LT3010EMS8E_技术文档

LT3010/LT3010-5

50mA, 3V to 80V

Low Dropout

Micropower Linear Regulator

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FEATURES

DESCRIPTIO

The LT^®3010 is a high voltage, micropower low dropout

linear regulator. The device is capable of supplying 50mA

outputcurrentwithadropoutvoltageof300mV. Designed

for use in battery-powered or high voltage systems, the

low quiescent current (30µA operating and 1µA in shut-

down) makes the LT3010 an ideal choice. Quiescent

current is also well controlled in dropout.

■

Wide Input Voltage Range: 3V to 80V

■

Low Quiescent Current: 30µA

■

Low Dropout Voltage: 300mV

Output Current: 50mA

Thermally Enhanced 8-Lead MSOP Package

■

No Protection Diodes Needed

Fixed Output Voltage: 5V (LT3010-5)

■

Adjustable Output from 1.275V to 60V (LT3010)

Other features of the LT3010 include the ability to operate

with very small output capacitors. The regulators are

stable with only 1µF 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.

■

1µA Quiescent Current in Shutdown

■

Stable with 1µF Output Capacitor

■

Stable with Aluminum, Tantalum or Ceramic

Capacitors

Reverse-Battery Protection

No Reverse Current Flow from Output

Thermal Limiting

■

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APPLICATIO S

The device is available in a fixed output voltage of 5V and

as an adjustable device with a 1.275V reference voltage.

The LT3010 regulator is available in the 8-lead MSOP

package with an exposed pad for enhanced thermal han-

dling capability.

■

Low Current High Voltage Regulators

■

Regulator for Battery-Powered Systems

■

Telecom Applications

Automotive Applications

■

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

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TYPICAL APPLICATIO

Dropout Voltage

350

5V Supply with Shutdown

300

V

OUT

250

200

150

100

50

IN

OUT

LT3010-5

5V

50mA

V

IN

5.4V TO

80V

1µF

SHDN SENSE

GND

3010 TA01

V

(PIN 5) OUTPUT

SHDN

<0.3V

>2.0V

NC

OFF

ON

0

10

20

30

50

0

40

OUTPUT CURRENT (mA)

3010 TA02

3010f

1

LT3010/LT3010-5

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ABSOLUTE AXI U RATI GS

PACKAGE/ORDER I FOR ATIO

(Note 1)

IN Pin Voltage................................................... ±80V

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 ............ –65°C to 150°C

Operating Junction Temperature Range

ORDER PART

TOP VIEW

NUMBER

OUT

SENSE/ADJ*

NC

1

2

3

4

8 IN

7 NC

6 NC

5 SHDN

LT3010EMS8E

LT3010EMS8E-5

GND

MS8E PACKAGE

8-LEAD PLASTIC MSOP

*SENSE FOR LT3010-5, ADJ FOR LT3010

T_JMAX= 125°C, θ_JA= 40°C/ W, θ_JC= 16°C/ W^†

SEE APPLICATIONS INFORMATION SECTION.

EXPOSED PAD IS GND

MS8 PART MARKING

LTZF

LTAEF

(MUST BE SOLDERED TO PCB)

^†MEASURED AT BOTTOM PAD

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

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

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_J= 25°C.

PARAMETER

CONDITIONS

LT3010

MIN

TYP

MAX

UNITS

Minimum Input Voltage

Regulated Output Voltage (Note 3)

I

= 50mA

●

3

4

V

LOAD

LT3010-5

V

= 5.5V, I

= 1mA

LOAD

4.925

4.850

5.000

5.075

5.150

V

IN

6V < V < 80V, 1mA < I

< 50mA

IN

LOAD

ADJ Pin Voltage

(Notes 2,3)

LT3010

V

= 3V, I

= 1mA

1.258

1.237

1.275

1.292

1.313

V

IN

LOAD

4V < V < 80V, 1mA < I

IN

LOAD

Line Regulation

LT3010-5

LT3010 (Note 2)

∆V = 5.5V to 80V, I

= 1mA

LOAD

●

3

15

13

mV

IN

∆V = 3V to 80V, I

= 1mA

IN

LOAD

Load Regulation

LT3010-5

V

= 6V, ∆I

= 1mA to 50mA

25

50

90

mV

IN

LOAD

●

LT3010 (Note 2)

