LT3992EUH#PBF datasheet, PDF - EEWORLD Datasheet

FeaTures

n

LT3992

Monolithic Dual Tracking

3A Step-Down Switching Regulator

DescripTion

The

LT

®

3992

is a dual current mode PWM step-down

DC/DC converter with two internal 4.6A switches. Inde-

pendent input voltage, shutdown, feedback, soft-start,

UVLO current limit and comparator pins for each channel

simplify complex power supply tracking and sequencing

requirements.

To optimize efficiency and component size, both convert-

ers have a programmable maximum current limit and are

synchronized to either a common external clock input, or

a resistor settable fixed 250kHz to 2MHz internal oscillator.

A frequency divider is provided for channel 1 to further

optimize component size. At all frequencies, a 180° phase

relationship between channels is maintained, reducing volt-

age ripple and component size. A clock output is available

for synchronizing multiple regulators.

Minimum input to output voltage ratios are improved by

allowing the switch to stay on through multiple clock cycles

only switching off when the boost capacitor needs recharg-

ing. Independent channel operation can be programmed

using the SHDN pin. Disabling both converters reduces

the total quiescent current to <10µA.

L,

LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of

Linear Technology Corporation. All other trademarks are the property of their respective owners.

n

Wide Input Range:

– Operation from 3V to 60V

Independent Supply, Shutdown, Soft-Start, UVLO,

Programmable Current Limit and Programmable

Power Good for Each 3A Regulator

Die Temperature Monitor

Adjustable/Synchronizable Fixed Frequency

Operation from 250kHz to 2MHz with Synchronized

Clock Output

Independent Synchronized Switching Frequencies

Optimize Component Size

Antiphase Switching

Outputs Can Be Paralleled

Flexible Output Voltage Tracking

Low Dropout: 95% Maximum Duty Cycle

5mm

×

5mm QFN Package

FMEA Compliant 38-Pin Exposed Pad TSSOP Package

Automotive Supplies

Distributed Supply Regulation

applicaTions

n

Typical applicaTion

12V and 5V 2-Stage Multi-Frequency Step-Down Converter

V

IN1

15V TO 60V

4.7µF

Independent Synchronized

Switching Frequencies Extend

Full Frequency Input Range

V

OUT2

V

IN1

SHDN1

BST1

0.1µF

22µH

SW1

IND1

V

OUT1

V

IN2

SHDN2

BST2

SW2

2.2µH

0.1µF

CH1

400kHz

20V/DIV

V

OUT1

12V

1A

400kHz

PG

LT3992

IND2

V

OUT2

FB2

CMPI2

100k

22µF

8.06k

113k

FB1

CMPI1

CMPO1

SS1

ILIM1

V

C1

42.2k

FB1

8.06k

V

OUT2

5V

2A

47µF 1600kHz

CH2

1.6MHz

5V/DIV

CMPO2

SS2

ILIM2

V

C2

CLKOUT

T

J

V

IN

= 60V

500ns/DIV

3992 TA01b

0.1µF

33pF

680pF

RT/SYNC

DIV

48.7k

102k

CLKOUT

1600kHz

10nF

GND

33pF

680pF

10k

60.4k

3992 TA01a

0.1µF

100k

15k

3992fa

For more information

www.linear.com/LT3992

1

LT3992

absoluTe MaxiMuM raTings

(Note 1)

V

IN1/2

, SHDN1/2, CMPO1/2 .......................................60V

SW1/2 ....................................................................V

IN1/2

BST1/2 ......................................................................75V

BST1/2 Pin Above SW1/2..........................................25V

IND1/2, V

OUT1/2

.........................................................60V

FB1/2, CMPI1/2, SS1/2................................................5V

RT/SYNC .....................................................................5V

DIV, ILIM1/2 .............................................................2.5V

V

C1/2

, T

J

.............................................................. ±100µA

Operating Junction Temperature Range (Note 2)

