LT3435IFE#TR datasheet, PDF - EEWORLD Datasheet

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LT3435IFE#TR: DescriptionLT3435 - High Voltage 3A, 500kHz Step-Down Switching Regulator with 100µA Quiescent Current; Package: TSSOP; Pins: 16; Temperature Range: -40°C to 85°C; CategoryPower/power management The power supply circuit; File Size290KB，24 Pages; ManufacturerLinear ( ADI ); Websitehttp://www.analog.com/cn/index.html

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LT3435IFE#TR Overview

LT3435 - High Voltage 3A, 500kHz Step-Down Switching Regulator with 100µA Quiescent Current; Package: TSSOP; Pins: 16; Temperature Range: -40°C to 85°C

LT3435IFE#TR Parametric

Parameter Name	Attribute value
Brand Name	Linear Technology
Is it Rohs certified?	incompatible
Maker	Linear ( ADI )
Parts packaging code	TSSOP
package instruction	HTSSOP, TSSOP16,.25
Contacts	16
Manufacturer packaging code	FE
Reach Compliance Code	not_compliant
ECCN code	EAR99
Analog Integrated Circuits - Other Types	SWITCHING REGULATOR
control mode	CURRENT-MODE
Maximum input voltage	60 V
Minimum input voltage	3.3 V
Nominal input voltage	12 V
JESD-30 code	R-PDSO-G16
JESD-609 code	e0
length	5 mm
Humidity sensitivity level	1
Number of functions	1
Number of terminals	16
Maximum operating temperature	125 °C
Minimum operating temperature	-40 °C
Maximum output current	6.5 A
Package body material	PLASTIC/EPOXY
encapsulated code	HTSSOP
Encapsulate equivalent code	TSSOP16,.25
Package shape	RECTANGULAR
Package form	SMALL OUTLINE, HEAT SINK/SLUG, THIN PROFILE, SHRINK PITCH
Peak Reflow Temperature (Celsius)	235
Certification status	Not Qualified
Maximum seat height	1.1 mm
surface mount	YES
Switch configuration	BUCK
Maximum switching frequency	575 kHz
Temperature level	AUTOMOTIVE
Terminal surface	Tin/Lead (Sn/Pb)
Terminal form	GULL WING
Terminal pitch	0.65 mm
Terminal location	DUAL
Maximum time at peak reflow temperature	20
width	4.4 mm

LT3435IFE#TR Preview

LT3435

High Voltage 3A, 500kHz

Step-Down Switching Regulator

with 100µA Quiescent Current

DESCRIPTIO

The LT

®

3435 is a 500kHz monolithic buck switching

regulator that accepts input voltages up to 60V. A high

efficiency 3A, 0.1Ω switch is included on the die along with

all the necessary oscillator, control and logic circuitry.

Current mode topology is used for fast transient response

and good loop stability.

Innovative design techniques along with a new high volt-

age process achieve high efficiency over a wide input

range. Efficiency is maintained over a wide output current

range by employing Burst Mode operation at low currents,

utilizing the output to bias the internal circuitry, and by

using a supply boost capacitor to fully saturate the power

switch. Patented circuitry maintains peak switch current

over the full duty cycle range.* Shutdown reduces input

supply current to less than 1µA. External synchronization

can be implemented by driving the SYNC pin with logic-level

inputs. A single capacitor from the C

SS

pin to the output

provides a controlled output voltage ramp (soft-start). The

device also has a power good flag with a programmable

threshold and time-out and thermal shutdown protection.

The LT3435 is available in a 16-pin TSSOP package with an

exposed pad leadframe for low thermal resistance.

