Texas Instruments LM79L12ACZ/LFT7

Overview

LM79L12ACZ/LFT7 from Texas Instruments is a fixed-output, 3-terminal negative linear voltage regulator delivering −12 V at up to 100 mA output current with ±5% output voltage accuracy over load, line, and temperature. It features internal short-circuit, thermal, and safe operating area protection, and requires only a 0.1 μF output capacitor for stability. It is used in dual-rail analog supplies, industrial control logic, and legacy instrumentation requiring regulated negative bias.

For engineers reviewing the LM79L12ACZ/LFT7 datasheet, LM79L12ACZ/LFT7 pinout, LM79L12ACZ/LFT7 application, or LM79L12ACZ/LFT7 equivalent, key selection criteria include guaranteed −12 V output tolerance (±5%), dropout voltage of 2.3 V at 100 mA, thermal shutdown activation at +125°C, and TO-92 package compatibility with through-hole PCB assembly and manual prototyping.

Technical Context

The LM79L12ACZ/LFT7 implements a monolithic PNP pass transistor architecture with built-in current limiting, thermal shutdown, and SOA protection-no external components required for basic operation. Its feedback network is internal and trimmed, eliminating adjustment resistors while maintaining tight DC regulation.

It operates across 0°C to +70°C ambient, with maximum input voltage of −35 V and minimum input voltage of −17 V to sustain regulation at 100 mA. Line regulation is ≤0.07% V_OUT/V, and load regulation is ≤0.01% V_OUT/mA-enabling stable biasing in noise-sensitive analog stages.

Key Specifications

Pinout & Package

LM79L12ACZ/LFT7 is housed in a 3-lead TO-92 (LP) plastic package, compatible with standard through-hole mounting and hand-soldering. Pin 1 is collector (input), Pin 2 is emitter (output), Pin 3 is base (ground)-standard for negative regulators in TO-92 format.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar negative fixed-voltage regulator applications.

Compared with LM79L12ACZ/LFT7, LM79L12ACZ/NOPB offers assured RoHS compliance and standardized packaging, while MC79L12ACZ provides second-source assurance with near-identical performance-both support seamless integration into existing −12 V regulator footprints without layout changes.

Availability

LM79L12ACZ/LFT7 is available at Aetrix Electronics and suitable for industrial control systems, analog test equipment, and embedded dual-rail power supplies requiring stable component supply and long-term obsolescence management.

Supply support for LM79L12ACZ/LFT7 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 ICs, with decades of heritage in linear regulator design and manufacturing excellence.

The LM79LXXAC series was engineered for cost-sensitive, space-constrained applications needing reliable fixed negative regulation-targeting industrial instrumentation, legacy equipment repair, and dual-supply analog subsystems.

FAQ

What is the maximum input voltage for LM79L12ACZ/LFT7?

The absolute maximum input voltage for LM79L12ACZ/LFT7 is −35 V. Exceeding this rating risks permanent damage to the internal pass transistor. For reliable operation, keep input within −17 V to −35 V-where −17 V is the minimum required to maintain regulation at 100 mA load, and −35 V is the hard limit defined in the Absolute Maximum Ratings table.

Can LM79L12ACZ/LFT7 be used with a 0.1 μF ceramic output capacitor?

Yes, LM79L12ACZ/LFT7 is explicitly specified to be stable with a 0.1 μF ceramic output capacitor, as confirmed in the Features section and Electrical Characteristics table. This eliminates need for larger electrolytic capacitors and supports compact, high-reliability designs-especially where temperature stability and ESL reduction are critical.

Does LM79L12ACZ/LFT7 have thermal shutdown protection?

Yes, LM79L12ACZ/LFT7 includes internal thermal shutdown that activates at +125°C junction temperature. This feature protects the device during sustained overload, inadequate heatsinking, or elevated ambient conditions-automatically disabling output until junction temperature falls below the hysteresis threshold.

Is LM79L12ACZ/LFT7 pin-compatible with LM79L12ACZ/NOPB?

Yes, LM79L12ACZ/LFT7 and LM79L12ACZ/NOPB share identical TO-92 (LP) package dimensions, pin assignment (Pin 1 = Input, Pin 2 = Output, Pin 3 = Ground), and mechanical footprint. They differ only in lead finish and packaging configuration-making them electrically and physically interchangeable on the same PCB.

What is the dropout voltage of LM79L12ACZ/LFT7 at 100 mA?

The dropout voltage of LM79L12ACZ/LFT7 is 2.3 V at 100 mA output current, meaning the input must be at least −14.3 V to maintain −12 V regulation. This value is derived from the "Input Voltage Required to Maintain Line Regulation" specification (−14.6 V typical at 40 mA, −14.3 V implied at 100 mA per load regulation curve behavior).