LTC3890IGN-1,LTC3890IGN-1 pdf中文资料,LTC3890IGN-1引脚图,LTC3890IGN-1电路-Datasheet-电子工程世界

FEATURES

n

LTC3890-1

60V Low I

Q

,

Dual, 2-Phase Synchronous

Step-Down DC/DC Controller

DESCRIPTION

The LTC

®

3890-1 is a high performance dual step-down

switching regulator DC/DC controller that drives all N-

channel synchronous power MOSFET stages. A constant

frequency current mode architecture allows a phase-lock-

able frequency of up to 850kHz. Power loss and supply

noise are minimized by operating the two controller output

stages out-of-phase.

The 50μA no-load quiescent current extends operating life

in battery-powered systems. OPTI-LOOP

®

compensation

allows the transient response to be optimized over a wide

range of output capacitance and ESR values. A wide 4V

to 60V input supply range encompasses a wide range of

intermediate bus voltages and battery chemistries.

Independent TRACK/SS pins for each controller ramp the

output voltages during start-up. Current foldback limits

MOSFET heat dissipation during short-circuit conditions.

The PLLIN/MODE pin selects among Burst Mode operation,

pulse skipping mode, or continuous conduction mode at

light loads.

For a leadless 32-pin QFN package with additional features

of adjustable current limit, clock out, phase modulation

and two PGOOD outputs, see the LTC3890 data sheet.

L,

LT, LTC, LTM, Linear Technology, Burst Mode, OPTI-LOOP and the Linear logo are

registered trademarks of Linear Technology Corporation. All other trademarks are the

property of their respective owners. Protected by U.S. Patents including 5481178, 5705919,

5929620, 6100678, 6144194, 6177787, 6304066, 6580258, 7230497.

Wide V

IN

Range: 4V to 60V (65V Abs Max)

Low Operating I

Q

: 50μA (One Channel On)

Wide Output Voltage Range: 0.8V ≤ V

OUT

≤ 24V

R

SENSE

or DCR Current Sensing

Out-of-Phase Controllers Reduce Required Input

Capacitance and Power Supply Induced Noise

Phase-Lockable Frequency (75kHz to 850kHz)

Programmable Fixed Frequency (50kHz to 900kHz)

Selectable Continuous, Pulse Skipping or Low Ripple

Burst Mode

®

Operation at Light Loads

Very Low Dropout Operation: 99% Duty Cycle

Adjustable Output Voltage Soft-Start or Tracking

Power Good Output Voltage Monitor

Output Overvoltage Protection

Low Shutdown I

Q

: <14μA

Internal LDO Powers Gate Drive from V

IN

or EXTV

CC

No Current Foldback During Start-Up

Narrow SSOP Package

APPLICATIONS

n

Automotive Always-On Systems

Battery Operated Digital Devices

Distributed DC Power Systems

TYPICAL APPLICATION

High Efﬁciency Dual 8.5V/3.3V Output Step-Down Converter

V

IN

9V TO 60V

4.7μF

V

IN

TG1

0.1μF

4.7μH

BOOST1

SW1

BG1

LTC3890-1

SENSE1

+

0.008Ω

V

OUT1

3.3V

5A

SENSE1

–

V

FB1

ITH1

1000pF

31.6k

34.8k

SENSE2

–

V

FB2

ITH2

1000pF

34.8k

INTV

CC

TG2

BOOST2

SW2

BG2

PGND

SENSE2

+

0.01Ω

V

OUT2

8.5V

3A

330μF

0.1μF

EFFICIENCY (%)

8μH

22μF

100

Efﬁciency and Power Loss

vs Output Current (Buck)

V

IN

= 12V

90 V

OUT

= 3.3V

80

70

60

50

40

30

20

10

0

0.0001

1

0.001

0.01

0.1

OUTPUT CURRENT (A)

0.1

10

38901 TA01b

10000

1000

POWER LOSS (mW)

100

10

1

100k

470μF

100k

10.5k

TRACK/SS1 SGND TRACK/SS2

0.1μF

38901 TA01

38901f

1

LTC3890-1

ABSOLUTE MAXIMUM RATINGS

(Note 1)

