on November 15th 82

Comprehensive Guide to the LM2577 Voltage Regulator

The LM2577 monolithic integrated circuit offers a versatile solution for power management, excelling in boost, flyback, and forward converter applications. With its capacity to integrate multiple functions into a single design, the LM2577 simplifies circuit complexity, reducing the need for various discrete components. This enhances energy efficiency and supports streamlined and dependable designs, making it a go-to choice for consumer electronics and industrial applications. Through consistent voltage regulation and adaptable configurations, the LM2577 addresses performance and efficiency needs, setting a high standard in switching regulators.

Catalog

Pinout

CAD Model

Symbol

Footprint

Overview of the LM2577

The LM2577 emerges as an advanced monolithic integrated circuit, expertly engineered to facilitate step-up (boost), flyback, and forward converter regulation with remarkable efficiency. Its versatility is highlighted by three distinct output voltage options: 12V, 15V, and an adjustable variant. This thoughtful design minimizes the demand for additional external components, offering a pathway to greater affordability and an easier experience.

The LM2577 features a powerful 3.0A NPN switch, which is useful for optimizing operational performance. By integrating this switch, the circuit alleviates the typical challenges associated with external switching components, thus streamlining circuit design and mitigating potential errors. Additionally, it includes built-in protective features such as current limiting, thermal shutdown, and Undervoltage lockout, fostering reliable operation by maintaining the device within safe parameters.

The device operates with a frequency regulated by a 52 kHz oscillator, which eliminates the need for additional components, promoting a simpler design and bolstering energy efficiency. This frequency balances the physical size of magnetic components and the overall operational efficiency, making it feasible to create compact circuit designs that deliver substantial performance. A principally noteworthy attribute is its soft start capability. This feature plays a key role in managing inrush current at startup, allowing for a gradual increase in output voltage. This controlled ramp-up not only safeguards the circuit and load from abrupt power surges but can also extend the lifespan of connected components while enhancing overall system stability.

Features

Feature	Description
Minimal External Components	Requires few external components for operation
High Output Switch Current	NPN output switches 3.0A, with a 65V standoff capability
Wide Input Voltage Range	Operates within a range of 3.5V to 40V
Current-Mode Operation	Enhances transient response, line regulation, and current limit
Internal Oscillator Frequency	52 kHz internal oscillator
Soft-Start Function	Reduces in-rush current during start-up
Protection Mechanisms	Output switch protected by current limit, under-voltage lockout, and thermal shutdown

Technical Specifications

Here's the table content for the Texas Instruments LM2577T-12 specifications and related details.

Type	Parameter
Mount	Through Hole
Mounting Type	Through Hole
Package / Case	TO-220-5
Number of Pins	5
Operating Temperature	-40°C ~ 125°C TJ
Packaging	Tube
Series	SIMPLE SWITCHER®
JESD-609 Code	e0
Pbfree Code	No
Part Status	Obsolete
Moisture Sensitivity Level (MSL)	1 (Unlimited)
Number of Terminations	5
ECCN Code	EAR99
Terminal Finish	Tin/Lead (Sn/Pb)
Terminal Position	SINGLE
Base Part Number	LM2577
Function	Step-Up, Step-Up/Step-Down
Number of Outputs	1
Efficiency	80%
Voltage - Input (Max)	40V
Output Voltage	12V
Output Type	Fixed
Max Output Current	3A
Operating Supply Voltage	40V
Voltage - Input (Min)	3.5V
Input Voltage - Nominal	5V
Analog IC - Other Type	Switching Regulator
Output Configuration	Positive or Negative
Quiescent Current	10mA
Topology	Boost, Flyback, Forward Converter
Control Mode	Current-Mode
Frequency - Switching	52kHz
Control Technique	Pulse Width Modulation
Synchronous Rectifier	No
Nominal Output Voltage	12V
Height	8.89mm
Length	10.16mm
Width	4.7mm
REACH SVHC	No SVHC
RoHS Status	Non-RoHS Compliant
Lead Free	Contains Lead

