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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

Texas Instruments LM2597M-3.3

Name: LM2597M-3.3
Brand: Texas Instruments
SKU: LM2597M-3.3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LM2597M-3.3

Manufacturer:: Texas Instruments

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: LM2597M-3.3.pdf

Description:: IC REG BUCK 3.3V 500MA 8SOIC

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Product details

Overview

LM2597M-3.3 from Texas Instruments is a monolithic nonsynchronous step-down (buck) DC-DC switching regulator delivering 0.5-A output at fixed 3.3 V with ±4% output voltage tolerance, 150-kHz fixed-frequency operation, and input voltage range up to 40 V. It integrates internal frequency compensation, thermal shutdown, current limiting, and bias supply (VBS) functionality for improved efficiency at high VIN/low VOUT conditions - used in industrial power supplies and embedded system point-of-load conversion.

For engineers reviewing the LM2597M-3.3 datasheet, LM2597M-3.3 pinout, LM2597M-3.3 application, or LM2597M-3.3 equivalent, key selection criteria include its 3.3-V fixed output accuracy over line/load/temperature, 85-μA standby current, soft-start/shutdown control, error flag with delay, and SOIC-8 package compatibility with standard buck layout practices.

Technical Context

The LM2597M-3.3 implements a pulse-width modulation (PWM) buck topology with a fixed 150-kHz oscillator and internal current-mode control. Its integrated 0.5-A N-channel DMOS switch operates with 0.9–1.2 V saturation voltage, enabling efficient conversion across 4.5–40 V input while maintaining ±4% output regulation.

It features dual-function Shutdown/Soft-Start (SD/SS) pin for logic-level enable/disable and controlled output ramp-up via external capacitor, plus an open-collector Error_Flag output activated when VOUT drops below 95% of nominal - delayed by an external capacitor on the Delay pin for reliable microprocessor reset sequencing.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 3.3 V ±4% over full line, load, and temperature range - ensures stable logic rail for 3.3-V microcontrollers and FPGAs.
Max Output Current	0.5 A DC - supports moderate-power digital loads without external current boosting.
Input Voltage Range	4.5 V to 40 V - accommodates wide-input industrial and automotive-supplied systems.
Switching Frequency	150 kHz (±15%) - enables use of compact, low-cost off-the-shelf inductors and reduces EMI compared to lower-frequency alternatives.
Standby Quiescent Current	85 μA typical - minimizes battery drain in always-on or low-power standby modes.
Efficiency	80% typical at VIN = 12 V, IOUT = 0.5 A - reduces thermal stress and PCB copper area required for heat sinking.
Thermal Resistance	95 °C/W (SOIC-8, 1 in² copper) - allows operation up to 125°C ambient without forced cooling in standard layouts.

Pinout & Package

LM2597M-3.3 is housed in an 8-pin SOIC (D) package measuring 4.90 mm × 3.91 mm, optimized for surface-mount assembly and thermal performance with standard PCB copper pour.

Pin/Terminal	Circuit Role	Design Meaning
1 - Error_Flag	Open-collector fault indicator	Asserts low when VOUT falls below 95% of 3.3 V; requires pull-up for microprocessor reset signaling.
2 - Delay	Capacitor-based timing node	Sets delay between VOUT reaching regulation and Error_Flag deassertion - prevents false resets during startup.
3 - Bias_Supply (VBS)	Internal circuit power source	Accepts regulated 3.3 V output (not applicable here due to 3.3-V output limitation) or external ≥4 V supply to reduce VIN current and improve efficiency.
4 - Feedback	Output voltage sensing input	Internally connected to 3.3-V reference; not user-accessible in fixed-output version - simplifies design vs adjustable variants.
5 - Shutdown/Soft-Start	Enable and ramp control	Logic-low disables regulator (IQ ≈ 85 μA); capacitor adds soft-start to limit inrush current and control VOUT rise time.
6 - Ground	Power and signal reference	Common return for internal switch, control circuitry, and external components - must be low-impedance plane for stability.
7 - +VIN	Main power input	Accepts 4.5–40 V DC; requires local ceramic bypass capacitor to handle high di/dt switching currents.
8 - Output	Internal switch drain	Drives external catch diode and inductor; voltage swings between VIN−VSAT and ~−0.5 V - demands minimal PCB copper area to reduce EMI.

Key Features

Feature	Design Value
Fixed 3.3-V output	Eliminates external feedback resistor network - reduces BOM count and layout sensitivity for dedicated 3.3-V rail generation.
Integrated soft-start	Prevents input inrush current spikes up to 700 mA; external capacitor sets ramp duration - critical for current-limited sources like USB or PoE injectors.
Error_Flag with programmable delay	Provides synchronized, glitch-free reset signal to microcontrollers after stable 3.3-V rail establishment - avoids premature firmware execution.
Thermal shutdown & current limit	Two-stage current limiting (0.65–1.4 A peak) plus 150°C junction cutoff - protects against short-circuit, overload, and poor heatsinking without external protection circuits.
Low IQ standby mode	Reduces total system power to <100 μA during shutdown - extends battery life in portable instrumentation and remote sensors.