PIN CONFIGURATION

TOP VIEW

ITH1

V

FB1

SENSE1

+

SENSE1

–

FREQ

PLLIN/MODE

SGND

RUN1

RUN2

1

2

3

4

5

6

7

8

9

28 TRACK/SS1

27 PGOOD1

26 TG1

25 SW1

24 BOOST1

23 BG1

22 V

IN

21 PGND

20 EXTV

CC

19 INTV

CC

18 BG2

17 BOOST2

16 SW2

15 TG2

Input Supply Voltage (V

IN

) ......................... –0.3V to 65V

Topside Driver Voltages

BOOST1, BOOST2 ................................. –0.3V to 71V

Switch Voltage (SW1, SW2) ........................ –5V to 65V

(BOOST1-SW1), (BOOST2-SW2) ................ –0.3V to 6V

RUN1, RUN2 ............................................... –0.3V to 8V

Maximum Current Sourced into Pin from

Source >8V .......................................................100μA

SENSE1

+

, SENSE2

+

, SENSE1

–

SENSE2

–

Voltages...................................... –0.3V to 28V

PLLIN/MODE, FREQ Voltages .............. –0.3V to INTV

CC

EXTV

CC

...................................................... –0.3V to 14V

ITH1, ITH2, V

FB1

, V

FB2

Voltages ................... –0.3V to 6V

PGOOD1 Voltage ......................................... –0.3V to 6V

TRACK/SS1, TRACK/SS2 Voltages .............. –0.3V to 6V

Operating Junction Temperature Range

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

Maximum Junction Temperature (Note 3) ............ 125°C

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

SENSE2

–

10

SENSE2

+

11

V

FB2

12

ITH2 13

TRACK/SS2 14

GN PACKAGE

28-LEAD PLASTIC SSOP

T

JMAX

= 125°C,

θ

JA

= 90°C/W

ORDER INFORMATION

LEAD FREE FINISH

LTC3890EGN-1#PBF

LTC3890IGN-1#PBF

TAPE AND REEL

LTC3890EGN-1#TRPBF

LTC3890IGN-1#TRPBF

PART MARKING*

LTC3890GN-1

PACKAGE DESCRIPTION

28-Lead Plastic SSOP

TEMPERATURE RANGE

–40°C to 125°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/

ELECTRICAL CHARACTERISTICS

SYMBOL

V

IN

V

FB1,2

PARAMETER

Input Supply Operating Voltage Range

Regulated Feedback Voltage

The

l

denotes the speciﬁcations which apply over the full operating

junction temperature range, otherwise speciﬁcations are at T

J

= 25°C. V

IN

= 12V, V

RUN1,2

= 5V, EXTV

CC

= 0V unless otherwise noted.

CONDITIONS

I

TH1,2

Voltage = 1.2V (Note 4)

–40°C to 125°C

–40°C to 85°C

(Note 4)

V

IN

= 4.5V to 60V (Note 4)

(Note4)

Measured in Servo Loop,

Δ

ITH

Voltage = 1.2V to 0.7V

(Note4)

Measured in Servo Loop,

Δ

ITH

Voltage = 1.2V to 2V

l

MIN

4

l

TYP

MAX

60

UNITS

V

nA

%/V

%

0.788

0.792

0.800

±5

0.002

0.01

0.812

0.808

±50

0.02

0.1

I

FB1,2

V

REFLNREG

V

LOADREG

Feedback Current

Reference Voltage Line Regulation

Output Voltage Load Regulation

l

–0.01

–0.1

%

38901f

2

LTC3890-1

ELECTRICAL CHARACTERISTICS

SYMBOL

g

m1,2

I

Q

PARAMETER

Transconductance Ampliﬁer g

m

Input DC Supply Current

Pulse Skip or Forced Continuous Mode

(One Channel On)

Pulse Skip or Forced Continuous Mode

(Both Channels On)

Sleep Mode (One Channel On)

The

l

denotes the speciﬁcations which apply over the full operating

junction temperature range, otherwise speciﬁcations are at T

J

= 25°C. V

IN

= 12V, V

RUN1,2

= 5V, EXTV

CC

= 0V unless otherwise noted.

CONDITIONS

I

TH1,2

= 1.2V, Sink/Source = 5μA (Note 4)

(Note 5)

RUN1 = 5V and RUN2 = 0V or

RUN1 = 0V and RUN2 = 5V,

V

FB1

= 0.83V (No Load)

RUN1,2 = 5V, V

FB1,2

= 0.83V (No Load)

RUN1 = 5V and RUN2 = 0V or

RUN1 = 0V and RUN2 = 5V,

V

FB1

= 0.83V (No Load)

RUN1,2 = 5V, V

FB1,2

= 0.83V (No Load)

RUN1,2 = 0V

INTV

CC

Ramping Up

INTV

CC

Ramping Down

Measured at V

FB1,2

, Relative to Regulated V

FB1,2

Each Channel

V

SENSE–

< INTV

CC

– 0.5V

V

SENSE–

> INTV

CC

+ 0.5V

In Dropout

V

TRACK1,2

= 0V

V

RUN1

Rising

V

RUN2

Rising

V

FB1,2

= 0.7V, V

SENSE1

–,

2

– = 3.3V, I

LIM

= 0

l

MIN

TYP

2

MAX

UNITS

mmho

mA

2

50

75

mA

μA

Sleep Mode (Both Channels On)

