well under the time constant

of the board), power dissipation is as follows:

Current limit protection and thermal overload protection

areintendedtoprotectthedeviceagainstcurrentoverload

conditions at the output of the device. For normal opera-

tion, the junction temperature should not exceed 125°C.

P1(48V in, 5mA load) = 5mA • (48V – 5V)

+ (100µA • 48V) = 0.22W

The input of the device will withstand reverse voltages of

80V.Currentflowintothedevicewillbelimitedtolessthan

6mA (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.

P2(48V in, 20mA load) = 20mA • (48V – 5V)

+ (0.55mA • 48V) = 0.89W

P3(72V in, 5mA load) = 5mA • (72V – 5V)

+ (100µA • 72V) = 0.34W

P4(72V in, 20mA load) = 20mA • (72V – 5V)

+ (0.55mA • 72V) = 1.38W

The ADJ pin can be pulled above or below ground by as

muchas7Vwithoutdamagingthedevice.Iftheinputisleft

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. Iftheinputispoweredbyavoltagesource, pulling

the ADJ pin below the reference voltage will cause the

device to current limit. This will cause the output to go to

an unregulated high voltage. Pulling the ADJ pin above the

reference voltage will turn off all output current.

Operation at the different power levels is as follows:

76% operation at P1, 19% for P2, 4% for P3, and

1% for P4.

P

_EFF= 76%(0.22W) + 19%(0.89W) + 4%(0.34W)

+ 1%(1.38W) = 0.36W

With a thermal resistance in the range of 40°C/W to

62°C/W, this translates to a junction temperature rise

above ambient of 20°C.

3014fb

10

LT3014

W U U

APPLICATIO S I FOR ATIO

U

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

fromthe1.22Vreferencewhentheoutputisforcedto60V.

The top resistor of the resistor divider must be chosen to

limitthecurrentintotheADJpintolessthan5mAwhenthe

ADJ pin is at 7V. The 53V difference between the OUT and

ADJ pins divided by the 5mA maximum current into the

ADJ pin yields a minimum top resistor value of 10.6k.

open circuit. Current flow back into the output will follow

the curve shown in Figure 4. The rise in reverse output

current above 7V occurs from the breakdown of the 7V

clamp on the ADJ pin. With a resistor divider on the

regulator output, this current will be reduced depending

on the size of the resistor divider.

When the IN pin of the LT3014 is forced below the OUT pin

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

typicallydroptolessthan2µA. Thiscanhappeniftheinput

of the LT3014 is connected to a discharged (low voltage)

battery and the output is held up by either a backup battery

orasecondregulatorcircuit.ThestateoftheSHDNpinwill

have no effect on the reverse output current when the

output is pulled above the input.

In circuits where a backup battery is required, several

different input/output conditions can occur. The output

voltage may be held up while the input is either pulled to

ground, pulled to some intermediate voltage, or is left

50

T

V

= 25°C

J

45

40

35

30

25

20

15

10

5

= 0V

IN

OUT

ADJ PIN

ESD CLAMP

= V

ADJ

CURRENT FLOWS

INTO OUTPUT PIN

0

1

2

3

4

5

6

7

8

9

10

OUTPUT VOLTAGE (V)

3014 F04

Figure 4. Reverse Output Current

3014fb

11

LT3014

TYPICAL APPLICATIO S

U

5V Buck Converter with Low Current Keep Alive Backup

D2

D1N914

6

C2

L1^†

15µH

0.33µF

BOOST

V

IN

OUT

4

2

5.5V*

V

SW

5V

IN

C3

4.7µF

100V

D1

TO 60V

1A/20mA

10MQ060N

LT1766

CERAMIC

15

14

10

12

SHDN

BIAS

FB

R1

C1

+

15.4k

100µF 10V

SOLID

SYNC

GND

R2

4.99k

TANTALUM

V

C

1, 8, 9, 16 11

C

1nF

3014 TA03

IN

OUT

*FOR INPUT VOLTAGES BELOW 7.5V,

SOME RESTRICTIONS MAY APPLY

^†INCREASE L1 TO 30µH FOR LOAD

CURRENTS ABOVE 0.6A AND TO

60µH ABOVE 1A

LT3014

3.92M

1.27M

OPERATING

CURRENT

SHDN

ADJ

HIGH

LOW

GND

Buck Converter

Efficiency vs Load Current

100

V

= 5V

OUT

L = 68µH

V

= 10V

= 42V

IN

90

80

70

60

50

0

0.25

0.50

0.75

1.00

1.25

LOAD CURRENT (A)