LT3992EUH........................................ –40°C to 125°C

LT3992IUH......................................... –40°C to 125°C

LT3992EFE......................................... –40°C to 125°C

LT3992IFE.......................................... –40°C to 125°C

LT3992HFE ........................................ –40°C to 150°C

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

pin conFiguraTion

TOP VIEW

NC

1

2

3

4

5

6

7

8

9

39

GND

38 SW1

37 NC

36 V

IN1

35 SHDN1

34 SS1

33 I

LIM1

32 V

C1

31 NC

30 RT/SYNC

29 CLKOUT

28 T

J

27 DIV

26 VC2

25 I

LIM2

24 SS2

23 SHDN2

22 V

IN2

21 NC

20 SW2

SHDN1

TOP VIEW

V

OUT1

DNC*

IND1

SW1

V

IN1

IND1

NC

SS1

V

OUT1

NC

32 31 30 29 28 27 26 25

BST1 1

CMPO1 2

CMPI1 3

FB1 4

FB2 5

CMPI2 6

CMPO2 7

BST2 8

9 10 11 12 13 14 15 16

SHDN2

V

OUT2

DNC*

IND2

DNC*

SW2

V

IN2

SS2

33

GND

24 ILIM1

23 V

C1

22 RT/SYNC

21 CLKOUT

20 T

J

19 DIV

18 V

C2

17 ILIM2

BST1

CMPO1

CMPI1

FB1

NC 10

FB2 11

CMPI2 12

CMPO2 13

BST2 14

NC 15

V

OUT2

16

NC 17

IND2 18

NC 19

UH PACKAGE

32-LEAD (5mm

×

5mm) PLASTIC QFN

θ

JA

= 44°C/W,

θ

JC(PAD)

= 7.3°C/W

EXPOSED PAD (PIN 33) IS GND, MUST BE SOLDERED TO PCB

*DO NOT CONNECT

FE PACKAGE

38-LEAD PLASTIC TSSOP

θ

JA

= 17.5°C/W,

θ

JC(PAD)

= 10°C/W

EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB

orDer inForMaTion

LEAD FREE FINISH

LT3992EUH#PBF

LT3992IUH#PBF

LT3992EFE#PBF

LT3992IFE#PBF

LT3992HFE#PBF

TAPE AND REEL

LT3992EUH#TRPBF

LT3992IUH#TRPBF

LT3992EFE#TRPBF

LT3992IFE#TRPBF

LT3992HFE#TRPBF

PART MARKING*

3992

LT3992FE

PACKAGE DESCRIPTION

32-Lead (5mm

×

5mm) Plastic QFN

32-Lead (5mm

×

5mm) Plastic QFN

38-Lead Plastic TSSOP

TEMPERATURE RANGE

–40°C to 125°C

–40°C to 150°C

Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.

Consult LTC Marketing for information on non-standard lead based finish parts.

For more information on lead free part marking, go to:

http://www.linear.com/leadfree/

For more information on tape and reel specifications, go to:

http://www.linear.com/tapeandreel/

2

3992fa

For more information

www.linear.com/LT3992

LT3992

elecTrical characTerisTics

PARAMETER

SHDN Voltage Threshold CH1/2

SHDN Input Current CH1/2

V

IN1

Undervoltage Lockout (Note 3)

V

IN1

Shutdown Current

V

IN2

Shutdown Current

V

IN1

Quiescent Current

V

IN2

Quiescent Current

Feedback Voltage CH1/2

Feedback Voltage Regulation

Feedback Voltage Offset CH1 to CH2

Feedback Bias Current CH1/2

T

J

Output Voltage (Note 4)