FEATURES

■

Wide Input Range: 3.3V to 60V

3A Peak Switch Current

Burst Mode

®

Operation: 100µA Quiescent Current**

Low Shutdown Current: I

Q

< 1µA

Power Good Flag with Programmable Threshold

Load Dump Protection to 60V

500kHz Switching Frequency

Saturating Switch Design: 0.1Ω On-Resistance

Peak Switch Current Maintained Over

Full Duty Cycle Range*

1.25V Feedback Reference Voltage

Easily Synchronizable

Soft-Start Capability

Small 16-Pin Thermally Enhanced TSSOP Package

APPLICATIO S

■

High Voltage Power Conversion

14V and 42V Automotive Systems

Industrial Power Systems

Distributed Power Systems

Battery-Powered Systems

USB Powered Systems

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

Burst Mode is a registered trademark of Linear Technology Corporation. All other trademarks

are the property of their respective owners. *Protected by U.S. Patents including 6498466

**See Burst Mode Operation section for conditions.

TYPICAL APPLICATIO

14V to 3.3V Step-Down Converter with

100µA No Load Quiescent Current

V

IN

SHDN

LT3435

V

C

4700pF

10k

1µF

C

T

SYNC

GND

470pF

C

SS

V

BIAS

FB

PGFB

PG

27pF

165k

1%

100k

1%

4148

Supply Current vs Input Voltage

150

V

OUT

3.3V

2A

V

OUT

= 3.3V

T

A

= 25°C

SUPPLY CURRENT (µA)

0.1µF

EFFICIENCY (%)

4.7µF

100V

CER

V

IN

BOOST

0.33µF 15µH

SW

B360A

125

100

75

50

25

0

+

100µF

10V

TANT

3435 TA01

0

10

30

40

20

INPUT VOLTAGE (V)

50

60

3435 TA03

U

Efficiency and Power Loss

vs Load Current

100

90

80

70

60

50

40

30

20

10

0

0.0001

0.001

0.1

0.01

LOAD CURRENT (A)

1

0.001

10

3435 TA02

V

IN

= 12V

10

V

OUT

= 5V

EFFICIENCY

V

OUT

= 3.3V

1

POWER LOSS (W)

0.1

TYPICAL

POWER LOSS

0.01

3435fa

1

LT3435

ABSOLUTE

(Note 1)

AXI U RATI GS

PACKAGE/ORDER I FOR ATIO

TOP VIEW

NC

SW

V

IN

V

IN

SW

BOOST

C

T

GND

1

2

3

4

5

6

7

8

17

16 PGOOD

15 SHDN

14 SYNC

13 PGFB

12 FB

11 V

C

10 BIAS

9

C

SS

V

IN

, SHDN, BIAS, PGOOD, SW ............................... 60V

BOOST Pin Above SW ............................................ 35V

BOOST Pin Voltage ................................................. 68V

SYNC, C

SS

, PGFB, FB ................................................ 6V

Operating JunctionTemperature Range

(Note 2) ........................................... – 40°C to 125°C

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

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

FE PACKAGE

16-LEAD PLASTIC TSSOP

T

JMAX

= 125°C,

θ

JA

= 45°C/W,

θ

JC(PAD)

= 10°C/W

EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO GND (PIN 8)

ORDER PART NUMBER

LT3435EFE

LT3435IFE

FE PART MARKING

3435EFE

3435IFE

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.

The

●

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at T

J

= 25°C. V

IN

= 12V, SHDN = 12V, BIAS = 5V, FB/PGFB = 1.25V, C

SS

/SYNC = 0V

unless otherwise noted.

SYMBOL

V

SHDN

I

SHDN

I

VINS

PARAMETER

SHDN Threshold

SHDN Input Current

Minimum Input Voltage (Note 3)

Supply Shutdown Current

Supply Sleep Current (Note 4)

I

VIN

Supply Quiescent Current

Minimum BIAS Voltage (Note 5)

I

BIASS

I

BIAS

BIAS Sleep Current (Note 4)

BIAS Quiescent Current

Minimum Boost Voltage (Note 6)

Input Boost Current (Note 7)

V

REF

I

FB

Reference Voltage (V

REF

)

FB Input Bias Current

EA Voltage Gain (Note 8)