3014 TA04

3014fb

12

LT3014

U

TYPICAL APPLICATIO S

LT3014 Automotive Application

IN

OUT

ADJ

NO PROTECTION

DIODE NEEDED!

+

V

IN

LT3014

SHDN

R1

R2

1µF

12V

1µF

LOAD: CLOCK,

SECURITY SYSTEM

ETC

(LATER 42V)

GND

OFF

ON

LT3014 Telecom Application

V

IN

48V

(72V TRANSIENT)

IN

OUT

+

–

LT3014

BACKUP

BATTERY

R1

R2

NO PROTECTION

DIODE NEEDED!

1µF

LOAD:

SYSTEM MONITOR

ETC

SHDN

ADJ

GND

3014 TA05

OFF

ON

Constant Brightness for Indicator LED over Wide Input Voltage Range

RETURN

IN

OUT

LT3014

1µF

OFF ON

–48V

SHDN ADJ

GND

R

SET

3014 TA06

I

= 1.22V/R

SET

LED

–48V CAN VARY FROM –3.3V TO –80V

3014fb

13

LT3014

U

PACKAGE DESCRIPTIO

S5 Package

5-Lead Plastic TSOT-23

(Reference LTC DWG # 05-08-1635)

0.62

MAX

0.95

REF

2.90 BSC

(NOTE 4)

1.22 REF

1.50 – 1.75

(NOTE 4)

2.80 BSC

1.4 MIN

3.85 MAX 2.62 REF

PIN ONE

RECOMMENDED SOLDER PAD LAYOUT

PER IPC CALCULATOR

0.30 – 0.45 TYP

5 PLCS (NOTE 3)

0.95 BSC

0.80 – 0.90

0.20 BSC

DATUM ‘A’

0.01 – 0.10

1.00 MAX

0.30 – 0.50 REF

1.90 BSC

0.09 – 0.20

(NOTE 3)

NOTE:

S5 TSOT-23 0302 REV B

1. DIMENSIONS ARE IN MILLIMETERS

2. DRAWING NOT TO SCALE

3. DIMENSIONS ARE INCLUSIVE OF PLATING

4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR

5. MOLD FLASH SHALL NOT EXCEED 0.254mm

6. JEDEC PACKAGE REFERENCE IS MO-193

3014fb

14

LT3014

U

PACKAGE DESCRIPTIO

DD Package

8-Lead Plastic DFN (3mm × 3mm)

(Reference LTC DWG # 05-08-1698)

0.675 ±0.05

3.5 ±0.05

2.15 ±0.05 (2 SIDES)

1.65 ±0.05

PACKAGE

OUTLINE

0.25 ± 0.05

0.50

BSC

2.38 ±0.05

(2 SIDES)

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

R = 0.115

0.38 ± 0.10

TYP

5

8

3.00 ±0.10

(4 SIDES)

1.65 ± 0.10

(2 SIDES)

PIN 1

TOP MARK

(NOTE 6)

(DD) DFN 1203

4

1

0.25 ± 0.05

0.75 ±0.05

0.200 REF

0.50 BSC

2.38 ±0.10

(2 SIDES)

0.00 – 0.05

BOTTOM VIEW—EXPOSED PAD

NOTE:

1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1)

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 TOP AND BOTTOM OF PACKAGE

3014fb

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-

tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.