T

J

Error

Error Amp g

m

CH1/2

Error Amp Source Current CH1/2

Error Amp Sink Current CH1/2

Error Amp High Clamp CH1/2

Error Amp Switching Threshold CH1/2

Soft-Start Source Current CH1/2

Soft-Start V

OH

CH1/2

Soft-Start Sink Current CH1/2

Soft-Start V

OL

CH1/2

Soft-Start to Feedback Offset CH1/2

SS POR Threshold CH1/2

Soft-Start Sink Current CH1/2 POR

Soft-Start SW Disable CH1/2

CMPI Bias Current CH1/2

CMPO Leakage CH1/2

CMPI Threshold CH1/2

CMPI Threshold CH1/2 of V

FB1/2

CMPI Hysteresis CH1/2

CMPO Sink Current CH1/2

RT/SYNC Reference Current

Minimum Switching Frequency

Switching Frequency

Maximum Switching Frequency

Switching Phase Angle CH1 ≥ CH2

DIV Reference Current

CH1 DIV 2 Threshold

V

DIV

= 1V

R

RT/SYNC

= 0V

l

The

l

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at T

A

= 25°C. V

VIN1/2

= 15V unless otherwise specified. (Note 2)

CONDITIONS

l

MIN

1.24

–1

2.6

l

TYP

1.32

0

2.9

6

0.1

MAX

1.4

1

3.2

13

2

6

900

824

830

13

300

UNITS

V

µA

V

µA

mA

µA

mV

nA

mV

V

mV

V

SHDN

= 1.35V

V

SHDN

= 0V

V

SHDN

= 0V

V

FB1/2

= 2V

V

FB1/2

= 2V

V

VC1/2

= 1V

V

VIN1/2

= 4V to 60V

V

VC1/2

= 1V

V

VC1/2

= 1V

T

J

= 25°C, I

TJ

= 25µA, Temperature = 25°C

I

TJ

= 25µA, Temperature = 125°C

I

TJ

= 25µA, Temperature = –40°C

Temperature = 25°C to 125°C

V

VC1/2

= 1V, I

VC1/2

= ±10µA

V

FB1/2

= 0.7V, V

VC1/2

= 1V

V

FB1/2

=0.9V, V

VC1/2

= 1V

V

FB1/2

= 0.7V

V

FB1/2

= 0V

V

FB1/2

= 2V, V

SS1/2

= 0.07V

V

FB1/2

= 2.0V

V

FB1/2

= 0.7V, V

SS1/2

= 2V

V

FB1/2

= 0V

V

VC1/2

= 1V, V

SS1/2

= 0.4V

V

FB1/2

= 2V, V

SS1/2

= 0.14V (Note 5)

V

FB1/2

= 0V (Note 5)

V

CMPI1/2

= 0.8V

V

CMP1/2

= 0.8V, V

CMPO1/2

= 60V

V

CMPI1/2

Rising

V

CMPI1/2

Rising (Note 6)

V

CMPI1/2

V

CMPI1/2

= 0.6V, V

CMPO1/2

= 0.2V

V

RT/SYNC

= 0.36V E- & I-Grade

V

RT/SYNC

= 0.36V H-Grade

R

RT/SYNC

=0Ω

R

RT/SYNC

= 28k

R

RT/SYNC

=100k

l

3

300

786

780

–13

0

4.2

530

806

0

85

250

1.23

–380

–100

250

15

1.7

0.8

9

1.9

0.4

130

16

70

150

80

–100

690

86

50

150

11.3

11.2

50

900

2.2

10.7

0.44

0

350

25

1.9

1.0

13.5

2.15

0.9

170

0

110

450

115

0

70

725

90

80

250

12

110

1000

2.5

185

12

0.5

100

450

40

2.1

1.2

17

2.4

2

210

16

140

600

150

100

500

760

94

105

12.7

13

150

1100

3.0

13.3

0.56

mV

µMho

µA

V

µA

V

mA

mV

µA

mV

nA

mV

%

mV

µA

kHz

MHz

Deg

µA

V

3992fa

For more information

www.linear.com/LT3992

3

LT3992

elecTrical characTerisTics

PARAMETER

CH1 DIV 4 Threshold

CH1 DIV 8 Threshold

CLKOUT V

OL

CLKOUT V

OH

CLKOUT to SW1ON Delay ( t

DCLKOSW1

)