V

= 4V, ∆I

= 1mA to 50mA

10

20

32

mV

IN

LOAD

Dropout Voltage

I

= 1mA

100

200

300

150

190

mV

LOAD

V

IN

= V

OUT(NOMINAL)

(Notes 4, 5)

I

= 10mA

260

350

mV

LOAD

I

= 50mA

370

550

mV

LOAD

GND Pin Current

I

= 0mA

= 1mA

= 10mA

= 50mA

●

30

100

400

1.8

60

180

700

3.3

µA

LOAD

V

IN

= V

OUT(NOMINAL)

(Notes 4, 6)

mA

Output Voltage Noise

ADJ Pin Bias Current

Shutdown Threshold

C

= 10µF, I

= 50mA, BW = 10Hz to 100kHz

100

50

µV

RMS

OUT

LOAD

(Note 7)

100

2

nA

V

OUT

V

OUT

= Off to On

= On to Off

1.3

0.8

V

0.3

SHDN Pin Current

(Note 8)

V

SHDN

V

SHDN

= 0V

= 6V

0.5

0.1

2

0.5

µA

Quiescent Current in Shutdown

V

IN

= 6V, V

= 0V

1

5

µA

SHDN

3010f

2

LT3010/LT3010-5

ELECTRICAL CHARACTERISTICS

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

PARAMETER

CONDITIONS

MIN TYP

MAX

UNITS

Ripple Rejection

LT3010

LT3010-5

V

IN

V

IN

= 7V(Avg), V

= 0.5V , f

= 120Hz, I

= 50mA

65

60

75

68

dB

RIPPLE

P-P RIPPLE

LOAD

= 0.5V , f

P-P RIPPLE

Current Limit

V

= 7V, V

= 0V

140

mA

IN

OUT

LT3010-5

LT3010 (Note 2) V = 4V, ∆V

V

IN

= 6V, ∆V

= –0.1V

●

60

OUT

Input Reverse

V

IN

= –80V, V

= 0V

●

6

mA

OUT

Leakage Current

Reverse Output Current

(Note 9)

LT3010-5

LT3010 (Note 2) V

V

= 5V, V < 5V

10

8

20

15

µA

OUT

IN

= 1.275V, V < 1.275V

IN

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

(nominal) and a current

OUT

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

IN

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.

of a device may be impaired.

Note 2: The LT3010 (adjustable version) is tested and specified for these

conditions with the ADJ pin connected to the OUT pin.

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

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

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 the GND pin.

Note 10: The LT3010E 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 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 LT3010

(adjustable version) 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 will add a 5µA DC load on the output.

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 will be equal to (V – V

).

IN

DROPOUT

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TYPICAL PERFOR A CE CHARACTERISTICS

Typical Dropout Voltage

Guaranteed Dropout Voltage

Dropout Voltage

500

450

400

350

300

250

200

150

100

50

600

500

450

400

350

300

250

200

150

100

50

= TEST POINTS

I

L

= 50mA

400

300

T

= 125°C

J

T

≤ 125°C

≤ 25°C

J

I

= 10mA

= 1mA

L

T

J

T

= 25°C

200

100

0

J

I

L

0

5

10 15 20 25 30 35 40 45 50

OUTPUT CURRENT (mA)

–50

0

25

50

75 100 125

–25

0

5

10 15 20 25 30 35 40 45 50

OUTPUT CURRENT (mA)

3010 G01

TEMPERATURE (°C)

3010 G02

3010 G03

3010f

3

LT3010/LT3010-5

TYPICAL PERFOR A CE CHARACTERISTICS

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Quiescent Current

LT3010 ADJ Pin Voltage

LT3010-5 Output Voltage

40

1.295

5.08

I

L

= 1mA

I

L

= 1mA

35

30

1.290

1.285

5.06

5.04

V

SHDN

= V

IN

25

20

15

10

5

1.280

1.275

1.270

1.265

1.260

5.02

5.00

4.98

4.96

4.94

V

R

> 6V

IN

L

= ∞, I = 0 (LT3010-5)

L

= 250k, I = 5µA (LT3010)

L

V

= 0V

50

SHDN

0

1.255

4.92

–25

0

75 100 125

–25

0

50

75 100 125

–25

0

50

75 100 125

–50

25

–50

25

–50

25

TEMPERATURE (°C)

