100

90

80

70

60

50

0.1

1

LOAD (A)

"X"

GND

FB

EN

VIN

SW

VIN = 5V

C1

R3

D1

L1

R2

R1

C2

C3

VO = 3.3V @ 1.5A

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Design

LM2831

SNVS422D – AUGUST 2006 – REVISED SEPTEMBER 2015

LM2831 High-Frequency 1.5-A Load — Step-Down DC-DC Regulator

1 Features

3 Description

The

LM2831

regulator

is

a

monolithic,

high-

1

•

Space-Saving SOT-23 Package

frequency, PWM step-down DC-DC converter in a 5-

•

Input Voltage Range of 3 V to 5.5 V

pin SOT-23 and a 6-Pin WSON package. The

•

Output Voltage Range of 0.6 V to 4.5 V

LM2831 provides all the active functions to provide

local DC-DC conversion with fast transient response

•

1.5-A Output Current

and accurate regulation in the smallest possible PCB

•

High Switching Frequencie

area. With a minimum of external components, the

–

1.6 MHz (LM2831X)

LM2831 is easy to use. The ability to drive 1.5-A

loads with an internal 130-m

Ω PMOS switch using

–

0.55 MHz (LM2831Y)

state-of-the-art 0.5-µm BiCMOS technology results in

–

3 MHz (LM2831Z)

the best power density available. The world-class

•

130-m

Ω PMOS Switch

control circuitry allows on-times as low as 30 ns, thus

•

0.6-V, 2% Internal Voltage Reference

supporting exceptionally high frequency conversion

over the entire 3 V to 5.5 V input operating range,

•

Internal Soft Start

down to the minimum output voltage of 0.6 V.

•

Current Mode, PWM Operation

Switching frequency is internally set to 550 kHz, 1.6

•

Thermal Shutdown

MHz, or 3 MHz, allowing the use of extremely small

surface mount inductors and chip capacitors. Even

•

Overvoltage Protection

though the operating frequency is high, efficiencies of

up to 93% are easy to achieve. External shutdown is

2 Applications

included, featuring an ultra-low standby current of 30

•

Local 5 V to Vcore Step-Down Converters

nA. The LM2831 utilizes current-mode control and

internal compensation to provide high-performance

•

Core Power in HDDs

regulation over a wide range of operating conditions.

•

Set-Top Boxes

Additional features include internal soft-start circuitry

•

USB Powered Devices

to reduce inrush current, pulse-by-pulse current limit,

•

DSL Modems

thermal shutdown, and output overvoltage protection.

Device Information(1)

PART NUMBER

PACKAGE

BODY SIZE (NOM)

WSON (6)

3.00 mm × 3.00 mm

LM2831

SOT-23 (5)

1.60 mm × 2.90 mm

(1) For all available packages, see the orderable addendum at

the end of the data sheet.

Typical Application Circuit

Efficiency vs Load

1

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.