CLKOUT to SW2ON Delay ( t

DCLKOSW2

)

RT/SYNC to CLKOUT Delay ( t

DRTSYNCH

)

RT/SYNC to CLKOUT Delay ( t

DRTSYNCL

)

SYNC Frequency Range

SYNC Phase Angle CH1 to CH2

Minimum Switch On-Time CH1/2

Minimum Switch Off-Time CH1/2

Minimum Boost for 100% DC CH1/2 (Note 7)

IND + V

OUT

Current CH1/2

ILIM1/2 Reference Current

IND to V

OUT

Maximum Current CH1/2

V

VOUT1/2

= 0V

V

VOUT1/2

= 5V

V

ILIM

= 0V

V

ILIM1/2

= 0.5V, V

VOUT

= 1V (Note 8)

V

ILIM1/2

= 0.5V, V

VOUT

= 5V (Note 8)

V

ILIM1/2

= 1.5V, V

VOUT

= 1V (Note 8)

V

ILIM1/2

= 1.5V, V

VOUT

= 5V (Note 8)

V

SW1/2

= 0V

I

SW1/2

= 500mA, V

BST1/2

= 18V

I

SW1/2

= 3A, V

BST1/2

= 18V

I

SW1/2

= 500mA, V

BST1/2

= 8V

I

SW1/2

= 3A, V

BST1/2

= 8V

I

SW1/2

= 3A, V

BST1/2

= 8V

5

35

1.0

l

The

l

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at T

A

= 25°C. V

VIN1/2

= 15V unless otherwise specified. (Note 2)

CONDITIONS

R

RT/SYNC

= 0V

R

RT/SYNC

= 0V

MIN

0.89

1.39

TYP

1.0

1.5

0.25

2

CLKOUT Rising

CLKOUT Falling

V

RT/SYNC

= 0V to 2V Rising Edge

V

RT/SYNC

= 2V to 0V Falling Edge

250

SYNC Frequency = 250kHz

180

160

200

1.6

2.2

1.5

0.5

10

0.5

0.7

3.5

12

1.5

1.8

4.6

1

200

325

8

55

2.2

25

85

3.0

2.6

5

16

3

6.4

10

60

30

300

150

2000

MAX

1.06

1.56

UNITS

V

ns

kHz

Deg

ns

V

µA

A

µA

mV

mA

V

l

Switch Leakage Current CH1/2

Switch Saturation Voltage CH1/2

Boost Current CH1/2

Minimum Boost Voltage CH1/2 (Note 9)

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 LT3992EUH/LT3992EFE 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 LT3992IUH/LT3992IFE is guaranteed over the full –40°C to 125°C

operating junction temperature range. The LT3992HFE is guaranteed

over the full –40°C to 150°C operating junction temperature range. High

junction temperatures degrade operating lifetimes. Operating lifetime is

derated at junction temperatures greater than 125°C.

Note 3:

V

IN

undervoltage lockout is defined as the voltage which the V

IN

pin must exceed for operation. The threshold guarantees that internal bias

lines are regulated and switching frequency is constant. Actual minimum

input voltage to maintain a regulated output will depend upon output

voltage and load current. See the Applications Information section.

Note 4:

The T

J

output voltage represents the temperature at the center

of the die while dissipating quiescent power. Due to switch power

dissipation and temperature gradients across the die, the T

J

output

voltage measurement does not guarantee that absolute maximum junction

temperature will not be exceeded.

Note 5:

An internal power on reset (POR) latch is set on the positive

transition of the SHDN1/2 pin through its threshold, thermal shutdown or

overvoltage lockout. The output of the latch activates current sources on

each SS pin which typically sink 450µA and discharge the SS capacitor.

The latch is reset when both SS pins are driven below the soft-start POR

threshold or the SHDN pin is taken below its threshold.

Note 6:

The threshold is expressed as a percentage of the feedback

reference voltage for the channel.

