LM3481 Datasheet: Analysis and Evaluation

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9 months ago

Texas Instruments’ LM3481 high-efficiency controller

Texas Instruments’ LM3481MMX/NOPB high-efficiency controller

Low-side N-FET high-performance controllers are electronic circuits that control the switching of N-channel MOSFETs (N-FETs) connected to the ground side of load in applications like power management, motor control, and DC-DC converters. These controllers drive the gate of the N-FET, allowing it to turn on and off rapidly, thereby managing power delivery with minimal losses. Its high-performance characteristics, such as fast switching times and low on-resistance, make it best for applications requiring efficient energy conversion and thermal management. A commonly used low-side N-FET high-performance controller is the LM3481. It is employed in boost converters, single-ended primary-inductor converters (SEPIC), and flyback converters and topologies that need a low-side FET as the primary switch. For the best PCB design, engineers should leverage information, such as features, applications, and specifications, from Texas Instruments’ LM3481 datasheet.

LM3481 Datasheet: Features and Applications

The LM3481 is a versatile low-side N-FET high-performance controller for switching regulators. Its features and applications, as described in the datasheet, are listed below.

IMPORTANT LM3481 FEATURES & APPLICATIONS
Features	Applications
✔ 10-lead VSSOP package	+ Boost for audio amplifiers in portable speakers
✔ Internal push-pull driver with 1A peak current capability	+ Wide input boost, SEPIC, and flyback power modules
✔ Current limit and thermal shutdown	+ Isolated supply (flyback)
✔ Frequency compensation optimized with a capacitor and a resistor	+ Battery-powered boost, SEPIC, and flyback
✔ Internal soft start
✔ Current mode operation
✔ Adjustable undervoltage lockout with hysteresis
✔ Pulse skipping at light loads

A boost converter is a typical application for LM3481. Here is a diagram from the datasheet showing the boost converter configuration.

The LM3481 can operate at very high switching frequencies. A single external resistor or an external clock can be used to adjust the switching frequency of the LM3481 to values between 100 kHz and 1 MHz. With the use of current mode control, engineers can achieve superior bandwidth and transient response, as well as cycle-by-cycle current limiting. A single external resistor can be used to set the current limit.

LM3481: Parameters and Specifications

According to the datasheet, the LM3481 has the following absolute maximum electrical and thermal ratings:

ABSOLUTE MAXIMUM RATINGS (over operating free-air temperature range)
		MIN	MAX	UNIT
VIN	Pin Voltage	−0.4	50	V
FB	Pin Voltage	−0.4	6	V
FA/SYNC/SD	Pin Voltage	−0.4	6	V
COMP	Pin Voltage	−0.4	6	V
UVLO	Pin Voltage	−0.4	6	V
VCC	Pin Voltage	−0.4	7	V
ISEN	Pin Voltage	−400	600	mV
	Peak Driver		1	A
	Output Current
	Power Dissipation	Internally Limited	Internally Limited
	Junction Temperature		150span>	℃
Lead Temperature (only applies to operating conditions)	DGS Package		220	℃
Peak Body Temperature			260	℃
TSTG	Storage Temperature Range	-65	150	℃

The electrical characteristics of high-efficiency controllers directly affect the performance, reliability, and energy consumption of electronic systems. These controllers regulate power delivery, optimize energy usage, and ensure that electronic components operate within safe parameters. Knowledge of their electrical properties enables engineers to design more efficient circuits, reduce heat generation, and extend the lifespan of components. Below are the electrical characteristics for the LM3481 from the datasheet. LM3481 ELECTRICAL CHARACTERISTICS

Understanding electrical characteristics also aids in compliance with industry standards, leading to more sustainable and cost-effective solutions in a range of applications.

LM3481: Layout and Operation

The component pinout and functional diagram provided in the LM3481 datasheet, is shown below.

LM3481 component pinout and functional diagram

PCB Design and the LM3481 Datasheet

LM3481 datasheet information is helpful, but it is not recommended to create PCB footprints manually. It is relatively easy to make mistakes, which can lead to redesigns, turnaround time delays, and additional costs.

LM3481 schematic symbol, footprint, and 3D CAD model from Ultra Librarian

A more reliable approach is to obtain schematic symbols, footprints, and 3D CAD models from a reputable source, such as Ultra Librarian, and procure the LM3481 from a reputable distributor. If you’re looking for CAD models for common components or important design information like how to best use the LM3481 datasheet for your PCB project, Ultra Librarian helps by compiling all your sourcing and CAD information in one place. Working with Ultra Librarian sets up your team for success to ensure streamlined and error-free design, production, and sourcing. Register today for free.