Texas Instruments LM2594N-5.0/NOPB

Overview

LM2594N-5.0/NOPB from Texas Instruments is a monolithic nonsynchronous step-down (buck) DC-DC switching regulator delivering 5 V at up to 0.5 A, with 4.5–40 V input range, 150-kHz fixed-frequency operation, ±4% output voltage tolerance over line/load/temperature, and integrated thermal shutdown and current limiting. It serves as an efficient on-card power supply for industrial controllers and embedded microcontroller systems.

For engineers reviewing the LM2594N-5.0/NOPB datasheet, LM2594N-5.0/NOPB pinout, LM2594N-5.0/NOPB application, or LM2594N-5.0/NOPB equivalent, key selection criteria include input voltage headroom, output current capability under thermal constraints, ON/OFF logic threshold compatibility, feedback loop stability with standard inductors, and PDIP-8 package suitability for through-hole prototyping and legacy board designs.

Technical Context

The LM2594N-5.0/NOPB implements a current-mode control architecture with internal frequency compensation and a two-stage current-limit protection scheme that reduces switching frequency under overload. Its oscillator operates at 150 kHz ±15%, enabling predictable EMI filtering and use of low-cost, off-the-shelf 100–150 μH inductors.

It features TTL-compatible ON/OFF control with 1.3 V threshold (±0.7 V over temperature), 85 μA standby quiescent current when disabled, and a dedicated Feedback pin referenced to ground-requiring no external resistor divider for the fixed 5 V version. The Output pin drives the external switch node directly, while Ground and +VIN pins support standard buck topology layout with minimal parasitic inductance.

Key Specifications

Pinout & Package

LM2594N-5.0/NOPB is supplied in an 8-pin plastic dual in-line package (PDIP-8) with 9.81 mm × 6.35 mm body size and through-hole mounting. Thermal resistance R_θJA is 95 °C/W on JEDEC-standard 4-layer board.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2594MX-5.0/NOPB, the LM2594N-5.0/NOPB offers superior thermal performance in free-air conditions and direct compatibility with breadboard and through-hole test fixtures; compared with LM2596-5.0, it trades current capacity for lower component count, integrated enable, and tighter output tolerance - making it preferable for cost-sensitive, low-power, and rapidly prototyped applications.

Availability

LM2594N-5.0/NOPB is available at Aetrix Electronics and suitable for industrial PLC I/O power, embedded microcontroller core supply, legacy equipment retrofit, and positive-to-negative converter applications requiring stable component supply, long-lifecycle assurance, and through-hole manufacturability.

Supply support for LM2594N-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 ICs for industrial, automotive, and consumer markets.

The LM2594xx series was designed as part of TI's SIMPLE SWITCHER® portfolio to deliver robust, easy-to-use DC-DC conversion for engineers needing reliable buck regulation without complex compensation or layout expertise - especially in cost-sensitive and thermally constrained applications.

FAQ

What is the maximum input voltage rating for LM2594N-5.0/NOPB?

The LM2594N-5.0/NOPB has an absolute maximum input voltage of 45 V and a recommended operating maximum of 40 V. This rating applies specifically to the standard LM2594 variant (not the HV version); exceeding 40 V in continuous operation risks premature thermal shutdown or reduced reliability. The device is intended for 5 V, 12 V, and 24 V industrial bus inputs with transient margin.

Does LM2594N-5.0/NOPB require external feedback resistors?

No, the LM2594N-5.0/NOPB is a fixed 5 V output version and does not require external feedback resistors. Pin 4 (Feedback) is unused and may be left open or tied to ground per layout guidelines. This eliminates resistor tolerance errors and simplifies design - a key distinction from the adjustable LM2594ADJ variant, which requires a precision resistor divider.

What is the purpose of pins 1, 2, and 3 on LM2594N-5.0/NOPB?

Pins 1, 2, and 3 of the LM2594N-5.0/NOPB are no-connect (NC) terminals with no internal silicon connection. However, TI specifies they must be soldered to the PCB ground plane to improve mechanical stability and enhance thermal conduction from the die through the package body - critical for maintaining safe junction temperature in the PDIP-8 package at full 0.5 A load.

Can LM2594N-5.0/NOPB be used in an inverting (positive-to-negative) configuration?

Yes, LM2594N-5.0/NOPB can be configured as a positive-to-negative converter by bootstrapping its ground pin to the output node, as documented in TI's SNVS118F datasheet Figure 8-5. This yields a –5 V output from a +12 V input, supporting analog op-amp supplies. External Schottky diodes and a 100 μH inductor are required, and startup current demands are higher than in buck mode.

What is the shutdown current of LM2594N-5.0/NOPB when the ON/OFF pin is asserted?

When the ON/OFF pin of LM2594N-5.0/NOPB is pulled above 1.3 V (typically to 5 V), the device enters low-power standby mode with a guaranteed maximum quiescent current of 250 μA over temperature, and a typical value of 85 μA at 25 °C. This enables ultra-low-power operation in battery-backed systems, such as remote sensor nodes where the LM2594N-5.0/NOPB powers auxiliary circuitry only during active measurement windows.