LINEAR TECHNOLOGY LT3463, LT3463A Technical data

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FEATURES

LT3463/LT3463A

Dual Micropower

DC/DC Converters

with Schottky Diodes

U

DESCRIPTIO

■

Generates Well-Regulated Positive and
Negative Outputs

■

Low Quiescent Current:

20µA (per Converter) in Active Mode
<1µA in Shutdown Mode

■

Internal 42V Power Switches

■

Internal 42V Schottky Diodes

■

Low V

■

Input Voltage Range: 2.4V to 15V

■

High Output Voltages: Up to ±40V

■

Low Profile (0.8mm) 3mm x 3mm DFN Package

Switch: 180mV at 150mA

CESAT

U

APPLICATIO S

■

CCD Bias

■

LCD Bias

■

Handheld Computers

■

Digital Cameras

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TYPICAL APPLICATIO

The LT®3463/LT3463A are dual micropower DC/DC con­verters with internal Schottky diodes in a 10-lead 3mm ×
3mm DFN package. Negative and positive LT3463 con­verters have a 250mA current limit. The LT3463A positive
converter also has a 250mA limit, while the negative
converter has a 400mA limit. Both devices have an input
voltage range of 2.4V to 15V, making them ideal for a wide
variety of applications. Each converter features a quies­cent current of only 20µA, which drops to under 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. The 42V switch enables
high voltage outputs up to ±40V to be easily generated
without the use of costly transformers. The low 300ns off­time permits the use of tiny, low profile inductors and
capacitors to minimize footprint and cost in space-con­scious portable applications.

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

V

2.7V

TO 5V

IN

4.7µF

CCD Bias Supply (15V, –8V)

10µH

V

IN

SHDN2
GND SW2 D2

10µH

SW1

LT3463A

1µF

V

OUT1

FB1SHDN1

V

REF

FB2

1M

90.9k

154k

1M 10pF

4.7µF

3463 TA01a

2.2µF

V

OUT1

15V
10mA

V

OUT2

–8V
50mA

Efficiency and Power Loss

80

15V EFFICIENCY

75

70

65

EFFICIENCY (%)

60

55

50

0.1

VIN = 3.6V

–8V EFFICIENCY

15V LOSS

–8V LOSS

1 10 100

LOAD CURRENT (mA)

3463 TA01b

240

200

POWER LOSS (mW)

160

120

80

40

0

3463f

1

LT3463/LT3463A

TOP VIEW

DD PACKAGE

10-LEAD (3mm × 3mm) PLASTIC DFN

10

9

6

7

8
4
5

3

2

1

FB1
SHDN1
SHDN2
V

REF

FB2

V

OUT1

SW1

V

IN

SW2

D2

11

ABSOLUTE AXI U RATI GS

(Note 1)

VIN, SHDN1, SHDN2 Voltage ................................... 15V

SW1, SW2, V

D2 Voltage ............................................................. –42V

FB1, FB2 Voltage Range .............................. –0.3V to 2V

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

Operating Ambient Temperature Range

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

Storage Temperature Range ................. –65°C to 125°C

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at TA = 25°C. VIN = 2.5V, V

PARAMETER CONDITIONS MIN TYP MAX UNITS

Minimum Input Voltage 2.2 2.4 V
Total Quiescent Current For Both Switchers, Not Switching 40 60 µA
Shutdown Current V
V

Pin Voltage With 124kΩ to GND ● 1.23 1.25 1.27 V

REF

V

Pin Voltage Line Regulation With 124kΩ to GND 0.05 0.10 %/V

REF

FB1 Comparator Trip Voltage High to Low Transition ● 1.225 1.25 1.275 V
FB1 Comparator Hysteresis 8mV
FB1 Line Regulation 2.5V < VIN < 15V 0.05 0.10 %/V
FB1 Pin Bias Current (Note 3) V
FB2 Comparator Trip Voltage Low to High Transition ● 0312mV
FB2 Comparator Hysteresis 8mV
FB2 Line Regulation (V
FB2 Pin Bias Current (Note 4) V
SW1 Switch Off Time V

SW2 Switch Off Time V

Switch V

CESAT

Switch Current Limit (SW1) 180 250 320 mA
Switch Current Limit (SW2) LT3463 180 250 320 mA

Swith Leakage Current (SW1, SW2) Switch Off, VSW = 42V 0.01 1 µA
Schottky Forward Voltage (V
Schottky Reverse Leakage Current V

SHDN1 Pin Current V
SHDN2 Pin Current V
SHDN1/SHDN2 Start-Up Threshold 0.3 1 1.5 V

