LINEAR TECHNOLOGY LT3483 Technical data

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FEATURES

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Internal 40V Schottky Diode

■

One Resistor Feedback (Other Resistor Inside)

■

Internal 40V, 200mA Power Switch

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Generates Regulated Negative Outputs to –38V

■

Low Quiescent Current:

40µA in Active Mode
<1µA in Shutdown Mode

■

Low V

■

Wide Input Range: 2.5V to 16V

■

Uses Small Surface Mount Components

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Output Short-Circuit Protected

■

Available in a 6-Lead SOT-23 Package

Switch: 200mV at 150mA

CESAT

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APPLICATIO S

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LCD Bias

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Handheld Computers

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Battery Backup

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Digital Cameras

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OLED Bias

LT3483

Inverting Micropower

DC/DC Converter with

Schottky in ThinSOT Package

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DESCRIPTIO

The LT®3483 is a micropower inverting DC/DC converter
with integrated Schottky and one resistor feedback. The
small package size, high level of integration and use of tiny
surface mount components yield a solution size as small
as 40mm
40µA at no load, which further reduces to 0.1µA in
shutdown. A current limited, fixed off-time control scheme
conserves operating current, resulting in high efficiency
over a broad range of load current. A precisely trimmed
10µA feedback current enables one resistor feedback and
virtually eliminates feedback loading of the output. The
40V switch enables voltage outputs up to –38V to be
generated without the use of costly transformers. The
LT3483’s low 300ns off-time permits the use of tiny low
profile inductors and capacitors to minimize footprint and
cost in space-conscious portable applications.

The LT3483 is available in the low profile (1mm) SOT-23
(ThinSOTTM) package.

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

ThinSOT is a trademark of Linear Technology Corporation.
Patent pending.

2

. The device features a quiescent current of only

TYPICAL APPLICATIO

3.6V to –8V DC/DC Converter

V

IN

LT3483

SHDN

0.22µF

SW

D

FB

GND

V

3.6V

4.7µF

IN

10µH

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10Ω

806k5pF

2.2µF

3483 TA01a

V

OUT

–8V
25mA

Efficiency and Power Loss

75

= 3.6V

V

IN

70

65

EFFICIENCY (%)

60

55

0.1

EFFICIENCY

POWER

LOSS

110

LOAD CURRENT (mA)

3483 TA01b

1000

100

POWER LOSS (mW)

10

1

0.1

100

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LT3483

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ABSOLUTE AXI U RATI GS

(Note 1)

VIN Voltage ............................................................. 16V

SW Voltage ............................................................. 40V

D Voltage .............................................................. –40V

FB Voltage ............................................................. 2.5V

SHDN Voltage ......................................................... 16V

Operating Ambient Temperature Range

(Note 2) .................................................. – 40°C to 85°C

Junction Temperature.......................................... 125°C

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

PACKAGE/ORDER I FOR ATIO

TOP VIEW

SW 1

GND 2

FB 3

S6 PACKAGE

6-LEAD PLASTIC TSOT-23

T

= 125°C, θJA = 256°C/W IN FREE AIR

JMAX

= 120°C/W ON BOARD OVER GROUND PLANE

θ

JA

6 V

5 D

4 SHDN

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W

ORDER PART

NUMBER

IN

LT3483ES6

S6 PART MARKING

LTBKX

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 TA = 25°C.
VIN = 3.6V, V

PARAMETER CONDITIONS MIN TYP MAX UNITS

VIN Operating Range 2.5 16 V

VIN Undervoltage Lockout 2 2.4 V

FB Comparator Trip Voltage to GND (VFB) FB Falling ● 0512 mV

FB Output Current (Note 3) FB = VFB – 5mV ● –10.15 –10 –9.75 µA

FB Comparator Hysteresis FB Rising 10 mV

Quiescent Current in Shutdown V

Quiescent Current (Not Switching) FB = –0.05V 40 50 µA

IFB Line Regulation 2.5V ≤ VIN ≤ 16V 0.07 %/V

Switch Off-Time 300 ns

Switch Current Limit 170 200 230 mA

Switch V

CESAT

Switch Leakage Current SW = 40V 1 µA

Rectifier Leakage Current D = – 40V 4 µA

Rectifier Forward Drop ID = 150mA to GND 0.64 V

SHDN Input Low Voltage 0.4 V

SHDN Input High Voltage 1.5 V

SHDN Pin Current 610 µA

= 3.6V unless otherwise specified.

SHDN

= GND 1 µA

SHDN

ISW = 150mA to GND 200 mV

Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.

Note 2: The LTC3483E is guaranteed to meet specifications from 0°C to
70°C. Specifications over the –40°C to 85°C operating temperature range
are assured by design, characterization and correlation with statistical
process controls.

2

Note 3: Current flows out of the pin.

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TYPICAL PERFOR A CE CHARACTERISTICS

LT3483

CURRENT (µA)
V

FB

10.2

10.1

10.0

9.9

9.8
–50

VFB Current

–20

40

10

TEMPERATURE (°C)

70

100

3483 G01

VFB Voltage Switch Off Time

12

9

6

VOLTAGE (mV)

FB

V

3

0

–50

–20

10

TEMPERATURE (°C)

40

70

100

3483 G02

400

350

300

250

200

150

SWITCH OFF TIME (ns)

100

50

0

–50

–20 10 70

TEMPERATURE (°C)

Switch Current Limit Quiescent Current SHDN Pin Bias Current

230

220

210

200

190

SWITCH CURRENT LIMIT (mA)

180

170

–50

–20 10 40 70

TEMPERATURE (°C)

100

3483 G04

50

40

30

20

QUIESCENT CURRENT (µA)

10

0

–50

NOT SWITCHING

= –0.05V

V

FB

–20

TEMPERATURE (°C)

10

= 25°C

T

A

8

6

4

2

SHDN PIN BIAS CURRENT (µA)

40

70

10

100

3483 G05

0

0

4

SHDN PIN VOLTAGE (V)

40

8

12

100

3483 G03

16

3483 G06

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PI FU CTIO S

SW: Switch. Connect to external inductor L1 and positive
terminal of transfer capacitor.

GND: Ground.

FB: Feedback. Place resistor to negative output here. Set

resistor value R1 = V

SHDN: Shutdown. Connect to GND to turn device off.
Connect to supply to turn device on.

OUT

/10µA.

D: Anode Terminal of Integrated Schottky Diode. Con­nect to negative terminal of transfer capacitor and exter­nal inductor L2 (flyback configuration) or to cathode of
external Schottky diode (inverting charge pump
configuration).

VIN: Input Supply. Must be locally bypassed with 1µF or
greater.

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