EA Voltage g

m

dI(V

C

)=

±10µA

400

SYNC = 3.3V

I

SW

= 1.5A

I

SW

= 3A

3.3V < V

VIN

< 60V

●

ELECTRICAL CHARACTERISTICS

CONDITIONS

SHDN = 12V

SHDN = 0V, BOOST = 0V, FB/PGFB = 0V

BIAS = 0V, FB = 1.35V

FB = 1.35V

BIAS = 0V, FB = 1.15V

BIAS = 5V, FB = 1.15V

●

MIN

1.15

TYP

1.3

5

2.4

0.1

170

45

3.3

2.6

2.7

125

700

1.8

65

MAX

1.45

20

3

2

250

75

7

6

3.1

180

900

85

1.275

200

900

UNITS

V

µA

V

µA

mA

V

µA

V

mA

V

nA

V/V

µMho

3435fa

1.225

1.25

75

900

650

2

U

W

U

W W

W

LT3435

The

●

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at T

J

= 25°C. V

IN

= 12V, SHDN = 12V, BIAS = 5V, FB/PGFB = 1.25V, C

SS

/SYNC = 0V

unless otherwise noted.

SYMBOL

PARAMETER

EA Source Current

EA Sink Current

V

C

to SW g

m

V

C

High Clamp

I

PK

SW Current Limit

Switch On Resistance (Note 9)

Switching Frequency

Maximum Duty Cycle

Minimum SYNC Amplitude

SYNC Frequency Range

SYNC Input Impedance

I

CSS

I

PGFB

V

PGFB

I

CT

V

CT

C

SS

Current Threshold (Note 10)

PGFB Input Current

PGFB Voltage Threshold (Note 11)

C

T

Source Current (Note 11)

C

T

Sink Current (Note 11)

C

T

Voltage Threshold (Note 11)

PG Leakage (Note 11)

PG Sink Current (Note 11)

PGFB = 1V, PG = 400mV

100

●

ELECTRICAL CHARACTERISTICS

CONDITIONS

FB = 1.15V

FB = 1.35V

FB = 1.15V

●

MIN

20

15

2.1

3

425

86

575

TYP

40

30

6

2.2

5.2

0.1

500

92

1.5

45

MAX

55

40

2.4

6.5

0.25

575

2.0

700

UNITS

µA

A/V

V

A

Ω

kHz

%

V

kHz

kΩ

µA

nA

%

µA

mA

V

µA

FB = 0V

7

88

2

1

1.16

13

25

90

3.6

2

1.2

0.1

200

20

100

92

5.5

1.26

1

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 LT3435EFE is guaranteed to meet performance specifications

from 0°C to 125°C 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. The

LT3435IFE is guaranteed and tested over the full –40°C to 125°C

operating junction temperature range.

Note 3:

Minimum input voltage is defined as the voltage where switching

starts. Actual minimum input voltage to maintain a regulated output will

depend upon output voltage and load current. See Applications

Information.

Note 4:

Supply input current is the quiescent current drawn by the input

pin. Its typical value depends on the voltage on the BIAS pin and operating

state of the LT3435. With the BIAS pin at 0V, all of the quiescent current

required to operate the LT3435 will be provided by the V

IN

pin. With the

BIAS voltage above its minimum input voltage, a portion of the total

quiescent current will be supplied by the BIAS pin. Supply sleep current is

defined as the quiescent current during the “sleep” portion of Burst Mode

operation. See Applications Information for determining application supply

currents.

Note 5:

Minimum BIAS voltage is the voltage on the BIAS pin when I

BIAS

is

sourced into the pin.

Note 6:

This is the minimum voltage across the boost capacitor needed to

guarantee full saturation of the internal power switch.

Note 7:

Boost current is the current flowing into the BOOST pin with the

pin held 3.3V above input voltage. It flows only during switch on time.

Note 8:

Gain is measured with a V

C

swing from 1.15V to 750mV.

Note 9:

Switch on resistance is calculated by dividing V

IN

to SW voltage by

the forced current (3A). See Typical Performance Characteristics for the

graph of switch voltage at other currents.

Note 10:

The C

SS

threshold is defined as the value of current sourced into

the C

SS

pin which results in an increase in sink current from the V

C

pin.

See the Soft-Start section in Applications Information.