Note 7:

To enhance dropout operation, the output switch will be turned off

for the minimum off-time only when the voltage across the boost capacitor

drops below the minimum boost for 100% duty cycle threshold.

Note 8:

The IND to V

OUT

maximum current is defined as the value of

current flowing from the IND pin to the V

OUT

pin which resets the switch

latch when the V

C

pin is at its high clamp.

Note 9:

This is the minimum voltage across the boost capacitor needed to

guarantee full saturation of the internal power switch.

3992fa

4

For more information

www.linear.com/LT3992

LT3992

Typical perForMance characTerisTics

Shutdown Threshold and Minimum

Input Voltage vs Temperature

3.5

3.0

2.5

CURRENT (µA)

VOLTAGE (V)

2.0

1.5

1.0

0.5

0

–50 –25

0

25 50 75 100 125 150

TEMPERATURE (°C)

3992 G01

Shutdown Quiescent Current

vs Temperature

10

820

9

FEEDBACK VOLTAGE (mV)

8

7

6

5

4

3

2

1

0

–50 –25

0

I

Q2

25 50 75 100 125 150

TEMPERATURE (°C)

3992 G02

FB Voltage and CH1-CH2 FB

Offset vs Temperature

8

6

815

OFFSET

810

CH2

805

CH1

4

2

0

–2

–4

–6

800

–50 –25

0

–8

25 50 75 100 125 150

TEMPERATURE (°C)

3992 G03

MINIMUM

INPUT VOLTAGE

OFFSET VOLTAGE (mV)

I

Q1

SHUTDOWN

THRESHOLD VOLTAGE

T

J

Output Voltage vs Temperature

1.50

1.25

TRANSCONDUCTANCE (µMho)

1.00

VOLTAGE (V)

0.75

0.50

0.25 R

TJ

= 30k

TO GND

0

R

TJ

= 30k TO –1V

0

25 50 75 100 125 150

TEMPERATURE (°C)

3992 G04

Error Amplifier Transconductance

vs Temperature

415

400

385

370

VOLTAGE (mV)

355

340

325

310

295

280

265

250

–50 –30 –10 10 30 50 70 90 110 130 150

TEMPERATURE (°C)

3992 G05

Soft-Start-to-Feedback Offset

vs Temperature

4

3

2

1

0

–1

–2

–3

–4

–50 –25

0

25 50 75 100 125 150

TEMPERATURE (°C)

3992 G06

V

SS

= 0.4V

–0.25

–0.50

–50 –25

Comparator Thresholds

vs Temperature

730

720

710

700

VOLTAGE (mV)

CURRENT (µA)

690

680

670

660

650

640

FALLING THRESHOLD

RISING THRESHOLD

400

350

300

Comparator Sink Current

vs Temperature

SINK CURRENT AT V

CMPO

= 0.4V

1800

1600

1400

FREQUENCY (kHz)

1200

1000

800

600

400

200

0

25 50 75 100 125 150

TEMPERATURE (°C)

3992 G08

Switching Frequency

vs Temperature

R

RT/SYNC

= 44.2k

250

200

150

100

50

0

–50 –25

R

RT/SYNC

= 28.0k

R

RT/SYNC

= 13.0k

R

RT/SYNC

= 0k

0

25 50 75 100 125 150

TEMPERATURE (°C)

3992 G09

630

–50 –25

0

25 50 75 100 125 150

TEMPERATURE (°C)

3992 G07

0

–50 –25

3992fa

For more information

www.linear.com/LT3992

5

Parameter Name	Attribute value
Product Attribute	Attribute Value
Manufacturer	ADI
Product Category	Switching Voltage Regulators
RoHS	Details
Mounting Style	SMD/SMT
Package / Case	QFN-32
Output Voltage	0.8 V to 58.8 V
Output Current	3 A
Number of Outputs	2 Output
Input Voltage MAX	60 V
Topology	Buck
Input Voltage MIN	3 V
Switching Frequency	2.5 MHz
Minimum Operating Temperature	- 40 C
Maximum Operating Temperature	+ 125 C
Packaging	Tube
Input Voltage	3 V to 60 V
Operating Temperature Range	- 40 C to + 125 C
Quiescent Current	4.2 mA, 530 uA
Type	Monolithic Dual Tracking Step-Down Switching Regulator
Shutdown	Shutdown
Development Kit	DC1537A
Operating Supply Current	4.2 mA
Factory Pack Quantity	73

