Texas Instruments LM2598T-5.0/NOPB

Overview

LM2598T-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, input voltage range up to 40 V, and thermal shutdown/current limit protection - used in on-card switching regulators for industrial power supplies.

For engineers reviewing the LM2598T-5.0/NOPB datasheet, LM2598T-5.0/NOPB pinout, LM2598T-5.0/NOPB application, or LM2598T-5.0/NOPB equivalent, key selection criteria include output accuracy under varying input conditions, soft-start/enable control timing, error flag delay behavior, junction-to-ambient thermal resistance in TO-220 package, and compatibility with standard off-the-shelf inductors.

Technical Context

The LM2598T-5.0/NOPB integrates a PWM controller, power switch, oscillator, and protection circuitry into a single TO-220-7 package. It operates at a fixed 150-kHz switching frequency (±15%), enabling compact external filter components while maintaining stable regulation across 7 V–40 V input and 0.1 A–1 A load ranges.

Its internal architecture includes a two-stage current-limiting mechanism, thermal shutdown triggered at 150°C junction temperature, and an open-collector error flag that asserts low when output drops >5% below nominal - with programmable delay via external capacitor on the DELAY pin.

Key Specifications

Pinout & Package

LM2598T-5.0/NOPB is supplied in a 7-pin TO-220 (NDZ) package with vertical lead bend, 14.986 mm × 10.16 mm body size, and internally connected tab serving as thermal path to PCB copper area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2598T-5.0/NOPB, LM2598HVS-5.0/NOPB extends input surge capability and thermal rating without layout changes, while LM2576T-5.0/NOPB trades feature set for lower BOM cost and reduced EMI sensitivity at the expense of design flexibility.

Availability

LM2598T-5.0/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, embedded system rails, and preregulator applications requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for LM2598T-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 specializing in analog, embedded processing, and power management technologies, with leadership in high-reliability industrial and automotive solutions.

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 and proven thermal performance are critical.

FAQ

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

The LM2598T-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 thermal shutdown or reduce lifetime reliability, though brief transients up to 45 V are tolerated per Absolute Maximum Ratings. Always verify input filtering and clamping for systems with potential overvoltage events.

Does LM2598T-5.0/NOPB require external feedback resistors to set output voltage?

No, LM2598T-5.0/NOPB does not require external feedback resistors because it is a fixed 5-V output version - the feedback reference is internally trimmed and connected. The FB pin must be left unconnected per datasheet guidance; adding external components risks regulation instability or damage.

How does the error flag (FLAG pin) behave during startup of LM2598T-5.0/NOPB?

During startup, the FLAG pin of LM2598T-5.0/NOPB remains low until the output reaches 95% of 5 V (i.e., 4.75 V), then stays low for a user-defined delay determined by the capacitor on the DELAY pin before transitioning high. This prevents premature system reset assertion and ensures stable power-up sequencing.

Can LM2598T-5.0/NOPB be used in a positive-to-negative inverting configuration?

Yes, LM2598T-5.0/NOPB can be configured as a positive-to-negative inverter generating –5 V, as documented in TI's SNVS125D datasheet Figure 21. It requires external diode, inductor, and capacitor, with the regulator's GND pin referenced to the negative output - enabling dual-rail analog circuits without a second dedicated negative supply IC.

What thermal management guidance applies to LM2598T-5.0/NOPB in TO-220 package?

For LM2598T-5.0/NOPB in TO-220, junction-to-ambient thermal resistance is 50°C/W with no heatsink and standard PCB copper. At 1-A load and 12-V input, power dissipation is ~0.7 W - resulting in ~35°C rise above ambient. For ambient >50°C or sustained 1-A loads, a small heatsink or ≥1 in² copper pour is recommended to maintain junction temperature below 125°C.