LINEAR TECHNOLOGY LT3014 Technical data

LT3014

20mA, 3V to 80V

Low Dropout Micropower

Linear Regulator

FEATURES

n

Wide Input Voltage Range: 3V to 80V

n

Low Quiescent Current: 7µA

n

Low Dropout Voltage: 350mV

n

Output Current: 20mA

n

LT3014HV Survives 100V Transients (2ms)

n

No Protection Diodes Needed

n

Adjustable Output from 1.22V to 60V

n

1µA Quiescent Current in Shutdown

n

Stable with 0.47µF Output Capacitor

n

Stable with Aluminum, Tantalum or Ceramic

Capacitors

n

Reverse-Battery Protection

n

No Reverse Current Flow from Output

n

Thermal Limiting

■

Available in 5-Lead ThinSOTTM and
8-Lead DFN Packages

APPLICATIONS

n

Low Current High Voltage Regulators

n

Regulator for Battery-Powered Systems

n

Telecom Applications

n

Automotive Applications

DESCRIPTION

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. Designed
for use in battery-powered or high voltage systems, the low
quiescent current (7μA operating and 1μA in shutdown)
makes the LT3014 an ideal choice. Quiescent current is
also well controlled in dropout.

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 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 device is available as an adjustable device with a 1.22V
reference voltage. The LT3014 regulator is available in the
5-lead ThinSOT and 8-lead DFN packages.

L, 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.

TYPICAL APPLICATION

5V Supply with Shutdown

IN

SHDN

OUT

LT3014

ADJ

GND

V

SHDN

<0.3V
>2.0V

V

IN

5.4V TO
80V

1μF

OUTPUT

OFF

ON

3.92M

1.27M

3014 TA01

V

OUT

5V
20mA

0.47μF

Dropout Voltage

400

350

300

250

200

150

100

DROPOUT VOLTAGE (mV)

50

0

0 4 10 12268 14161820

OUTPUT CURRENT (mA)

3014 TA02

3014fd

1

LT3014

ABSOLUTE MAXIMUM RATINGS

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 ......................Indefi nite

PIN CONFIGURATION

TOP VIEW

IN 1

GND 2

SHDN 3

S5 PACKAGE

5-LEAD PLASTIC SOT-23

T

= 125°C, θJA = 150°C/ W

JMAX

= 25°C/W MEASURED AT PIN 2

θ

JC

SEE APPLICATIONS INFORMATION SECTION

5 OUT

4 ADJ

(Note 1)