Functional Block Diagram

Equivalent

Model Number	Manufacturer	Description
LM2577T-12/LF03	Texas Instruments	SIMPLE SWITCHER® 3.5V to 40V, 3A Low Component Count Step-Up Regulator 5-TO-220
LM2577T-12/LB03	Texas Instruments	SIMPLE SWITCHER® 3.5V to 40V, 3A Low Component Count Step-Up Regulator 5-TO-220
LM2577T-12	Texas Instruments	SIMPLE SWITCHER® 3.5V to 40V, 3A Low Component Count Step-Up Regulator 5-TO-220 -40 to 125
LM2577T-12FLOWLB03	Texas Instruments	6A SWITCHING REGULATOR, 62kHz SWITCHING FREQ-MAX, PSFM5, TO-220, 5 PIN

Comparable Parts

Part Number

Manufacturer

Package / Case

Number of Pins

Number of Outputs

Max Output Current

Frequency - Switching

Input Voltage - Nom

Voltage - Input (Min)

Voltage - Input (Max)

Nominal Output Voltage

Output Voltage

Efficiency

LM2577T-12

Texas Instruments

TO-220-5

5

1

3A

52 kHz

5 V

3.5 V

40 V

12 V

12 V

80%

LM2575T-ADJ

ON Semiconductor

TO-220-5

5

1

3A

-

5 V

3.5 V

40 V

5 V

60 V

80%

LM2576T-5.0

Texas Instruments

TO-220-5

5

1

3A

-

12 V

4.75 V

40 V

5 V

5 V

77%

LM2577T-ADJ

Texas Instruments

TO-220-5 Formed Leads

5

1

3A

-

12 V

3.5 V

40 V

5 V

5 V

80%

LM2596T-5.0

Texas Instruments

TO-220-5

220

1

-

-

12 V

4.75 V

40 V

37 V

5 V

-

Applications

Basic Boost Regulator

The LM2577 is a highly adaptable switch-mode power supply (SMPS) integrated circuit that intelligently steps up voltage levels for a variety of applications. When incorporated into a standard boost regulator circuit, it facilitates efficient voltage conversion, making it an excellent choice for battery-operated devices that depend on a consistent output. Actual observations indicate the significance of carefully choosing inductor and capacitor values, as this choice can greatly enhance efficiency and minimize voltage ripple. Additionally, diligent thermal management plays a dynamic role in ensuring dependable operation since excessive heat may compromise both performance and lifespan.

Flyback and Forward Converters

The LM2577’s versatility extends to more advanced topologies such as flyback and forward converters. These arrangements are frequently found in scenarios requiring electrical isolation or multiple voltage outputs, commonly seen in power adapters and industrial machinery. Designing these converters necessitates meticulous attention to transformer specifications, which directly influence system efficiency and overall performance. Practical applications reveal the serious importance of grasping transformer winding configurations and insulation techniques, as these factors can significantly impact the reliability of the circuit.

Multi-Output Regulator

The capability of the LM2577 to manage multiple outputs is mostly beneficial for systems that require distinct voltage levels from a singular power source. This feature becomes increasingly relevant in compact embedded systems and communication devices where both space and energy efficiency are dominant. The design process of a multi-output regulator necessitates a delicate balance of load requirements while maintaining stability across each output. A strong focus on component choices and circuit layout is a must, as industry standards highlight the value of minimizing cross-regulation issues and ensuring that each output can uphold its designated voltage levels across a range of load conditions.

Package

LM2577 Manufacturer

Texas Instruments (TI) stands as a prominent figure in the global semiconductor landscape, boasting operations in 35 countries. Established in 1958, TI has consistently pushed the boundaries of technological progress and is widely recognized for its groundbreaking work in integrated circuits. With a dedicated workforce of over 30,000 employees, the company meticulously engages in the design, manufacturing, and marketing of advanced analog and embedded processing chips. Centered in Dallas, Texas, TI’s commitment to analog chips and embedded processors generates over 80% of its revenue, reflecting a focused strategic direction in these essential areas.

As a dynamic leader in advancing technology, TI not only thrives in analog and processing innovation but also expertly navigates into complementary dominions such as digital light processing (DLP) and educational tools, which include calculators and multi-core processors. This diversification signifies the company’s resolve to widen its technological horizons while steadfastly upholding its initial strengths.

Datasheet PDF

LM2575T-ADJ Datasheets:

Cylindrical Battery Holders.pdf

LM2575.pdf

LM2596T-5.0 Datasheets:

LM2596.pdf