Applications

Industrial PLC I/O Module Power	Automotive Body Control Unit (BCU)
Use Scenario: Generating isolated 3.3-V logic supply from 12–24 V vehicle battery or 24 V industrial bus under wide temperature and load transients. IC Role / Device Role / Timing Role: Primary buck regulator providing clean, regulated 3.3-V rail for microcontroller, CAN transceiver, and sensor interface ICs. Use Value: ±4% output tolerance and 125°C max operating temperature ensure reliable operation across −40°C to +105°C ambient without derating.	Use Scenario: Powering low-power MCU and EEPROM in door module or lighting controller where input voltage varies from 9 V (cranking) to 16 V (charging). IC Role / Device Role / Timing Role: Step-down converter with shutdown control synchronized to vehicle ignition state - enables zero-current sleep mode. Use Value: 85-μA standby current and logic-compatible SD/SS pin allow direct connection to MCU GPIO for precise power sequencing.
Medical Point-of-Care Diagnostic Device	Industrial Ethernet Node Power
Use Scenario: Converting 5 V or 12 V from USB or wall adapter to stable 3.3 V for ARM Cortex-M based data acquisition subsystem. IC Role / Device Role / Timing Role: Primary DC-DC stage feeding LDOs that supply analog front-end and ADC reference rails. Use Value: 150-kHz switching frequency permits use of small, shielded inductors - minimizing board space and magnetic coupling into sensitive analog sections.	Use Scenario: Providing 3.3-V supply for Ethernet PHY and MAC in DIN-rail mounted gateway with 24 V DC input and strict EMC requirements. IC Role / Device Role / Timing Role: High-efficiency buck regulator preceding filtering and isolation stages - reduces heat generation in enclosed enclosures. Use Value: 80% efficiency at full load and SOIC-8 thermal resistance (95 °C/W) eliminate need for heatsinks in convection-cooled designs.

Industrial PLC I/O Module Power

Automotive Body Control Unit (BCU)

Use Scenario: Generating isolated 3.3-V logic supply from 12–24 V vehicle battery or 24 V industrial bus under wide temperature and load transients.

IC Role / Device Role / Timing Role: Primary buck regulator providing clean, regulated 3.3-V rail for microcontroller, CAN transceiver, and sensor interface ICs.

Use Value: ±4% output tolerance and 125°C max operating temperature ensure reliable operation across −40°C to +105°C ambient without derating.

Use Scenario: Powering low-power MCU and EEPROM in door module or lighting controller where input voltage varies from 9 V (cranking) to 16 V (charging).

IC Role / Device Role / Timing Role: Step-down converter with shutdown control synchronized to vehicle ignition state - enables zero-current sleep mode.

Use Value: 85-μA standby current and logic-compatible SD/SS pin allow direct connection to MCU GPIO for precise power sequencing.

Medical Point-of-Care Diagnostic Device

Industrial Ethernet Node Power

Use Scenario: Converting 5 V or 12 V from USB or wall adapter to stable 3.3 V for ARM Cortex-M based data acquisition subsystem.

IC Role / Device Role / Timing Role: Primary DC-DC stage feeding LDOs that supply analog front-end and ADC reference rails.

Use Value: 150-kHz switching frequency permits use of small, shielded inductors - minimizing board space and magnetic coupling into sensitive analog sections.

Use Scenario: Providing 3.3-V supply for Ethernet PHY and MAC in DIN-rail mounted gateway with 24 V DC input and strict EMC requirements.

IC Role / Device Role / Timing Role: High-efficiency buck regulator preceding filtering and isolation stages - reduces heat generation in enclosed enclosures.

Use Value: 80% efficiency at full load and SOIC-8 thermal resistance (95 °C/W) eliminate need for heatsinks in convection-cooled designs.

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM2596-3.3	Same 3.3-V fixed output, but 150-kHz frequency and 3-A rating - larger die, higher quiescent current (5 mA), no Error_Flag or Delay pins.	Lacks supervisory features; suited for cost-sensitive, non-critical rails where reset signaling is unnecessary.	Select LM2596-3.3 only if higher output current (up to 3 A) is required and fault monitoring is omitted.
TPS54302DDCR	3-A synchronous buck with 2.5–6 V input, 3.3-V output, 2.5-MHz switching, and integrated MOSFETs - no Error_Flag, but includes power-good and thermal foldback.	Requires lower input voltage; better for compact, high-density designs needing >0.5 A, but incompatible with 24+ V inputs.	Choose TPS54302DDCR for space-constrained 5-V input systems demanding higher current and modern sync architecture - not a drop-in replacement.