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

(Soldering, 10 sec, SOT-23 Package) ............300°C

TOP VIEW

1OUT

ADJ

2

NC

3

GND

4

EXPOSED PAD IS GND (PIN 9) MUST BE SOLDERED TO PCB

8-LEAD (3mm s 3mm) PLASTIC DFN

T

JMAX

θ

= 10°C/W MEASURED AT PIN 9

JC

9

DD PACKAGE

= 125°C, θJA = 40°C/ W

8

IN

NC

7

NC

6

SHDN

5

ORDER INFORMATION

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

LT3014ES5#PBF LT3014ES5#TRPBF LTBMF 5-Lead Plastic SOT-23 –40°C to 125°C

LT3014IS5#PBF LT3014IS5#TRPBF LTBMF 5-Lead Plastic SOT-23 –40°C to 125°C

LT3014HVES5#PBF LT3014HVES5#TRPBF LTBRS 5-Lead Plastic SOT-23 –40°C to 125°C

LT3014HVIS5#PBF LT3014HVIS5#TRPBF LTBRS 5-Lead Plastic SOT-23 –40°C to 125°C

LT3014EDD#PBF LT3014EDD#TRPBF LBMG

LT3014IDD#PBF LT3014IDD#TRPBF LBMG

LT3014HVEDD#PBF LT3014HVEDD#TRPBF LBRT

LT3014HVIDD#PBF LT3014HVIDD#TRPBF LBRT

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

LT3014ES5 LT3014ES5#TR LTBMF 5-Lead Plastic SOT-23 –40°C to 125°C

LT3014IS5 LT3014IS5#TR LTBMF 5-Lead Plastic SOT-23 –40°C to 125°C

LT3014HVES5 LT3014HVES5#TR LTBRS 5-Lead Plastic SOT-23 –40°C to 125°C

LT3014HVIS5 LT3014HVIS5#TR LTBRS 5-Lead Plastic SOT-23 –40°C to 125°C

LT3014EDD LT3014EDD#TR LBMG

LT3014IDD LT3014IDD#TR LBMG

LT3014HVEDD LT3014HVEDD#TR LBRT

LT3014HVIDD LT3014HVIDD#TR LBRT

Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/

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

8-Lead (3mm × 3mm) Plastic DFN

8-Lead (3mm × 3mm) Plastic DFN

8-Lead (3mm × 3mm) Plastic DFN

8-Lead (3mm × 3mm) Plastic DFN

8-Lead (3mm × 3mm) Plastic DFN

8-Lead (3mm × 3mm) Plastic DFN

8-Lead (3mm × 3mm) Plastic DFN

8-Lead (3mm × 3mm) Plastic DFN

–40°C to 125°C

–40°C to 125°C

–40°C to 125°C

–40°C to 125°C

–40°C to 125°C

–40°C to 125°C

–40°C to 125°C

–40°C to 125°C

3014fd

2

LT3014

ELECTRICAL CHARACTERISTICS

The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T

SYMBOL CONDITIONS MIN TYP MAX UNITS

Minimum Input Voltage I

ADJ Pin Voltage
(Notes 2, 3)

Line Regulation

Load Regulation (Note 2)

Dropout Voltage
V

= V

IN

OUT(NOMINAL)

(Notes 4, 5)

GND Pin Current
V

= V

IN

OUT(NOMINAL)

(Notes 4, 6)

Output Voltage Noise C

ADJ Pin Bias Current (Note 7) 4 10 nA

Shutdown Threshold V

SHDN Pin Current (Note 8) V

Quiescent Current in Shutdown VIN = 6V, V

Ripple Rejection V

Current Limit V

Input Reverse Leakage Current V

Reverse Output Current (Note 9) V

= 20mA

LOAD

VIN = 3.3V, I

3.3V < V

ΔVIN = 3.3V to 80V, I

V

= 3.3V, ΔI

IN

V

= 3.3V, ΔI

IN

= 100μA

I

LOAD

I

= 100μA

LOAD

I

= 1mA

LOAD

I

= 1mA

LOAD

= 10mA

I

LOAD

I

= 10mA

LOAD

I

= 20mA

LOAD

I

= 20mA

LOAD

= 0mA

I

LOAD

I

= 100μA

LOAD

I

= 1mA

LOAD

I

= 10mA

LOAD

I

= 20mA

LOAD

= 0.47μF, I

OUT

= Off to On

OUT

V

= On to Off

OUT

= 0V

SHDN

V

= 6V

SHDN

= 7V (Avg), V

IN

I

= 20mA

LOAD

= 7V, V

IN

V

= 3.3V, ΔV

IN

= –80V, V

IN

= 1.22V, VIN < 1.22V (Note 2) 2 4 μA

OUT

= 25°C.

J

= 100μA

LOAD

< 80V, 100μA < I

IN

LOAD

= 100μA to 20mA

LOAD

= 100μA to 20mA

LOAD

= 20mA, BW = 10Hz to 100kHz 115 μV

LOAD

= 0V

SHDN

RIPPLE

= 0V

OUT

= –0.1V (Note 2)

OUT

= 0V

OUT

< 20mA

LOAD

= 100μA (Note 2)

= 0.5V

P-P

, f

RIPPLE

= 120Hz,

l

1.200

l

1.180

l

3 3.3 V

1.220

1.220

1.240

1.260

110 mV

13 25

l

120 180

l

200 270

l

300 350

l

350 410

l

l
l
l
l
l

l
l

0.25

l
l

l

7
12
40

250
650

1.3

1.3

1

0

14 μA

60 70 dB

70 mA

l

25

l

40

mV

mV

mV

250

mV

mV

360

mV

mV

450

mV

mV

570

20

30
100
450

1000

mV

μA
μA
μA
μA
μA

RMS

2V

4
1

μA
μA

mA

6mA

V
V

V

Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.

Note 2: The LT3014 is tested and specifi ed 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 specifi cation 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 specifi ed 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 5: Dropout voltage is the minimum input to output voltage differential
needed to maintain regulation at a specifi ed output current. In dropout, the
output voltage is equal to (V

Note 6: GND pin current is tested with V

IN

– V

DROPOUT

IN

).