3010 G04

3010 G06

3010 G05

LT3010 Quiescent Current

LT3010-5 Quiescent Current

LT3010 GND Pin Current

50

45

40

35

30

25

20

15

10

5

200

180

160

140

120

100

80

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

T

= 25°C

T

= 25°C

R = ∞

L

T

= 25°C

J

L

J

R

=

∞

*FOR V

= 1.275V

OUT

V

= V

IN

R

= 25.5Ω

= 50mA*

SHDN

L

I

R

L

= 51Ω

L

I

= 25mA*

R

L

= 127Ω

= 10mA*

L

60

I

V

= V

IN

SHDN

40

R

= 1.27k I = 1mA*

L

20

L

V

= 0V

6

SHDN

5

V

6

= 0V

8

SHDN

7

0

1

2

3

4

7

8

9

10

0

1

2

3

4

5

9

10

0

1

2

3

4

5

6

7

8

9

10

INPUT VOLTAGE (V)

3010 G08

3010 G07

3010 G10

LT3010-5 GND Pin Current

GND Pin Current vs I_LOAD

SHDN Pin Threshold

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

1.6

T

= 25°C

V

= V

+ 1V

OUT(NOMINAL)

J

IN

*FOR V

= 5V

T = 25°C

J

OUT

1.4

1.2

OFF-TO-ON

R

I

= 100Ω

= 50mA*

L

1.0

0.8

0.6

0.4

0.2

R

L

= 200Ω

= 25mA*

L

I

ON-TO-OFF

R

I

= 500Ω

= 10mA*

L

R

= 5k, I = 1mA*

L

0

1

2

3

4

5

6

7

8

9

10

0

5

10 15 20 25 30 35 40 45 50

OUTPUT CURRENT (mA)

3010 G11

–50 –25

0

25

50

75 100 125

TEMPERATURE (°C)

INPUT VOLTAGE (V)

3010 G09

3010 G12

3010f

4

LT3010/LT3010-5

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TYPICAL PERFOR A CE CHARACTERISTICS

SHDN Pin Current

ADJ Pin Bias Current

0.6

0.5

0.8

80

T = 25°C

J

V

SHDN

= 0V

CURRENT FLOWS

OUT OF SHDN PIN

CURRENT FLOWS

OUT OF SHDN PIN

0.7

0.6

70

60

0.4

0.3

0.5

0.4

0.3

0.2

0.1

50

40

30

20

10

0.2

0.1

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

–25

0

50

75 100 125

–25

0

50

75 100 125

–50

25

–50

25

SHDN PIN VOLTAGE (V)

TEMPERATURE (°C)

3010 G13

3010 G14

3010 G15

Current Limit

Reverse Output Current

200

180

160

140

120

100

80

200

180

160

140

120

100

80

100

90

80

70

60

50

40

30

20

10

0

V

= 7V

IN

OUT

V

T

= 0V

T

= 25°C

IN

OUT

J

= 0V

= 25°C

V

= 0V

CURRENT FLOWS

INTO OUTPUT PIN

V

= V

(LT3010)

ADJ

SENSE

OUT

ADJ

(LT3010-5)

PIN CLAMP

(SEE APPLICATIONS

INFORMATION)

LT3010

60

40

LT3010-5

20

0

–50

0

25

50

75 100 125

–25

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

TEMPERATURE (°C)

INPUT VOLTAGE (V)

OUTPUT VOLTAGE (V)

3010 G17

3010 G16

3010 G18

Reverse Output Current

Input Ripple Rejection

100

90

24

80

78

76

74

72

70

68

66

64

62

60

V

I

= 7V + 50mV

RIPPLE

V

= 0V

= V

IN

L

RMS

IN

OUT

= 50mA

= 1.275V (LT3010)

ADJ

21

18

= V

= 5V (LT3010-5)

SENSE

80

70

15

12

9

C

OUT

= 10µF

60

50

LT3010-5

LT3010

40

30

20

10

0

C

OUT

= 1µF

6

V

L

= 7V + 0.5V RIPPLE AT f = 120Hz

P-P

IN

3

I

= 50mA

V

OUT

= 1.275V

0

–25

0

50

75 100 125

10

100

1k

10k

100k

1M

–50

25

–50

0

25

50

75 100 125

–25

TEMPERATURE (°C)

FREQUENCY (Hz)

TEMPERATURE (°C)

