Texas Instruments LM2598S-5.0/NOPB

Overview

LM2598S-5.0/NOPB from Texas Instruments is a monolithic 150-kHz nonsynchronous step-down (buck) DC-DC converter delivering 1-A output current with fixed 5-V output, ±4% output voltage tolerance over line and load, 4.5–40 V input range, and integrated thermal shutdown/current limit protection. It serves as an efficient on-card switching regulator in industrial power supplies and embedded systems.

For engineers reviewing the LM2598S-5.0/NOPB datasheet, LM2598S-5.0/NOPB pinout, LM2598S-5.0/NOPB application, or LM2598S-5.0/NOPB equivalent, key selection criteria include its fixed 5-V output accuracy, 150-kHz switching frequency enabling compact filter design, TO-263-7 surface-mount package thermal performance, and integrated soft-start/shutdown control for inrush management.

Technical Context

The LM2598S-5.0/NOPB implements a nonsynchronous buck topology with internal 150-kHz oscillator, fixed-frequency PWM control, and self-protection circuitry including two-stage current limiting and thermal shutdown. Its feedback loop uses a precision 1.23-V reference to regulate output via external resistor divider (not required for fixed 5-V version).

It features dedicated open-collector error flag output with built-in 5% dropout detection and programmable delay via external capacitor on the DELAY pin, plus dual-function SHUTDOWN/SOFT-START pin supporting logic-level disable (ISTBY = 85 μA typical) and controlled output ramp-up using external capacitance.

Key Specifications

Pinout & Package

LM2598S-5.0/NOPB is housed in a 7-pin TO-263 (DDPAK) surface-mount package with exposed thermal pad, measuring 10.10 mm × 8.89 mm, optimized for PCB thermal conduction without mandatory heatsink below 50°C ambient and <12-V output.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2596S-5.0/NOPB, LM2598S-5.0/NOPB offers tighter thermal management in TO-263-7 package and better-defined soft-start behavior; versus TPS54202DRCT, it trades higher efficiency for simpler design, integrated protection, and direct power-good signaling - making it preferable for cost-sensitive, thermally constrained, or safety-monitored applications.

Availability

LM2598S-5.0/NOPB is available at Aetrix Electronics and suitable for industrial PLC power rails, automotive body control modules, and medical point-of-care devices requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LM2598S-5.0/NOPB 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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management technologies with broad industrial, automotive, and consumer market reach.

The LM2598 series belongs to TI's SIMPLE SWITCHER® power converter family, designed specifically for ease-of-use in non-isolated DC-DC buck applications where minimal external components, predictable thermal behavior, and integrated fault protection are prioritized over maximum efficiency or ultra-small footprint.

FAQ

What is the maximum input voltage rating for LM2598S-5.0/NOPB?

The LM2598S-5.0/NOPB has an absolute maximum input voltage rating of 45 V, with recommended operating range from 4.5 V to 40 V. Exceeding 40 V continuously may trigger internal protection or reduce reliability; operation above 45 V risks permanent damage per Absolute Maximum Ratings table in the datasheet.

Does LM2598S-5.0/NOPB require external feedback resistors to set its output voltage?

No, LM2598S-5.0/NOPB is a fixed-output version with internal resistor divider calibrated for 5.0 V ±4%. The FB pin is internally connected and must remain unconnected in standard operation - unlike the adjustable LM2598ADJ variant which requires external resistors.

How does the ERROR FLAG pin function on LM2598S-5.0/NOPB?

The ERROR FLAG pin on LM2598S-5.0/NOPB is an open-collector output that pulls low when the regulated 5-V output drops more than 5% below nominal (i.e., below 4.75 V). It remains low until VOUT reaches 95% of 5 V and the DELAY pin capacitor times out - enabling precise power-good signaling for microcontroller reset circuits.

Can LM2598S-5.0/NOPB be used in an inverting (positive-to-negative) configuration?

Yes, LM2598S-5.0/NOPB supports inverting regulator topologies to generate –5 V from a positive input. The datasheet provides Figure 21 showing the required external diode, inductor, and level-shifting for shutdown control. Maximum |VIN| + |VOUT| must not exceed 40 V, and startup current may reach 1.5 A briefly.

What thermal considerations apply to LM2598S-5.0/NOPB in TO-263-7 package?

In TO-263-7 (KTW) package, LM2598S-5.0/NOPB achieves RθJA ≈ 30°C/W with 0.5 in² copper and ≈ 20°C/W with 3 in² double-sided copper. For 1-A operation at 12-V input, junction temperature rise is ~30°C above ambient - typically eliminating need for external heatsink below 50°C ambient, provided thermal pad is soldered to adequate PCB copper area.