= V

(nominal) and a current

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 fl ows into the ADJ pin.
Note 8: SHDN pin current fl ows 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 fl ows into the OUT
pin and out of the GND pin.

Note 10: The LT3014 is tested and specifi ed under pulse load conditions
such that T

≅ TA. The LT3014E is 100% tested at TA = 25°C. Performance

J

at –40°C to 125°C is assured by design, characterization, and statistical

3014fd

3

LT3014

ELECTRICAL CHARACTERISTICS

process controls. The LT3014I is guaranteed over the full –40°C to 125°C
operating junction temperature.

Note 11: This IC includes overtemperature protection that is intended

temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specifi ed maximum operating junction
temperature may impair device reliability.

to protect the device during momentary overload conditions. Junction

TYPICAL PERFORMANCE CHARACTERISTICS

Typical Dropout Voltage Guaranteed Dropout Voltage Dropout Voltage

500

450

400

350

300

250

200

150

DROPOUT VOLTAGE (mV)

100

TJ = 125oC

TJ = 25oC

50

0

01642 6 10 14 18812 20

OUTPUT CURRENT (mA)

3014 G01

600

500

400

300

200

DROPOUT VOLTAGE (mV)

100

0

= TEST POINTS

TJb 125oC

TJb 25oC

4 8 12 16

OUTPUT CURRENT (mA)

3014 G02

500

450

400

350

300

250

200

150

DROPOUT VOLTAGE (mV)

100

2020 6 10 14 18

IL = 20mA

IL = 10mA

IL = 1mA

IL = 100MA

50

0

–50

–25

0

TEMPERATURE (oC)

50

25

75

100

125

3014 G03

10

QUIESCENT CURRENT (μA)

Quiescent Current ADJ Pin Voltage Quiescent Current

16

VIN = 6V

= d

R

L

14

= 0

I

L

12

8

6

4

2

0

–25 0 50

–50

V

= V

SHDN

IN

V

= 0V

SHDN

25

TEMPERATURE (oC)

75 100 125

3014 G04

1.240
IL = 100μA

1.235

1.230

1.225

1.220

1.215

ADJ PIN VOLTAGE (V)

1.210

1.205

1.200

–25 0 50

–50

25

TEMPERATURE (oC)

75 100 125

3014 G05

16

TJ = 25oC

= d

R

L

14

= 1.22V

V

OUT

12

10

8

6

4

QUIESCENT CURRENT (μA)

2

0

08

V

213579

INPUT VOLTAGE (V)

SHDN

V

= V

SHDN

IN

= 0V

6

4

10

3014 G06

3014fd

4

TYPICAL PERFORMANCE CHARACTERISTICS

LT3014

GND Pin Current GND Pin Current vs I

1000

900

800

700

600

500

400

300

GND PIN CURRENT (μA)

200

100

0

0

TJ = 25oC
*FOR V

= 1.22V

OUT

RL = 617

= 20mA*

I

L

RL = 1227

= 10mA*

I

L

RL = 1.22k

= 1mA*

I

L

2143679510

INPUT VOLTAGE (V)

8

3014 G07

1000

GND PIN CURRENT (μA)

900

800

700

600

500

400

300

200

100

VIN = 3.3V
T
V

0

0

= 25oC

J

= 1.22V

OUT

42

OUTPUT CURRENT (mA)

86

10

LOAD

12 14 18

16

20

3014 G08

SHDN Pin Threshold

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

SHDN PIN THRESHOLD (V)

0.4

0.2

0

–50

TEMPERATURE (oC)

SHDN Pin Current SHDN Pin Current ADJ Pin Bias Current

1.2
TJ = 25oC

CURRENT FLOWS
OUT OF SHDN PIN

1.0

0.8

0.6

0.4

SHDN PIN CURRENT (μA)

0.2

0

012

SHDN PIN VOLTAGE (V)

2.5

1.6
V

= 0V

SHDN

CURRENT FLOWS

1.4
OUT OF SHDN PIN

1.2

1.0

0.8

0.6

0.4

SHDN PIN CURRENT (μA)