15

LT3014

RELATED PARTS

PART NUMBER

DESCRIPTION

COMMENTS

V : 4.2V to 30V, V

LT1129

700mA, Micropower, LDO

= 3.75V, V = 0.4V, I = 50µA, I = 16µA,

OUT(MIN) DO Q SD

IN

DD, SOT-223, S8, TO220, TSSOP-20 Packages

LT1175

LT1185

LT1761

LT1762

LT1763

500mA, Micropower Negative LDO

3A, Negative LDO

V : –20V to –4.3V, V = –3.8V, V = 0.50V, I = 45µA, I = 10µA,

IN

OUT(MIN)

DO

Q

SD

DD, SOT-223, S8 Packages

V : –35V to –4.2V, V

TO220-5 Package

= –2.40V, V = 0.80V, I = 2.5mA, I <1µA,

DO Q SD

IN

OUT(MIN)

100mA, Low Noise Micropower, LDO

150mA, Low Noise Micropower, LDO

500mA, Low Noise Micropower, LDO

V : 1.8V to 20V, V

ThinSOT Package

= 1.22V, V = 0.30V, I = 20µA, I <1µA,

DO Q SD

IN

OUT(MIN)

V : 1.8V to 20V, V

= 1.22V, V = 0.30V, I = 25µA, I <1µA,

DO Q SD

IN

MS8 Package

V : 1.8V to 20V, V

= 1.22V, V = 0.30V, I = 30µA, I <1µA,

DO Q SD

IN

S8 Package

LT1764/LT1764A 3A, Low Noise, Fast Transient Response, LDO

V : 2.7V to 20V, V

= 1.21V, V = 0.34V, I = 1mA, I <1µA,

DO Q SD

IN

DD, TO220 Packages

LTC1844

LT1962

150mA, Very Low Dropout LDO

V : 1.6V to 6.5V, V

ThinSOT Package

= 1.25V, V = 0.08V, I = 40µA, I <1µA,

DO Q SD

IN

OUT(MIN)

300mA, Low Noise Micropower, LDO

V : 1.8V to 20V, V

= 1.22V, V = 0.27V, I = 30µA, I <1µA,

DO Q SD

IN

MS8 Package

LT1963/LT1963A 1.5A, Low Noise, Fast Transient Response, LDO V : 2.1V to 20V, V

= 1.21V, V = 0.34V, I = 1mA, I <1µA,

DO Q SD

IN

DD, TO220, SOT Packages

LT1964

LT3010

LT3020

LT3023

LT3024

LT3027

LT3028

200mA, Low Noise Micropower, Negative LDO

50mA, 80V, Low Noise Micropower, LDO

V : –1.9V to –20V, V

ThinSOT Package

= –1.21V, V = 0.34V, I = 30µA, I = 3µA,

OUT(MIN) DO Q SD

IN

V : 3V to 80V, V

IN

= 1.28V, V = 0.3V, I = 30µA, I <1µA,

DO Q SD

OUT(MIN)

MS8E Package

100mA, Low V , Low V

Micropower, VLDO V : 0.9V to 10V, V

= 0.20V, V = 0.15V, I = 120µA, I <1µA,

OUT(MIN) DO Q SD

IN

OUT

IN

DFN, MS8 Packages

Dual 100mA, Low Noise Micropower, LDO

V : 1.8V to 20V, V

IN

= 1.22V, V = 0.30V, I = 40µA, I <1µA,

DO Q SD

OUT(MIN)

DFN, MS10 Packages

Dual 100mA/500mA, Low Noise Micropower,

LDO

V : 1.8V to 20V, V

IN

= 1.22V, V = 0.30V, I = 60µA, I <1µA,

DO Q SD

OUT(MIN)

DFN, TSSOP-16E Packages

Dual 100mA, Low Noise LDO with Independent V : 1.8V to 20V, V

Inputs

= 1.22V, V = 0.30V, I = 40µA, I <1µA,

DO Q SD

IN

OUT(MIN)

DFN, MS10E Packages

Dual 100mA/500mA, Low Noise LDO with

Independent Inputs

V : 1.8V to 20V, V

IN

= 1.22V, V = 0.30V, I = 60µA, I <1µA,

DO Q SD

OUT(MIN)

DFN, TSSOP-16E Packages

3014fb

LT/LWI 0706 REV B • PRINTED IN USA

LinearTechnology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

16

●

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


型号：	LT3014HVES5#TRM
厂家：	Linear
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