Note 11:

The PGFB threshold is defined as the percentage of V

REF

voltage

which causes the current source output of the C

T

pin to change from

sinking (below threshold) to sourcing current (above threshold). When

sourcing current, the voltage on the C

T

pin rises until it is clamped

internally. When the clamp is activated, the output of the PG pin will be set

to a high impedance state. When the C

T

clamp is inactive the PG pin will

be set active low with a current sink capability of 200µA.

3435fa

3

LT3435

TYPICAL PERFOR A CE CHARACTERISTICS

FB Voltage

1.30

1.29

1.28

FREQUENCY (kHz)

1.27

VOLTAGE (V)

1.26

1.25

1.24

1.23

1.22

1.21

1.20

–50

–25

50

25

0

75

TEMPERATURE (°C)

100

125

510

500

490

480

470

460

450

–50 –25

50

25

0

75

TEMPERATURE (°C)

100

125

VOLTAGE (V)

SHDN Pin Current

5.5

5.0

4.5

4.0

T

J

= 25°C

CURRENT (µA)

3.5

3.0

2.5

2.0

1.5

1.0

0

10

30

40

20

SHDN VOLTAGE (V)

50

60

3435 G04

15

CURRENT (µA)

Bias Sleep Current

200

180

160

140

CURRENT (µA)

VOLTAGE (V)

120

100

80

60

40

20

0

–50 –25

50

25

0

75

TEMPERATURE (°C)

100

125

4

U W

3435 G01

3435 G07

Oscillator Frequency

550

540

530

520

1.25

1.20

0.15

1.10

1.05

1.40

1.35

1.30

SHDN Threshold

1.00

–50 –25

50

25

0

75

TEMPERATURE (°C)

100

125

3435 G02

3435 G03

Shutdown Supply Current

25

200

180

20

V

IN

= 60V

160

140

120

100

80

60

5

V

IN

= 42V

0

–50 –25

V

IN

= 12V

100

125

40

20

Sleep Mode Supply Current

V

BIAS

= 0V

10

V

BIAS

= 5V

50

25

0

75

TEMPERATURE (°C)

0

–50 –25

50

25

0

75

TEMPERATURE (°C)

100

125

3435 G05

3435 G06

PGFB Threshold

1.20

1.18

1.16

1.14

1.12

1.10

1.08

1.06

1.04

1.02

1.00

–50 –25

50

25

0

75

TEMPERATURE (°C)

100

125

50

150

200

250

PG Sink Current

100

0

–50 –25

50

25

0

75

TEMPERATURE (°C)

100

125

3435 G08

3435 G09

3435fa

LT3435

TYPICAL PERFOR A CE CHARACTERISTICS

Switch Peak Current Limit

6.0

5.5

5.0

4.5

4.0

3.5

3.0

–50 –25

50

45

PEAK SWITCH CURRENT (A)

NORMALIZED FREQUENCY (%)

CURRENT (µA)

–0

25

50

75

TEMPERATURE (°C)

500

450

400

350

VOLTAGE (mV)

300

250

200

150

100

50

0

Switch On Voltage (V

CESAT

)

8.0

7.5

INPUT VOLTAGE (V)

6.5

6.0

5.5

5.0

4.5

4.0

3.5

START-UP

V

OUT

= 5V

RUNNING

START-UP

V

OUT

= 3.3V

RUNNING

0

0.5

1.0

1.5

2.0

LOAD CURRENT (A)

3.0

T

J

= 25°C

LOAD CURRENT (mA)

T

J

= 125°C

T

J

= –40°C

0.5

1.0

2.0

1.5

LOAD CURRENT (A)

Minimum On-Time for Continuous

Mode Operation

600

550

500

LOAD CURRENT = 1A

1000

950

900

BOOST CURRENT (mA)

FREQUENCY (kHz)

450

ON TIME (ns)

400

350

300

250

200

150

100

–50 –25

50

25

0

75

TEMPERATURE (°C)

100

125

U W

100

3435 G10

Soft-Start Current Threshold

vs FB Voltage

T

J

= 25°C

100

90

80

70

60

50

40

30

20

10

0

0.2

0.6

0.8

0.4

FB VOLTAGE (V)