3010 G21

3010 G19

3010 G20

3010f

5

LT3010/LT3010-5

TYPICAL PERFOR A CE CHARACTERISTICS

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LT3010 Minimum Input Voltage

Load Regulation

Output Noise Spectral Density

10

1

4.0

0

∆I = 1mA TO 50mA

L

C

= 1µF

OUT

= 50mA

I

= 50mA

LOAD

I

L

3.5

3.0

–5

LT3010

–10

2.5

2.0

1.5

1.0

0.5

–15

–20

–25

–30

–35

LT3010-5

0.1

0.01

0

–40

–25

0

50

75 100 125

–25

0

50

75 100 125

–50

25

–50

25

10

100

1k

10k

100k

FREQUENCY (Hz)

TEMPERATURE (°C)

3010 G24

3010 G22

3010 G23

LT3010-5 10Hz to 100kHz

Output Noise

LT3010-5 Transient Response

0.2

0.1

0

V_OUT

100µV/DIV

–0.1

–0.2

V

C

= 6V

IN

= 1µF CERAMIC

= 1mA TO 50mA

OUT

∆I

LOAD

50

25

0

C_OUT= 1µF

I_L= 50mA

1ms/DIV

3010 G25

0

200

400

600

800

1000

TIME (µs)

3010 G26

3010f

6

LT3010/LT3010-5

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PI FU CTIO S

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

load. A minimum output capacitor of 1µF is required to

prevent oscillations. Larger output capacitors will be re-

quired 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.

the Typical Performance Characteristics). The ADJ pin

voltage is 1.275V referenced to ground, and the output

voltage range is 1.275V to 60V.

GND (Pin 4, Tab): Ground. The exposed backside of the

package is an electrical connection for GND. As such, to

ensure optimum device operation, the exposed pad must

be connected directly to pin 4 on the PC board.

SENSE (Pin 2): Sense. For the LT3010-5, 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 resistance (R_P) 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 Connec-

tion). Note that the voltage drop across the external PC

traces will add to the dropout voltage of the regulator. The

SENSEpinbiascurrentis10µAatthenominalratedoutput

voltage.

SHDN (Pin 5): Shutdown. The SHDN pin is used to put the

LT3010 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

can be left open circuit. The device will be active, output

on, if the SHDN pin is not connected.

IN (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 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 1µF to 10µF is sufficient. The

LT3010 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 LT3010 will act as if there is a

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

current flow into the LT3010 and no reverse voltage will

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

the load.

ADJ (Pin 2): Adjust. For the adjustable LT3010, this is the

input to the error amplifier. This pin is internally clamped

to ±7V. It has a bias current of 50nA which flows into the

pin (see curve of ADJ Pin Bias Current vs Temperature in

R

P

8

5

1

2

IN

OUT

LT3010

+

SHDN SENSE

GND

LOAD

V

IN

4, TAB

3010 F01

Figure 1. Kelvin Sense Connection

3010f

7

LT3010/LT3010-5

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APPLICATIO S I FOR ATIO

The LT3010 is a 50mA high voltage low dropout regulator

with micropower quiescent current and shutdown. The

device is capable of supplying 50mA at a dropout voltage

of 300mV. The low operating quiescent current (30µA)

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

current, the LT3010 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,theLT3010acts

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

reverse current flow.

A small capacitor (C1) placed in parallel with the top

resistor(R2)oftheoutputdividerisnecessaryforstability

and transient performance of the adjustable LT3010. The

impedance of C1 at 10kHz should be less than the value of

R1.

The adjustable device is tested and specified with the ADJ

pintiedtotheOUTpinanda5µADCload(unlessotherwise

specified) for an output voltage of 1.275V. Specifications

for output voltages greater than 1.275V will be propor-

tional to the ratio of the desired output voltage to 1.275V;

(V_OUT/1.275V). For example, load regulation for an

output current change of 1mA to 50mA is –10mV typical

at V_OUT= 1.275V. At V_OUT= 12V, load regulation is:

Adjustable Operation

(12V/1.275V) • (–10mV) = –94mV

The adjustable version of the LT3010 has an output

voltage range of 1.275V to 60V. The output voltage is set

bytheratiooftwoexternalresistorsasshowninFigure 2.

The device servos the output to maintain the voltage at

the adjust pin at 1.275V referenced to ground. The

current in R1 is then equal to 1.275V/R1 and the current

in R2 is the current in R1 plus the ADJ pin bias current.

