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LTC3801/LTC3801B

sn3801 3801fs

Micropower

Constant Frequency Step-Down

DC/DC Controllers in ThinSOT

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High Efficiency: Up to 94%

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Very Low No-Load Quiescent Current:

Only 16

µA (LTC3801)

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High Output Currents Easily Achieved

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Internal Soft-Start

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Low Dropout: 100% Duty Cycle

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Constant Frequency 550kHz Operation

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Burst Mode

at Light Loads (LTC3801)

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Burst Mode Operation Disabled for Lower Output

Ripple at Light Loads (LTC3801B)

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Output Voltage as Low as 0.8V

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±1.5% Voltage Reference Accuracy

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Current Mode Operation for Excellent Line and Load

Transient Response

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Only 6

µA Supply Current in Shutdown (LTC3801)

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Low Profile (1mm) SOT-23 Package

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1- or 2-Cell Li-Ion Battery-Powered Applications

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Wireless Devices

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Portable Computers

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Distributed Power Systems

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

550kHz Micropower Step-Down DC/DC Controller

The LTC

rent mode step-down DC/DC controllers in a low profile

(1mm max) 6-lead SOT-23 (ThinSOT

parts provide excellent AC and DC load and line regula-

tion with

±1.5% output voltage accuracy. The LTC3801

consumes only 195

µA of quiescent current in normal

operation, dropping to 16

µA under no-load conditions.

The LTC3801/LTC3801B incorporate an undervoltage lock-

out feature that shuts down the device when the input

voltage falls below 2.2V. The LTC3801 automatically

switches into Burst Mode operation at light loads which

enhances efficiency at low output current. In the LTC3801B,

Burst Mode operation is disabled for lower output ripple at

light loads.

To further maximize the life of a battery source, the

external P-channel MOSFET is turned on continuously in

dropout (100% duty cycle). High switching frequency of

550kHz allows the use of a small inductor.

Burst Mode is a registered trademark of Linear Technology Corporation.

ThinSOT is a trademark of Linear Technology Corporation.

LTC3801/

LTC3801B

10k

402k

866k

0.025

Ω

4.7

µH

220pF

GND

3801 TA01

PGATE

10

µF

2.7V TO 9.8V

2.5V

2A

47

µF

+

LTC3801 Efficiency vs Load Current*

LOAD CURRENT (mA)

0.1

70

75

80

85

90

1

10

100

10000

1000

3801 TA02

65

60

55

50

95

100

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO