Texas Instruments LM2594N-5.0

Overview

LM2594N-5.0 from Texas Instruments is a monolithic nonsynchronous step-down (buck) DC-DC switching regulator delivering 5.0 V at up to 0.5 A with ±4% output voltage tolerance, 150-kHz fixed-frequency operation, and input voltage support up to 40 V. It integrates PWM controller, power switch, and protection circuitry in an 8-pin PDIP package and is used in industrial power supplies, embedded system point-of-load conversion, and battery-powered equipment requiring stable 5-V rails.

For engineers reviewing the LM2594N-5.0 datasheet, LM2594N-5.0 pinout, LM2594N-5.0 application, or LM2594N-5.0 equivalent, key selection criteria include its 0.5-A guaranteed output current, 85-μA standby quiescent current in shutdown mode, thermal shutdown and current-limit protection, and compatibility with standard off-the-shelf inductors and catch diodes.

Technical Context

The LM2594N-5.0 implements a fixed-frequency (127–173 kHz) current-mode PWM control architecture with internal frequency compensation and TTL-compatible ON/OFF logic control. Its internal power switch features 0.9–1.2 V saturation voltage at 0.5-A load, enabling efficient conversion across wide input ranges.

It operates in continuous conduction mode by default but supports discontinuous mode at light loads via inductor selection. Protection functions include two-stage current limiting (peak limit 0.58–1.4 A) and thermal shutdown at 150°C junction temperature, ensuring robust operation under fault conditions without external circuitry.

Key Specifications

Pinout & Package

LM2594N-5.0 is housed in an 8-pin plastic dual in-line package (PDIP) with 9.81 mm × 6.35 mm body size and through-hole mounting. Thermal resistance R_θJA is 95°C/W on JEDEC 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, the LM2594N-5.0 offers superior thermal performance in through-hole applications but lacks SMT compatibility; versus LM2596-5.0, it provides lower standby current and simpler layout for sub-0.5-A loads but cannot scale to higher currents without redesign.

Availability

LM2594N-5.0 is available at Aetrix Electronics and suitable for industrial power supplies, embedded microcontroller rails, and on-card switching regulators requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for LM2594N-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 over 90 years of innovation history.

The LM2594xx series was designed as part of TI's SIMPLE SWITCHER® portfolio to deliver easy-to-use, robust, and cost-effective DC-DC conversion for industrial, automotive, and consumer applications where reliability and minimal external components are critical.

FAQ

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

The LM2594N-5.0 has an absolute maximum input voltage of 45 V and a recommended maximum operating input voltage of 40 V. Exceeding 40 V during normal operation risks exceeding thermal limits or triggering protection circuits. The HV variant (LM2594HV-5.0) supports up to 60 V input, but the LM2594N-5.0 is specifically rated for 4.5 V to 40 V operation per TI's SNVS118F datasheet.

Does the LM2594N-5.0 require external feedback resistors to set the output voltage?

No, the LM2594N-5.0 does not require external feedback resistors. It is a fixed-output version with the 5.0-V regulation network integrated internally. Pin 4 (Feedback) is unused and must be left unconnected. This differs from the adjustable LM2594ADJ variant, which requires two external resistors to program V_OUT.

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

Yes, the LM2594N-5.0 can be configured as a positive-to-negative converter by grounding the feedback pin and referencing the regulator's ground pin to the negative output. This topology generates −5 V from a positive input, subject to the constraint that |V_IN| + |V_OUT| ≤ 40 V. TI provides a validated schematic (Figure 8-5 in SNVS118F) using LM2594-5 for this purpose.

What is the typical efficiency of the LM2594N-5.0 at full load?

The LM2594N-5.0 achieves 82% typical efficiency at V_IN = 12 V and I_OUT = 0.5 A, as specified in Section 7.6 of the datasheet. Efficiency varies with input voltage and load - e.g., 80% at V_IN = 7 V and 88% at V_IN = 24 V for the 12-V variant - but the 5.0-V version maintains ≥80% across its recommended operating range.

How does the ON/OFF pin function on the LM2594N-5.0?

The ON/OFF pin (Pin 5) provides TTL-compatible shutdown control: pulling it below ~1.3 V (vs. GND) enables regulation, while pulling it above ~1.3 V disables switching and reduces total supply current to 85 μA. If unused, the pin may be tied directly to GND (ensuring ON state) or left open - both configurations default to active operation per datasheet Table 6-1.