Texas Instruments LM341T-12

Overview

LM341T-12 from Texas Instruments is a fixed-output, 3-terminal positive voltage regulator delivering 12 V at up to 500 mA output current with ±1% initial accuracy (11.4–12.6 V over temperature), 240 mV load regulation, and 71 dB ripple rejection at 120 Hz. It operates from 14.5 V to 35 V input, features internal thermal shutdown and short-circuit protection, and is used in motor drives and building automation systems requiring stable local DC power.

For engineers reviewing the LM341T-12 datasheet, LM341T-12 pinout, LM341T-12 application, or LM341T-12 equivalent, key selection considerations include dropout headroom (≥2.5 V), TO-220 thermal resistance (22.6°C/W), quiescent current (4–10 mA), and compatibility with standard 0.33 µF input / 0.1 µF output capacitor configurations.

Technical Context

The LM341T-12 employs a monolithic NPN Darlington pass transistor with built-in safe-area compensation, enabling robust operation under transient overload. Its control loop maintains regulation without external components while integrating thermal foldback and current limiting that activate before junction temperature exceeds 125°C.

It requires minimum 14.5 V input for full-load regulation and exhibits 240 mV load regulation across 5–500 mA, 71 dB AC ripple rejection at 120 Hz, and 48 mV/khrs long-term output stability - all specified over –40°C to +125°C operating range.

Key Specifications

Pinout & Package

LM341T-12 is supplied in a 3-pin TO-220 (NDE) package with tab connected internally to Pin 2 (Ground). The case serves as thermal path and electrical ground reference.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed-output linear regulator applications.

Compared with LM78M12CT and UA78M12CKC, the LM341T-12 offers guaranteed –40°C operation and integrated safe-area compensation, making it more robust in automotive-adjacent or outdoor-rated equipment - though its 240 mV load regulation is looser than LM78M12CT's 120 mV.

Availability

LM341T-12 is available at Aetrix Electronics and suitable for motor drives, building automation controllers, and appliance control boards requiring stable component supply with full industrial temperature support (–40°C to +125°C) and long-lifecycle availability.

Supply support for LM341T-12 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 ICs, with decades of leadership in linear regulator technology and industrial-grade reliability.

The LM341 series was designed specifically for cost-effective, rugged local regulation in industrial and appliance applications - prioritizing fault tolerance (thermal/short-circuit protection) and ease of use (no external components) over ultra-low quiescent current or ultra-tight regulation.

FAQ

What is the minimum input voltage required for LM341T-12 to maintain regulation?

The LM341T-12 requires a minimum input voltage of 14.5 V under full 500 mA load to sustain regulation, per TI's SNVS090G datasheet Section 7.5. This 2.5 V headroom accounts for dropout voltage and line/load regulation margins. At lighter loads, input can be reduced slightly, but operation below 14.5 V risks output collapse into dropout.

Does LM341T-12 require external capacitors to operate stably?

No - the LM341T-12 is internally compensated and stable without external capacitors. However, TI recommends a 0.33 µF ceramic capacitor at the input and 0.1 µF at the output (Section 9.2) to suppress high-frequency noise and improve transient response during load steps. These values are not mandatory for stability but are essential for robust real-world performance.

What is the thermal resistance (θ_JA) of LM341T-12 in its TO-220 package?

The LM341T-12 in TO-220 (NDE) package has a junction-to-ambient thermal resistance (θ_JA) of 22.6°C/W, as specified in Section 7.3 of the SNVS090G datasheet. This value assumes standard JEDEC 2S2P test board conditions; actual θ_JA improves significantly with PCB copper area and heatsinking - e.g., 1 in² copper reduces θ_JA to ~47°C/W.

Can LM341T-12 replace LM78M12CT in an existing design?

No - LM341T-12 and LM78M12CT have reversed pinouts: LM341T-12 uses Pin 1=Input, Pin 2=Ground, Pin 3=Output, while LM78M12CT uses Pin 1=Output, Pin 2=Ground, Pin 3=Input. Swapping them without PCB modification will cause immediate failure. Always verify pin configuration before substitution.

What protection features does LM341T-12 include?

The LM341T-12 integrates three protection mechanisms: (1) internal short-circuit current limiting (clamps output to ~700 mA), (2) thermal shutdown (activates at ~165°C junction temperature), and (3) safe-area compensation for the Darlington pass transistor. All operate autonomously without external circuitry and recover automatically once fault conditions subside.