LM3481

COMP

FB

AGND

UVLO

DR

PGND

FA/SYNC/SD

+

+

R7

121 k:

R8

121 k:

82 nF

C8

390 pF

22.6 k:

20 k:

169 k:

90.9 k:

20 m:

1 nF

1 PF

150 PF

L1

6.8 PH

150 PF

C9

D1

Q1

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LM3481, LM3481-Q1

SNVS346F – NOVEMBER 2007 – REVISED NOVEMBER 2014

LM3481 / -Q1 High-Efficiency Controller for Boost, SEPIC and Flyback DC-DC Converters

1 Features

3 Description

The LM3481 device is a versatile Low-Side N-FET

1

•

LM3481QMM are Automotive-Grade Products

high-performance controller for switching regulators.

That are AEC-Q100 Grade 1 Qualified (–40°C to

The device is designed for use in Boost, SEPIC and

+125°C Operating Junction Temperature)

Flyback converters and topologies requiring a low-

•

10-Lead VSSOP Package

side FET as the primary switch. The LM3481 device

can be operated at very high switching frequencies to

•

Internal Push-Pull Driver With 1-A Peak Current

reduce the overall solution size. The switching

Capability

frequency of the LM3481 device can be adjusted to

•

Current Limit and Thermal Shutdown

any value between 100kHz and 1MHz by using a

•

Frequency Compensation Optimized With a

single external resistor or by synchronizing it to an

Capacitor and a Resistor

external

clock.

Current

mode

control

provides

superior bandwidth and transient response in addition

•

Internal Softstart

to cycle-by-cycle current limiting. Current limit can be

•

Current Mode Operation

programmed with a single external resistor.

•

Adjustable Undervoltage Lockout With Hysteresis

The LM3481 device has built-in protection features

•

Pulse Skipping at Light Loads

such as thermal shutdown, short-circuit protection

•

Key Specifications

and overvoltage protection. Power-saving shutdown

mode reduces the total supply current to 5 µA and

–

Wide Supply Voltage Range of 2.97 V to 48 V

allows power supply sequencing. Internal soft-start

–

100-kHz to 1-MHz Adjustable and

limits the inrush current at start-up. Integrated current

Synchronizable Clock Frequency

slope compensation simplifies the design and, if

–

±1.5% (Over Temperature) Internal Reference

needed for specific applications, can be increased

using a single resistor.

–

10-µA Shutdown Current (Over Temperature)

Device Information(1)

2 Applications

PART NUMBER

PACKAGE

BODY SIZE (NOM)

•

Automotive Start-Stop Applications

LM3481

•

Automotive ADAS Driver Information

VSSOP (10)

3.00 mm × 3.00 mm

LM3481-Q1

•

One Cell/Two Cell Li-ion Battery Powered

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

Portable Bluetooth Audio Systems

the end of the data sheet.

•

Notebooks, PDAs, Digital Cameras, and Other

Portable Applications

•

Offline Power Supplies

•

Set-Top Boxes

•

Boost for Audio Amplifiers

Figure 1. LM3481 Typical 5Vin to 12Vout Boost Converter Application

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.