0.2

0

3

3.5

40.5 1.5

3014 G10

–25 0 50

–50

25

TEMPERATURE (oC)

75 100 125

3014 G11

14

12

10

8

6

4

ADJ PIN BIAS CURRENT (nA)

2

0

–25 0 50

–50

TEMPERATURE (oC)

250–25 50 75

25

75 100 125

125100

3014 G09

3014 G12

Current Limit Current Limit Reverse Output Current

80

V

= 0V

OUT

= 25oC

T

J

70

60

50

40

30

CURRENT LIMIT (mA)

20

10

0

428612141810 20

0

16

INPUT VOLTAGE (V)

3014 G13

100

VIN = 7V

90

= 0V

V

OUT

80

70

60

50

40

30

CURRENT LIMIT (mA)

20

10

0

–50

–25

50

25

0

TEMPERATURE (oC)

50

TJ = 25oC

45

= 0V

V

IN

= V

V

OUT

40

35

30

25

20

15

10

REVERSE OUTPUT CURRENT (μA)

5

100

125

3014 G14

75

0

ADJ

CURRENT FLOWS
INTO OUTPUT PIN

21

0

OUTPUT VOLTAGE (V)

ADJ PIN

ESD CLAMP

43

5

67 9

8

3014 G15

3014fd

10

5

LT3014

TYPICAL PERFORMANCE CHARACTERISTICS

Reverse Output Current Input Ripple Rejection Input Ripple Rejection

8

VIN = 0V

= V

V

OUT

7

6

5

4

3

2

REVERSE OUTPUT CURRENT (μA)

1

0

–50

= 1.22V

ADJ

–25 0 50

25

TEMPERATURE (oC)

75 100 125

3014 G16

72

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

70

= 20mA

I

L

68

66

64

62

RIPPLE REJECTION (dB)

60

58

56

–25 0 50

–50

TEMPERATURE (oC)

P-P

25

75 100 125

3014 G17

80

70

60

50

40

30

RIPPLE REJECTION (dB)

20

10

0

100 1k 10k 100k 1M

10

VIN = 7V + 50mV

= 20mA

I

L

FREQUENCY (Hz)

Minimum Input Voltage Load Regulation Output Noise Spectral Density

3.5
I

= 20mA

LOAD

3.0

2.5

2.0

1.5

1.0

MINIMUM INPUT VOLTAGE (V)

0.5

0

–25 0 50 100 125

–50

25 75

TEMPERATURE (oC)

3014 G19

0

$IL = 100μA TO 20mA

= 1.22V

V

OUT

–5

–10

–15

–20

–25

LOAD REGULATION (mV)

–30

–35

–40

–50

–25 0 50

TEMPERATURE (oC)

25

75 100 125

3014 G20

10

C

= 0.47μF

OUT

= 20mA

I

L

= 1.22V

V

OUT

1

0.1

OUTPUT NOISE SPECTRAL DENSITY (MV/Hz)

0.01
10 1k 10k 100k

100

FREQUENCY (Hz)

C

OUT

C

OUT

RMS

= 4.7μF

= 0.47μF

RIPPLE

3014 G18

3014 G21

6

V

OUT

200μV/DIV

10Hz to 100kHz Output Noise Transient Response

0.04

0.02

0

–0.02

DEVIATION (V)

C

= 0.47μF

OUT

= 200mA

I

L

= 1.22V

V

OUT

1ms/DIV

3014 G22

OUTPUT VOLTAGE

–0.04

6

4

2

0

LOAD CURRENT (mA)

0

200

C

IN

400

= C

= 0.47μF CERAMIC

OUT

$I

LOAD

TIME (μs)

V

= 1mA TO 5mA

600

VIN = 7V

= 5V

OUT

800

1000

3014 G23

3014fd

LT3014

PIN FUNCTIONS

IN (Pin 1/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 fi lter 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 suffi cient. 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 fl ow
into the LT3014 and no reverse voltage will appear at the
load. The device will protect both itself and the load.

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

(SOT-23 Package/DD Package)

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.

ADJ (Pin 4/Pin 2): Adjust. This is the input to the error
amplifi er. This pin is internally clamped to ±7V. It has a
bias current of 4nA which fl ows into the pin (see curve
of ADJ Pin Bias Current vs Temperature in the Typical
Performance Characteristics). The ADJ pin voltage is

1.22V referenced to ground, and the output voltage range
is 1.22V to 60V.