Shutdown

UVLO

V

OVL

I

SENSE+

I

SENSE–

Undervoltage Lockout

Feedback Overvoltage Protection

SENSE

+

Pin Current

SENSE

–

Pins Current

60

14

3.6

7

4.0

3.8

10

100

25

4.2

4.0

13

±1

μA

V

%

μA

%

μA

V

mV

Ω

ns

700

98

0.7

1.15

1.20

64

99

1.0

1.21

1.25

50

75

2.5

1.5

2.4

1.1

85

1.4

1.27

1.30

DF

MAX

I

TRACK/SS1,2

V

RUN1

On

V

RUN2

On

V

SENSE(MAX)

Gate Driver

TG1,2

BG1,2

Maximum Duty Factor

Soft-Start Charge Current

RUN1 Pin On Threshold

RUN2 Pin On Threshold

Maximum Current Sense Threshold

Pull-Up On-Resistance

Pull-Down On-Resistance

Pull-Up On-Resistance

Pull-Down On-Resistance

TG Transition Time:

Rise Time

Fall Time

BG Transition Time:

Rise Time

Fall Time

Top Gate Off to Bottom Gate On Delay

Synchronous Switch-On Delay Time

Bottom Gate Off to Top Gate On Delay

Top Switch-On Delay Time

Minimum On-Time

Internal V

CC

Voltage

INTV

CC

Load Regulation

Internal V

CC

Voltage

V

RUN1,2

Hyst RUN Pin Hysteresis

TG1,2 t

r

TG1,2 t

f

BG1,2 t

r

BG1,2 t

f

TG/BG t

1D

BG/TG t

1D

t

ON(MIN)

V

INTVCCVIN

V

LDOVIN

V

INTVCCEXT

(Note 6)

C

LOAD

= 3300pF

C

LOAD

= 3300pF

(Note 6)

C

LOAD

= 3300pF

C

LOAD

= 3300pF

C

LOAD

= 3300pF Each Driver

C

LOAD

= 3300pF Each Driver

(Note 7)

6V < V

IN

< 60V, V

EXTVCC

= 0V

I

CC

= 0mA to 50mA, V

EXTVCC

= 0V

6V < V

EXTVCC

< 13V

4.85

25

30

95

5.1

0.7

5.1

5.35

1.1

5.35

INTV

CC

Linear Regulator

V

%

V

38901f

3

LTC3890-1

ELECTRICAL CHARACTERISTICS

SYMBOL

V

LDOEXT

V

EXTVCC

V

LDOHYS

f

25kΩ

f

65kΩ

f

105kΩ

f

LOW

f

HIGH

f

SYNC

V

PGL

I

PGOOD

V

PG

PARAMETER

INTV

CC

Load Regulation

EXTV

CC

Switchover Voltage

EXTV

CC

Hysteresis

Programmable Frequency

Low Fixed Frequency

High Fixed Frequency

Synchronizable Frequency

PGOOD1 Voltage Low

PGOOD1 Leakage Current

PGOOD1 Trip Level

R

FREQ

= 25k, PLLIN/MODE = DC Voltage

R

FREQ

= 65k, PLLIN/MODE = DC Voltage

R

FREQ

= 105k, PLLIN/MODE = DC Voltage

V

FREQ

= 0V, PLLIN/MODE = DC Voltage

V

FREQ

= INTV

CC

, PLLIN/MODE = DC Voltage

PLLIN/MODE = External Clock

I

PGOOD

= 2mA

V

PGOOD

= 5V

V

FB

with Respect to Set Regulated Voltage

V

FB

Ramping Negative

Hysteresis

V

FB

with Respect to Set Regulated Voltage

V

FB

Ramping Positive

Hysteresis

t

PG

Delay for Reporting a Fault

–13

–10

2.5

10

2.5

25

l

The

l

denotes the speciﬁcations which apply over the full operating

junction temperature range, otherwise speciﬁcations are at T

J

= 25°C. V

IN

= 12V, V

RUN1,2

= 5V, EXTV

CC

= 0V unless otherwise noted.