1.0

1.2

3435 G11

Oscillator Frequency

vs FB Voltage

40

35

30

25

20

15

10

5

0

125

SOFT-START

DEFEATED

0

0.25

0.50

0.75

FB VOLTAGE (V)

1.00

1.25

3435 G12

Minimum Input Voltage

1000

Burst Mode Threshold vs Input

Voltage

V

OUT

= 3.3V

900 L = 15µH

C

OUT

= 100µF

800 T = 25°C

A

700

600

500

400

300

200

100

0

2.5

BURST MODE EXIT

(INCREASING LOAD)

7.0

BURST MODE ENTER

(DECREASING LOAD)

2.5

3.0

3435 G13

3.0

5

10

15

INPUT VOLTAGE (V)

20

3435 G16

3435 G15

Maximum Synchronization

Frequency vs Temperature

70

60

50

40

30

20

10

50

25

0

75

TEMPERATURE (°C)

125

Boost Current vs Switch Current

850

800

750

700

650

600

550

500

–50 –25

100

0

500

1000 1500 2000 2500

SWITCH CURRENT (mA)

3000

3435 G17

3435 G14

3435 G18

3435fa

5

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LT3435IFE#TR Related Products

	LT3435IFE#TR	LT3435EFE#TR
Description	LT3435 - High Voltage 3A, 500kHz Step-Down Switching Regulator with 100µA Quiescent Current; Package: TSSOP; Pins: 16; Temperature Range: -40°C to 85°C	LT3435 - High Voltage 3A, 500kHz Step-Down Switching Regulator with 100µA Quiescent Current; Package: TSSOP; Pins: 16; Temperature Range: -40°C to 85°C
Brand Name	Linear Technology	Linear Technology
Is it Rohs certified?	incompatible	incompatible
Maker	Linear ( ADI )	Linear ( ADI )
Parts packaging code	TSSOP	TSSOP
package instruction	HTSSOP, TSSOP16,.25	HTSSOP, TSSOP16,.25
Contacts	16	16
Manufacturer packaging code	FE	FE
Reach Compliance Code	not_compliant	not_compliant
ECCN code	EAR99	EAR99
Analog Integrated Circuits - Other Types	SWITCHING REGULATOR	SWITCHING REGULATOR
control mode	CURRENT-MODE	CURRENT-MODE
Maximum input voltage	60 V	60 V
Minimum input voltage	3.3 V	3.3 V
Nominal input voltage	12 V	12 V
JESD-30 code	R-PDSO-G16	R-PDSO-G16
JESD-609 code	e0	e0
length	5 mm	5 mm
Humidity sensitivity level	1	1
Number of functions	1	1
Number of terminals	16	16
Maximum operating temperature	125 °C	125 °C
Maximum output current	6.5 A	6.5 A
Package body material	PLASTIC/EPOXY	PLASTIC/EPOXY
encapsulated code	HTSSOP	HTSSOP
Encapsulate equivalent code	TSSOP16,.25	TSSOP16,.25
Package shape	RECTANGULAR	RECTANGULAR
Package form	SMALL OUTLINE, HEAT SINK/SLUG, THIN PROFILE, SHRINK PITCH	SMALL OUTLINE, HEAT SINK/SLUG, THIN PROFILE, SHRINK PITCH
Peak Reflow Temperature (Celsius)	235	235
Certification status	Not Qualified	Not Qualified
Maximum seat height	1.1 mm	1.1 mm
surface mount	YES	YES
Switch configuration	BUCK	BUCK
Maximum switching frequency	575 kHz	575 kHz
Temperature level	AUTOMOTIVE	OTHER
Terminal surface	Tin/Lead (Sn/Pb)	Tin/Lead (Sn/Pb)
Terminal form	GULL WING	GULL WING
Terminal pitch	0.65 mm	0.65 mm
Terminal location	DUAL	DUAL
Maximum time at peak reflow temperature	20	20
width	4.4 mm	4.4 mm

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