OUT (Pin 5/Pin 1): Output. The output supplies power to
the load. A minimum output capacitor of 0.47μF 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.

3014fd

7

LT3014

APPLICATIONS INFORMATION

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 features
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 battery
when the input is pulled to ground, the LT3014 acts like it
has a diode in series with its output and prevents reverse
current fl ow.

Adjustable Operation

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 1. 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

1.22V/R1 and the current in R2 is the current in R1 plus
the ADJ pin bias current. The ADJ pin bias current, 4nA
at 25°C, fl ows through R2 into the ADJ pin. The output
voltage can be calculated using the formula in Figure 1.
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
and the divider current will be zero.

The device is tested
and specifi ed with the ADJ pin tied to the OUT pin and a
5μA DC load (unless otherwise specifi ed) for an output
voltage of 1.22V. Specifi cations for output voltages greater
than 1.22V will be proportional to the ratio of the desired
output voltage to 1.22V (V

/1.22V). For example, load

OUT

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

ADJ

V

OUT

+

3014 F01

)(R2)1 +

IN

OUT

R2

•

 

R1

R2

R1

+ (I

LT3014

V

IN

V

V
I
OUTPUT RANGE = 1.22V TO 60V

Figure 1. Adjustable Operation

GND

= 1.22V

OUT

= 1.22V

ADJ

= 4nA AT 25oC

ADJ

ADJ

is –13mV typical at V

= 1.22V. At V

OUT

= 12V, load

OUT

regulation is:

(12V/1.22V) • (–13mV) = –128mV

Output Capacitance and Transient Response

The LT3014 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 0.47μF with an ESR of 3Ω or less is
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
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.

Extra consideration must be given to the use of ceramic
capacitors. Ceramic capacitors are manufactured with a
variety of dielectrics, each with different behavior across
temperature and applied voltage. The most common
dielectrics used are specifi ed with EIA temperature char­acteristic codes of Z5U, Y5V, X5R and X7R. The Z5U and
Y5V dielectrics are good for providing high capacitances
in a small package, but they tend to have strong voltage
and temperature coeffi cients as shown in Figures 2 and 3.
When used with a 5V regulator, a 16V 10μF Y5V capacitor
can exhibit an effective value as low as 1μF to 2μF for the
DC bias voltage applied and over the operating tempera­ture range. The X5R and X7R dielectrics result in more
stable characteristics and are more suitable for use as the
output capacitor. The X7R type has better stability across
temperature, while the X5R is less expensive and is avail­able in higher values. Care still must be exercised when
using X5R and X7R capacitors; the X5R and X7R codes
only specify operating temperature range and maximum
capacitance change over temperature. Capacitance change
due to DC bias with X5R and X7R capacitors is better than
Y5V and Z5U capacitors, but can still be signifi cant enough
to drop capacitor values below appropriate levels. Capaci­tor DC bias characteristics tend to improve as component
case size increases, but expected capacitance at operating
voltage should be verifi ed.

3014fd

8

APPLICATIONS INFORMATION

LT3014

Voltage and temperature coeffi cients are not the only
sources of problems. Some ceramic capacitors have a
piezoelectric response. A piezoelectric device generates
voltage across its terminals due to mechanical stress, simi­lar to the way a piezoelectric accelerometer or microphone
works. For a ceramic capacitor the stress can be induced
by vibrations in the system or thermal transients.

20

0

–20

–40

–60

CHANGE IN VALUE (%)

–80

–100

0

26

Figure 2. Ceramic Capacitor DC Bias Characteristics

BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10μF

X5R

Y5V

4

8

DC BIAS VOLTAGE (V)

10

14

12

16

3014 F02

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:

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 gener­ated by power devices.

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.

