Texas Instruments LM2597HVMX-3.3

Overview

LM2597HVMX-3.3 from Texas Instruments is a monolithic 150 kHz step-down (buck) switching voltage regulator IC delivering a fixed 3.3 V output at up to 0.5 A, with input voltage support up to 60 V, ±4% output voltage tolerance over line and load, and integrated soft-start/shutdown control. It serves as a primary DC-DC power conversion stage in industrial power supplies requiring high-input-voltage tolerance and stable low-voltage rail generation.

For engineers reviewing the LM2597HVMX-3.3 datasheet, LM2597HVMX-3.3 pinout, LM2597HVMX-3.3 application, or LM2597HVMX-3.3 equivalent, key selection considerations include its 60 V max input rating, 3.3 V fixed output accuracy, thermal shutdown protection, bias supply (VBS) pin for high-efficiency operation, and compatibility with standard off-the-shelf inductors and Schottky catch diodes.

Technical Context

The LM2597HVMX-3.3 integrates a 0.5 A N-channel DMOS switch, 150 kHz fixed-frequency oscillator, internal frequency compensation, and feedback error amplifier. Its high-voltage (HV) variant supports up to 60 V input, enabling direct regulation from 48 V telecom or industrial bus rails without pre-regulation.

It features a dedicated bias supply (VBS) pin that powers internal circuitry independently of VIN, improving efficiency at high input voltages; an out-of-regulation flag pin with programmable delay; and soft-start functionality controlled via the SD/SS pin to limit inrush current during startup.

Key Specifications

Pinout & Package

LM2597HVMX-3.3 is housed in an 8-pin SOIC (D) surface-mount package (Package Number D0008A), with exposed pad for enhanced thermal performance. Pin functions are validated per TI SNVS119C Rev. April 2013.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck regulator applications.

Compared with LM2596HVMX-3.3 and TPS54302DDAR, the LM2597HVMX-3.3 offers optimal balance of high-input-voltage resilience, integrated fault signaling, ultra-low standby current, and minimal external component count for 0.5 A applications - making it ideal where reliability, simplicity, and 48 V bus compatibility are prioritized over peak current or footprint reduction.

Availability

LM2597HVMX-3.3 is available at Aetrix Electronics and suitable for industrial power conversion, telecom line card supply, automotive body control modules, and test & measurement equipment requiring stable component supply across extended lifecycle programs.

Supply support for LM2597HVMX-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/LM2597HV series was designed specifically for rugged, high-input-voltage DC-DC buck conversion in industrial, telecom, and automotive environments where simplicity, fault visibility, and wide VIN range are critical.

FAQ

What is the maximum input voltage rating for the LM2597HVMX-3.3?

The LM2597HVMX-3.3 supports a maximum input voltage of 60 V, as specified in the Absolute Maximum Ratings table of the TI SNVS119C datasheet. This HV rating distinguishes it from the standard LM2597 (45 V max) and enables direct regulation from 48 V industrial or telecom bus rails without pre-regulation. Operation above 60 V risks permanent damage.

Does the LM2597HVMX-3.3 require external feedback resistors to set its output voltage?

No, the LM2597HVMX-3.3 does not require external feedback resistors. As a fixed-output variant, its 3.3 V regulation is achieved via internal resistor divider and reference circuitry connected to the FB pin. The FB pin is not user-accessible in this version - unlike the LM2597HV-ADJ - simplifying design and improving output accuracy and stability.

How does the VBS (bias supply) pin improve efficiency in the LM2597HVMX-3.3?

The VBS pin in the LM2597HVMX-3.3 supplies regulated power to internal control circuitry independently of VIN. At high input voltages (e.g., 48 V), this prevents excessive power dissipation in the internal LDO that would otherwise supply bias current. As a result, the LM2597HVMX-3.3 maintains >80% efficiency even at 48 V input - a key advantage over non-VBS regulators in high-VIN applications.

Can the LM2597HVMX-3.3 be used in discontinuous conduction mode (DCM)?

Yes, the LM2597HVMX-3.3 operates reliably in both continuous and discontinuous conduction modes depending on load and inductor value. DCM occurs naturally at light loads (<100 mA) and is explicitly characterized in the datasheet (Figure 23). No external mode control is needed - the IC automatically transitions between modes while maintaining regulation and FLAG functionality.

What is the purpose of the DELAY pin on the LM2597HVMX-3.3?

The DELAY pin on the LM2597HVMX-3.3 sets the time delay before the FLAG pin asserts during an output undervoltage condition. By connecting an external capacitor (e.g., 100 nF), designers can program delays from ~10 µs to >1 ms to avoid false triggering from brief transients. This enables selective fault response - for example, ignoring short dips while reacting to sustained dropout - without adding external timers.