TheADJpinbiascurrent,50nAat25°C,flowsthroughR2

into the ADJ pin. The output voltage can be calculated

using the formula in Figure 2. The value of R1 should be

less than 250k to minimize errors in the output voltage

caused by the ADJ pin bias current. Note that in shut-

down the output is turned off and the divider current will

be zero.

Output Capacitance and Transient Response

The LT3010 is designed to be stable with a wide range of

output capacitors. The ESR of the output capacitor affects

stability, most notably with small capacitors. A minimum

output capacitor of 1µF with an ESR of 3Ω or less is

recommended to prevent oscillations. The LT3010 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 LT3010, will increase the

effective output capacitor value.

V

IN

OUT

LT3010

ADJ

OUT

+

R2

R1

C1

V

IN

GND

3010 F02

R2

R1

V

= 1.275V 1 +

+ (I )(R2)

ADJ

OUT

ADJ

(

)

= 1.275V

I

= 50nA AT 25°C

OUTPUT RANGE = 1.275V TO 60V

ADJ

Figure 2. Adjustable Operation

3010f

8

LT3010/LT3010-5

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APPLICATIO S I FOR ATIO

U

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 3 and 4. 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

–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)

3010 F04

3010 F03

Figure 4. Ceramic Capacitor Temperature Characterics

Figure 3. Ceramic Capacitor DC Bias Characterics

3010f

9

LT3010/LT3010-5

W U U

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APPLICATIO S I FOR ATIO

maximumtopsideandbacksideareaforoneouncecopper

is 3 seconds. This time constant will increase as more

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

components).

The LT3010 series regulators have internal thermal limit-

ing designed to protect the device during overload condi-

tions. For continuous normal conditions the maximum

junction temperature rating of 125°C must not be ex-

ceeded. 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 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.

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.

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

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

what will the maximum junction temperature be?

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.

The power dissipated by the device will be equal to:

I

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

where:

I_OUT(MAX)= 50mA

)

Table 1. Measured Thermal Resistance

COPPER AREA

THERMAL RESISTANCE

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

V_IN(MAX)= 30V

45°C/W

I_GNDat (I_OUT= 50mA, V_IN= 30V) = 1mA

50°C/W

62°C/W

So:

P = 50mA • (30V – 5V) + (1mA • 30V) = 1.28W

The thermal resistance junction-to-case (θ_JC), measured

at the exposed pad on the back of the die, is 16°C/W.

The thermal resistance will be in the range of 40°C/W to

62°C/W depending on the copper area. So the junction

temperature rise above ambient will be approximately

equal to:

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

1.31W • 50°C/W = 65.5°C

3010f

10

LT3010/LT3010-5

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APPLICATIO S I FOR ATIO

U

The maximum junction temperature will then be equal to

the maximum junction temperature rise above ambient

plus the maximum ambient temperature or:

Protection Features

TheLT3010incorporatesseveralprotectionfeatureswhich

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 + 65.5°C = 115.5°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 50mA 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)

+ (200µA • 48V) = 0.23W

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, 50mA load) = 50mA • (48V – 5V)

+ (1mA • 48V) = 2.20W

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

+ (200µA • 72V) = 0.35W

P4(72V in, 50mA load) = 50mA • (72V – 5V)

+ (1mA • 72V) = 3.42W

The ADJ pin of the adjustable device can be pulled above

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

device. Iftheinputisleftopencircuitorgrounded, theADJ

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. If the input is powered

by a voltage source, pulling the ADJ pin below the refer-

ence voltage will cause the device to try and force the

current limit current out of the output. This will cause the

output to go to a 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%(0.23W) + 19%(2.20W) + 4%(0.35W)

+ 1%(3.42W) = 0.64W

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 26°C to 38°C.