Table 1. SOT-23 Measured Thermal Resistance

COPPER AREA

BOARD AREA

2500 sq mm 2500 sq mm 2500 sq mm 125°C/W

1000 sq mm 2500 sq mm 2500 sq mm 125°C/W

225 sq mm 2500 sq mm 2500 sq mm 130°C/W

100 sq mm 2500 sq mm 2500 sq mm 135°C/W

50 sq mm 2500 sq mm 2500 sq mm 150°C/W

Table 2. DFN Measured Thermal Resistance

COPPER AREA

BOARD AREA

2500 sq mm 2500 sq mm 2500 sq mm 40°C/W

1000 sq mm 2500 sq mm 2500 sq mm 45°C/W

225 sq mm 2500 sq mm 2500 sq mm 50°C/W

100 sq mm 2500 sq mm 2500 sq mm 62°C/W

THERMAL RESISTANCE

(JUNCTION-TO-AMBIENT)TOPSIDE BACKSIDE

THERMAL RESISTANCE

(JUNCTION-TO-AMBIENT)TOPSIDE BACKSIDE

1. Output current multiplied by the input/output voltage

differential: I

OUT

IN

– V

OUT

) and,

• (V

2. GND pin current multiplied by the input voltage:

• VIN.

I

GND

The GND pin current can be found by examining the GND
Pin Current curves in the Typical Performance Character­istics. Power dissipation will be equal to the sum of the
two components listed above.

The LT3014 regulator has internal thermal limiting de­signed to protect the device during overload conditions.
For continuous normal conditions the maximum junction
temperature rating of 125°C must not be exceeded. It is
important to give careful consideration to all sources of
thermal resistance from junction to ambient. Additional
heat sources mounted nearby must also be considered.

For the DFN package, the thermal resistance junction-to­case (θ

), measured at the Exposed Pad on the back of

JC

the die, is 16°C/W.

40

20

0

–20

–40

–60

CHANGE IN VALUE (%)

–80

BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10μF

–100

–50

–25 0

TEMPERATURE (oC)

X5R

Y5V

50 100 125

25 75

3014 F03

Figure 3. Ceramic Capacitor Temperature Characteristics

3014fd

9

LT3014

APPLICATIONS INFORMATION

Continuous operation at large input/output voltage dif­ferentials 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 maximum topside and backside area for one ounce
copper is 3 seconds. This time constant will increase as
more thermal mass is added (i.e. vias, larger board, and
other components).

For an application with transient high power peaks, average
power dissipation can be used for junction temperature
calculations as long as the pulse period is signifi cantly less
than the thermal time constant of the device and board.

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?

The power dissipated by the device will be equal to:

I

OUT(MAX)

• (V

IN(MAX)

– V

OUT

) + (I

GND

• V

IN(MAX)

)

where:

at (I

= 20mA

= 30V

= 20mA, V

OUT

= 30V) = 0.55mA

IN

I

OUT(MAX)

V

IN(MAX)

I

GND

area. So the junction temperature rise above ambient will
be approximately equal to:

0.52W

• 50°C/W = 26°C

The maximum junction temperature will then be equal to
the maximum junction temperature rise above ambient
plus the maximum ambient temperature or:

= 50°C + 26°C = 76°C

T

JMAX

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 ambi­ent? Using a 500ms period (well under the time constant
of the board), power dissipation is as follows:

P1(48V in, 5mA load) = 5mA • (48V – 5V)
+ (100μA • 48V) = 0.22W

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

Operation at the different power levels is as follows:

76% operation at P1, 19% for P2, 4% for P3, and
1% for P4.

So:

P = 20mA

• (30V – 5V) + (0.55mA • 30V) = 0.52W

The thermal resistance for the DFN package will be in the
range of 40°C/W to 62°C/W depending on the copper

10

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

P

EFF

+ 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.

3014fd

APPLICATIONS INFORMATION

LT3014

Protection Features

The LT3014 incorporates several protection features which
make it 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 device is protected against reverse-input volt­ages, and reverse voltages from output to input.

Current limit protection and thermal overload protection
are intended to protect the device against current overload
conditions at the output of the device. For normal operation,
the junction temperature should not exceed 125°C.

The input of the device will withstand reverse voltages
of 80V. Current fl ow into the device will be limited to less
than 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.

The ADJ pin can be pulled above or below ground by as
much as 7V without damaging the device. If the input is
left open circuit or grounded, the ADJ pin will act like an
open circuit when pulled below ground, and like a large
resistor (typically 100k) in series with a diode when pulled
above ground. If the input is powered by a voltage source,
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.