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

Note 2: The LT3463/LT3463A are guaranteed to meet performance
specifications from 0°C to 70°C. Specifications over the –40°C to 85°C

2

W

Voltage ....................................... 42V

OUT1

– V

REF

(SW1, SW2) I

) 2.5V < VIN < 15V 0.05 0.10 %/V

FB2

, D2) ID = 150mA 750 mV

OUT1

WW

U

UUW

PACKAGE/ORDER I FOR ATIO

ORDER PART

NUMBER

LT3463EDD
LT3463AEDD

DD PART MARKING

T

= 125°C, θJA = 43°C/W, θJC = 3°C/W

JMAX

EXPOSED PAD (PIN 11) IS GND

AND MUST BE SOLDERED TO PCB

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

The ● denotes the specifications which apply over the full operating

= 2.5V unless otherwise noted.

SHDN

= V

SHDN1

= 1.3V ● 20 50 nA

FB1

= –0.1V ● 20 50 nA

FB2

– VIN = 4V 300 ns

OUT1

– VIN = 0V 1.5 µs

V

OUT1

< 0.1V 300 ns

FB2

= 1V 1.5 µs

V

FB2

= 150mA 180 mV

SW

LT3463A 320 400 460 mA

– VSW = 42V 1 5 µA

OUT1

= –42V 1 5 µA

V

D2

= 2.5V 4 10 µA

SHDN1

= 2.5V 4 10 µA

SHDN2

= 0V 0.1 1 µA

SHDN2

operating ambient temperature range are assured by design,
characterization and correlation with statistical process controls.

Note 3: Bias current flows into the FB1 pin.
Note 4: Bias current flows out of the FB2 pin.

LAFC
LBJK

3463f

UW

TYPICAL PERFOR A CE CHARACTERISTICS

V

and V

CESAT

900

800

I

700

600

VOLTAGE (V)

500

DIODE

400

300

AND V

200

CESAT

V

100

0

= 150mA

DIODE

I

= 150mA

SWITCH

–50 100

050–25 25 75 125

TEMPERATURE (°C)

Voltage

DIODE

FOR BOTH SWITCHERS

3463 G01

V

and V

REF

1.27

1.26

1.25

VOLTAGE (V)

FB1

1.24

AND V

REF

V

1.23

1.22
–50 100

Voltage V

FB1

V

FB1

050–25 25 75 125

TEMPERATURE (°C)

V

REF

3463 G02

LT3463/LT3463A

Voltage

FB2

10

8

6

4

VOLTAGE (mV)

FB2

V

2

0

–50 25 75

–25 0

TEMPERATURE (°C)

50 100 125

3463 G03

Switch Off Time

400

350

300

250

200

150

SWITCH OFF TIME (ns)

100

50

0

–50

050

–25 25 75 125

100

TEMPERATURE (°C)

3463 G04

Switch Current Limit

450

400

350

300

250

200

150

100

SWITCH CURRENT LIMIT (mA)

50

0

–25 25 75 125

–50

LT3463A SW2

LT3463 SW1, SW2

LT3463A SW1

050

TEMPERATURE (°C)

UUU

PI FU CTIO S

V

(Pin 1): Output Voltage Switcher 1. This is the

OUT1

cathode of an internal Schottky diode whose anode is
connected to the SW1 pin.

Quiescent Current

60

50

40

30

20

QUIESCENT CURRENT (µA)

NOT SWITCHING

10

= 1.3V

V

FB1

V

= –0.1V

FB2

100

3463 G05

0

–50

–25 0

50 100 125

25 75

TEMPERATURE (°C)

3463 G06

D2 (Pin 5): Diode for Switcher 2. This is the anode of an
internal Schottky diode whose cathode connected to the
GND pin.

SW1 (Pin 2): Switch Pin for Switcher 1. This is the
collector of the internal NPN switch. Minimize the metal
trace area connected to this pin to minimize EMI.

VIN (Pin 3): Input Supply Pin. Bypass this pin with a
capacitor as close to the device as possible.

SW2 (Pin 4): Switch Pin for Switcher 2. This is the
collector of the internal NPN switch. Minimize the metal
trace area connected to this pin to minimize EMI.

FB2 (Pin 6): Feedback Pin for Switcher 2. Set the output
voltage by selecting values for R3 and R4.

V

(Pin 7): Voltage Reference Pin (1.25V). This pin is

REF

used along with FB2 to set the negative output voltage for
Switcher 2.

SHDN2 (Pin 8): Shutdown Pin for Switcher 2. Pull this pin
above 1.5V to enable Switcher 2. Pull below 0.3V to turn
it off. Do not leave this pin floating.

3463f

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