	LT3992EUH#PBF	LT3992IUH#PBF	LT3992EUH#TRPBF	LT3992HFE#PBF	LT3992IUH#TRPBF	LT3992IFE#TRPBF
Description	Switching Voltage Regulators Monolithic Dual Tracking 3A Step-Down Switching Regulator	Switching Voltage Regulators Monolithic Dual Tracking 3A Step-Down Switching Regulator	Switching Voltage Regulators Monolithic Dual Tracking 3A Step-Down Switching Regulator	Switching Voltage Regulators Monolithic Dual Tracking 3A Step-Down Switching Regulator	Switching RegulatorMonolithic Dual Tracking 3A Step-Down Switching Regulator	Switching RegulatorMonolithic Dual Tracking 3A Step-Down Switching Regulator
Product Category	Switching Voltage Regulators	Switching Voltage Regulators	Switching Voltage Regulators	Switching Voltage Regulators	switching regulator	switching regulator
Topology	Buck	Buck	Buck	Buck	Buck	Buck
Quiescent Current	4.2 mA, 530 uA	4.2 mA, 530 uA	4.2 mA, 530 uA	4.2 mA, 530 uA	4.2 mA, 530 uA	4.2 mA, 530 uA
Product Attribute	Attribute Value	Attribute Value	Attribute Value	Attribute Value	-	-
Manufacturer	ADI	ADI	ADI	ADI	-	-
RoHS	Details	Details	Details	Details	-	-
Mounting Style	SMD/SMT	SMD/SMT	SMD/SMT	SMD/SMT	-	-
Package / Case	QFN-32	QFN-32	QFN-32	TSSOP-38	-	-
Output Voltage	0.8 V to 58.8 V	0.8 V to 58.8 V	0.8 V to 58.8 V	0.8 V to 58.8 V	-	-
Output Current	3 A	3 A	3 A	3 A	-	-
Number of Outputs	2 Output	2 Output	2 Output	2 Output	-	-
Input Voltage MAX	60 V	60 V	60 V	60 V	-	-
Input Voltage MIN	3 V	3 V	3 V	3 V	-	-
Switching Frequency	2.5 MHz	2.5 MHz	2.5 MHz	2.5 MHz	-	-
Minimum Operating Temperature	- 40 C	- 40 C	- 40 C	- 40 C	-	-
Maximum Operating Temperature	+ 125 C	+ 125 C	+ 125 C	+ 150 C	-	-
Packaging	Tube	Tube	Reel	Tube	-	-
Input Voltage	3 V to 60 V	3 V to 60 V	3 V to 60 V	3 V to 60 V	-	-
Operating Temperature Range	- 40 C to + 125 C	- 40 C to + 125 C	- 40 C to + 125 C	- 40 C to + 150 C	-	-
Type	Monolithic Dual Tracking Step-Down Switching Regulator	Monolithic Dual Tracking Step-Down Switching Regulator	Monolithic Dual Tracking Step-Down Switching Regulator	Monolithic Dual Tracking Step-Down Switching Regulator	-	-
Shutdown	Shutdown	Shutdown	Shutdown	Shutdown	-	-
Development Kit	DC1537A	DC1537A	DC1537A	DC1537A	-	-
Operating Supply Current	4.2 mA	4.2 mA	4.2 mA	4.2 mA	-	-
Factory Pack Quantity	73	73	2500	150	-	-

LT3992EUH#PBF

LT3992EUH#PBF Overview

LT3992EUH#PBF Parametric

Preview

LT3992EUH#PBF Related Products

Recommended Resources