50

TJ = 25oC

45

= 0V

V

40

35

30

25

20

15

10

REVERSE OUTPUT CURRENT (μA)

5

0

IN

= V

V

OUT

ADJ

CURRENT FLOWS
INTO OUTPUT PIN

21357946 10

0

ADJ PIN

ESD CLAMP

OUTPUT VOLTAGE (V)

In situations where the ADJ pin is connected to a resistor
divider that would pull the ADJ pin above its 7V clamp volt­age if the output is pulled high, the ADJ pin input current
must be limited to less than 5mA. For example, a resistor
divider is used to provide a regulated 1.5V output from the

1.22V reference when the output is forced to 60V. 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 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.

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 fl ow 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 typically drop to less than 2μA. This can happen
if the input of the LT3014 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.

8

3014 F04

Figure 4. Reverse Output Current

3014fd

11

LT3014

TYPICAL APPLICATIONS

5V Buck Converter with Low Current Keep Alive Backup

D2

D1N914

V

IN

5.5V*
TO 60V

OPERATING

CURRENT

HIGH

LOW

C3

4.7μF
100V
CERAMIC

6

BOOST

4

V

IN

15

SHDN

14

SYNC

GND

1, 8, 9, 16

SHDN

LT1766

LT3014

GND

SW

BIAS

V

OUTIN

ADJ

FB

C

11

C
1nF

C2

0.33μF

2

D1
10MQ060N

10

12

C

3.92M

1.27M

†

L1

15μH

R1

15.4k

R2

4.99k

*

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

+

C1
100μF 10V
SOLID
TANTALUM

3014 TA03

V

OUT

5V
1A/20mA

Buck Converter

Effi ciency vs Load Current

100

90

80

= 5V

V

OUT

L = 68μH

VIN = 10V

VIN = 42V

12

70

EFFICIENCY (%)

60

50

0

0.25

0.50

LOAD CURRENT (A)

0.75

1.00

1.25

3014 TA04

3014fd

TYPICAL APPLICATIONS

LT3014

LT3014 Automotive Application

V

IN

12V

(LATER 42V)

OFF

ON

V

OFF

48V

ON

(72V TRANSIENT)

+

1μF

NO PROTECTION
DIODE NEEDED!

SHDN

LT3014

GND

OUTIN

R1

ADJ

R2

LT3014 Telecom Application

IN

1μF

SHDN

LT3014

GND

OUTIN

ADJ

R1

NO PROTECTION
DIODE NEEDED!

R2

1μF

Constant Brightness for Indicator LED over Wide Input Voltage Range

RETURN

OFF ON

–48V

I

= 1.22V/R

LED

–48V CAN VARY FROM –3.3V TO –80V

1μF

SET

IN

LT3014

SHDN

GND

OUT

ADJ

R

SET

3014 TA06

1μF

LOAD: CLOCK,

SECURITY SYSTEM

LOAD:

SYSTEM MONITOR

1μF

ETC

ETC

3014 TA05

+

BACKUP
BATTERY

–

3014fd

13

LT3014

PACKAGE DESCRIPTION

S5 Package

5-Lead Plastic TSOT-23

(Reference LTC DWG # 05-08-1635)

0.62

MAX

3.85 MAX

0.20 BSC

DATUM ‘A’

NOTE:

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

2.62 REF

RECOMMENDED SOLDER PAD LAYOUT

PER IPC CALCULATOR

0.30 – 0.50 REF

0.95
REF

1.22 REF

1.4 MIN

0.09 – 0.20
(NOTE 3)

2.80 BSC

1.50 – 1.75
(NOTE 4)

1.00 MAX

PIN ONE

0.95 BSC

0.80 – 0.90

2.90 BSC
(NOTE 4)

0.30 – 0.45 TYP
5 PLCS (NOTE 3)

0.01 – 0.10

1.90 BSC

S5 TSOT-23 0302 REV B

14

3014fd

PACKAGE DESCRIPTION

LT3014

DD Package

8-Lead Plastic DFN (3mm × 3mm)

(Reference LTC DWG # 05-08-1698)

0.675 p0.05

3.5 p0.05

1.65 p0.05
(2 SIDES)2.15 p0.05

PACKAGE
OUTLINE

0.25 p 0.05

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

PIN 1

TOP MARK

(NOTE 6)

0.200 REF

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

0.50
BSC

2.38 p0.05

(2 SIDES)