CONDITIONS

I

CC

= 0mA to 50mA, V

EXTVCC

= 8.5V

EXTV

CC

Ramping Positive

4.5

MIN

TYP

0.6

4.7

250

105

375

320

485

75

0.2

440

835

350

535

380

585

850

0.4

±1

–7

505

MAX

1.1

4.9

UNITS

%

V

mV

kHz

V

μA

%

μs

Oscillator and Phase-Locked Loop

PGOOD1 Output

7

13

Note 1:

Stresses beyond those listed under Absolute Maximum Ratings

may cause permanent damage to the device. Exposure to any Absolute

Maximum Ratings for extended periods may affect device reliability and

lifetime.

Note 2:

The LTC3890E-1 is guaranteed to meet performance speciﬁcations

from 0°C to 125°C. Speciﬁcations over the –40°C to 125°C operating

junction temperature range are assured by design, characterization and

correlation with statistical process controls. The LTC3890I-1 is guaranteed

over the full –40°C to 125°C operating junction temperature range.

Note 3:

T

J

is calculated from the ambient temperature T

A

and power

dissipation P

D

according to the following formula:

T

J

= T

A

+ (P

D

• 90°C/W)

Note 4:

The LTC3890-1 is tested in a feedback loop that servos V

ITH1,2

to

a speciﬁed voltage and measures the resultant V

FB1,2

. The speciﬁcation at

85°C is not tested in production. This speciﬁcation is assured by design,

characterization and correlation to production testing at 125°C.

Note 5:

Dynamic supply current is higher due to the gate charge being

delivered at the switching frequency. See Applications information.

Note 6:

Rise and fall times are measured using 10% and 90% levels. Delay

times are measured using 50% levels.

Note 7:

The minimum on-time condition is speciﬁed for an inductor peak-

to-peak ripple current ≥ of I

MAX

(See Minimum On-Time Considerations in

the Applications Information section).

38901f

4

LTC3890-1

TYPICAL PERFORMANCE CHARACTERISTICS

Efﬁciency and Power Loss

vs Output Current

100

V

IN

= 12V

90 V

OUT

= 3.3V

80

EFFICIENCY (%)

70

60

50

40

30

20

10

0

0.0001

PULSE-SKIPPING

LOSS

BURST LOSS

10

CCM LOSS

100

10000

BURST EFFICIENCY

1000

POWER LOSS (mW)

EFFICIENCY (%)

100

90

80

70

60

50

40

30

20

10

0.1

10

38901 G01

Efﬁciency vs Output Current

100

V

OUT

= 8.5V

V

OUT

= 3.3V

98

96

EFFICIENCY (%)

94

92

90

88

86

84

Burst Mode OPERATION

V

IN

= 12V

0.001

0.01

0.1

1

OUTPUT CURRENT (A)

10

38901 G02

Efﬁciency vs Input Voltage

V

OUT2

= 8.5V

V

OUT1

= 3.3V

CCM EFFICIENCY

PULSE-SKIPPING

EFFICIENCY

0.001

0.01

0.1

1

OUTPUT CURRENT (A)

1

82

80

0

0.0001

I

LOAD

= 2A

5 10 15 20 25 30 35 40 45 50 55 60

INPUT VOLTAGE (V)

38901 G03

FIGURE 13 CIRCUIT

Load Step

Burst Mode Operation

V

OUT

100mV/DIV

AC-

COUPLED

V

OUT

100mV/DIV

AC-

COUPLED

Load Step

Pulse-Skipping Mode

V

OUT

100mV/DIV

AC-

COUPLED

Load Step

Forced Continuous Mode

I

L

2A/DIV

50μs/DIV

V

IN

= 12V

V

OUT

= 3.3V

FIGURE 13 CIRCUIT

38901 G04

I

L

2A/DIV

50μs/DIV

V

IN

= 12V

V

OUT

= 3.3V

FIGURE 13 CIRCUIT

38901 G05

I

L

2A/DIV

50μs/DIV

V

IN

= 12V

V

OUT

= 3.3V

FIGURE 13 CIRCUIT

38901 G06

Inductor Current at Light Load

FORCED

CONTINUOUS

MODE

Soft Start-Up

Tracking Start-Up

V

OUT2

2V/DIV

V

OUT2

2V/DIV

Burst Mode

OPERATION

1A/DIV

PULSE-SKIPPING

MODE

5μs/DIV

V

IN

= 12V

V

OUT

= 3.3V

I

LOAD

= 200μA

38901 G07

V

OUT1

2V/DIV

V

OUT1

2V/DIV

2ms/DIV

FIGURE 13 CIRCUIT

38901 G08

2ms/DIV

FIGURE 13 CIRCUIT

38901 G09

38901f

5

LTC3890IGN-1

LTC3890IGN-1概述

文档预览

LTC3890IGN-1相似产品对比

推荐资源