Texas Instruments LM2596T-ADJ/LB05

Overview

LM2596T-ADJ/LB05 from Texas Instruments is a nonsynchronous step-down DC-DC converter IC delivering up to 3 A output current, operating at a fixed 150-kHz switching frequency, with adjustable output voltage from 1.2 V to 37 V (±4% tolerance), and input voltage support up to 40 V - used in industrial power supplies requiring compact, low-component-count buck regulation.

For engineers reviewing the LM2596T-ADJ/LB05 datasheet, LM2596T-ADJ/LB05 pinout, LM2596T-ADJ/LB05 application, or LM2596T-ADJ/LB05 equivalent, key selection criteria include its TO-263-5 (KTT) package thermal performance, ON/OFF logic-controlled shutdown (80 μA standby), feedback bias current (≤50 nA), and compatibility with standard off-the-shelf inductors for rapid prototyping.

Technical Context

The LM2596T-ADJ/LB05 integrates a PWM controller, power switch, and internal frequency compensation in a monolithic buck topology. It uses external diode, inductor, and capacitors to form a complete switching regulator - no synchronous rectification, no integrated catch diode, and no soft-start capacitor required.

Its feedback loop senses output voltage via a resistive divider connected to the Feedback pin (V_FB = 1.23 V typical), enabling precise output programming. The ON/OFF pin provides TTL-compatible enable control with 1.3 V threshold, while thermal shutdown and peak-current limiting (4.5 A typical) ensure fault protection without external circuitry.

Key Specifications

Pinout & Package

LM2596T-ADJ/LB05 is supplied in a 5-pin TO-263 (KTT) surface-mount package with exposed thermal pad, measuring 10.10 mm × 8.89 mm, optimized for PCB heat dissipation using ≥2.5 in² copper area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2596T-ADJ/LB05, LM2596S-ADJ/NOPB offers identical performance with RoHS compliance, while LMR51430RGER trades simplicity and 40-V tolerance for higher efficiency and frequency flexibility - making it better suited for next-gen compact designs rather than legacy replacements.

Availability

LM2596T-ADJ/LB05 is available at Aetrix Electronics and suitable for industrial power supplies, embedded system rail generation, appliance main power stages, and grid infrastructure monitoring units requiring stable component supply with long-term manufacturability.

Supply support for LM2596T-ADJ/LB05 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 LM2596 series was designed as a SIMPLE SWITCHER® solution for cost-sensitive, medium-power DC-DC applications where ease of use, minimal external components, and ruggedness outweigh the need for synchronous efficiency or MHz-frequency operation.

FAQ

What is the maximum input voltage rating for LM2596T-ADJ/LB05?

The absolute maximum input voltage for LM2596T-ADJ/LB05 is 45 V, but the recommended operating range is 4.5 V to 40 V. Exceeding 40 V continuously risks exceeding internal transistor breakdown limits and may trigger thermal shutdown. For reliable long-term operation, maintain VIN ≤40 V with appropriate derating for transients - as confirmed in Section 7.1 Absolute Maximum Ratings of the TI SNVS124G datasheet.

Does LM2596T-ADJ/LB05 require an external catch diode, and what type is recommended?

Yes, LM2596T-ADJ/LB05 requires an external catch diode because it is a nonsynchronous buck converter with only a high-side internal switch. Texas Instruments recommends a Schottky diode rated for ≥3 A average current and ≥45 V PIV - such as the SB560 or MBR360 - to minimize conduction loss and reverse recovery effects. Fast-recovery diodes are acceptable for higher input voltages where Schottky leakage becomes problematic.

How is the output voltage set on LM2596T-ADJ/LB05, and what is the feedback reference voltage?

The output voltage of LM2596T-ADJ/LB05 is set using a two-resistor voltage divider from V_OUT to GND, with the midpoint connected to the Feedback pin. The internal reference is 1.23 V (typical), with ±2.7% variation over temperature. For example, to achieve 5 V output, use R1 = 3.1 kΩ and R2 = 1.0 kΩ (V_OUT = 1.23 × (1 + R1/R2)). Resistor tolerance directly impacts final output accuracy - LM2596T-ADJ/LB05's ±4% total output error includes this contribution.

Can LM2596T-ADJ/LB05 be used in an inverting (buck-boost) configuration?

Yes, LM2596T-ADJ/LB05 supports inverting regulator topologies per TI Application Note SLVA001 and Figure 8-5 in the SNVS124G datasheet. In this mode, the ground pin is referenced to the negative output, and the feedback pin connects to system ground. The maximum |V_IN| + |V_OUT| must remain ≤40 V - e.g., +24 V input to –12 V output is valid. Startup current can reach 4.5 A, so delayed start-up using the ON/OFF pin is strongly advised for reliability.

What thermal performance can be expected from LM2596T-ADJ/LB05 in its TO-263 package?

In the TO-263-5 (KTT) package, LM2596T-ADJ/LB05 achieves 20°C/W junction-to-ambient thermal resistance when mounted on a double-sided PCB with 3 in² of 1-oz copper on the device side and ~16 in² on the opposite layer (per Section 7.4 Thermal Information). This allows full 3-A operation at up to 85°C ambient without a heatsink - provided the thermal pad is soldered to the copper pour with ≥6 thermal vias. Junction temperature must stay below 150°C for continuous reliability.