3.00 p0.10

(4 SIDES)

0.75 p0.05

0.00 – 0.05

1.65 p 0.10

(2 SIDES)

R = 0.115

TYP

0.25 p 0.05

2.38 p0.10

(2 SIDES)

BOTTOM VIEW—EXPOSED PAD

0.38 p 0.10

85

14

0.50 BSC

(DD) DFN 1203

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

3014fd

15

LT3014

RELATED PARTS

PART NUMBER DESCRIPTION COMMENTS

LT1129 700mA, Micropower, LDO VIN: 4.2V to 30V, V

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

LT1175 500mA, Micropower Negative LDO V

: –20V to –4.3V, V

IN

DD, SOT-223, S8 Packages

LT1185 3A, Negative LDO VIN: –35V to –4.2V, V

TO220-5 Package

LT1761 100mA, Low Noise Micropower, LDO V

: 1.8V to 20V, V

IN

ThinSOT Package

LT1762 150mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, V

MS8 Package

LT1763 500mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, V

S8 Package

LT1764/LT1764A 3A, Low Noise, Fast Transient Response, LDO VIN: 2.7V to 20V, V

DD, TO220 Packages

LTC1844 150mA, Very Low Dropout LDO VIN: 1.6V to 6.5V, V

ThinSOT Package

LT1962 300mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, V

MS8 Package

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

DD, TO220, SOT Packages

LT1964 200mA, Low Noise Micropower, Negative LDO VIN: –1.9V to –20V, V

ThinSOT Package

LT3010 50mA, 80V, Low Noise Micropower, LDO V

: 3V to 80V, V

IN

MS8E Package

LT3020 100mA, Low VIN, Low V

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

OUT

DFN, MS8 Packages

LT3023 Dual 100mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, V

DFN, MS10 Packages

LT3024 Dual 100mA/500mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, V

DFN, TSSOP-16E Packages

LT3027 Dual 100mA, Low Noise LDO with Independent

Inputs

LT3028 Dual 100mA/500mA, Low Noise LDO with

Independent Inputs

VIN: 1.8V to 20V, V
DFN, MS10E Packages

VIN: 1.8V to 20V, V
DFN, TSSOP-16E Packages

OUT(MIN)

OUT(MIN)

OUT(MIN)

OUT(MIN)

OUT(MIN)

OUT(MIN)

OUT(MIN)

OUT(MIN)

OUT(MIN)

OUT(MIN)

OUT(MIN)

OUT(MIN)

OUT(MIN)

= 3.75V, VDO = 0.4V, IQ = 50μA, ISD = 16μA,

= –3.8V, VDO = 0.50V, IQ = 45μA, ISD = 10μA,

OUT(MIN)

= –2.40V, VDO = 0.80V, IQ = 2.5mA, ISD <1μA,

OUT(MIN)

= 1.22V, VDO = 0.30V, IQ = 20μA, ISD <1μA,

= 1.22V, VDO = 0.30V, IQ = 25μA, ISD <1μA,

= 1.22V, VDO = 0.30V, IQ = 30μA, ISD <1μA,

= 1.21V, VDO = 0.34V, IQ = 1mA, ISD <1μA,

= 1.25V, VDO = 0.08V, IQ = 40μA, ISD <1μA,

OUT(MIN)

= 1.22V, VDO = 0.27V, IQ = 30μA, ISD <1μA,

= 1.21V, VDO = 0.34V, IQ = 1mA, ISD <1μA,

= –1.21V, VDO = 0.34V, IQ = 30μA, ISD = 3μA,

OUT(MIN)

= 1.28V, VDO = 0.3V, IQ = 30μA, ISD <1μA,

= 0.20V, VDO = 0.15V, IQ = 120μA, ISD <1μA,

= 1.22V, VDO = 0.30V, IQ = 40μA, ISD <1μA,

= 1.22V, VDO = 0.30V, IQ = 60μA, ISD <1μA,

= 1.22V, VDO = 0.30V, IQ = 40μA, ISD <1μA,

= 1.22V, VDO = 0.30V, IQ = 60μA, ISD <1μA,

16

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

[phone] ● FAX: [phone]

●

www.linear.com

3014fd

LT 0808 REV D • PRINTED IN USA

© LINEAR TECHNOLOGY CORPORATION 2005