Compared with LM2597M-3.3, LM2596-3.3 trades supervisory features for higher current capacity and simpler pinout, while TPS54302DDCR offers modern synchronous efficiency and integration at the cost of input voltage range and fault signaling - making LM2597M-3.3 optimal for robust, wide-input, monitored 0.5-A buck conversion.

Availability

LM2597M-3.3 is available at Aetrix Electronics and suitable for industrial PLCs, automotive body control units, medical diagnostics equipment, and industrial Ethernet nodes requiring stable component supply and long-term manufacturability.

Supply support for LM2597M-3.3 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in high-reliability power conversion ICs.

The LM2597 series was designed as a SIMPLE SWITCHER® solution for cost-effective, easy-to-implement buck regulators targeting industrial, automotive, and medical applications needing robust 0.5-A DC-DC conversion with built-in protection and supervision.

FAQ

What is the maximum input voltage supported by the LM2597M-3.3?

The LM2597M-3.3 supports a maximum input voltage of 40 V under recommended operating conditions. This rating applies specifically to the standard LM2597 variant (not the HV version), and operation beyond this voltage risks permanent damage per absolute maximum ratings. The device maintains regulation and protection features across its full 4.5–40 V input range, making it suitable for 24-V industrial buses and automotive applications with transient suppression.

Does the LM2597M-3.3 require external feedback resistors?

No, the LM2597M-3.3 does not require external feedback resistors. As a fixed-output variant, its 3.3-V regulation is implemented internally using precision trimming - pin 4 (Feedback) is internally connected to the reference and not accessible to the user. This eliminates resistor tolerance errors and layout sensitivity, simplifying design versus the adjustable LM2597 versions which require two external resistors to set VOUT.

Can the LM2597M-3.3 be used in an inverting (positive-to-negative) configuration?

Yes, the LM2597M-3.3 can be configured as a positive-to-negative inverter by bootstrapping its ground pin to the negative output, as documented in TI's LM2597 datasheet Figure 24. In this topology, it generates −3.3 V from a positive input. However, the maximum input-to-ground voltage remains limited to 40 V, and output current capability decreases significantly with increasing |VIN| + |VOUT| - e.g., converting 20 V to −3.3 V subjects the IC to 23.3 V differential, staying within rating but reducing deliverable load.

What is the purpose of the Bias_Supply (VBS) pin on the LM2597M-3.3?

On the LM2597M-3.3, the Bias_Supply (VBS) pin is intended to power internal circuitry from a source other than VIN - typically the regulated output - to improve efficiency at high input voltages. However, because the output is 3.3 V and the VBS pin requires ≥4 V to operate, this feature cannot be used with the LM2597M-3.3. The pin must be left open, causing internal circuitry to draw from VIN, which is the default operational mode specified in the datasheet.

How does the Error_Flag output function on the LM2597M-3.3?

The Error_Flag output on the LM2597M-3.3 is an open-collector pin that pulls low when the regulated 3.3-V output drops more than 5% below nominal (i.e., below 3.135 V). At startup, it remains low until VOUT reaches 95% of 3.3 V and the Delay pin capacitor charges - then transitions high. This provides a clean, delayed reset signal for microcontrollers, and requires an external pull-up resistor to VOUT or another logic rail to function correctly.

LM2597M-3.3 Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: SIMPLE SWITCHER®

Package/Case:: 8-SOIC (0.154", 3.90mm Width)

Packaging:: Tube

Product Status:: Obsolete

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Fixed

Number of Outputs:: 1

Voltage - Input (Min):: 4.5V

Voltage - Input (Max):: 40V

Voltage - Output (Min/Fixed):: 3.3V

Voltage - Output (Max):: -

Current - Output:: 500mA

Frequency - Switching:: 150kHz

Synchronous Rectifier:: No

Operating Temperature:: -40°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

LM2597M-3.3 FAQ

1.How can I place an order for LM2597M-3.3 through Aetrix?

Please submit a Request for Quotation (RFQ) for LM2597M-3.3 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for LM2597M-3.3 reliable?

The price and inventory of LM2597M-3.3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2597M-3.3 is usually 5 days.

3.What payment methods are accepted for LM2597M-3.3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2597M-3.3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LM2597M-3.3?

LM2597M-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LM2597M-3.3 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for LM2597M-3.3?

For technical support, including LM2597M-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2597M-3.3 requirements.

6.How does Aetrix verify that LM2597M-3.3 is sourced from the original manufacturer or authorized distributors?

All LM2597M-3.3 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM2597M-3.3 meets industry standards.

7.What is the process for return or replacement of LM2597M-3.3?

All LM2597M-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2597M-3.3, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The LM2597M-3.3 part is unused and in its original packaging.

Return procedure for LM2597M-3.3:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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