Texas Instruments LM2598T-5.0

Overview

LM2598T-5.0 from Texas Instruments is a monolithic 150 kHz step-down (buck) switching voltage regulator delivering a fixed 5.0 V output at up to 1 A, with ±4% output voltage tolerance over line and load, 4.5–40 V input range, and integrated thermal shutdown and current limiting. It enables compact, high-efficiency DC/DC conversion in industrial power supplies and embedded systems where space and thermal constraints limit use of linear regulators.

For engineers reviewing the LM2598T-5.0 datasheet, LM2598T-5.0 pinout, LM2598T-5.0 application, or LM2598T-5.0 equivalent, key selection criteria include guaranteed 1 A output current, fixed-frequency operation enabling predictable EMI filtering, low 85 μA standby quiescent current, out-of-regulation flag output, and TO-220 package compatibility with standard heat-sink mounting without forced airflow below 50°C ambient.

Technical Context

The LM2598T-5.0 integrates a PWM controller, power switch, and internal frequency compensation in a single IC. Its 150 kHz fixed-frequency oscillator drives an N-channel MOSFET switch with 1.2 V typical saturation voltage at 1 A, supporting continuous conduction mode operation with external catch diode, inductor, and input/output capacitors.

It features dual-stage current limiting (1.2 A min / 2.6 A max peak), thermal shutdown at +150°C junction temperature, and a dedicated FLAG pin that asserts low when output drops below 92–98% of nominal voltage, with programmable delay via external capacitor. Shutdown/soft-start is controlled by a single SD/SS pin with 1.3 V threshold and sub-10 μA control current.

Key Specifications

Pinout & Package

LM2598T-5.0 is supplied in a 7-pin TO-220 package (package number NDZ0007B) with bent/staggered leads for through-hole mounting. The tab is electrically connected to Pin 2 (Ground) and serves as the primary thermal path.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2596T-5.0, LM2598T-5.0 adds fault flagging and wider input range; versus MP1584EN-LF-Z, it trades higher integration and thermal resilience for larger footprint and lower switching frequency - making it optimal for industrial environments where reliability outweighs miniaturization.

Availability

LM2598T-5.0 is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and legacy equipment retrofit requiring stable component supply, long-lifecycle availability, and proven thermal performance in TO-220 packages.

Supply support for LM2598T-5.0 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 switching regulator design and manufacturing.

The LM2598 series was developed as part of TI's SIMPLE SWITCHER® portfolio to deliver easy-to-use, highly reliable buck converters for cost-sensitive industrial and automotive applications - emphasizing minimal external components, robust protection, and wide input voltage tolerance.

FAQ

What is the maximum input voltage rating for the LM2598T-5.0?

The absolute maximum input voltage for the LM2598T-5.0 is 45 V, but the recommended operating range is 4.5 V to 40 V. Operation at 40 V is fully characterized per datasheet specifications, including output regulation, efficiency, and thermal performance. Exceeding 40 V risks violating the 4.5–40 V operating condition limits defined in the Electrical Characteristics table, even if within absolute maximum ratings.

Does the LM2598T-5.0 require external compensation components?

No, the LM2598T-5.0 includes internal frequency compensation and requires no external compensation network. This is confirmed in the device description ("include internal frequency compensation†") and verified across all test circuits in the datasheet (e.g., Figure 24). Only external passive components - input/output capacitors, inductor, catch diode, and optional FLAG delay capacitor - are needed for full operation of the LM2598T-5.0.

Can the LM2598T-5.0 be used without a heatsink?

Yes - the LM2598T-5.0 can operate at full 1 A output without a heatsink when ambient temperature remains below 50°C and the TO-220 package is mounted vertically on a PCB with ~1 in² of 1 oz. copper area, achieving θJA = 50 °C/W. At higher ambient temperatures or loads, thermal derating applies; the datasheet explicitly states "no heat sink is required" under those specific conditions for the LM2598T-5.0.

What is the purpose of the FLAG pin on the LM2598T-5.0?

The FLAG pin on the LM2598T-5.0 is an open-collector error output that goes low when the regulated 5.0 V output falls below 92–98% of nominal (i.e., below ~4.6 V). It provides system-level fault signaling without external circuitry. A 0.1 μF capacitor on the DELAY pin sets a ~10 ms delay before flag assertion, preventing false triggers during transient load steps - a feature unique to the LM2598T-5.0 among TI's 1 A buck regulators.

Is the LM2598T-5.0 pin-compatible with the LM2596T-5.0?

No - although both use 7-pin TO-220 packages and share identical pin numbering (IN, GND, OUT, FB, SD/SS, FLAG, DELAY), the LM2596T-5.0 does not have a FLAG or DELAY pin; those pins are No Connect (NC) in the LM2596T-5.0. Therefore, LM2598T-5.0 cannot be substituted into an LM2596T-5.0 layout without modifying the PCB to route and terminate FLAG/DELAY functions, making them functionally incompatible despite identical footprints.