LT8601

1

8601fa

For more information www.linear.com/LT8601

Typical applicaTion

FeaTures

DescripTion

42V Triple Monolithic

Synchronous Step-Down Regulator

The LT®8601 is a triple channel, current mode, monolithic

buck switching regulator with a programmable power-on

reset. All regulators are synchronized to a single oscillator

with an adjustable frequency from 250kHz to 2.2MHz. The

LT8601 can be configured for micropower Burst Mode or

pulse-skipping operation at light load. Micropower opera-

tion results in quiescent current of 30µA with all three

regulators operating as shown in the application below

with no load applied.

The high voltage channels are synchronous buck regula-

tors that operate from an input of 3.0V to 42V. The output

currents are up to 1.5A (OUT1) and 2.5A (OUT2). The

low voltage channel operates from an input of 2.6V to

5.5V. Internal synchronous power switches provide high

efficiency with output currents up to 1.8A. The LT8601

uses a 2-phase clock with channel 1 operating 180° from

channels 2 and 3 to reduce input ripple current on both

HV and LV inputs. All channels have cycle-by-cycle cur-

rent limit, providing protection against shorted outputs.

Thermal shutdown provides additional protection.

The LT8601 is available in a 40-lead 6mm × 6mm QFN

package.

Automotive Input Stepped Down to 5V, 3.3V and 1.8V Outputs at 2MHz

applicaTions

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Flexible Power Supply System Providing Three

Outputs Over a Wide Input Voltage Range

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Two High Voltage Synchronous Buck Regulators

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3V to 42V Input Voltage Range

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Output Currents Up to 2.5A and 1.5A

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High Efficiency Up to 93%

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One Low Voltage Synchronous Buck Regulator

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2.6V to 5.5V Input Voltage Range

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Output Current Up to 1.8A and 95% Efficiency

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Resistor Programmable and Synchronizable

from 250kHz to 2.2MHz Switching Frequency

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n

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Output Ripple < 15mV

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Programmable Power-On Reset

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Power Good Indicators

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2-Phase Clock Reduces Input Current Ripple

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Available in Thermally Enhanced 40-Lead QFN

(6mm × 6mm) Package

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Automotive Systems

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Distributed Supply Regulation

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Industrial Controls and Power Supplies

L

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

of Analog Devices, Inc. All other trademarks are the property of their respective owners.

8601 TA01a

GND

IN

6V TO 24V,

TRANSIENTS

TO 42V

LT8601

POREN

EN/UVLO

OUT3

1.8V, 1.8A

SW3

FB3

BST1

OUT1

5V, 1.5A

SW1

FB1

BST2

OUT2

3.3V, 1A*

SW2

FB2

BIAS

CPOR

TRKSS1, 2

RT

SYNC

RST

PG1-3

RUN3

2

3

3.3H

1H

1H

22F

47F

22F

OUT2

EFFICIENCY

LOAD CURRENT (A)

0

0.3

0.6

0.9

1.2

1.5

0

10

20

30

40

50

60

70

80

90

100

0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

POWER

LOSS

8601 TA01b

LOAD CURRENT (A)

0

0.3

0.6

0.9

1.2

1.5

1.8

0

10

20

30

40

50

60

70

80

90

100

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

8601 TA01c

EFFICIENCY

POWER

LOSS