3010f

11

LT3010/LT3010-5

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APPLICATIO S I FOR ATIO

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 5. 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 LT3010 is forced below the OUT pin

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

typicallydroptolessthan2µA. Thiscanhappeniftheinput

of the LT3010 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

100

T

= 25°C

IN

A

V

90

80

70

60

50

40

30

20

10

0

= 0V

CURRENT FLOWS

INTO OUTPUT PIN

ADJ

PIN CLAMP

(SEE ABOVE)

V

= V

ADJ

= V

SENSE

(LT3010)

OUT

(LT3010-5)

LT3010

LT3010-5

4

0

1

2

3

5

6

7

8

9

10

OUTPUT VOLTAGE (V)

3010 F05

Figure 5. Reverse Output Current

3010f

12

LT3010/LT3010-5

U

TYPICAL APPLICATIO S

5V Buck Converter with Low Current Keep Alive Backup

D2

D1N914

6

C2

L1^†

0.33µF

BOOST

15µH

V

IN

OUT

4

2

5.5V*

V

SW

5V

IN

C3

4.7µF

100V

D1

TO 60V

1A/50mA

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

8

5

1

2

3010 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

LT3010-5

OPERATING

CURRENT

SHDN

SENSE

HIGH

LOW

GND

4

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)

3010 TA04

3010f

13

LT3010/LT3010-5

U

TYPICAL APPLICATIO

LT3010 Automotive Application

IN

OUT

NO PROTECTION

DIODE NEEDED!

+

V

IN

LT3010-5

1µF

12V

1µF

LOAD: CLOCK,

SECURITY SYSTEM

ETC

(LATER 42V)

SHDN

SENSE

GND

OFF

ON

LT3010 Telecom Application

V

IN

OUT

48V

(72V TRANSIENT)

+

–

LT3010-5

BACKUP

BATTERY

NO PROTECTION

DIODE NEEDED!

1µF

LOAD:

SYSTEM MONITOR

ETC

SHDN

SENSE

GND

3010 TA05

OFF

ON

Constant Brightness for Indicator LED over Wide Input Voltage Range

RETURN

IN

OUT

LT3010

1µF

OFF ON

–48V

SHDN ADJ

GND

R

SET

3010 TA06

I

= 1.275V/R

LED

SET

–48V CAN VARY FROM –4V TO –80V

3010f

14

LT3010/LT3010-5

U

PACKAGE DESCRIPTIO

MS8E Package

8-Lead Plastic MSOP

(Reference LTC DWG # 05-08-1662)

BOTTOM VIEW OF

EXPOSED PAD OPTION

2.06 ± 0.102

(.080 ± .004)

1

1.83 ± 0.102

(.072 ± .004)

0.889 ± 0.127

(.035 ± .005)

2.794 ± 0.102

(.110 ± .004)

5.23

(.206)

MIN

3.2 – 3.45

(.126 – .136)

2.083 ± 0.102

(.082 ± .004)

8

3.00 ± 0.102

(.118 ± .004)

(NOTE 3)

0.52

(.206)

REF

0.65

(.0256)

BSC

0.42 ± 0.04

(.0165 ± .0015)

8

7 6

5

TYP

RECOMMENDED SOLDER PAD LAYOUT

3.00 ± 0.102

(.118 ± .004)

NOTE 4

4.90 ± 0.15

(1.93 ± .006)

DETAIL “A”

0.254

(.010)

0° – 6° TYP

GAUGE PLANE

1

2

3

4

0.53 ± 0.015

(.021 ± .006)

1.10

(.043)

MAX

0.86

(.034)

REF

DETAIL “A”

0.18

(.077)

SEATING

PLANE

0.22 – 0.38

(.009 – .015)

TYP

0.13 ± 0.076

(.005 ± .003)

0.65

(.0256)

BSC

MSOP (MS8E) 0802

NOTE:

1. DIMENSIONS IN MILLIMETER/(INCH)

2. DRAWING NOT TO SCALE

3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.

MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE

4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.

INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE

5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX

3010f

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

LT3010/LT3010-5

RELATED PARTS

PART NUMBER

DESCRIPTION

COMMENTS

V : 4.5V to 36V, V

LT1020

125mA, Micropower Regulator and Comparator

= 2.5V, V = 0.4V, I = 40µA, I = 40µA,

OUT DO Q SD

IN

Comparator and Reference, Class B Outputs, S16, PDIP14 Packages

LT1120/LT1120A 125mA, Micropower Regulator and Comparator

V : 4.5V to 36V, V = 2.5V, V = 0.4V, I = 40µA, I = 10µA,

Comparator and Reference,Logic Shutdown, Ref Sources and Sinks 2/4mA,

S8, N8 Packages

IN

OUT

DO

Q

SD

LT1121/

LT1121HV

150mA, Micropower, LDO

700mA, Micropower, LDO

V : 4.2V to 30/36V, V

Reverse Battery Protection, SOT-223, S8, Z Packages

= 3.75V, V = 0.42V, I = 30µA, I = 16µA,

OUT DO Q SD

IN

LT1129

LT1616

LT1676

LT1761

LT1762

LT1763

V : 4.2V to 30V, V = 3.75V, V = 0.4V, I = 50µA, I = 16µA,

IN

OUT

DO

Q

SD

DD, S0T-223, S8,TO220-5, TSSOP20 Packages

25V, 500mA (I ), 1.4MHz, High Efficiency

V : 3.6V to 25V, V

= 1.25V, I = 1.9mA, I = <1µA, ThinSOT Package

Q SD

OUT

IN

OUT

Step-Down DC/DC Converter

60V, 440mA (I ), 100kHz, High Efficiency

V : 7.4V to 60V, V

IN

= 1.24V, I = 3.2mA, I = 2.5µA, S8 Package

Q SD

OUT

Step-Down DC/DC Converter

100mA, Low Noise Micropower, LDO

V : 1.8V to 20V, V

IN

= 1.22V, V = 0.3V, I = 20µA, I = <1µA,

OUT DO Q SD

Low Noise < 20µV

, Stable with 1µF Ceramic Capacitors, ThinSOT Package

RMS P-P

150mA, Low Noise Micropower, LDO

500mA, Low Noise Micropower, LDO

V : 1.8V to 20V, V

IN

= 1.22V, V = 0.3V, I = 25µA, I = <1µA,

OUT

DO

Q

SD

Low Noise < 20µV

, MS8 Package

RMS P-P

V : 1.8V to 20V, V

IN

= 1.22V, V = 0.3V, I = 30µA, I = <1µA,

OUT

DO

Q

SD

Low Noise < 20µV

, S8 Package

RMS P-P

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

V : 2.7V to 20V, V

= 1.21V, V = 0.34V, I = 1mA, I = <1µA,

OUT DO Q SD

IN

Low Noise < 40µV

, “A” Version Stable with Ceramic Capacitors,

RMS P-P

DD, TO220-5 Packages

LT1766

LT1776

60V, 1.2A (I ), 200kHz, High Efficiency

Step-Down DC/DC Converter

V : 5.5V to 60V, V

= 1.20V, I = 2.5mA, I = 25µA, TSSOP16/E Package

Q SD

OUT

IN

OUT

40V, 550mA (I ), 200kHz, High Efficiency

V : 7.4V to 40V, V

IN

= 1.24V, I = 3.2mA, I = 30µA, N8, S8 Packages

Q SD

OUT

Step-Down DC/DC Converter

LT1934/

LT1934-1

300mA/60mA, (I ), Constant Off-Time, High

Efficiency Step-Down DC/DC Converter

90% Efficiency, V : 3.2V to 34V, V

ThinSOT Package

= 1.25V, I = 14µA, I = <1µA,

OUT Q SD

OUT

IN

LT1956

60V, 1.2A (I ), 500kHz, High Efficiency

Step-Down DC/DC Converter

V : 5.5V to 60V, V

IN

= 1.20V, I = 2.5mA, I = 25µA, TSSOP16/E Package

OUT Q SD

OUT

LT1962

300mA, Low Noise Micropower, LDO

V : 1.8V to 20V, V

= 1.22V, V = 0.27V, I = 30µA, I = <1µA,

, MS8 Package

IN

OUT

DO

Q

SD

Low Noise < 20µV

RMS P-P

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,

OUT DO Q SD

IN

Low Noise < 40µV

, “A” Version Stable with Ceramic Capacitors,

RMS P-P

DD, TO220-5, S0T-223, S8 Packages

LT1964

200mA, Low Noise Micropower, Negative LDO

V : –0.9V to –20V, V

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

OUT DO Q SD

IN

Low Noise < 30µV

, Stable with Ceramic Capacitors, ThinSOT Package

RMS P-P

3010f

LT/TP 0403 2K • PRINTED IN USA

16 ^{LinearTechnology Corporation}

1630 McCarthy Blvd., Milpitas, CA 95035-7417

●

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

LINEAR TECHNOLOGY CORPORATION 2003


型号：	LT3010EMS8E
厂家：	Linear
描述：	50mA, 3V to 80V Low Dropout Micropower Linear Regulator 50mA时3V至80V低压差微功耗线性稳压器稳压器
文件：	总16页 (文件大小：245K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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